"""
Flask 数据服务 API
==================
提供 RESTful API 接口，支持获取各类资产的 K 线数据

支持的资产类型:
- A股指数 (000300.SH, 399006.SZ)
- A股ETF (510300.SH, 159915.SZ)
- A股股票 (600000.SH, 000001.SZ)
- 港股指数 (HSI, HSTECH.HK)
- 美股指数 (NDX, SPX, DJI)
- 美股股票 (AAPL, MSFT, GOOGL)
- 期货合约 (AU.SHF, CU.SHF)
- 加密货币 (BTC, ETH)

运行:
    python core/datasource/flask_server.py

API 文档:
    GET /health - 健康检查
    GET /api/v1/asset-type?code=000300.SH - 检测资产类型
    GET /api/v1/ohlcv?code=000300.SH&start=2024-01-01&end=2024-03-31 - 获取K线数据
    POST /api/v1/ohlcv/batch - 批量获取K线数据
"""

import os
import sys
import json
from pathlib import Path
from datetime import datetime, timedelta
from typing import Optional, Dict, Any, List
from functools import lru_cache

# 添加项目根目录到路径
project_root = Path(__file__).parent.parent.parent
sys.path.insert(0, str(project_root))

from dotenv import load_dotenv
load_dotenv()

from flask import Flask, request, jsonify
from flask_cors import CORS
import pandas as pd

from core.datasource.universal_fetcher import (
    UniversalDataFetcher,
    AssetTypeDetector,
)


# ============================================================
# Flask 应用配置
# ============================================================

app = Flask(__name__)
CORS(app)  # 启用跨域支持

# 全局数据获取器实例
fetcher: Optional[UniversalDataFetcher] = None
ssh_config: Optional[Dict] = None


def get_ssh_config() -> Optional[Dict]:
    """
    从环境变量获取 SSH 配置
    
    环境变量:
        SSH_ENABLED: 是否启用 SSH 隧道 (true/false)
        SSH_HOST: SSH 服务器地址
        SSH_PORT: SSH 端口 (默认 22)
        SSH_USERNAME: SSH 用户名
        SSH_KEY_PATH: SSH 私钥路径
        SSH_LOCAL_PORT: 本地 SOCKS5 端口 (默认 1080)
    """
    enabled = os.getenv('SSH_ENABLED', 'false').lower() == 'true'
    
    if not enabled:
        return None
    
    return {
        "enabled": True,
        "host": os.getenv('SSH_HOST', ''),
        "port": int(os.getenv('SSH_PORT', '22')),
        "username": os.getenv('SSH_USERNAME', ''),
        "key_path": os.getenv('SSH_KEY_PATH', 'hk_ecs.pem'),
        "local_port": int(os.getenv('SSH_LOCAL_PORT', '1080')),
    }


def get_fetcher() -> UniversalDataFetcher:
    """获取或创建数据获取器实例"""
    global fetcher, ssh_config
    
    if fetcher is None:
        ssh_config = get_ssh_config()
        fetcher = UniversalDataFetcher(ssh_config=ssh_config)
    
    return fetcher


# 缓存配置
CACHE_MAXSIZE = int(os.getenv('CACHE_MAXSIZE', '128'))  # 默认缓存128条数据
CACHE_TTL_SECONDS = int(os.getenv('CACHE_TTL_SECONDS', '7200'))  # 默认5分钟过期

# 带时间戳的缓存条目
class TimedCacheEntry:
    def __init__(self, data):
        self.data = data
        self.timestamp = datetime.now()
    
    def is_expired(self) -> bool:
        return (datetime.now() - self.timestamp).total_seconds() > CACHE_TTL_SECONDS


