/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

import {
  describe,
  it,
  expect,
  vi,
  beforeEach,
  afterEach,
  type Mock,
} from 'vitest';

import type { Content, GenerateContentResponse, Part } from '@google/genai';
import {
  isThinkingDefault,
  isThinkingSupported,
  GeminiClient,
} from './client.js';
import { findCompressSplitPoint } from '../services/chatCompressionService.js';
import {
  AuthType,
  type ContentGenerator,
  type ContentGeneratorConfig,
} from './contentGenerator.js';
import { type GeminiChat } from './geminiChat.js';
import type { Config } from '../config/config.js';
import { ApprovalMode } from '../config/config.js';
import {
  CompressionStatus,
  GeminiEventType,
  Turn,
  type ChatCompressionInfo,
} from './turn.js';
import { getCoreSystemPrompt } from './prompts.js';
import { DEFAULT_GEMINI_FLASH_MODEL } from '../config/models.js';
import { FileDiscoveryService } from '../services/fileDiscoveryService.js';
import { setSimulate429 } from '../utils/testUtils.js';
import { tokenLimit } from './tokenLimits.js';
import { ideContextStore } from '../ide/ideContext.js';
import { uiTelemetryService } from '../telemetry/uiTelemetry.js';

// Mock fs module to prevent actual file system operations during tests
const mockFileSystem = new Map<string, string>();

vi.mock('node:fs', () => {
  const fsModule = {
    mkdirSync: vi.fn(),
    writeFileSync: vi.fn((path: string, data: string) => {
      mockFileSystem.set(path, data);
    }),
    readFileSync: vi.fn((path: string) => {
      if (mockFileSystem.has(path)) {
        return mockFileSystem.get(path);
      }
      throw Object.assign(new Error('ENOENT: no such file or directory'), {
        code: 'ENOENT',
      });
    }),
    existsSync: vi.fn((path: string) => mockFileSystem.has(path)),
  };

  return {
    default: fsModule,
    ...fsModule,
  };
});

// --- Mocks ---
const mockTurnRunFn = vi.fn();

vi.mock('./turn', async (importOriginal) => {
  const actual = await importOriginal<typeof import('./turn.js')>();
  // Define a mock class that has the same shape as the real Turn
  class MockTurn {
    pendingToolCalls = [];
    // The run method is a property that holds our mock function
    run = mockTurnRunFn;

    constructor() {
      // The constructor can be empty or do some mock setup
    }
  }
  // Export the mock class as 'Turn'
  return {
    ...actual,
    Turn: MockTurn,
  };
});

vi.mock('../config/config.js');
vi.mock('./prompts');
vi.mock('../utils/getFolderStructure', () => ({
  getFolderStructure: vi.fn().mockResolvedValue('Mock Folder Structure'),
}));
vi.mock('../utils/errorReporting', () => ({ reportError: vi.fn() }));
vi.mock('../utils/nextSpeakerChecker', () => ({
  checkNextSpeaker: vi.fn().mockResolvedValue(null),
}));
vi.mock('../utils/environmentContext', () => ({
  getEnvironmentContext: vi
    .fn()
    .mockResolvedValue([{ text: 'Mocked env context' }]),
  getInitialChatHistory: vi.fn(async (_config, extraHistory) => [
    {
      role: 'user',
      parts: [{ text: 'Mocked env context' }],
    },
    {
      role: 'model',
      parts: [{ text: 'Got it. Thanks for the context!' }],
    },
    ...(extraHistory ?? []),
  ]),
}));
vi.mock('../utils/generateContentResponseUtilities', () => ({
  getResponseText: (result: GenerateContentResponse) =>
    result.candidates?.[0]?.content?.parts?.map((part) => part.text).join('') ||
    undefined,
  getFunctionCalls: (result: GenerateContentResponse) => {
    // Extract function calls from the response
    const parts = result.candidates?.[0]?.content?.parts;
    if (!parts) {
      return undefined;
    }
    const functionCallParts = parts
      .filter((part) => !!part.functionCall)
      .map((part) => part.functionCall);
    return functionCallParts.length > 0 ? functionCallParts : undefined;
  },
}));
// Create shared mock for uiTelemetryService that's used by both telemetry mocks
const mockUiTelemetryService = vi.hoisted(() => ({
  setLastPromptTokenCount: vi.fn(),
  getLastPromptTokenCount: vi.fn(),
}));

vi.mock('../telemetry/index.js', async (importOriginal) => {
  const actual = await importOriginal<typeof import('../telemetry/index.js')>();
  return {
    ...actual,
    uiTelemetryService: mockUiTelemetryService,
    // We keep the real implementations of logChatCompression, etc.
    // but we can spy on QwenLogger if needed
  };
});
vi.mock('../ide/ideContext.js');
vi.mock('../telemetry/uiTelemetry.js', () => ({
  uiTelemetryService: mockUiTelemetryService,
}));
vi.mock('../telemetry/loggers.js', () => ({
  logChatCompression: vi.fn(),
  logNextSpeakerCheck: vi.fn(),
}));

/**
 * Array.fromAsync ponyfill, which will be available in es 2024.
 *
 * Buffers an async generator into an array and returns the result.
 */
async function fromAsync<T>(promise: AsyncGenerator<T>): Promise<readonly T[]> {
  const results: T[] = [];
  for await (const result of promise) {
    results.push(result);
  }
  return results;
}

describe('findCompressSplitPoint', () => {
  it('should throw an error for non-positive numbers', () => {
    expect(() => findCompressSplitPoint([], 0)).toThrow(
      'Fraction must be between 0 and 1',
    );
  });

  it('should throw an error for a fraction greater than or equal to 1', () => {
    expect(() => findCompressSplitPoint([], 1)).toThrow(
      'Fraction must be between 0 and 1',
    );
  });

  it('should handle an empty history', () => {
    expect(findCompressSplitPoint([], 0.5)).toBe(0);
  });

  it('should handle a fraction in the middle', () => {
    const history: Content[] = [
      { role: 'user', parts: [{ text: 'This is the first message.' }] }, // JSON length: 66 (19%)
      { role: 'model', parts: [{ text: 'This is the second message.' }] }, // JSON length: 68 (40%)
      { role: 'user', parts: [{ text: 'This is the third message.' }] }, // JSON length: 66 (60%)
      { role: 'model', parts: [{ text: 'This is the fourth message.' }] }, // JSON length: 68 (80%)
      { role: 'user', parts: [{ text: 'This is the fifth message.' }] }, // JSON length: 65 (100%)
    ];
    expect(findCompressSplitPoint(history, 0.5)).toBe(4);
  });

  it('should handle a fraction of last index', () => {
    const history: Content[] = [
      { role: 'user', parts: [{ text: 'This is the first message.' }] }, // JSON length: 66 (19%)
      { role: 'model', parts: [{ text: 'This is the second message.' }] }, // JSON length: 68 (40%)
      { role: 'user', parts: [{ text: 'This is the third message.' }] }, // JSON length: 66 (60%)
      { role: 'model', parts: [{ text: 'This is the fourth message.' }] }, // JSON length: 68 (80%)
      { role: 'user', parts: [{ text: 'This is the fifth message.' }] }, // JSON length: 65 (100%)
    ];
    expect(findCompressSplitPoint(history, 0.9)).toBe(4);
  });

  it('should handle a fraction of after last index', () => {
    const history: Content[] = [
      { role: 'user', parts: [{ text: 'This is the first message.' }] }, // JSON length: 66 (24%%)
      { role: 'model', parts: [{ text: 'This is the second message.' }] }, // JSON length: 68 (50%)
      { role: 'user', parts: [{ text: 'This is the third message.' }] }, // JSON length: 66 (74%)
      { role: 'model', parts: [{ text: 'This is the fourth message.' }] }, // JSON length: 68 (100%)
    ];
    expect(findCompressSplitPoint(history, 0.8)).toBe(4);
  });

  it('should return earlier splitpoint if no valid ones are after threshhold', () => {
    const history: Content[] = [
      { role: 'user', parts: [{ text: 'This is the first message.' }] },
      { role: 'model', parts: [{ text: 'This is the second message.' }] },
      { role: 'user', parts: [{ text: 'This is the third message.' }] },
      { role: 'model', parts: [{ functionCall: {} }] },
    ];
    // Can't return 4 because the previous item has a function call.
    expect(findCompressSplitPoint(history, 0.99)).toBe(2);
  });

  it('should handle a history with only one item', () => {
    const historyWithEmptyParts: Content[] = [
      { role: 'user', parts: [{ text: 'Message 1' }] },
    ];
    expect(findCompressSplitPoint(historyWithEmptyParts, 0.5)).toBe(0);
  });

  it('should handle history with weird parts', () => {
    const historyWithEmptyParts: Content[] = [
      { role: 'user', parts: [{ text: 'Message 1' }] },
      { role: 'model', parts: [{ fileData: { fileUri: 'derp' } }] },
      { role: 'user', parts: [{ text: 'Message 2' }] },
    ];
    expect(findCompressSplitPoint(historyWithEmptyParts, 0.5)).toBe(2);
  });
});

describe('isThinkingSupported', () => {
  it('should return true for gemini-2.5', () => {
    expect(isThinkingSupported('gemini-2.5')).toBe(true);
  });

