const pool = require('../config/db');

const StoryModel = {
  // 获取故事列表
  async getList(options = {}) {
    const { category, featured, limit = 20, offset = 0 } = options;
    let sql = `SELECT id, title, cover_url, description, category, play_count, like_count, is_featured 
               FROM stories WHERE status = 1`;
    const params = [];
    
    if (category) {
      sql += ' AND category = ?';
      params.push(category);
    }
    if (featured) {
      sql += ' AND is_featured = 1';
    }
    
    sql += ' ORDER BY is_featured DESC, play_count DESC LIMIT ? OFFSET ?';
    params.push(limit, offset);
    
    const [rows] = await pool.query(sql, params);
    return rows;
  },

  // 获取故事详情（含节点和选项）
  async getDetail(storyId) {
    // 获取故事基本信息
    const [stories] = await pool.query(
      'SELECT * FROM stories WHERE id = ? AND status = 1',
      [storyId]
    );
    if (stories.length === 0) return null;
    
    const story = stories[0];
    
    // 获取所有节点
    const [nodes] = await pool.query(
      `SELECT id, node_key, content, speaker, background_image, character_image, bgm,
              is_ending, ending_name, ending_score, ending_type
       FROM story_nodes WHERE story_id = ? ORDER BY sort_order`,
      [storyId]
    );
    
    // 获取所有选项
    const [choices] = await pool.query(
      'SELECT id, node_id, text, next_node_key, is_locked FROM story_choices WHERE story_id = ? ORDER BY sort_order',
      [storyId]
    );
    
    // 组装节点和选项
    const nodesMap = {};
    nodes.forEach(node => {
      nodesMap[node.node_key] = {
        ...node,
        choices: []
      };
    });
    
    choices.forEach(choice => {
      const node = nodes.find(n => n.id === choice.node_id);
      if (node && nodesMap[node.node_key]) {
        nodesMap[node.node_key].choices.push({
          text: choice.text,
          nextNodeKey: choice.next_node_key,
          isLocked: choice.is_locked
        });
      }
    });
    
    story.nodes = nodesMap;
    return story;
  },

  // 增加游玩次数
  async incrementPlayCount(storyId) {
    await pool.query(
      'UPDATE stories SET play_count = play_count + 1 WHERE id = ?',
      [storyId]
    );
  },

  // 点赞/取消点赞
  async toggleLike(storyId, increment) {
    const delta = increment ? 1 : -1;
    await pool.query(
      'UPDATE stories SET like_count = like_count + ? WHERE id = ?',
      [delta, storyId]
    );
  },

  // 获取热门故事
  async getHotStories(limit = 10) {
    const [rows] = await pool.query(
      `SELECT id, title, cover_url, description, category, play_count, like_count 
       FROM stories WHERE status = 1 ORDER BY play_count DESC LIMIT ?`,
      [limit]
    );
    return rows;
  },

  // 获取分类列表
  async getCategories() {
    const [rows] = await pool.query(
      'SELECT DISTINCT category FROM stories WHERE status = 1'
    );
    return rows.map(r => r.category);
  },

  // AI改写结局
  async aiRewriteEnding({ storyId, endingName, endingContent, prompt }) {
    // 获取故事信息用于上下文
    const [stories] = await pool.query(
      'SELECT title, category, description FROM stories WHERE id = ?',
      [storyId]
    );
    const story = stories[0];

    // TODO: 接入真实AI服务（OpenAI/Claude/自建模型）
    // 这里先返回模拟结果，后续替换为真实AI调用
    const aiContent = await this.callAIService({
      storyTitle: story?.title,
      storyCategory: story?.category,
      originalEnding: endingContent,
      userPrompt: prompt
    });

    return {
      content: aiContent,
      speaker: '旁白',
      is_ending: true,
      ending_name: `${endingName}（改写版）`,
      ending_type: 'rewrite'
    };
  },

  // AI服务调用（模拟/真实）
  async callAIService({ storyTitle, storyCategory, originalEnding, userPrompt }) {
    // 模拟AI生成内容
    // 实际部署时替换为真实API调用
    const templates = [
      `根据你的愿望「${userPrompt}」，故事有了新的发展...\n\n`,
      `命运的齿轮开始转动，${userPrompt}...\n\n`,
      `在另一个平行世界里，${userPrompt}成为了现实...\n\n`
    ];
    
    const template = templates[Math.floor(Math.random() * templates.length)];
    const newContent = template + 
      `原本的结局被改写，新的故事在这里展开。\n\n` +
      `【AI改写提示】这是基于「${userPrompt}」生成的新结局。\n` +
      `实际部署时，这里将由AI大模型根据上下文生成更精彩的内容。`;
    
    return newContent;
  }
};

module.exports = StoryModel;