# 使用 lru_cache 包装数据获取函数
@lru_cache(maxsize=CACHE_MAXSIZE)
def _fetch_data_cached(code: str, start: str, end: str, retry: int) -> Optional[str]:
    """
    获取数据的缓存版本
    返回 JSON 序列化的字符串，因为 lru_cache 需要可哈希的参数
    """
    fetcher = get_fetcher()
    
    try:
        with fetcher:
            df = fetcher.fetch(code, start, end, retry=retry)
        
        if df is None or len(df) == 0:
            return None
        
        result = dataframe_to_json(df)
        result['code'] = code
        result['asset_type'] = AssetTypeDetector.detect(code)
        
        return json.dumps(result)
    except Exception as e:
        return json.dumps({"error": str(e)})


def fetch_data_with_ttl(code: str, start: str, end: str, retry: int = 3, nocache: bool = False) -> Optional[Dict]:
    """
    获取数据，支持TTL缓存
    """
    if nocache:
        # 直接获取，不使用缓存
        result_json = _fetch_data_cached.__wrapped__(code, start, end, retry)
        return json.loads(result_json) if result_json else None
    
    # 使用缓存
    cache_key = (code, start, end, retry)
    
    # 检查内存中的TTL缓存
    if hasattr(fetch_data_with_ttl, '_ttl_cache'):
        if cache_key in fetch_data_with_ttl._ttl_cache:
            entry = fetch_data_with_ttl._ttl_cache[cache_key]
            if not entry.is_expired():
                return entry.data
            # 过期，删除
            del fetch_data_with_ttl._ttl_cache[cache_key]
    else:
        fetch_data_with_ttl._ttl_cache = {}
    
    # 从 lru_cache 获取
    result_json = _fetch_data_cached(code, start, end, retry)
    
    if result_json is None:
        return None
    
    result = json.loads(result_json)
    
    # 存入TTL缓存
    fetch_data_with_ttl._ttl_cache[cache_key] = TimedCacheEntry(result)
    
    return result


def clear_data_cache():
    """清理缓存"""
    _fetch_data_cached.cache_clear()
    if hasattr(fetch_data_with_ttl, '_ttl_cache'):
        fetch_data_with_ttl._ttl_cache.clear()


def get_cache_info() -> Dict:
    """获取缓存信息"""
    info = _fetch_data_cached.cache_info()
    ttl_size = len(fetch_data_with_ttl._ttl_cache) if hasattr(fetch_data_with_ttl, '_ttl_cache') else 0
    return {
        "lru_cache": {
            "hits": info.hits,
            "misses": info.misses,
            "maxsize": info.maxsize,
            "currsize": info.currsize,
        },
        "ttl_cache_size": ttl_size,
        "ttl_seconds": CACHE_TTL_SECONDS,
    }


def dataframe_to_json(df: pd.DataFrame) -> Dict:
    """将 DataFrame 转换为 JSON 可序列化的字典"""
    if df is None or len(df) == 0:
        return {"data": [], "count": 0}
    
    # 重置索引，将日期转为列
    df_reset = df.reset_index()
    
    # 处理日期列（支持多种可能的列名）
    date_columns = ['date', 'Date', 'index', 'trade_date', 'datetime']
    for col in date_columns:
        if col in df_reset.columns:
            try:
                df_reset[col] = pd.to_datetime(df_reset[col]).dt.strftime('%Y-%m-%d')
                # 统一重命名为 'date'
                if col != 'date':
                    df_reset = df_reset.rename(columns={col: 'date'})
                break
            except Exception:
                pass
    
    # 确保所有数据都是 JSON 可序列化的
    for col in df_reset.columns:
        if df_reset[col].dtype == 'object':
            # 转换可能的 Timestamp 对象
            try:
                df_reset[col] = df_reset[col].apply(
                    lambda x: x.strftime('%Y-%m-%d') if hasattr(x, 'strftime') else x
                )
            except Exception:
                pass
    
    # 转换为字典列表
    records = df_reset.to_dict(orient='records')
    
    return {
        "data": records,
        "count": len(records),
        "columns": list(df_reset.columns),
        "date_range": {
            "start": df.index.min().strftime('%Y-%m-%d') if hasattr(df.index.min(), 'strftime') else str(df.index.min()),
            "end": df.index.max().strftime('%Y-%m-%d') if hasattr(df.index.max(), 'strftime') else str(df.index.max()),
        } if len(df) > 0 else None
    }


def validate_date(date_str: str) -> bool:
    """验证日期格式"""
    try:
        datetime.strptime(date_str, '%Y-%m-%d')
        return True
    except ValueError:
        return False


def get_default_dates() -> tuple:
    """获取默认日期范围（最近3个月）"""
    end = datetime.now()
    start = end - timedelta(days=90)
    return start.strftime('%Y-%m-%d'), end.strftime('%Y-%m-%d')