  it('should return true for gemini-2.5-pro', () => {
    expect(isThinkingSupported('gemini-2.5-pro')).toBe(true);
  });

  it('should return false for other models', () => {
    expect(isThinkingSupported('gemini-1.5-flash')).toBe(false);
    expect(isThinkingSupported('some-other-model')).toBe(false);
  });
});

describe('isThinkingDefault', () => {
  it('should return false for gemini-2.5-flash-lite', () => {
    expect(isThinkingDefault('gemini-2.5-flash-lite')).toBe(false);
  });

  it('should return true for gemini-2.5', () => {
    expect(isThinkingDefault('gemini-2.5')).toBe(true);
  });

  it('should return true for gemini-2.5-pro', () => {
    expect(isThinkingDefault('gemini-2.5-pro')).toBe(true);
  });

  it('should return false for other models', () => {
    expect(isThinkingDefault('gemini-1.5-flash')).toBe(false);
    expect(isThinkingDefault('some-other-model')).toBe(false);
  });
});

describe('Gemini Client (client.ts)', () => {
  let mockContentGenerator: ContentGenerator;
  let mockConfig: Config;
  let client: GeminiClient;
  let mockGenerateContentFn: Mock;
  beforeEach(async () => {
    vi.resetAllMocks();
    vi.mocked(uiTelemetryService.setLastPromptTokenCount).mockClear();

    mockGenerateContentFn = vi.fn().mockResolvedValue({
      candidates: [{ content: { parts: [{ text: '{"key": "value"}' }] } }],
    });

    // Disable 429 simulation for tests
    setSimulate429(false);

    mockContentGenerator = {
      generateContent: mockGenerateContentFn,
      generateContentStream: vi.fn(),
      batchEmbedContents: vi.fn(),
      countTokens: vi.fn().mockResolvedValue({ totalTokens: 100 }),
    } as unknown as ContentGenerator;

    // Because the GeminiClient constructor kicks off an async process (startChat)
    // that depends on a fully-formed Config object, we need to mock the
    // entire implementation of Config for these tests.
    const mockToolRegistry = {
      getFunctionDeclarations: vi.fn().mockReturnValue([]),
      getTool: vi.fn().mockReturnValue(null),
    };
    const fileService = new FileDiscoveryService('/test/dir');
    const contentGeneratorConfig: ContentGeneratorConfig = {
      model: 'test-model',
      apiKey: 'test-key',
      vertexai: false,
      authType: AuthType.USE_GEMINI,
    };
    const mockSubagentManager = {
      listSubagents: vi.fn().mockResolvedValue([]),
      addChangeListener: vi.fn().mockReturnValue(() => {}),
    };
    mockConfig = {
      getContentGeneratorConfig: vi
        .fn()
        .mockReturnValue(contentGeneratorConfig),
      getToolRegistry: vi.fn().mockReturnValue(mockToolRegistry),
      getModel: vi.fn().mockReturnValue('test-model'),
      getEmbeddingModel: vi.fn().mockReturnValue('test-embedding-model'),
      getApiKey: vi.fn().mockReturnValue('test-key'),
      getVertexAI: vi.fn().mockReturnValue(false),
      getUserAgent: vi.fn().mockReturnValue('test-agent'),
      getUserMemory: vi.fn().mockReturnValue(''),
      getFullContext: vi.fn().mockReturnValue(false),
      getSessionId: vi.fn().mockReturnValue('test-session-id'),
      getProxy: vi.fn().mockReturnValue(undefined),
      getWorkingDir: vi.fn().mockReturnValue('/test/dir'),
      getFileService: vi.fn().mockReturnValue(fileService),
      getMaxSessionTurns: vi.fn().mockReturnValue(0),
      getSessionTokenLimit: vi.fn().mockReturnValue(32000),
      getQuotaErrorOccurred: vi.fn().mockReturnValue(false),
      setQuotaErrorOccurred: vi.fn(),
      getNoBrowser: vi.fn().mockReturnValue(false),
      getUsageStatisticsEnabled: vi.fn().mockReturnValue(true),
      getApprovalMode: vi.fn().mockReturnValue(ApprovalMode.DEFAULT),
      getIdeModeFeature: vi.fn().mockReturnValue(false),
      getIdeMode: vi.fn().mockReturnValue(true),
      getDebugMode: vi.fn().mockReturnValue(false),
      getWorkspaceContext: vi.fn().mockReturnValue({
        getDirectories: vi.fn().mockReturnValue(['/test/dir']),
      }),
      getGeminiClient: vi.fn(),
      getModelRouterService: vi.fn().mockReturnValue({
        route: vi.fn().mockResolvedValue({ model: 'default-routed-model' }),
      }),
      isInFallbackMode: vi.fn().mockReturnValue(false),
      setFallbackMode: vi.fn(),
      getCliVersion: vi.fn().mockReturnValue('1.0.0'),
      getChatCompression: vi.fn().mockReturnValue(undefined),
      getSkipNextSpeakerCheck: vi.fn().mockReturnValue(false),
      getUseSmartEdit: vi.fn().mockReturnValue(false),
      getUseModelRouter: vi.fn().mockReturnValue(false),
      getProjectRoot: vi.fn().mockReturnValue('/test/project/root'),
      storage: {
        getProjectTempDir: vi.fn().mockReturnValue('/test/temp'),
      },
      getContentGenerator: vi.fn().mockReturnValue(mockContentGenerator),
      getBaseLlmClient: vi.fn().mockReturnValue({
        generateJson: vi.fn().mockResolvedValue({
          next_speaker: 'user',
          reasoning: 'test',
        }),
      }),
      getSubagentManager: vi.fn().mockReturnValue(mockSubagentManager),
      getSkipLoopDetection: vi.fn().mockReturnValue(false),
    } as unknown as Config;

    client = new GeminiClient(mockConfig);
    await client.initialize();
    vi.mocked(mockConfig.getGeminiClient).mockReturnValue(client);
  });

  afterEach(() => {
    vi.restoreAllMocks();
  });

  describe('addHistory', () => {
    it('should call chat.addHistory with the provided content', async () => {
      const mockChat = {
        addHistory: vi.fn(),
      } as unknown as GeminiChat;
      client['chat'] = mockChat;

      const newContent = {
        role: 'user',
        parts: [{ text: 'New history item' }],
      };
      await client.addHistory(newContent);

      expect(mockChat.addHistory).toHaveBeenCalledWith(newContent);
    });
  });

  describe('resetChat', () => {
    it('should create a new chat session, clearing the old history', async () => {
      // 1. Get the initial chat instance and add some history.
      const initialChat = client.getChat();
      const initialHistory = await client.getHistory();
      await client.addHistory({
        role: 'user',
        parts: [{ text: 'some old message' }],
      });
      const historyWithOldMessage = await client.getHistory();
      expect(historyWithOldMessage.length).toBeGreaterThan(
        initialHistory.length,
      );

      // 2. Call resetChat.
      await client.resetChat();

      // 3. Get the new chat instance and its history.
      const newChat = client.getChat();
      const newHistory = await client.getHistory();

      // 4. Assert that the chat instance is new and the history is reset.
      expect(newChat).not.toBe(initialChat);
      expect(newHistory.length).toBe(initialHistory.length);
      expect(JSON.stringify(newHistory)).not.toContain('some old message');
    });
  });

  describe('tryCompressChat', () => {
    const mockGetHistory = vi.fn();

    beforeEach(() => {
      vi.mock('./tokenLimits', () => ({
        tokenLimit: vi.fn(),
      }));

      client['chat'] = {
        getHistory: mockGetHistory,
        addHistory: vi.fn(),
        setHistory: vi.fn(),
      } as unknown as GeminiChat;
    });

    function setup({
      chatHistory = [
        { role: 'user', parts: [{ text: 'Long conversation' }] },
        { role: 'model', parts: [{ text: 'Long response' }] },
      ] as Content[],
      originalTokenCount = 1000,
      summaryText = 'This is a summary.',
    } = {}) {
      const mockOriginalChat: Partial<GeminiChat> = {
        getHistory: vi.fn((_curated?: boolean) => chatHistory),
        setHistory: vi.fn(),
      };
      client['chat'] = mockOriginalChat as GeminiChat;

      vi.mocked(uiTelemetryService.getLastPromptTokenCount).mockReturnValue(
        originalTokenCount,
      );

      mockGenerateContentFn.mockResolvedValue({
        candidates: [
          {
            content: {
              role: 'model',
              parts: [{ text: summaryText }],
            },
          },
        ],
      } as unknown as GenerateContentResponse);

      // Calculate what the new history will be
      const splitPoint = findCompressSplitPoint(chatHistory, 0.7); // 1 - 0.3
      const historyToKeep = chatHistory.slice(splitPoint);

