/**
 * Skill Discovery - Agent-driven skill search, recommendation, and management
 *
 * Enables ZCLAW agents to:
 * - Search available skills by keyword/capability
 * - Recommend skills based on recent conversation patterns
 * - Manage skill installation lifecycle (with user approval)
 *
 * Dynamically loads skills from the backend Kernel's SkillRegistry.
 *
 * Reference: ZCLAW_AGENT_INTELLIGENCE_EVOLUTION.md §6.5.2
 */

import { intelligenceClient } from './intelligence-client';
import { canAutoExecute } from './autonomy-manager';
import { createLogger } from './logger';

const log = createLogger('SkillDiscovery');

// === Types ===

export interface SkillInfo {
  id: string;
  name: string;
  description: string;
  triggers: string[];
  capabilities: string[];
  toolDeps: string[];
  installed: boolean;
  category?: string;
  path?: string;
  version?: string;
  mode?: string;
}

/** Backend skill response format */
interface BackendSkillInfo {
  id: string;
  name: string;
  description: string;
  version: string;
  capabilities: string[];
  tags: string[];
  mode: string;
  enabled: boolean;
}

export interface SkillSuggestion {
  skill: SkillInfo;
  reason: string;
  confidence: number;         // 0-1
  matchedPatterns: string[];
}

export interface SkillSearchResult {
  query: string;
  results: SkillInfo[];
  totalAvailable: number;
}

export interface ConversationContext {
  role: string;
  content: string;
}

// === Storage ===

const SKILL_INDEX_KEY = 'zclaw-skill-index';
const SKILL_SUGGESTIONS_KEY = 'zclaw-skill-suggestions';

// === Skill Discovery Engine ===

export class SkillDiscoveryEngine {
  private skills: SkillInfo[] = [];
  private suggestionHistory: SkillSuggestion[] = [];
  private loadedFromBackend: boolean = false;

  constructor() {
    this.loadIndex();
    this.loadSuggestions();
    // Try to load from backend, fallback to cache
    this.loadFromBackend();
  }

  /**
   * Load skills from backend Tauri command.
   * Falls back to cached skills if backend is unavailable.
   */
  private async loadFromBackend(): Promise<void> {
    try {
      // Dynamic import to avoid bundling issues in non-Tauri environments
      const { invoke } = await import('@tauri-apps/api/core');
      const backendSkills = await invoke<BackendSkillInfo[]>('skill_list');

      // Convert backend format to frontend format
      this.skills = backendSkills.map(this.convertFromBackend);
      this.loadedFromBackend = true;
      this.saveIndex();
      log.debug(`Loaded ${this.skills.length} skills from backend`);
    } catch (error) {
      log.warn('Failed to load skills from backend:', error);
      // Keep using cached skills (loaded in loadIndex)
      this.loadedFromBackend = false;
    }
  }

  /**
   * Convert backend skill format to frontend format.
   */
  private convertFromBackend(backend: BackendSkillInfo): SkillInfo {
    return {
      id: backend.id,
      name: backend.name,
      description: backend.description,
      version: backend.version,
      triggers: backend.tags, // Use tags as triggers
      capabilities: backend.capabilities,
      mode: backend.mode,
      toolDeps: [], // Backend doesn't have this field
      installed: backend.enabled,
      category: backend.tags[0] || 'general',
    };
  }

  /**
   * Refresh skills from backend.
   * Optionally specify a custom directory to scan.
   */
  async refresh(skillDir?: string): Promise<number> {
    try {
      const { invoke } = await import('@tauri-apps/api/core');
      const backendSkills = await invoke<BackendSkillInfo[]>('skill_refresh', {
        skillDir
      });

      this.skills = backendSkills.map(this.convertFromBackend);
      this.loadedFromBackend = true;
      this.saveIndex();
      log.debug(`Refreshed ${this.skills.length} skills`);
      return this.skills.length;
    } catch (error) {
      console.error('[SkillDiscovery] Failed to refresh skills:', error);
      throw error;
    }
  }

  /**
   * Check if skills were loaded from backend.
   */
  isLoadedFromBackend(): boolean {
    return this.loadedFromBackend;
  }