# ============================================================
# API 路由
# ============================================================

@app.route('/')
def index():
    """首页 - API 信息"""
    cache_info = get_cache_info()
    return jsonify({
        "name": "Universal Data Fetcher API",
        "version": "1.1.0",
        "description": "统一数据获取服务，支持A股、港股、美股、期货、加密货币",
        "features": [
            "自动资产类型识别",
            "LRU+TTL 双缓存机制",
            "SSH隧道支持（港美股）",
            "批量数据获取"
        ],
        "endpoints": {
            "health": "/health",
            "asset_type": "/api/v1/asset-type?code={code}",
            "ohlcv": "/api/v1/ohlcv?code={code}&start={YYYY-MM-DD}&end={YYYY-MM-DD}",
            "ohlcv_nocache": "/api/v1/ohlcv?code={code}&start={YYYY-MM-DD}&end={YYYY-MM-DD}&nocache=true",
            "batch": "POST /api/v1/ohlcv/batch",
            "cache_clear": "POST /api/v1/cache/clear",
            "cache_stats": "/api/v1/cache/stats",
        },
        "supported_assets": [
            "A股指数 (000300.SH)",
            "A股ETF (510300.SH)",
            "A股股票 (600000.SH)",
            "港股指数 (HSI)",
            "美股指数 (NDX)",
            "美股股票 (AAPL)",
            "期货 (AU.SHF)",
            "加密货币 (BTC)",
        ],
        "cache_config": {
            "maxsize": CACHE_MAXSIZE,
            "ttl_seconds": CACHE_TTL_SECONDS,
            "stats": cache_info['lru_cache']
        },
        "ssh_status": "enabled" if ssh_config and ssh_config.get('enabled') else "disabled",
    })


@app.route('/health')
def health():
    """健康检查"""
    return jsonify({
        "status": "healthy",
        "timestamp": datetime.now().isoformat(),
        "ssh_configured": ssh_config is not None and ssh_config.get('enabled', False),
    })


@app.route('/api/v1/asset-type')
def detect_asset_type():
    """
    检测资产类型
    
    Query Parameters:
        code: 标的代码 (required)
        
    Returns:
        {
            "code": "000300.SH",
            "asset_type": "china_index",
            "description": "A股指数"
        }
    """
    code = request.args.get('code', '').strip()
    
    if not code:
        return jsonify({
            "error": "Missing required parameter: code",
            "example": "/api/v1/asset-type?code=000300.SH"
        }), 400
    
    asset_type = AssetTypeDetector.detect(code)
    
    # 资产类型描述映射
    descriptions = {
        'china_index': 'A股指数',
        'china_etf': 'A股ETF',
        'china_stock': 'A股股票',
        'hk_index': '港股指数',
        'hk_stock': '港股股票',
        'us_index': '美股指数',
        'us_stock': '美股股票',
        'futures': '期货合约',
        'crypto': '加密货币',
    }
    
    return jsonify({
        "code": code,
        "asset_type": asset_type,
        "description": descriptions.get(asset_type, '未知类型'),
    })


@app.route('/api/v1/ohlcv')
def get_ohlcv():
    """
    获取单只标的的 OHLCV 数据（支持LRU+TTL缓存）
    
    Query Parameters:
        code: 标的代码 (required)
        start: 开始日期，格式 YYYY-MM-DD (optional, 默认90天前)
        end: 结束日期，格式 YYYY-MM-DD (optional, 默认今天)
        retry: 重试次数 (optional, 默认3)
        nocache: 是否跳过缓存 (optional, 默认false)
        
    Returns:
        {
            "code": "000300.SH",
            "asset_type": "china_index",
            "data": [...],
            "count": 58,
            "date_range": {"start": "2024-01-02", "end": "2024-03-29"},
            "cached": false
        }
    """
    code = request.args.get('code', '').strip()
    start = request.args.get('start', '').strip()
    end = request.args.get('end', '').strip()
    retry = request.args.get('retry', '3')
    nocache = request.args.get('nocache', 'false').lower() == 'true'
    