      // This is the history that the new chat will have.
      // It includes the default startChat history + the extra history from tryCompressChat
      const newCompressedHistory: Content[] = [
        // Mocked envParts + canned response from startChat
        {
          role: 'user',
          parts: [{ text: 'Mocked env context' }],
        },
        {
          role: 'model',
          parts: [{ text: 'Got it. Thanks for the context!' }],
        },
        // extraHistory from tryCompressChat
        {
          role: 'user',
          parts: [{ text: summaryText }],
        },
        {
          role: 'model',
          parts: [{ text: 'Got it. Thanks for the additional context!' }],
        },
        ...historyToKeep,
      ];

      const mockNewChat: Partial<GeminiChat> = {
        getHistory: vi.fn().mockReturnValue(newCompressedHistory),
        setHistory: vi.fn(),
      };

      client['startChat'] = vi
        .fn()
        .mockResolvedValue(mockNewChat as GeminiChat);

      const totalChars = newCompressedHistory.reduce(
        (total, content) => total + JSON.stringify(content).length,
        0,
      );
      const estimatedNewTokenCount = Math.floor(totalChars / 4);

      return {
        client,
        mockOriginalChat,
        mockNewChat,
        estimatedNewTokenCount,
      };
    }

    describe('when compression inflates the token count', () => {
      it('allows compression to be forced/manual after a failure', async () => {
        // Call 1 (Fails): Setup with a long summary to inflate tokens
        const longSummary = 'long summary '.repeat(100);
        const { client, estimatedNewTokenCount: inflatedTokenCount } = setup({
          originalTokenCount: 100,
          summaryText: longSummary,
        });
        expect(inflatedTokenCount).toBeGreaterThan(100); // Ensure setup is correct

        await client.tryCompressChat('prompt-id-4', false); // Fails

        // Call 2 (Forced): Re-setup with a short summary
        const shortSummary = 'short';
        const { estimatedNewTokenCount: compressedTokenCount } = setup({
          originalTokenCount: 100,
          summaryText: shortSummary,
        });
        expect(compressedTokenCount).toBeLessThanOrEqual(100); // Ensure setup is correct

        const result = await client.tryCompressChat('prompt-id-4', true); // Forced

        expect(result).toEqual({
          compressionStatus: CompressionStatus.COMPRESSED,
          newTokenCount: compressedTokenCount,
          originalTokenCount: 100,
        });
      });

      it('yields the result even if the compression inflated the tokens', async () => {
        const longSummary = 'long summary '.repeat(100);
        const { client, estimatedNewTokenCount } = setup({
          originalTokenCount: 100,
          summaryText: longSummary,
        });
        expect(estimatedNewTokenCount).toBeGreaterThan(100); // Ensure setup is correct

        const result = await client.tryCompressChat('prompt-id-4', false);

        expect(result).toEqual({
          compressionStatus:
            CompressionStatus.COMPRESSION_FAILED_INFLATED_TOKEN_COUNT,
          newTokenCount: estimatedNewTokenCount,
          originalTokenCount: 100,
        });
        // IMPORTANT: The change in client.ts means setLastPromptTokenCount is NOT called on failure
        expect(
          uiTelemetryService.setLastPromptTokenCount,
        ).not.toHaveBeenCalled();
      });

      it('does not manipulate the source chat', async () => {
        const longSummary = 'long summary '.repeat(100);
        const { client, mockOriginalChat, estimatedNewTokenCount } = setup({
          originalTokenCount: 100,
          summaryText: longSummary,
        });
        expect(estimatedNewTokenCount).toBeGreaterThan(100); // Ensure setup is correct

        await client.tryCompressChat('prompt-id-4', false);

        // On failure, the chat should NOT be replaced
        expect(client['chat']).toBe(mockOriginalChat);
      });

      it('will not attempt to compress context after a failure', async () => {
        const longSummary = 'long summary '.repeat(100);
        const { client, estimatedNewTokenCount } = setup({
          originalTokenCount: 100,
          summaryText: longSummary,
        });
        expect(estimatedNewTokenCount).toBeGreaterThan(100); // Ensure setup is correct

        await client.tryCompressChat('prompt-id-4', false); // This fails and sets hasFailedCompressionAttempt = true

        // This call should now be a NOOP
        const result = await client.tryCompressChat('prompt-id-5', false);

        // generateContent (for summary) should only have been called once
        expect(mockGenerateContentFn).toHaveBeenCalledTimes(1);
        expect(result).toEqual({
          compressionStatus: CompressionStatus.NOOP,
          newTokenCount: 0,
          originalTokenCount: 0,
        });
      });
    });

    it('should not trigger summarization if token count is below threshold', async () => {
      const MOCKED_TOKEN_LIMIT = 1000;
      vi.mocked(tokenLimit).mockReturnValue(MOCKED_TOKEN_LIMIT);
      mockGetHistory.mockReturnValue([
        { role: 'user', parts: [{ text: '...history...' }] },
      ]);
      const originalTokenCount = MOCKED_TOKEN_LIMIT * 0.699;
      vi.mocked(uiTelemetryService.getLastPromptTokenCount).mockReturnValue(
        originalTokenCount,
      );

      const initialChat = client.getChat();
      const result = await client.tryCompressChat('prompt-id-2', false);
      const newChat = client.getChat();

      expect(tokenLimit).toHaveBeenCalled();
      expect(result).toEqual({
        compressionStatus: CompressionStatus.NOOP,
        newTokenCount: originalTokenCount,
        originalTokenCount,
      });
      expect(newChat).toBe(initialChat);
    });

    it('logs a telemetry event when compressing', async () => {
      const { logChatCompression } = await import('../telemetry/loggers.js');
      vi.mocked(logChatCompression).mockClear();

      const MOCKED_TOKEN_LIMIT = 1000;
      const MOCKED_CONTEXT_PERCENTAGE_THRESHOLD = 0.5;
      vi.mocked(tokenLimit).mockReturnValue(MOCKED_TOKEN_LIMIT);
      vi.spyOn(client['config'], 'getChatCompression').mockReturnValue({
        contextPercentageThreshold: MOCKED_CONTEXT_PERCENTAGE_THRESHOLD,
      });
      // Need multiple history items so there's something to compress
      const history = [
        { role: 'user', parts: [{ text: '...history 1...' }] },
        { role: 'model', parts: [{ text: '...history 2...' }] },
        { role: 'user', parts: [{ text: '...history 3...' }] },
        { role: 'model', parts: [{ text: '...history 4...' }] },
      ];
      mockGetHistory.mockReturnValue(history);

      // Token count needs to be ABOVE the threshold to trigger compression
      const originalTokenCount =
        MOCKED_TOKEN_LIMIT * MOCKED_CONTEXT_PERCENTAGE_THRESHOLD + 1;

      vi.mocked(uiTelemetryService.getLastPromptTokenCount).mockReturnValue(
        originalTokenCount,
      );

      // Mock the summary response from the chat
      const summaryText = 'This is a summary.';
      mockGenerateContentFn.mockResolvedValue({
        candidates: [
          {
            content: {
              role: 'model',
              parts: [{ text: summaryText }],
            },
          },
        ],
      } as unknown as GenerateContentResponse);

      // Mock startChat to complete the compression flow
      const splitPoint = findCompressSplitPoint(history, 0.7);
      const historyToKeep = history.slice(splitPoint);
      const newCompressedHistory: Content[] = [
        { role: 'user', parts: [{ text: 'Mocked env context' }] },
        { role: 'model', parts: [{ text: 'Got it. Thanks for the context!' }] },
        { role: 'user', parts: [{ text: summaryText }] },
        {
          role: 'model',
          parts: [{ text: 'Got it. Thanks for the additional context!' }],
        },
        ...historyToKeep,
      ];
      const mockNewChat: Partial<GeminiChat> = {
        getHistory: vi.fn().mockReturnValue(newCompressedHistory),
      };
      client['startChat'] = vi
        .fn()
        .mockResolvedValue(mockNewChat as GeminiChat);

      await client.tryCompressChat('prompt-id-3', false);

      expect(logChatCompression).toHaveBeenCalledWith(
        expect.anything(),
        expect.objectContaining({
          tokens_before: originalTokenCount,
        }),
      );
      expect(uiTelemetryService.setLastPromptTokenCount).toHaveBeenCalled();
    });

    it('should trigger summarization if token count is above threshold with contextPercentageThreshold setting', async () => {
      const MOCKED_TOKEN_LIMIT = 1000;
      const MOCKED_CONTEXT_PERCENTAGE_THRESHOLD = 0.5;
      vi.mocked(tokenLimit).mockReturnValue(MOCKED_TOKEN_LIMIT);
      vi.spyOn(client['config'], 'getChatCompression').mockReturnValue({
        contextPercentageThreshold: MOCKED_CONTEXT_PERCENTAGE_THRESHOLD,
      });
      // Need multiple history items so there's something to compress
      const history = [
        { role: 'user', parts: [{ text: '...history 1...' }] },
        { role: 'model', parts: [{ text: '...history 2...' }] },
        { role: 'user', parts: [{ text: '...history 3...' }] },
        { role: 'model', parts: [{ text: '...history 4...' }] },
      ];
      mockGetHistory.mockReturnValue(history);

      // Token count needs to be ABOVE the threshold to trigger compression
      const originalTokenCount =
        MOCKED_TOKEN_LIMIT * MOCKED_CONTEXT_PERCENTAGE_THRESHOLD + 1;

      vi.mocked(uiTelemetryService.getLastPromptTokenCount).mockReturnValue(
        originalTokenCount,
      );

