/**
 * useIntentParser - Parse Claude messages for canvas updates
 *
 * Detects structured intents in chat messages and applies them to canvas
 */

import { useCallback } from 'react';
import { useCanvasStore, OptimizationConfig } from './useCanvasStore';
import { OptimizationIntent } from '../lib/canvas/intent';
import { Message } from '../components/chat/ChatMessage';

interface ParsedUpdate {
  type: 'intent' | 'config' | 'suggestion' | 'none';
  data?: OptimizationIntent | OptimizationConfig;
  suggestions?: string[];
}

export function useIntentParser() {
  const { loadFromIntent, loadFromConfig, updateNodeData, nodes } = useCanvasStore();

  /**
   * Parse a message for structured intent JSON
   */
  const parseIntent = useCallback((content: string): ParsedUpdate => {
    // Look for JSON blocks in the message
    const jsonBlockRegex = /```(?:json)?\s*\n?([\s\S]*?)\n?```/g;
    const matches = [...content.matchAll(jsonBlockRegex)];

    for (const match of matches) {
      try {
        const parsed = JSON.parse(match[1]);

        // Check if it's an OptimizationIntent
        if (parsed.version && parsed.source === 'canvas') {
          return { type: 'intent', data: parsed as OptimizationIntent };
        }

        // Check if it's an OptimizationConfig (has design_variables or objectives)
        if (parsed.design_variables || parsed.objectives || parsed.model?.path) {
          return { type: 'config', data: parsed as OptimizationConfig };
        }
      } catch {
        // Not valid JSON, continue
      }
    }

    // Look for inline JSON (without code blocks)
    const inlineJsonRegex = /\{[\s\S]*?"(?:version|design_variables|objectives)"[\s\S]*?\}/g;
    const inlineMatches = content.match(inlineJsonRegex);

    if (inlineMatches) {
      for (const jsonStr of inlineMatches) {
        try {
          const parsed = JSON.parse(jsonStr);
          if (parsed.version && parsed.source === 'canvas') {
            return { type: 'intent', data: parsed as OptimizationIntent };
          }
          if (parsed.design_variables || parsed.objectives) {
            return { type: 'config', data: parsed as OptimizationConfig };
          }
        } catch {
          // Not valid JSON
        }
      }
    }

    // Look for suggestions in the message
    const suggestions = extractSuggestions(content);
    if (suggestions.length > 0) {
      return { type: 'suggestion', suggestions };
    }

    return { type: 'none' };
  }, []);

  /**
   * Extract actionable suggestions from Claude's response
   */
  const extractSuggestions = (content: string): string[] => {
    const suggestions: string[] = [];

    // Common suggestion patterns
    const patterns = [
      /suggest(?:ing)?\s+(?:to\s+)?(?:add|include|use)\s+([^.!?\n]+)/gi,
      /recommend(?:ing)?\s+([^.!?\n]+)/gi,
      /consider\s+(?:adding|using|including)\s+([^.!?\n]+)/gi,
      /you\s+(?:should|could|might)\s+(?:add|include|use)\s+([^.!?\n]+)/gi,
    ];

    for (const pattern of patterns) {
      const matches = content.matchAll(pattern);
      for (const match of matches) {
        if (match[1]) {
          suggestions.push(match[1].trim());
        }
      }
    }

    return suggestions;
  };

  /**
   * Apply a parsed update to the canvas
   */
  const applyUpdate = useCallback((update: ParsedUpdate): boolean => {
    switch (update.type) {
      case 'intent':
        if (update.data && 'version' in update.data) {
          loadFromIntent(update.data as OptimizationIntent);
          return true;
        }
        break;
      case 'config':
        if (update.data && !('version' in update.data)) {
          loadFromConfig(update.data as OptimizationConfig);
          return true;
        }
        break;
      case 'suggestion':
        // Suggestions are returned but not auto-applied
        return false;
    }
    return false;
  }, [loadFromIntent, loadFromConfig]);

  /**
   * Process a message and optionally apply updates
   */
  const processMessage = useCallback((message: Message, autoApply = false): ParsedUpdate => {
    const update = parseIntent(message.content);

    if (autoApply && (update.type === 'intent' || update.type === 'config')) {
      applyUpdate(update);
    }

    return update;
  }, [parseIntent, applyUpdate]);

  /**
   * Check if a message contains canvas-related content
   */
  const hasCanvasContent = useCallback((content: string): boolean => {
    const keywords = [
      'design variable', 'objective', 'constraint', 'extractor',
      'optimization', 'algorithm', 'surrogate', 'model', 'solver',
      'canvas', 'workflow', 'node'
    ];
    const lowerContent = content.toLowerCase();
    return keywords.some(kw => lowerContent.includes(kw));
  }, []);

  /**
   * Apply parameter updates to specific nodes
   */
  const applyParameterUpdates = useCallback((updates: Record<string, Partial<unknown>>) => {
    for (const [nodeId, data] of Object.entries(updates)) {
      const node = nodes.find(n => n.id === nodeId);
      if (node) {
        updateNodeData(nodeId, data as Record<string, unknown>);
      }
    }
  }, [nodes, updateNodeData]);

  return {
    parseIntent,
    applyUpdate,
    processMessage,
    hasCanvasContent,
    applyParameterUpdates,
    extractSuggestions,
  };
}