Session-Level Conversation History Management (#1113)

packages/cli/src/acp-integration/session/HistoryReplayer.ts

@@ -0,0 +1,137 @@
+/**
+ * @license
+ * Copyright 2025 Qwen
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import type { ChatRecord } from '@qwen-code/qwen-code-core';
+import type { Content } from '@google/genai';
+import type { SessionContext } from './types.js';
+import { MessageEmitter } from './emitters/MessageEmitter.js';
+import { ToolCallEmitter } from './emitters/ToolCallEmitter.js';
+
+/**
+ * Handles replaying session history on session load.
+ *
+ * Uses the unified emitters to ensure consistency with normal flow.
+ * This ensures that replayed history looks identical to how it would
+ * have appeared during the original session.
+ */
+export class HistoryReplayer {
+  private readonly messageEmitter: MessageEmitter;
+  private readonly toolCallEmitter: ToolCallEmitter;
+
+  constructor(ctx: SessionContext) {
+    this.messageEmitter = new MessageEmitter(ctx);
+    this.toolCallEmitter = new ToolCallEmitter(ctx);
+  }
+
+  /**
+   * Replays all chat records from a loaded session.
+   *
+   * @param records - Array of chat records to replay
+   */
+  async replay(records: ChatRecord[]): Promise<void> {
+    for (const record of records) {
+      await this.replayRecord(record);
+    }
+  }
+
+  /**
+   * Replays a single chat record.
+   */
+  private async replayRecord(record: ChatRecord): Promise<void> {
+    switch (record.type) {
+      case 'user':
+        if (record.message) {
+          await this.replayContent(record.message, 'user');
+        }
+        break;
+
+      case 'assistant':
+        if (record.message) {
+          await this.replayContent(record.message, 'assistant');
+        }
+        break;
+
+      case 'tool_result':
+        await this.replayToolResult(record);
+        break;
+
+      default:
+        // Skip system records (compression, telemetry, slash commands)
+        break;
+    }
+  }
+
+  /**
+   * Replays content from a message (user or assistant).
+   * Handles text parts, thought parts, and function calls.
+   */
+  private async replayContent(
+    content: Content,
+    role: 'user' | 'assistant',
+  ): Promise<void> {
+    for (const part of content.parts ?? []) {
+      // Text content
+      if ('text' in part && part.text) {
+        const isThought = (part as { thought?: boolean }).thought ?? false;
+        await this.messageEmitter.emitMessage(part.text, role, isThought);
+      }
+
+      // Function call (tool start)
+      if ('functionCall' in part && part.functionCall) {
+        const functionName = part.functionCall.name ?? '';
+        const callId = part.functionCall.id ?? `${functionName}-${Date.now()}`;
+
+        await this.toolCallEmitter.emitStart({
+          toolName: functionName,
+          callId,
+          args: part.functionCall.args as Record<string, unknown>,
+        });
+      }
+    }
+  }
+
+  /**
+   * Replays a tool result record.
+   */
+  private async replayToolResult(record: ChatRecord): Promise<void> {
+    // message is required - skip if not present
+    if (!record.message?.parts) {
+      return;
+    }
+
+    const result = record.toolCallResult;
+    const callId = result?.callId ?? record.uuid;
+
+    // Extract tool name from the function response in message if available
+    const toolName = this.extractToolNameFromRecord(record);
+
+    await this.toolCallEmitter.emitResult({
+      toolName,
+      callId,
+      success: !result?.error,
+      message: record.message.parts,
+      resultDisplay: result?.resultDisplay,
+      // For TodoWriteTool fallback, try to extract args from the record
+      // Note: args aren't stored in tool_result records by default
+      args: undefined,
+    });
+  }
+
+  /**
+   * Extracts tool name from a chat record's function response.
+   */
+  private extractToolNameFromRecord(record: ChatRecord): string {
+    // Try to get from functionResponse in message
+    if (record.message?.parts) {
+      for (const part of record.message.parts) {
+        if ('functionResponse' in part && part.functionResponse?.name) {
+          return part.functionResponse.name;
+        }
+      }
+    }
+    return '';
+  }
+}