    # 参数验证
    if not code:
        return jsonify({
            "error": "Missing required parameter: code",
            "example": "/api/v1/ohlcv?code=000300.SH&start=2024-01-01&end=2024-03-31"
        }), 400
    
    # 设置默认日期
    if not start or not end:
        default_start, default_end = get_default_dates()
        start = start or default_start
        end = end or default_end
    
    # 日期格式验证
    if not validate_date(start) or not validate_date(end):
        return jsonify({
            "error": "Invalid date format. Use YYYY-MM-DD",
            "start": start,
            "end": end,
        }), 400
    
    try:
        retry_count = int(retry)
    except ValueError:
        retry_count = 3
    
    # 使用缓存获取数据
    result = fetch_data_with_ttl(code, start, end, retry_count, nocache)
    
    if result is None:
        return jsonify({
            "code": code,
            "asset_type": AssetTypeDetector.detect(code),
            "error": "No data available for the specified code and date range",
            "start": start,
            "end": end,
        }), 404
    
    if "error" in result:
        return jsonify({
            "code": code,
            "asset_type": AssetTypeDetector.detect(code),
            "error": result["error"],
            "start": start,
            "end": end,
        }), 500
    
    # 添加缓存状态
    result['cached'] = not nocache and _fetch_data_cached.cache_info().hits > 0
    
    return jsonify(result)


@app.route('/api/v1/ohlcv/batch', methods=['POST'])
def batch_ohlcv():
    """
    批量获取多只标的的 OHLCV 数据
    
    Request Body:
        {
            "codes": ["000300.SH", "NDX", "HSI"],
            "start": "2024-01-01",
            "end": "2024-03-31",
            "retry": 3
        }
        
    Returns:
        {
            "results": {
                "000300.SH": {"data": [...], "count": 58, ...},
                "NDX": {"data": [...], "count": 61, ...},
                "HSI": {"error": "No data available", ...}
            },
            "success_count": 2,
            "failed_count": 1,
            "total": 3
        }
    """
    data = request.get_json()
    
    if not data:
        return jsonify({
            "error": "Missing request body",
            "example": {
                "codes": ["000300.SH", "NDX"],
                "start": "2024-01-01",
                "end": "2024-03-31",
            }
        }), 400
    
    codes = data.get('codes', [])
    start = data.get('start', '').strip()
    end = data.get('end', '').strip()
    retry = data.get('retry', 3)
    
    if not codes or not isinstance(codes, list):
        return jsonify({
            "error": "Missing or invalid parameter: codes (must be a list)"
        }), 400
    
    # 设置默认日期
    if not start or not end:
        default_start, default_end = get_default_dates()
        start = start or default_start
        end = end or default_end
    
    # 日期格式验证
    if not validate_date(start) or not validate_date(end):
        return jsonify({
            "error": "Invalid date format. Use YYYY-MM-DD",
            "start": start,
            "end": end,
        }), 400
    
    # 获取数据
    fetcher = get_fetcher()
    results = {}
    success_count = 0
    failed_count = 0
    
    try:
        with fetcher:
            for code in codes:
                try:
                    # 使用缓存获取数据
                    result = fetch_data_with_ttl(code, start, end, retry, nocache=False)
                    
                    if result is not None and "error" not in result:
                        results[code] = result
                        success_count += 1
                    else:
                        results[code] = {
                            "code": code,
                            "asset_type": AssetTypeDetector.detect(code),
                            "error": result.get("error", "No data available") if result else "No data available",
                            "data": [],
                            "count": 0,
                        }
                        failed_count += 1
                        
                except Exception as e:
                    results[code] = {
                        "code": code,
                        "asset_type": AssetTypeDetector.detect(code),
                        "error": str(e),
                        "data": [],
                        "count": 0,
                    }
                    failed_count += 1
    
    except Exception as e:
        return jsonify({
            "error": f"Batch fetch failed: {str(e)}"
        }), 500
    
    return jsonify({
        "results": results,
        "success_count": success_count,
        "failed_count": failed_count,
        "total": len(codes),
        "start": start,
        "end": end,
    })


