import requests
import json
import time
from typing import List, Dict

API_KEY = "your_pangolinfo_api_key"
BASE_URL = "https://api.pangolinfo.com/v1/amazon/product"

def fetch_variation_prices(parent_asins: List[str], marketplace: str = "US") -> Dict:
    """
    批量采集亚马逊父 ASIN 下所有变体的价格数据。
    
    Args:
        parent_asins: 父 ASIN 列表，如 ["B08N5WRWNW", "B09G9FPHY6"]
        marketplace: 站点代码，支持 US / UK / DE / JP / CA 等
    
    Returns:
        以 ASIN 为 key 的变体价格字典
    """
    results = {}
    
    for asin in parent_asins:
        payload = {
            "asin": asin,
            "marketplace": marketplace,
            "include_variations": True,   # 请求返回完整变体列表
            "fields": ["price", "list_price", "price_prime", 
                       "availability", "variant_dimensions", "buybox_seller"]
        }
        
        headers = {
            "Authorization": f"Bearer {API_KEY}",
            "Content-Type": "application/json"
        }
        
        try:
            response = requests.post(BASE_URL, json=payload, headers=headers, timeout=30)
            response.raise_for_status()
            data = response.json()
            
            # 提取变体价格数据
            variations = data.get("data", {}).get("variations", [])
            results[asin] = {
                "parent_asin": asin,
                "total_variations": len(variations),
                "fetched_at": data.get("fetched_at"),
                "variants": [
                    {
                        "child_asin": v["asin"],
                        "dimensions": v.get("variant_dimensions", {}),
                        "price": v.get("price"),
                        "list_price": v.get("list_price"),
                        "prime_price": v.get("price_prime"),
                        "in_stock": v.get("availability") == "In Stock",
                        "buybox_seller": v.get("buybox_seller", {}).get("name")
                    }
                    for v in variations
                ]
            }
            
        except requests.RequestException as e:
            print(f"[ERROR] ASIN {asin} 采集失败: {e}")
            results[asin] = {"error": str(e)}
        
        # 控制请求速率，避免超出 API 限制
        time.sleep(0.5)
    
    return results


def find_price_outliers(variation_data: Dict, threshold_pct: float = 0.2) -> List[Dict]:
    """
    识别同一父 ASIN 下价格异常的变体（偏离均价超过 threshold_pct）。
    用于发现定价策略错误或竞争对手低价冲击。
    """
    outliers = []
    
    for parent_asin, data in variation_data.items():
        if "error" in data or not data.get("variants"):
            continue
        
        # 提取有效价格的变体
        priced_variants = [
            v for v in data["variants"] 
            if v.get("price") and v["in_stock"]
        ]
        
        if len(priced_variants) < 2:
            continue
        
        prices = [float(v["price"].replace("$", "").replace(",", "")) 
                  for v in priced_variants]
        avg_price = sum(prices) / len(prices)
        
        for variant, price in zip(priced_variants, prices):
            deviation = abs(price - avg_price) / avg_price
            if deviation > threshold_pct:
                outliers.append({
                    "parent_asin": parent_asin,
                    "child_asin": variant["child_asin"],
                    "dimensions": variant["dimensions"],
                    "price": price,
                    "avg_price": round(avg_price, 2),
                    "deviation_pct": round(deviation * 100, 1)
                })
    
    return sorted(outliers, key=lambda x: x["deviation_pct"], reverse=True)


# 使用示例
if __name__ == "__main__":
    # 监控清单：竞品父 ASIN 列表
    target_asins = [
        "B08N5WRWNW",  # 竞品 A
        "B09G9FPHY6",  # 竞品 B
        "B0BDJH3H79",  # 竞品 C
    ]
    
    print(f"开始采集 {len(target_asins)} 个父 ASIN 的变体价格数据...")
    variation_prices = fetch_variation_prices(target_asins, marketplace="US")
    
    # 输出结果摘要
    for asin, data in variation_prices.items():
        if "error" not in data:
            print(f"\n父 ASIN: {asin}")
            print(f"  变体总数: {data['total_variations']}")
            print(f"  采集时间: {data['fetched_at']}")
            for v in data["variants"][:3]:  # 展示前3个变体
                dims = " / ".join(f"{k}: {val}" for k, val in v["dimensions"].items())
                print(f"  [{dims}] 子ASIN: {v['child_asin']} → 售价: {v['price']}")
    
    # 检测价格异常变体
    outliers = find_price_outliers(variation_prices, threshold_pct=0.15)
    if outliers:
        print(f"\n⚠️ 发现 {len(outliers)} 个价格偏差超过 15% 的变体：")
        for item in outliers[:5]:
            dims = " / ".join(f"{k}: {v}" for k, v in item["dimensions"].items())
            print(f"  {item['parent_asin']} [{dims}] 售价 ${item['price']} vs 均价 ${item['avg_price']} (偏差 {item['deviation_pct']}%)")