      // Mock summary and new chat
      const summaryText = 'This is a summary.';
      const splitPoint = findCompressSplitPoint(history, 0.7);
      const historyToKeep = history.slice(splitPoint);
      const newCompressedHistory: Content[] = [
        { role: 'user', parts: [{ text: 'Mocked env context' }] },
        { role: 'model', parts: [{ text: 'Got it. Thanks for the context!' }] },
        { role: 'user', parts: [{ text: summaryText }] },
        {
          role: 'model',
          parts: [{ text: 'Got it. Thanks for the additional context!' }],
        },
        ...historyToKeep,
      ];
      const mockNewChat: Partial<GeminiChat> = {
        getHistory: vi.fn().mockReturnValue(newCompressedHistory),
      };
      client['startChat'] = vi
        .fn()
        .mockResolvedValue(mockNewChat as GeminiChat);

      const totalChars = newCompressedHistory.reduce(
        (total, content) => total + JSON.stringify(content).length,
        0,
      );
      const newTokenCount = Math.floor(totalChars / 4);

      // Mock the summary response from the chat
      mockGenerateContentFn.mockResolvedValue({
        candidates: [
          {
            content: {
              role: 'model',
              parts: [{ text: summaryText }],
            },
          },
        ],
      } as unknown as GenerateContentResponse);

      const initialChat = client.getChat();
      const result = await client.tryCompressChat('prompt-id-3', false);
      const newChat = client.getChat();

      expect(tokenLimit).toHaveBeenCalled();
      expect(mockGenerateContentFn).toHaveBeenCalled();

      // Assert that summarization happened and returned the correct stats
      expect(result).toEqual({
        compressionStatus: CompressionStatus.COMPRESSED,
        originalTokenCount,
        newTokenCount,
      });

      // Assert that the chat was reset
      expect(newChat).not.toBe(initialChat);
    });

    it('should not compress across a function call response', async () => {
      const MOCKED_TOKEN_LIMIT = 1000;
      vi.mocked(tokenLimit).mockReturnValue(MOCKED_TOKEN_LIMIT);
      const history: Content[] = [
        { role: 'user', parts: [{ text: '...history 1...' }] },
        { role: 'model', parts: [{ text: '...history 2...' }] },
        { role: 'user', parts: [{ text: '...history 3...' }] },
        { role: 'model', parts: [{ text: '...history 4...' }] },
        { role: 'user', parts: [{ text: '...history 5...' }] },
        { role: 'model', parts: [{ text: '...history 6...' }] },
        { role: 'user', parts: [{ text: '...history 7...' }] },
        { role: 'model', parts: [{ text: '...history 8...' }] },
        // Normally we would break here, but we have a function response.
        {
          role: 'user',
          parts: [{ functionResponse: { name: '...history 8...' } }],
        },
        { role: 'model', parts: [{ text: '...history 10...' }] },
        // Instead we will break here.
        { role: 'user', parts: [{ text: '...history 10...' }] },
      ];
      mockGetHistory.mockReturnValue(history);

      const originalTokenCount = 1000 * 0.7;
      vi.mocked(uiTelemetryService.getLastPromptTokenCount).mockReturnValue(
        originalTokenCount,
      );

      // Mock summary and new chat
      const summaryText = 'This is a summary.';
      const splitPoint = findCompressSplitPoint(history, 0.7); // This should be 10
      expect(splitPoint).toBe(10); // Verify split point logic
      const historyToKeep = history.slice(splitPoint); // Should keep last user message
      expect(historyToKeep).toEqual([
        { role: 'user', parts: [{ text: '...history 10...' }] },
      ]);

      const newCompressedHistory: Content[] = [
        { role: 'user', parts: [{ text: 'Mocked env context' }] },
        { role: 'model', parts: [{ text: 'Got it. Thanks for the context!' }] },
        { role: 'user', parts: [{ text: summaryText }] },
        {
          role: 'model',
          parts: [{ text: 'Got it. Thanks for the additional context!' }],
        },
        ...historyToKeep,
      ];
      const mockNewChat: Partial<GeminiChat> = {
        getHistory: vi.fn().mockReturnValue(newCompressedHistory),
      };
      client['startChat'] = vi
        .fn()
        .mockResolvedValue(mockNewChat as GeminiChat);

      const totalChars = newCompressedHistory.reduce(
        (total, content) => total + JSON.stringify(content).length,
        0,
      );
      const newTokenCount = Math.floor(totalChars / 4);

      // Mock the summary response from the chat
      mockGenerateContentFn.mockResolvedValue({
        candidates: [
          {
            content: {
              role: 'model',
              parts: [{ text: summaryText }],
            },
          },
        ],
      } as unknown as GenerateContentResponse);

      const initialChat = client.getChat();
      const result = await client.tryCompressChat('prompt-id-3', false);
      const newChat = client.getChat();

      expect(tokenLimit).toHaveBeenCalled();
      expect(mockGenerateContentFn).toHaveBeenCalled();

      // Assert that summarization happened and returned the correct stats
      expect(result).toEqual({
        compressionStatus: CompressionStatus.COMPRESSED,
        originalTokenCount,
        newTokenCount,
      });
      // Assert that the chat was reset
      expect(newChat).not.toBe(initialChat);

      // 1. standard start context message (env)
      // 2. standard canned model response
      // 3. compressed summary message (user)
      // 4. standard canned model response
      // 5. The last user message (historyToKeep)
      expect(newChat.getHistory().length).toEqual(5);
    });

    it('should always trigger summarization when force is true, regardless of token count', async () => {
      // Need multiple history items so there's something to compress
      const history = [
        { role: 'user', parts: [{ text: '...history 1...' }] },
        { role: 'model', parts: [{ text: '...history 2...' }] },
        { role: 'user', parts: [{ text: '...history 3...' }] },
        { role: 'model', parts: [{ text: '...history 4...' }] },
      ];
      mockGetHistory.mockReturnValue(history);

      const originalTokenCount = 100; // Well below threshold, but > estimated new count
      vi.mocked(uiTelemetryService.getLastPromptTokenCount).mockReturnValue(
        originalTokenCount,
      );

      // Mock summary and new chat
      const summaryText = 'This is a summary.';
      const splitPoint = findCompressSplitPoint(history, 0.7);
      const historyToKeep = history.slice(splitPoint);
      const newCompressedHistory: Content[] = [
        { role: 'user', parts: [{ text: 'Mocked env context' }] },
        { role: 'model', parts: [{ text: 'Got it. Thanks for the context!' }] },
        { role: 'user', parts: [{ text: summaryText }] },
        {
          role: 'model',
          parts: [{ text: 'Got it. Thanks for the additional context!' }],
        },
        ...historyToKeep,
      ];
      const mockNewChat: Partial<GeminiChat> = {
        getHistory: vi.fn().mockReturnValue(newCompressedHistory),
      };
      client['startChat'] = vi
        .fn()
        .mockResolvedValue(mockNewChat as GeminiChat);

      const totalChars = newCompressedHistory.reduce(
        (total, content) => total + JSON.stringify(content).length,
        0,
      );
      const newTokenCount = Math.floor(totalChars / 4);

      // Mock the summary response from the chat
      mockGenerateContentFn.mockResolvedValue({
        candidates: [
          {
            content: {
              role: 'model',
              parts: [{ text: summaryText }],
            },
          },
        ],
      } as unknown as GenerateContentResponse);

      const initialChat = client.getChat();
      const result = await client.tryCompressChat('prompt-id-1', true); // force = true
      const newChat = client.getChat();

      expect(mockGenerateContentFn).toHaveBeenCalled();

      expect(result).toEqual({
        compressionStatus: CompressionStatus.COMPRESSED,
        originalTokenCount,
        newTokenCount,
      });

      // Assert that the chat was reset
      expect(newChat).not.toBe(initialChat);
    });
  });

  describe('sendMessageStream', () => {
    it('emits a compression event when the context was automatically compressed', async () => {
      // Arrange
      mockTurnRunFn.mockReturnValue(
        (async function* () {
          yield { type: 'content', value: 'Hello' };
        })(),
      );

      const compressionInfo: ChatCompressionInfo = {
        compressionStatus: CompressionStatus.COMPRESSED,
        originalTokenCount: 1000,
        newTokenCount: 500,
      };

      vi.spyOn(client, 'tryCompressChat').mockResolvedValueOnce(
        compressionInfo,
      );

      // Act
      const stream = client.sendMessageStream(
        [{ text: 'Hi' }],
        new AbortController().signal,
        'prompt-id-1',
      );

      const events = await fromAsync(stream);

      // Assert
      expect(events).toContainEqual({
        type: GeminiEventType.ChatCompressed,
        value: compressionInfo,
      });
    });

    it.each([
      {
        compressionStatus:
          CompressionStatus.COMPRESSION_FAILED_INFLATED_TOKEN_COUNT,
      },
      { compressionStatus: CompressionStatus.NOOP },
    ])(
      'does not emit a compression event when the status is $compressionStatus',
      async ({ compressionStatus }) => {
        // Arrange
        const mockStream = (async function* () {
          yield { type: 'content', value: 'Hello' };
        })();
        mockTurnRunFn.mockReturnValue(mockStream);

        const compressionInfo: ChatCompressionInfo = {
          compressionStatus,
          originalTokenCount: 1000,
          newTokenCount: 500,
        };

        vi.spyOn(client, 'tryCompressChat').mockResolvedValueOnce(
          compressionInfo,
        );

