/**
 * Vision产品特征提取器
 * 支持超时重试 + 缓存
 */

const axios = require('axios');
const fs = require('fs');
const path = require('path');

const API_KEY = 'G9rXx3Ag2Xfa7Gs8zou6t6HqeZ';
const API_BASE = 'https://api.wuyinkeji.com/api';

// Vision提取Prompt
const VISION_EXTRACT_PROMPT = `Analyze this pet product image in EXTREME detail.

Output ONLY a valid JSON object (no markdown, no explanation, no thinking):

{
  "color": {
    "primary": "<hex code like #C3E6E8>",
    "name": "<descriptive name like 'ice blue', 'mint green'>",
    "secondary": "<accent colors>"
  },
  "shape": {
    "type": "<flower/fan/cone/donut>",
    "petal_count": <number of segments>,
    "opening": "<C-shaped/full-circle/adjustable>",
    "description": "<detailed shape description>"
  },
  "material": {
    "type": "<PU/nylon/polyester/fabric>",
    "finish": "<glossy/matte/satin>",
    "texture": "<smooth/quilted/padded>"
  },
  "edge_binding": {
    "color": "<color of inner neck edge>",
    "material": "<ribbed elastic/fabric>"
  },
  "closure": {
    "type": "<velcro/button/snap>",
    "color": "<white/matching>",
    "position": "<location description>"
  },
  "logo": {
    "text": "<brand name>",
    "style": "<embroidered/printed/tag>",
    "position": "<location>"
  },
  "unique_features": ["<list distinctive features>"],
  "overall_description": "<2-3 sentence summary for image generation>"
}`;

/**
 * 调用Vision API提取产品特征
 * @param {string} imageUrl - 图片URL
 * @param {object} options - 配置选项
 * @returns {object|null} - 提取的产品特征JSON
 */
async function extractProductFeatures(imageUrl, options = {}) {
  const {
    maxRetries = 3,
    timeout = 120000,  // 120秒
    retryDelay = 5000,
    cacheDir = null,
    cacheKey = null
  } = options;

  // 检查缓存
  if (cacheDir && cacheKey) {
    const cachePath = path.join(cacheDir, `vision-cache-${cacheKey}.json`);
    if (fs.existsSync(cachePath)) {
      try {
        const cached = JSON.parse(fs.readFileSync(cachePath, 'utf-8'));
        if (cached && cached.color) {
          console.log('   📦 使用缓存的Vision结果');
          return cached;
        }
      } catch (e) {
        // 缓存无效，继续请求
      }
    }
  }

  let lastError = null;
  
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    console.log(`   🔍 Vision分析 (尝试 ${attempt}/${maxRetries})...`);
    
    try {
      const response = await axios.post(`${API_BASE}/chat/index`, {
        key: API_KEY,
        model: 'gemini-3-pro',
        content: VISION_EXTRACT_PROMPT,
        image_url: imageUrl
      }, { timeout });

      const content = response.data.data?.choices?.[0]?.message?.content || 
                      response.data.data?.content;
      
      if (!content) {
        throw new Error('Vision响应为空');
      }

      // 提取JSON（跳过thinking部分）
      let jsonStr = content;
      
      // 如果有<think>标签，跳过它
      const thinkEnd = content.indexOf('</think>');
      if (thinkEnd !== -1) {
        jsonStr = content.substring(thinkEnd + 8);
      }
      
      // 提取JSON
      const jsonMatch = jsonStr.match(/\{[\s\S]*\}/);
      if (jsonMatch) {
        const parsed = JSON.parse(jsonMatch[0]);
        
        // 验证必要字段
        if (parsed.color && parsed.shape) {
          console.log('   ✓ Vision提取成功');
          
          // 保存缓存
          if (cacheDir && cacheKey) {
            const cachePath = path.join(cacheDir, `vision-cache-${cacheKey}.json`);
            fs.writeFileSync(cachePath, JSON.stringify(parsed, null, 2));
          }
          
          return parsed;
        }
      }
      
      throw new Error('无法解析有效的JSON');
      
    } catch (error) {
      lastError = error;
      console.log(`   ⚠️ 尝试 ${attempt} 失败: ${error.message}`);
      
      if (attempt < maxRetries) {
        console.log(`   ⏳ ${retryDelay/1000}秒后重试...`);
        await new Promise(r => setTimeout(r, retryDelay));
      }
    }
  }
  
  console.error(`   ❌ Vision提取最终失败: ${lastError?.message}`);
  return null;
}

/**
 * 将Vision结果转换为Golden Description
 */
function buildGoldenDescription(visionResult, productType = 'pet recovery cone') {
  if (!visionResult) {
    return `
PRODUCT: ${productType}
- Shape: Soft flower/petal shape with C-shaped opening
- Material: Soft waterproof fabric
- Closure: Velcro strap
- Comfortable design for pets

CRITICAL: Follow the reference image EXACTLY for product shape and color.
`;
  }

  const r = visionResult;
  
  return `
EXACT PRODUCT APPEARANCE (MUST MATCH REFERENCE IMAGE):

- Shape: ${r.shape?.petal_count || '7-8'}-PETAL ${(r.shape?.type || 'flower').toUpperCase()} shape
- Opening: ${r.shape?.opening || 'C-shaped'} (NOT a full circle)
- Color: ${(r.color?.name || 'ice blue').toUpperCase()} (${r.color?.primary || '#C3E6E8'})
- Material: ${r.material?.finish || 'Soft'} ${r.material?.type || 'waterproof fabric'} with ${r.material?.texture || 'padded'} texture
- Edge binding: ${r.edge_binding?.color || 'Matching color'} ${r.edge_binding?.material || 'ribbed elastic'} around inner neck hole
- Closure: ${r.closure?.color || 'White'} ${r.closure?.type || 'velcro'} on ${r.closure?.position || 'one segment'}
- Logo: "${r.logo?.text || 'TOUCHDOG'}" ${r.logo?.style || 'embroidered'} on ${r.logo?.position || 'one petal'}

UNIQUE FEATURES:
${(r.unique_features || ['Scalloped petal edges', 'Radial stitching', 'Soft padded construction']).map(f => `- ${f}`).join('\n')}

OVERALL: ${r.overall_description || 'A soft, comfortable pet recovery cone with flower-petal design.'}

CRITICAL PROHIBITIONS:
- ❌ NO printed colorful patterns (solid color only unless reference shows otherwise)
- ❌ NO hard plastic transparent cones
- ❌ NO fully circular/closed shapes (must match reference C-opening)
- ❌ NO random brand logos
- ❌ MUST match reference image product EXACTLY
`.trim();
}

module.exports = {
  extractProductFeatures,
  buildGoldenDescription,
  VISION_EXTRACT_PROMPT
};