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

import { useCallback, useRef } from 'react';
import { Box, Text } from 'ink';
import Spinner from 'ink-spinner';
import { WizardStepProps, WizardAction } from '../types.js';
import { sanitizeInput } from '../utils.js';
import { Config, subagentGenerator } from '@qwen-code/qwen-code-core';
import { useKeypress, Key } from '../../../hooks/useKeypress.js';
import { keyMatchers, Command } from '../../../keyMatchers.js';
import { theme } from '../../../semantic-colors.js';
import { Colors } from '../../../colors.js';
import { TextInput } from '../../shared/TextInput.js';

/**
 * Step 3: Description input with LLM generation.
 */
export function DescriptionInput({
  state,
  dispatch,
  onNext,
  config,
}: WizardStepProps) {
  const abortControllerRef = useRef<AbortController | null>(null);

  const handleTextChange = useCallback(
    (text: string) => {
      const sanitized = sanitizeInput(text);
      dispatch({
        type: 'SET_USER_DESCRIPTION',
        description: sanitized,
      });
    },
    [dispatch],
  );

  // TextInput will manage its own buffer; we just pass value and handlers

  const handleGenerate = useCallback(
    async (
      userDescription: string,
      dispatch: (action: WizardAction) => void,
      config: Config,
    ): Promise<void> => {
      const abortController = new AbortController();
      abortControllerRef.current = abortController;

      try {
        const generated = await subagentGenerator(
          userDescription,
          config.getGeminiClient(),
          abortController.signal,
        );

        // Only dispatch if not aborted
        if (!abortController.signal.aborted) {
          dispatch({
            type: 'SET_GENERATED_CONTENT',
            name: generated.name,
            description: generated.description,
            systemPrompt: generated.systemPrompt,
          });
          onNext();
        }
      } finally {
        abortControllerRef.current = null;
      }
    },
    [onNext],
  );

  const handleSubmit = useCallback(async () => {
    if (!state.canProceed || state.isGenerating) {
      return;
    }

    const inputValue = state.userDescription.trim();
    if (!inputValue) {
      return;
    }

    // Start LLM generation
    dispatch({ type: 'SET_GENERATING', isGenerating: true });

    try {
      if (!config) {
        throw new Error('Configuration not available');
      }

      // Use real LLM integration
      await handleGenerate(inputValue, dispatch, config);
    } catch (error) {
      dispatch({ type: 'SET_GENERATING', isGenerating: false });

      // Don't show error if it was cancelled by user
      if (error instanceof Error && error.name === 'AbortError') {
        return;
      }

      dispatch({
        type: 'SET_VALIDATION_ERRORS',
        errors: [
          `Failed to generate subagent: ${error instanceof Error ? error.message : 'Unknown error'}`,
        ],
      });
    }
  }, [
    state.canProceed,
    state.isGenerating,
    state.userDescription,
    dispatch,
    config,
    handleGenerate,
  ]);

  // Handle keyboard input during generation
  const handleGenerationKeypress = useCallback(
    (key: Key) => {
      if (keyMatchers[Command.ESCAPE](key)) {
        if (abortControllerRef.current) {
          // Cancel the ongoing generation
          abortControllerRef.current.abort();
          dispatch({ type: 'SET_GENERATING', isGenerating: false });
        }
      }
    },
    [dispatch],
  );

  // Use separate keypress handlers for different states
  useKeypress(handleGenerationKeypress, {
    isActive: state.isGenerating,
  });

  const placeholder =
    'e.g., Expert code reviewer that reviews code based on best practices...';

  return (
    <Box flexDirection="column" gap={1}>
      <Box>
        <Text color={Colors.Gray}>
          Describe what this subagent should do and when it should be used. (Be
          comprehensive for best results)
        </Text>
      </Box>

      {state.isGenerating ? (
        <Box>
          <Box marginRight={1}>
            <Spinner />
          </Box>
          <Text color={theme.text.accent}>
            Generating subagent configuration...
          </Text>
        </Box>
      ) : (
        <TextInput
          value={state.userDescription || ''}
          onChange={handleTextChange}
          onSubmit={handleSubmit}
          placeholder={placeholder}
          height={10}
          isActive={!state.isGenerating}
          validationErrors={state.validationErrors}
        />
      )}
    </Box>
  );
}