        // Act
        const stream = client.sendMessageStream(
          [{ text: 'Hi' }],
          new AbortController().signal,
          'prompt-id-1',
        );

        const events = await fromAsync(stream);

        // Assert
        expect(events).not.toContainEqual({
          type: GeminiEventType.ChatCompressed,
          value: expect.anything(),
        });
      },
    );

    it('should include editor context when ideMode is enabled', async () => {
      // Arrange
      vi.mocked(ideContextStore.get).mockReturnValue({
        workspaceState: {
          openFiles: [
            {
              path: '/path/to/active/file.ts',
              timestamp: Date.now(),
              isActive: true,
              selectedText: 'hello',
              cursor: { line: 5, character: 10 },
            },
            {
              path: '/path/to/recent/file1.ts',
              timestamp: Date.now(),
            },
            {
              path: '/path/to/recent/file2.ts',
              timestamp: Date.now(),
            },
          ],
        },
      });

      vi.mocked(mockConfig.getIdeMode).mockReturnValue(true);

      vi.spyOn(client, 'tryCompressChat').mockResolvedValue({
        originalTokenCount: 0,
        newTokenCount: 0,
        compressionStatus: CompressionStatus.COMPRESSED,
      });

      mockTurnRunFn.mockReturnValue(
        (async function* () {
          yield { type: 'content', value: 'Hello' };
        })(),
      );

      const mockChat = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      } as unknown as GeminiChat;
      client['chat'] = mockChat;

      const initialRequest: Part[] = [{ text: 'Hi' }];

      // Act
      const stream = client.sendMessageStream(
        initialRequest,
        new AbortController().signal,
        'prompt-id-ide',
      );
      for await (const _ of stream) {
        // consume stream
      }

      // Assert
      expect(ideContextStore.get).toHaveBeenCalled();
      const expectedContext = `
Here is the user's editor context as a JSON object. This is for your information only.
\`\`\`json
${JSON.stringify(
  {
    activeFile: {
      path: '/path/to/active/file.ts',
      cursor: {
        line: 5,
        character: 10,
      },
      selectedText: 'hello',
    },
    otherOpenFiles: ['/path/to/recent/file1.ts', '/path/to/recent/file2.ts'],
  },
  null,
  2,
)}
\`\`\`
      `.trim();
      const expectedRequest = [{ text: expectedContext }];
      expect(mockChat.addHistory).toHaveBeenCalledWith({
        role: 'user',
        parts: expectedRequest,
      });
    });

    it('should not add context if ideMode is enabled but no open files', async () => {
      // Arrange
      vi.mocked(ideContextStore.get).mockReturnValue({
        workspaceState: {
          openFiles: [],
        },
      });

      vi.spyOn(client['config'], 'getIdeMode').mockReturnValue(true);

      const mockStream = (async function* () {
        yield { type: 'content', value: 'Hello' };
      })();
      mockTurnRunFn.mockReturnValue(mockStream);

      const mockChat: Partial<GeminiChat> = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      };
      client['chat'] = mockChat as GeminiChat;

      const initialRequest = [{ text: 'Hi' }];

      // Act
      const stream = client.sendMessageStream(
        initialRequest,
        new AbortController().signal,
        'prompt-id-ide',
      );
      for await (const _ of stream) {
        // consume stream
      }

      // Assert
      expect(ideContextStore.get).toHaveBeenCalled();
      // The `turn.run` method is now called with the model name as the first
      // argument and the request parts are passed in a simplified format.
      // We verify that turn.run was called (indicating no IDE context was added).
      expect(mockTurnRunFn).toHaveBeenCalled();
    });

    it('should add context if ideMode is enabled and there is one active file', async () => {
      // Arrange
      vi.mocked(ideContextStore.get).mockReturnValue({
        workspaceState: {
          openFiles: [
            {
              path: '/path/to/active/file.ts',
              timestamp: Date.now(),
              isActive: true,
              selectedText: 'hello',
              cursor: { line: 5, character: 10 },
            },
          ],
        },
      });

      vi.spyOn(client['config'], 'getIdeMode').mockReturnValue(true);

      vi.spyOn(client, 'tryCompressChat').mockResolvedValue({
        originalTokenCount: 0,
        newTokenCount: 0,
        compressionStatus: CompressionStatus.COMPRESSED,
      });

      const mockStream = (async function* () {
        yield { type: 'content', value: 'Hello' };
      })();
      mockTurnRunFn.mockReturnValue(mockStream);

      const mockChat: Partial<GeminiChat> = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      };
      client['chat'] = mockChat as GeminiChat;

      const initialRequest = [{ text: 'Hi' }];

      // Act
      const stream = client.sendMessageStream(
        initialRequest,
        new AbortController().signal,
        'prompt-id-ide',
      );
      for await (const _ of stream) {
        // consume stream
      }

      // Assert
      expect(ideContextStore.get).toHaveBeenCalled();
      const expectedContext = `
Here is the user's editor context as a JSON object. This is for your information only.
\`\`\`json
${JSON.stringify(
  {
    activeFile: {
      path: '/path/to/active/file.ts',
      cursor: {
        line: 5,
        character: 10,
      },
      selectedText: 'hello',
    },
  },
  null,
  2,
)}
\`\`\`
      `.trim();
      const expectedRequest = [{ text: expectedContext }];
      expect(mockChat.addHistory).toHaveBeenCalledWith({
        role: 'user',
        parts: expectedRequest,
      });
    });

    it('should add context if ideMode is enabled and there are open files but no active file', async () => {
      // Arrange
      vi.mocked(ideContextStore.get).mockReturnValue({
        workspaceState: {
          openFiles: [
            {
              path: '/path/to/recent/file1.ts',
              timestamp: Date.now(),
            },
            {
              path: '/path/to/recent/file2.ts',
              timestamp: Date.now(),
            },
          ],
        },
      });

      vi.spyOn(client['config'], 'getIdeMode').mockReturnValue(true);

      vi.spyOn(client, 'tryCompressChat').mockResolvedValue({
        originalTokenCount: 0,
        newTokenCount: 0,
        compressionStatus: CompressionStatus.COMPRESSED,
      });

      const mockStream = (async function* () {
        yield { type: 'content', value: 'Hello' };
      })();
      mockTurnRunFn.mockReturnValue(mockStream);

      const mockChat: Partial<GeminiChat> = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      };
      client['chat'] = mockChat as GeminiChat;

      const initialRequest = [{ text: 'Hi' }];

      // Act
      const stream = client.sendMessageStream(
        initialRequest,
        new AbortController().signal,
        'prompt-id-ide',
      );
      for await (const _ of stream) {
        // consume stream
      }

      // Assert
      expect(ideContextStore.get).toHaveBeenCalled();
      const expectedContext = `
Here is the user's editor context as a JSON object. This is for your information only.
\`\`\`json
${JSON.stringify(
  {
    otherOpenFiles: ['/path/to/recent/file1.ts', '/path/to/recent/file2.ts'],
  },
  null,
  2,
)}
\`\`\`
      `.trim();
      const expectedRequest = [{ text: expectedContext }];
      expect(mockChat.addHistory).toHaveBeenCalledWith({
        role: 'user',
        parts: expectedRequest,
      });
    });

    it('should return the turn instance after the stream is complete', async () => {
      // Arrange
      const mockStream = (async function* () {
        yield { type: 'content', value: 'Hello' };
      })();
      mockTurnRunFn.mockReturnValue(mockStream);

      const mockChat: Partial<GeminiChat> = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      };
      client['chat'] = mockChat as GeminiChat;

      // Act
      const stream = client.sendMessageStream(
        [{ text: 'Hi' }],
        new AbortController().signal,
        'prompt-id-1',
      );

      // Consume the stream manually to get the final return value.
      let finalResult: Turn | undefined;
      while (true) {
        const result = await stream.next();
        if (result.done) {
          finalResult = result.value;
          break;
        }
      }

      // Assert
      expect(finalResult).toBeInstanceOf(Turn);
    });

    it('should stop infinite loop after MAX_TURNS when nextSpeaker always returns model', async () => {
      // Get the mocked checkNextSpeaker function and configure it to trigger infinite loop
      const { checkNextSpeaker } = await import(
        '../utils/nextSpeakerChecker.js'
      );
      const mockCheckNextSpeaker = vi.mocked(checkNextSpeaker);
      mockCheckNextSpeaker.mockResolvedValue({
        next_speaker: 'model',
        reasoning: 'Test case - always continue',
      });

      // Mock Turn to have no pending tool calls (which would allow nextSpeaker check)
      const mockStream = (async function* () {
        yield { type: 'content', value: 'Continue...' };
      })();
      mockTurnRunFn.mockReturnValue(mockStream);

      const mockChat: Partial<GeminiChat> = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      };
      client['chat'] = mockChat as GeminiChat;

      // Use a signal that never gets aborted
      const abortController = new AbortController();
      const signal = abortController.signal;

      // Act - Start the stream that should loop
      const stream = client.sendMessageStream(
        [{ text: 'Start conversation' }],
        signal,
        'prompt-id-2',
      );

      // Count how many stream events we get
      let eventCount = 0;
      let finalResult: Turn | undefined;