  // === Search ===

  /**
   * Search skills by keyword. Matches against name, description, triggers, capabilities.
   */
  searchSkills(query: string): SkillSearchResult {
    const q = query.toLowerCase().trim();
    if (!q) {
      return { query, results: [...this.skills], totalAvailable: this.skills.length };
    }

    const tokens = q.split(/[\s,;.!?。，；！？]+/).filter(t => t.length > 0);

    const scored = this.skills.map(skill => {
      let score = 0;

      // Name match (highest weight)
      if (skill.name.toLowerCase().includes(q)) score += 10;

      // Description match
      if (skill.description.toLowerCase().includes(q)) score += 5;

      // Trigger match (exact or partial)
      for (const trigger of skill.triggers) {
        const tLower = trigger.toLowerCase();
        if (tLower === q) { score += 15; break; }
        if (tLower.includes(q) || q.includes(tLower)) score += 8;
      }

      // Capability match
      for (const cap of skill.capabilities) {
        if (cap.toLowerCase().includes(q)) score += 4;
      }

      // Token-level matching
      for (const token of tokens) {
        if (skill.name.toLowerCase().includes(token)) score += 2;
        if (skill.description.toLowerCase().includes(token)) score += 1;
        for (const trigger of skill.triggers) {
          if (trigger.toLowerCase().includes(token)) score += 3;
        }
      }

      // Category match
      if (skill.category && skill.category.toLowerCase().includes(q)) score += 3;

      return { skill, score };
    });

    const results = scored
      .filter(s => s.score > 0)
      .sort((a, b) => b.score - a.score)
      .map(s => s.skill);

    return { query, results, totalAvailable: this.skills.length };
  }

  // === Recommendation ===

  /**
   * Suggest skills based on recent conversation content and memory patterns.
   */
  async suggestSkills(
    recentConversations: ConversationContext[],
    agentId: string,
    limit: number = 5
  ): Promise<SkillSuggestion[]> {
    const suggestions: SkillSuggestion[] = [];

    // 1. Extract key topics from conversations
    const topics = this.extractTopics(recentConversations);

    // 2. Match topics against skill triggers and capabilities
    for (const skill of this.skills) {
      const matchedPatterns: string[] = [];
      let confidence = 0;

      for (const topic of topics) {
        const topicLower = topic.toLowerCase();

        // Check triggers
        for (const trigger of skill.triggers) {
          if (trigger.toLowerCase().includes(topicLower) || topicLower.includes(trigger.toLowerCase())) {
            matchedPatterns.push(`话题"${topic}"匹配触发词"${trigger}"`);
            confidence += 0.3;
          }
        }

        // Check capabilities
        for (const cap of skill.capabilities) {
          if (cap.toLowerCase().includes(topicLower)) {
            matchedPatterns.push(`话题"${topic}"匹配能力"${cap}"`);
            confidence += 0.2;
          }
        }
      }

      // 3. Check memory patterns for recurring needs
      try {
        const memories = await intelligenceClient.memory.search({
          agentId,
          query: skill.name,
          limit: 5,
          minImportance: 3,
        });
        if (memories.length > 0) {
          matchedPatterns.push(`记忆中有${memories.length}条相关记录`);
          confidence += memories.length * 0.1;
        }
      } catch { /* non-critical */ }

      if (matchedPatterns.length > 0 && confidence > 0) {
        suggestions.push({
          skill,
          reason: matchedPatterns.slice(0, 3).join('；'),
          confidence: Math.min(confidence, 1),
          matchedPatterns,
        });
      }
    }

    // Sort by confidence
    const sorted = suggestions
      .sort((a, b) => b.confidence - a.confidence)
      .slice(0, limit);

    // Cache suggestions
    this.suggestionHistory = sorted;
    this.saveSuggestions();

    return sorted;
  }

  // === Skill Management ===

  /**
   * Get all available skills.
   */
  getAllSkills(): SkillInfo[] {
    return [...this.skills];
  }

  /**
   * Get skills by category.
   */
  getSkillsByCategory(category: string): SkillInfo[] {
    return this.skills.filter(s => s.category === category);
  }