@app.route('/api/v1/supported-codes')
def get_supported_codes():
    """
    获取支持的代码示例
    
    Returns:
        {
            "china_index": ["000300.SH", "399006.SZ", ...],
            "china_etf": ["510300.SH", "159915.SZ", ...],
            ...
        }
    """
    return jsonify({
        "china_index": {
            "description": "A股指数",
            "examples": ["000300.SH", "399006.SZ", "000016.SH", "H30269.CSI"],
        },
        "china_etf": {
            "description": "A股ETF",
            "examples": ["510300.SH", "159915.SZ", "510500.SH", "513100.SH"],
        },
        "china_stock": {
            "description": "A股股票",
            "examples": ["600000.SH", "000001.SZ"],
        },
        "hk_index": {
            "description": "港股指数",
            "examples": ["HSI", "HSTECH.HK"],
        },
        "us_index": {
            "description": "美股指数",
            "examples": ["NDX", "SPX", "DJI", "N225", "GDAXI"],
        },
        "us_stock": {
            "description": "美股股票",
            "examples": ["AAPL", "MSFT", "GOOGL", "AMZN", "TSLA"],
        },
        "futures": {
            "description": "期货合约",
            "examples": ["AU.SHF", "CU.SHF"],
        },
        "crypto": {
            "description": "加密货币",
            "examples": ["BTC", "ETH"],
        },
    })


@app.route('/api/v1/cache/clear', methods=['POST'])
def clear_cache_endpoint():
    """清理缓存"""
    info_before = get_cache_info()
    clear_data_cache()
    return jsonify({
        "message": "Cache cleared successfully",
        "before": info_before,
        "after": get_cache_info()
    })


@app.route('/api/v1/cache/stats')
def cache_stats():
    """获取缓存统计信息"""
    return jsonify(get_cache_info())


# ============================================================
# 错误处理
# ============================================================

@app.errorhandler(404)
def not_found(error):
    return jsonify({
        "error": "Endpoint not found",
        "available_endpoints": [
            "/",
            "/health",
            "/api/v1/asset-type?code={code}",
            "/api/v1/ohlcv?code={code}&start={YYYY-MM-DD}&end={YYYY-MM-DD}",
            "/api/v1/ohlcv/batch",
            "/api/v1/cache/clear",
            "/api/v1/cache/stats",
            "/api/v1/supported-codes",
        ]
    }), 404


@app.errorhandler(500)
def internal_error(error):
    return jsonify({
        "error": "Internal server error",
        "message": str(error)
    }), 500


# ============================================================
# 启动服务
# ============================================================

if __name__ == '__main__':
    import argparse
    
    parser = argparse.ArgumentParser(description='Universal Data Fetcher API Server')
    parser.add_argument('--host', default='0.0.0.0', help='Host to bind (default: 0.0.0.0)')
    parser.add_argument('--port', type=int, default=5000, help='Port to bind (default: 5000)')
    parser.add_argument('--debug', action='store_true', help='Enable debug mode')
    
    args = parser.parse_args()
    
    # 预加载 SSH 配置
    ssh_config = get_ssh_config()
    if ssh_config and ssh_config.get('enabled'):
        print(f"✓ SSH 隧道已配置: {ssh_config['host']}:{ssh_config['port']}")
    else:
        print("✗ SSH 隧道未启用（仅支持A股数据）")
    
    print(f"\n🚀 启动 Universal Data Fetcher API Server")
    print(f"   Host: {args.host}")
    print(f"   Port: {args.port}")
    print(f"   Debug: {args.debug}")
    print(f"   Cache: maxsize={CACHE_MAXSIZE}, ttl={CACHE_TTL_SECONDS}s")
    print(f"\n📖 API 文档: http://{args.host}:{args.port}/")
    print(f"   健康检查: http://{args.host}:{args.port}/health")
    print(f"   缓存统计: http://{args.host}:{args.port}/api/v1/cache/stats")
    print(f"\n💡 示例请求:")
    print(f"   curl 'http://{args.host}:{args.port}/api/v1/ohlcv?code=000300.SH&start=2024-01-01&end=2024-03-31'")
    print(f"\n")
    
    app.run(host=args.host, port=args.port, debug=args.debug)