      // Consume the stream and count iterations
      while (true) {
        const result = await stream.next();
        if (result.done) {
          finalResult = result.value;
          break;
        }
        eventCount++;

        // Safety check to prevent actual infinite loop in test
        if (eventCount > 200) {
          abortController.abort();
          throw new Error(
            'Test exceeded expected event limit - possible actual infinite loop',
          );
        }
      }

      // Assert
      expect(finalResult).toBeInstanceOf(Turn);

      // Debug: Check how many times checkNextSpeaker was called
      const callCount = mockCheckNextSpeaker.mock.calls.length;

      // If infinite loop protection is working, checkNextSpeaker should be called many times
      // but stop at MAX_TURNS (100). Since each recursive call should trigger checkNextSpeaker,
      // we expect it to be called multiple times before hitting the limit
      expect(mockCheckNextSpeaker).toHaveBeenCalled();

      // The test should demonstrate that the infinite loop protection works:
      // - If checkNextSpeaker is called many times (close to MAX_TURNS), it shows the loop was happening
      // - If it's only called once, the recursive behavior might not be triggered
      if (callCount === 0) {
        throw new Error(
          'checkNextSpeaker was never called - the recursive condition was not met',
        );
      } else if (callCount === 1) {
        // This might be expected behavior if the turn has pending tool calls or other conditions prevent recursion
        console.log(
          'checkNextSpeaker called only once - no infinite loop occurred',
        );
      } else {
        console.log(
          `checkNextSpeaker called ${callCount} times - infinite loop protection worked`,
        );
        // If called multiple times, we expect it to be stopped before MAX_TURNS
        expect(callCount).toBeLessThanOrEqual(100); // Should not exceed MAX_TURNS
      }

      // The stream should produce events and eventually terminate
      expect(eventCount).toBeGreaterThanOrEqual(1);
      expect(eventCount).toBeLessThan(200); // Should not exceed our safety limit
    });

    it('should yield MaxSessionTurns and stop when session turn limit is reached', async () => {
      // Arrange
      const MAX_SESSION_TURNS = 5;
      vi.spyOn(client['config'], 'getMaxSessionTurns').mockReturnValue(
        MAX_SESSION_TURNS,
      );

      const mockStream = (async function* () {
        yield { type: 'content', value: 'Hello' };
      })();
      mockTurnRunFn.mockReturnValue(mockStream);

      const mockChat: Partial<GeminiChat> = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      };
      client['chat'] = mockChat as GeminiChat;

      // Act & Assert
      // Run up to the limit
      for (let i = 0; i < MAX_SESSION_TURNS; i++) {
        const stream = client.sendMessageStream(
          [{ text: 'Hi' }],
          new AbortController().signal,
          'prompt-id-4',
        );
        // consume stream
        for await (const _event of stream) {
          // do nothing
        }
      }

      // This call should exceed the limit
      const stream = client.sendMessageStream(
        [{ text: 'Hi' }],
        new AbortController().signal,
        'prompt-id-5',
      );

      const events = [];
      for await (const event of stream) {
        events.push(event);
      }

      expect(events).toEqual([{ type: GeminiEventType.MaxSessionTurns }]);
      expect(mockTurnRunFn).toHaveBeenCalledTimes(MAX_SESSION_TURNS);
    });

    it('should respect MAX_TURNS limit even when turns parameter is set to a large value', async () => {
      // This test verifies that the infinite loop protection works even when
      // someone tries to bypass it by calling with a very large turns value

      // Get the mocked checkNextSpeaker function and configure it to trigger infinite loop
      const { checkNextSpeaker } = await import(
        '../utils/nextSpeakerChecker.js'
      );
      const mockCheckNextSpeaker = vi.mocked(checkNextSpeaker);
      mockCheckNextSpeaker.mockResolvedValue({
        next_speaker: 'model',
        reasoning: 'Test case - always continue',
      });

      // Mock Turn to have no pending tool calls (which would allow nextSpeaker check)
      const mockStream = (async function* () {
        yield { type: 'content', value: 'Continue...' };
      })();
      mockTurnRunFn.mockReturnValue(mockStream);

      const mockChat: Partial<GeminiChat> = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      };
      client['chat'] = mockChat as GeminiChat;

      // Use a signal that never gets aborted
      const abortController = new AbortController();
      const signal = abortController.signal;

      // Act - Start the stream with an extremely high turns value
      // This simulates a case where the turns protection is bypassed
      const stream = client.sendMessageStream(
        [{ text: 'Start conversation' }],
        signal,
        'prompt-id-3',
        Number.MAX_SAFE_INTEGER, // Bypass the MAX_TURNS protection
      );

      // Count how many stream events we get
      let eventCount = 0;
      const maxTestIterations = 1000; // Higher limit to show the loop continues

      // Consume the stream and count iterations
      try {
        while (true) {
          const result = await stream.next();
          if (result.done) {
            break;
          }
          eventCount++;

          // This test should hit this limit, demonstrating the infinite loop
          if (eventCount > maxTestIterations) {
            abortController.abort();
            // This is the expected behavior - we hit the infinite loop
            break;
          }
        }
      } catch (error) {
        // If the test framework times out, that also demonstrates the infinite loop
        console.error('Test timed out or errored:', error);
      }

      // Assert that the fix works - the loop should stop at MAX_TURNS
      const callCount = mockCheckNextSpeaker.mock.calls.length;

      // With the fix: even when turns is set to a very high value,
      // the loop should stop at MAX_TURNS (100)
      expect(callCount).toBeLessThanOrEqual(100); // Should not exceed MAX_TURNS
      expect(eventCount).toBeLessThanOrEqual(200); // Should have reasonable number of events

      console.log(
        `Infinite loop protection working: checkNextSpeaker called ${callCount} times, ` +
          `${eventCount} events generated (properly bounded by MAX_TURNS)`,
      );
    });

    describe('Editor context delta', () => {
      const mockStream = (async function* () {
        yield { type: 'content', value: 'Hello' };
      })();

      beforeEach(() => {
        client['forceFullIdeContext'] = false; // Reset before each delta test
        vi.spyOn(client, 'tryCompressChat').mockResolvedValue({
          originalTokenCount: 0,
          newTokenCount: 0,
          compressionStatus: CompressionStatus.COMPRESSED,
        });
        vi.spyOn(client['config'], 'getIdeMode').mockReturnValue(true);
        mockTurnRunFn.mockReturnValue(mockStream);

        const mockChat: Partial<GeminiChat> = {
          addHistory: vi.fn(),
          setHistory: vi.fn(),
          // Assume history is not empty for delta checks
          getHistory: vi
            .fn()
            .mockReturnValue([
              { role: 'user', parts: [{ text: 'previous message' }] },
            ]),
        };
        client['chat'] = mockChat as GeminiChat;
      });

      const testCases = [
        {
          description: 'sends delta when active file changes',
          previousActiveFile: {
            path: '/path/to/old/file.ts',
            cursor: { line: 5, character: 10 },
            selectedText: 'hello',
          },
          currentActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
            selectedText: 'hello',
          },
          shouldSendContext: true,
        },
        {
          description: 'sends delta when cursor line changes',
          previousActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 1, character: 10 },
            selectedText: 'hello',
          },
          currentActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
            selectedText: 'hello',
          },
          shouldSendContext: true,
        },
        {
          description: 'sends delta when cursor character changes',
          previousActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 1 },
            selectedText: 'hello',
          },
          currentActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
            selectedText: 'hello',
          },
          shouldSendContext: true,
        },
        {
          description: 'sends delta when selected text changes',
          previousActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
            selectedText: 'world',
          },
          currentActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
            selectedText: 'hello',
          },
          shouldSendContext: true,
        },
        {
          description: 'sends delta when selected text is added',
          previousActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
          },
          currentActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
            selectedText: 'hello',
          },
          shouldSendContext: true,
        },
        {
          description: 'sends delta when selected text is removed',
          previousActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
            selectedText: 'hello',
          },
          currentActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
          },
          shouldSendContext: true,
        },
        {
          description: 'does not send context when nothing changes',
          previousActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
            selectedText: 'hello',
          },
          currentActiveFile: {
            path: '/path/to/active/file.ts',
            cursor: { line: 5, character: 10 },
            selectedText: 'hello',
          },
          shouldSendContext: false,
        },
      ];

      it.each(testCases)(
        '$description',
        async ({
          previousActiveFile,
          currentActiveFile,
          shouldSendContext,
        }) => {
          // Setup previous context
          client['lastSentIdeContext'] = {
            workspaceState: {
              openFiles: [
                {
                  path: previousActiveFile.path,
                  cursor: previousActiveFile.cursor,
                  selectedText: previousActiveFile.selectedText,
                  isActive: true,
                  timestamp: Date.now() - 1000,
                },
              ],
            },
          };