  /**
   * Get unique categories.
   */
  getCategories(): string[] {
    return [...new Set(this.skills.map(s => s.category).filter(Boolean))] as string[];
  }

  /**
   * Register a new skill (e.g., from a SKILL.md file scan).
   */
  registerSkill(skill: SkillInfo): void {
    const existing = this.skills.findIndex(s => s.id === skill.id);
    if (existing >= 0) {
      this.skills[existing] = skill;
    } else {
      this.skills.push(skill);
    }
    this.saveIndex();
  }

  /**
   * Mark a skill as installed/uninstalled.
   * Includes autonomy check for skill_install/skill_uninstall actions.
   */
  setSkillInstalled(
    skillId: string,
    installed: boolean,
    options?: { skipAutonomyCheck?: boolean }
  ): { success: boolean; reason?: string } {
    const skill = this.skills.find(s => s.id === skillId);
    if (!skill) {
      return { success: false, reason: `Skill not found: ${skillId}` };
    }

    // Autonomy check - verify if skill installation is allowed
    if (!options?.skipAutonomyCheck) {
      const action = installed ? 'skill_install' : 'skill_uninstall';
      const { canProceed, decision } = canAutoExecute(action, 6);
      log.debug(`Autonomy check for ${action}: ${decision.reason}`);

      if (!canProceed) {
        return { success: false, reason: decision.reason };
      }
    }

    skill.installed = installed;
    this.saveIndex();
    log.debug(`Skill ${skillId} ${installed ? 'installed' : 'uninstalled'}`);
    return { success: true };
  }

  /**
   * Get last cached suggestions.
   */
  getLastSuggestions(): SkillSuggestion[] {
    return [...this.suggestionHistory];
  }

  // === Topic Extraction ===

  private extractTopics(conversations: ConversationContext[]): string[] {
    const topics = new Set<string>();

    const patterns = [
      // Chinese task patterns
      /帮我(.{2,15})/g,
      /我想(.{2,15})/g,
      /如何(.{2,15})/g,
      /怎么(.{2,15})/g,
      /需要(.{2,15})/g,
      /分析(.{2,15})/g,
      /写一个(.{2,15})/g,
      /做一个(.{2,15})/g,
      // English task patterns
      /(?:help me |I need to |how to |please )(.{3,30})/gi,
      // Technical terms
      /(?:React|Vue|Python|Docker|K8s|API|SQL|CSS|TypeScript|Node|Git)/gi,
      // Domain keywords
      /(?:部署|测试|审查|优化|设计|开发|分析|报告|运营|安全)/g,
    ];

    for (const msg of conversations.filter(m => m.role === 'user')) {
      for (const pattern of patterns) {
        const matches = msg.content.matchAll(pattern);
        for (const match of matches) {
          const topic = (match[1] || match[0]).trim();
          if (topic.length >= 2 && topic.length <= 30) {
            topics.add(topic);
          }
        }
      }
    }

    return [...topics].slice(0, 20);
  }

  // === Persistence ===

  private loadIndex(): void {
    try {
      const raw = localStorage.getItem(SKILL_INDEX_KEY);
      if (raw) this.skills = JSON.parse(raw);
    } catch {
      this.skills = [];
    }
  }

  private saveIndex(): void {
    try {
      localStorage.setItem(SKILL_INDEX_KEY, JSON.stringify(this.skills));
    } catch { /* silent */ }
  }

  private loadSuggestions(): void {
    try {
      const raw = localStorage.getItem(SKILL_SUGGESTIONS_KEY);
      if (raw) this.suggestionHistory = JSON.parse(raw);
    } catch {
      this.suggestionHistory = [];
    }
  }

  private saveSuggestions(): void {
    try {
      localStorage.setItem(SKILL_SUGGESTIONS_KEY, JSON.stringify(this.suggestionHistory));
    } catch { /* silent */ }
  }
}

// === Singleton ===

let _instance: SkillDiscoveryEngine | null = null;

export function getSkillDiscovery(): SkillDiscoveryEngine {
  if (!_instance) {
    _instance = new SkillDiscoveryEngine();
  }
  return _instance;
}

export function resetSkillDiscovery(): void {
  _instance = null;
}