          // Setup current context
          vi.mocked(ideContextStore.get).mockReturnValue({
            workspaceState: {
              openFiles: [
                { ...currentActiveFile, isActive: true, timestamp: Date.now() },
              ],
            },
          });

          const stream = client.sendMessageStream(
            [{ text: 'Hi' }],
            new AbortController().signal,
            'prompt-id-delta',
          );
          for await (const _ of stream) {
            // consume stream
          }

          const mockChat = client['chat'] as unknown as {
            addHistory: (typeof vi)['fn'];
          };

          if (shouldSendContext) {
            expect(mockChat.addHistory).toHaveBeenCalledWith(
              expect.objectContaining({
                parts: expect.arrayContaining([
                  expect.objectContaining({
                    text: expect.stringContaining(
                      "Here is a summary of changes in the user's editor context",
                    ),
                  }),
                ]),
              }),
            );
          } else {
            expect(mockChat.addHistory).not.toHaveBeenCalled();
          }
        },
      );

      it('sends full context when history is cleared, even if editor state is unchanged', async () => {
        const activeFile = {
          path: '/path/to/active/file.ts',
          cursor: { line: 5, character: 10 },
          selectedText: 'hello',
        };

        // Setup previous context
        client['lastSentIdeContext'] = {
          workspaceState: {
            openFiles: [
              {
                path: activeFile.path,
                cursor: activeFile.cursor,
                selectedText: activeFile.selectedText,
                isActive: true,
                timestamp: Date.now() - 1000,
              },
            ],
          },
        };

        // Setup current context (same as previous)
        vi.mocked(ideContextStore.get).mockReturnValue({
          workspaceState: {
            openFiles: [
              { ...activeFile, isActive: true, timestamp: Date.now() },
            ],
          },
        });

        // Make history empty
        const mockChat = client['chat'] as unknown as {
          getHistory: ReturnType<(typeof vi)['fn']>;
          addHistory: ReturnType<(typeof vi)['fn']>;
        };
        mockChat.getHistory.mockReturnValue([]);

        const stream = client.sendMessageStream(
          [{ text: 'Hi' }],
          new AbortController().signal,
          'prompt-id-history-cleared',
        );
        for await (const _ of stream) {
          // consume stream
        }

        expect(mockChat.addHistory).toHaveBeenCalledWith(
          expect.objectContaining({
            parts: expect.arrayContaining([
              expect.objectContaining({
                text: expect.stringContaining(
                  "Here is the user's editor context",
                ),
              }),
            ]),
          }),
        );

        // Also verify it's the full context, not a delta.
        const call = mockChat.addHistory.mock.calls[0][0];
        const contextText = call.parts[0].text;
        const contextJson = JSON.parse(
          contextText.match(/```json\n(.*)\n```/s)![1],
        );
        expect(contextJson).toHaveProperty('activeFile');
        expect(contextJson.activeFile.path).toBe('/path/to/active/file.ts');
      });
    });

    describe('IDE context with pending tool calls', () => {
      let mockChat: Partial<GeminiChat>;

      beforeEach(() => {
        vi.spyOn(client, 'tryCompressChat').mockResolvedValue({
          originalTokenCount: 0,
          newTokenCount: 0,
          compressionStatus: CompressionStatus.COMPRESSED,
        });

        const mockStream = (async function* () {
          yield { type: 'content', value: 'response' };
        })();
        mockTurnRunFn.mockReturnValue(mockStream);

        mockChat = {
          addHistory: vi.fn(),
          getHistory: vi.fn().mockReturnValue([]), // Default empty history
          setHistory: vi.fn(),
        };
        client['chat'] = mockChat as GeminiChat;

        vi.spyOn(client['config'], 'getIdeMode').mockReturnValue(true);
        vi.mocked(ideContextStore.get).mockReturnValue({
          workspaceState: {
            openFiles: [{ path: '/path/to/file.ts', timestamp: Date.now() }],
          },
        });
      });

      it('should NOT add IDE context when a tool call is pending', async () => {
        // Arrange: History ends with a functionCall from the model
        const historyWithPendingCall: Content[] = [
          { role: 'user', parts: [{ text: 'Please use a tool.' }] },
          {
            role: 'model',
            parts: [{ functionCall: { name: 'some_tool', args: {} } }],
          },
        ];
        vi.mocked(mockChat.getHistory!).mockReturnValue(historyWithPendingCall);

        // Act: Simulate sending the tool's response back
        const stream = client.sendMessageStream(
          [
            {
              functionResponse: {
                name: 'some_tool',
                response: { success: true },
              },
            },
          ],
          new AbortController().signal,
          'prompt-id-tool-response',
        );
        for await (const _ of stream) {
          // consume stream to complete the call
        }

        // Assert: The IDE context message should NOT have been added to the history.
        expect(mockChat.addHistory).not.toHaveBeenCalledWith(
          expect.objectContaining({
            parts: expect.arrayContaining([
              expect.objectContaining({
                text: expect.stringContaining("user's editor context"),
              }),
            ]),
          }),
        );
      });

      it('should add IDE context when no tool call is pending', async () => {
        // Arrange: History is normal, no pending calls
        const normalHistory: Content[] = [
          { role: 'user', parts: [{ text: 'A normal message.' }] },
          { role: 'model', parts: [{ text: 'A normal response.' }] },
        ];
        vi.mocked(mockChat.getHistory!).mockReturnValue(normalHistory);

        // Act
        const stream = client.sendMessageStream(
          [{ text: 'Another normal message' }],
          new AbortController().signal,
          'prompt-id-normal',
        );
        for await (const _ of stream) {
          // consume stream
        }

        // Assert: The IDE context message SHOULD have been added.
        expect(mockChat.addHistory).toHaveBeenCalledWith(
          expect.objectContaining({
            role: 'user',
            parts: expect.arrayContaining([
              expect.objectContaining({
                text: expect.stringContaining("user's editor context"),
              }),
            ]),
          }),
        );
      });

      it('should send the latest IDE context on the next message after a skipped context', async () => {
        // --- Step 1: A tool call is pending, context should be skipped ---

        // Arrange: History ends with a functionCall
        const historyWithPendingCall: Content[] = [
          { role: 'user', parts: [{ text: 'Please use a tool.' }] },
          {
            role: 'model',
            parts: [{ functionCall: { name: 'some_tool', args: {} } }],
          },
        ];
        vi.mocked(mockChat.getHistory!).mockReturnValue(historyWithPendingCall);

        // Arrange: Set the initial IDE context
        const initialIdeContext = {
          workspaceState: {
            openFiles: [{ path: '/path/to/fileA.ts', timestamp: Date.now() }],
          },
        };
        vi.mocked(ideContextStore.get).mockReturnValue(initialIdeContext);

        // Act: Send the tool response
        let stream = client.sendMessageStream(
          [
            {
              functionResponse: {
                name: 'some_tool',
                response: { success: true },
              },
            },
          ],
          new AbortController().signal,
          'prompt-id-tool-response',
        );
        for await (const _ of stream) {
          /* consume */
        }

        // Assert: The initial context was NOT sent
        expect(mockChat.addHistory).not.toHaveBeenCalledWith(
          expect.objectContaining({
            parts: expect.arrayContaining([
              expect.objectContaining({
                text: expect.stringContaining("user's editor context"),
              }),
            ]),
          }),
        );

        // --- Step 2: A new message is sent, latest context should be included ---

        // Arrange: The model has responded to the tool, and the user is sending a new message.
        const historyAfterToolResponse: Content[] = [
          ...historyWithPendingCall,
          {
            role: 'user',
            parts: [
              {
                functionResponse: {
                  name: 'some_tool',
                  response: { success: true },
                },
              },
            ],
          },
          { role: 'model', parts: [{ text: 'The tool ran successfully.' }] },
        ];
        vi.mocked(mockChat.getHistory!).mockReturnValue(
          historyAfterToolResponse,
        );
        vi.mocked(mockChat.addHistory!).mockClear(); // Clear previous calls for the next assertion

        // Arrange: The IDE context has now changed
        const newIdeContext = {
          workspaceState: {
            openFiles: [{ path: '/path/to/fileB.ts', timestamp: Date.now() }],
          },
        };
        vi.mocked(ideContextStore.get).mockReturnValue(newIdeContext);

        // Act: Send a new, regular user message
        stream = client.sendMessageStream(
          [{ text: 'Thanks!' }],
          new AbortController().signal,
          'prompt-id-final',
        );
        for await (const _ of stream) {
          /* consume */
        }

        // Assert: The NEW context was sent as a FULL context because there was no previously sent context.
        const addHistoryCalls = vi.mocked(mockChat.addHistory!).mock.calls;
        const contextCall = addHistoryCalls.find((call) =>
          JSON.stringify(call[0]).includes("user's editor context"),
        );
        expect(contextCall).toBeDefined();
        expect(JSON.stringify(contextCall![0])).toContain(
          "Here is the user's editor context as a JSON object",
        );
        // Check that the sent context is the new one (fileB.ts)
        expect(JSON.stringify(contextCall![0])).toContain('fileB.ts');
        // Check that the sent context is NOT the old one (fileA.ts)
        expect(JSON.stringify(contextCall![0])).not.toContain('fileA.ts');
      });

      it('should send a context DELTA on the next message after a skipped context', async () => {
        // --- Step 0: Establish an initial context ---
        vi.mocked(mockChat.getHistory!).mockReturnValue([]); // Start with empty history
        const contextA = {
          workspaceState: {
            openFiles: [
              {
                path: '/path/to/fileA.ts',
                isActive: true,
                timestamp: Date.now(),
              },
            ],
          },
        };
        vi.mocked(ideContextStore.get).mockReturnValue(contextA);

        // Act: Send a regular message to establish the initial context
        let stream = client.sendMessageStream(
          [{ text: 'Initial message' }],
          new AbortController().signal,
          'prompt-id-initial',
        );
        for await (const _ of stream) {
          /* consume */
        }

        // Assert: Full context for fileA.ts was sent and stored.
        const initialCall = vi.mocked(mockChat.addHistory!).mock.calls[0][0];
        expect(JSON.stringify(initialCall)).toContain(
          "user's editor context as a JSON object",
        );
        expect(JSON.stringify(initialCall)).toContain('fileA.ts');
        // This implicitly tests that `lastSentIdeContext` is now set internally by the client.
        vi.mocked(mockChat.addHistory!).mockClear();

        // --- Step 1: A tool call is pending, context should be skipped ---
        const historyWithPendingCall: Content[] = [
          { role: 'user', parts: [{ text: 'Please use a tool.' }] },
          {
            role: 'model',
            parts: [{ functionCall: { name: 'some_tool', args: {} } }],
          },
        ];
        vi.mocked(mockChat.getHistory!).mockReturnValue(historyWithPendingCall);

        // Arrange: IDE context changes, but this should be skipped
        const contextB = {
          workspaceState: {
            openFiles: [
              {
                path: '/path/to/fileB.ts',
                isActive: true,
                timestamp: Date.now(),
              },
            ],
          },
        };
        vi.mocked(ideContextStore.get).mockReturnValue(contextB);

        // Act: Send the tool response
        stream = client.sendMessageStream(
          [
            {
              functionResponse: {
                name: 'some_tool',
                response: { success: true },
              },
            },
          ],
          new AbortController().signal,
          'prompt-id-tool-response',
        );
        for await (const _ of stream) {
          /* consume */
        }

        // Assert: No context was sent
        expect(mockChat.addHistory).not.toHaveBeenCalled();

        // --- Step 2: A new message is sent, latest context DELTA should be included ---
        const historyAfterToolResponse: Content[] = [
          ...historyWithPendingCall,
          {
            role: 'user',
            parts: [
              {
                functionResponse: {
                  name: 'some_tool',
                  response: { success: true },
                },
              },
            ],
          },
          { role: 'model', parts: [{ text: 'The tool ran successfully.' }] },
        ];
        vi.mocked(mockChat.getHistory!).mockReturnValue(
          historyAfterToolResponse,
        );

        // Arrange: The IDE context has changed again
        const contextC = {
          workspaceState: {
            openFiles: [
              // fileA is now closed, fileC is open
              {
                path: '/path/to/fileC.ts',
                isActive: true,
                timestamp: Date.now(),
              },
            ],
          },
        };
        vi.mocked(ideContextStore.get).mockReturnValue(contextC);

        // Act: Send a new, regular user message
        stream = client.sendMessageStream(
          [{ text: 'Thanks!' }],
          new AbortController().signal,
          'prompt-id-final',
        );
        for await (const _ of stream) {
          /* consume */
        }

        // Assert: The DELTA context was sent
        const finalCall = vi.mocked(mockChat.addHistory!).mock.calls[0][0];
        expect(JSON.stringify(finalCall)).toContain('summary of changes');
        // The delta should reflect fileA being closed and fileC being opened.
        expect(JSON.stringify(finalCall)).toContain('filesClosed');
        expect(JSON.stringify(finalCall)).toContain('fileA.ts');
        expect(JSON.stringify(finalCall)).toContain('activeFileChanged');
        expect(JSON.stringify(finalCall)).toContain('fileC.ts');
      });
    });

    it('should not call checkNextSpeaker when turn.run() yields an error', async () => {
      // Arrange
      const { checkNextSpeaker } = await import(
        '../utils/nextSpeakerChecker.js'
      );
      const mockCheckNextSpeaker = vi.mocked(checkNextSpeaker);

      const mockStream = (async function* () {
        yield {
          type: GeminiEventType.Error,
          value: { error: { message: 'test error' } },
        };
      })();
      mockTurnRunFn.mockReturnValue(mockStream);

      const mockChat: Partial<GeminiChat> = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      };
      client['chat'] = mockChat as GeminiChat;

      // Act
      const stream = client.sendMessageStream(
        [{ text: 'Hi' }],
        new AbortController().signal,
        'prompt-id-error',
      );
      for await (const _ of stream) {
        // consume stream
      }

      // Assert
      expect(mockCheckNextSpeaker).not.toHaveBeenCalled();
    });

    it('should not call checkNextSpeaker when turn.run() yields a value then an error', async () => {
      // Arrange
      const { checkNextSpeaker } = await import(
        '../utils/nextSpeakerChecker.js'
      );
      const mockCheckNextSpeaker = vi.mocked(checkNextSpeaker);

      const mockStream = (async function* () {
        yield { type: GeminiEventType.Content, value: 'some content' };
        yield {
          type: GeminiEventType.Error,
          value: { error: { message: 'test error' } },
        };
      })();
      mockTurnRunFn.mockReturnValue(mockStream);

      const mockChat: Partial<GeminiChat> = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      };
      client['chat'] = mockChat as GeminiChat;

      // Act
      const stream = client.sendMessageStream(
        [{ text: 'Hi' }],
        new AbortController().signal,
        'prompt-id-error',
      );
      for await (const _ of stream) {
        // consume stream
      }

      // Assert
      expect(mockCheckNextSpeaker).not.toHaveBeenCalled();
    });

    it('does not run loop checks when skipLoopDetection is true', async () => {
      // Arrange
      // Ensure config returns true for skipLoopDetection
      vi.spyOn(client['config'], 'getSkipLoopDetection').mockReturnValue(true);

      // Replace loop detector with spies
      const ldMock = {
        turnStarted: vi.fn().mockResolvedValue(false),
        addAndCheck: vi.fn().mockReturnValue(false),
        reset: vi.fn(),
      };
      // @ts-expect-error override private for testing
      client['loopDetector'] = ldMock;

      const mockStream = (async function* () {
        yield { type: 'content', value: 'Hello' };
        yield { type: 'content', value: 'World' };
      })();
      mockTurnRunFn.mockReturnValue(mockStream);

      const mockChat: Partial<GeminiChat> = {
        addHistory: vi.fn(),
        getHistory: vi.fn().mockReturnValue([]),
      };
      client['chat'] = mockChat as GeminiChat;

      // Act
      const stream = client.sendMessageStream(
        [{ text: 'Hi' }],
        new AbortController().signal,
        'prompt-id-skip-loop',
      );
      for await (const _ of stream) {
        // consume stream
      }

      // Assert - loop detection methods should not be called when skipLoopDetection is true
      expect(ldMock.turnStarted).not.toHaveBeenCalled();
      expect(ldMock.addAndCheck).not.toHaveBeenCalled();
    });
  });

  describe('generateContent', () => {
    it('should call generateContent with the correct parameters', async () => {
      const contents = [{ role: 'user', parts: [{ text: 'hello' }] }];
      const generationConfig = { temperature: 0.5 };
      const abortSignal = new AbortController().signal;

      await client.generateContent(
        contents,
        generationConfig,
        abortSignal,
        DEFAULT_GEMINI_FLASH_MODEL,
      );

      expect(mockContentGenerator.generateContent).toHaveBeenCalledWith(
        {
          model: DEFAULT_GEMINI_FLASH_MODEL,
          config: {
            abortSignal,
            systemInstruction: getCoreSystemPrompt(''),
            temperature: 0.5,
            topP: 1,
          },
          contents,
        },
        'test-session-id',
      );
    });

    it('should use current model from config for content generation', async () => {
      const initialModel = client['config'].getModel();
      const contents = [{ role: 'user', parts: [{ text: 'test' }] }];
      const currentModel = initialModel + '-changed';

      vi.spyOn(client['config'], 'getModel').mockReturnValueOnce(currentModel);

      await client.generateContent(
        contents,
        {},
        new AbortController().signal,
        DEFAULT_GEMINI_FLASH_MODEL,
      );

      expect(mockContentGenerator.generateContent).not.toHaveBeenCalledWith({
        model: initialModel,
        config: expect.any(Object),
        contents,
      });
      expect(mockContentGenerator.generateContent).toHaveBeenCalledWith(
        {
          model: DEFAULT_GEMINI_FLASH_MODEL,
          config: expect.any(Object),
          contents,
        },
        'test-session-id',
      );
    });

    it('should use the Flash model when fallback mode is active', async () => {
      const contents = [{ role: 'user', parts: [{ text: 'hello' }] }];
      const generationConfig = { temperature: 0.5 };
      const abortSignal = new AbortController().signal;
      const requestedModel = 'gemini-2.5-pro'; // A non-flash model

      // Mock config to be in fallback mode
      vi.spyOn(client['config'], 'isInFallbackMode').mockReturnValue(true);

      await client.generateContent(
        contents,
        generationConfig,
        abortSignal,
        requestedModel,
      );

      expect(mockGenerateContentFn).toHaveBeenCalledWith(
        expect.objectContaining({
          model: DEFAULT_GEMINI_FLASH_MODEL,
        }),
        'test-session-id',
      );
    });
  });
});
