"""
ApiClient - HTTP 通信层

职责:
- 封装所有 HTTP 通信逻辑
- 管理 httpx.AsyncClient，维护连接池和 session
- 生成请求签名（timestamp, nonce, sign）
- 统一请求入口，自动注入 uid
- 批量 Push Log 查询
"""

import hashlib
import hmac
import time
import uuid
import json as json_lib
import logging
import asyncio
from typing import Dict, List, Any, Optional
from collections import defaultdict, deque
from pathlib import Path
from datetime import datetime
import httpx

from schemas.common.push_system import PushIdsSchema
from ...logging import get_logger


def _build_default_push_steps() -> List[Dict[str, str]]:
    """构造最小审批步骤字段，满足第三方 v2 push schema。"""
    return []


class ApiClient:
    """API HTTP 客户端"""
    _TRACE_TEXT_MAX_LEN = 1000
    _REQUEST_STATS_LOG_PREFIX = "📊 ApiClient request stats"
    
    def __init__(
        self, 
        base_url: str, 
        uid: str, 
        secret: str,
        debug: bool = False,
        log_file: Optional[Path] = None,
        rate_limit_max_requests: int = 30,
        rate_limit_window_seconds: float = 10.0,
    ):
        """
        初始化 API 客户端
        
        Args:
            base_url: API 基础 URL（如 https://api.example.com）
            uid: 用户标识
            secret: 签名密钥
            debug: 是否启用调试模式（打印请求详情）
            log_file: 日志文件路径（可选）
            rate_limit_max_requests: 限流窗口内最大请求数（<=0 表示禁用）
            rate_limit_window_seconds: 限流窗口秒数（<=0 表示禁用）
        """
        self._base_url = base_url.rstrip('/')
        self._uid = uid
        self._secret = secret
        self._client: Optional[httpx.AsyncClient] = None
        self._debug = debug
        self._log_file = log_file
        self._trace_seq = 0
        self._trace_by_push_id: Dict[str, deque[Dict[str, Any]]] = defaultdict(deque)
        self._trace_by_biz_id: Dict[str, deque[Dict[str, Any]]] = defaultdict(deque)
        self._trace_by_op: Dict[str, deque[Dict[str, Any]]] = defaultdict(deque)
        self._load_trace_by_item: Dict[tuple[str, str], deque[Dict[str, Any]]] = defaultdict(deque)
        self._logger = get_logger(__name__)
        self._rate_limit_max_requests = int(rate_limit_max_requests)
        self._rate_limit_window_seconds = float(rate_limit_window_seconds)
        self._rate_limit_lock = asyncio.Lock()
        self._rate_limit_timestamps: deque[float] = deque()
        self._request_total = 0
        self._request_success = 0
        self._request_failure = 0

    def _is_rate_limit_enabled(self) -> bool:
        return self._rate_limit_max_requests > 0 and self._rate_limit_window_seconds > 0

    async def _acquire_rate_limit_slot(self) -> None:
        if not self._is_rate_limit_enabled():
            return

        while True:
            wait_seconds = 0.0
            async with self._rate_limit_lock:
                now = time.monotonic()
                window_start = now - self._rate_limit_window_seconds
                while self._rate_limit_timestamps and self._rate_limit_timestamps[0] <= window_start:
                    self._rate_limit_timestamps.popleft()

                if len(self._rate_limit_timestamps) < self._rate_limit_max_requests:
                    self._rate_limit_timestamps.append(now)
                    return

                oldest = self._rate_limit_timestamps[0]
                wait_seconds = max(0.001, self._rate_limit_window_seconds - (now - oldest))

            await asyncio.sleep(wait_seconds)
    
    async def initialize(self):
        """初始化 HTTP 客户端"""
        if self._client is None:
            # trust_env=False 阻止从环境变量读取代理设置（避免 localhost 走代理导致超时）
            self._client = httpx.AsyncClient(timeout=300.0, trust_env=False)
    
    async def close(self):
        """关闭 HTTP 客户端"""
        self.log_request_stats()
        if self._client:
            await self._client.aclose()
            self._client = None

    def get_request_stats(self) -> Dict[str, int]:
        """返回当前客户端生命周期内的请求统计。"""
        return {
            "total": self._request_total,
            "success": self._request_success,
            "failure": self._request_failure,
        }

    def format_request_stats(self) -> str:
        """格式化当前客户端生命周期内的请求统计。"""
        stats = self.get_request_stats()
        return (
            f"{self._REQUEST_STATS_LOG_PREFIX}: "
            f"total={stats['total']}, success={stats['success']}, failure={stats['failure']}"
        )

    def log_request_stats(self, level: str = "DEBUG") -> None:
        """输出当前客户端生命周期内的请求统计。"""
        self._log(self.format_request_stats(), level=level)

    def _log_request_summary(self, *, method: str, endpoint: str, elapsed_seconds: float) -> None:
        if not self._debug:
            return
        self._log(
            f"🔎 ApiClient request: method={method.upper()} endpoint={endpoint} elapsed={elapsed_seconds:.3f}s",
            level="DEBUG",
        )
    
    def _log(self, message: str, level: str = "DEBUG"):
        """
        统一日志输出
        
        Args:
            message: 日志消息
            level: 日志级别（INFO/ERROR）
        """
        timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
        log_line = f"[{timestamp}] [{level}] {message}"
        
        level_num = logging.getLevelNamesMapping().get(level.upper(), logging.DEBUG)
        self._logger.log(level_num, log_line)
        
        # 文件输出
        if self._log_file:
            self._log_file.parent.mkdir(parents=True, exist_ok=True)
            with open(self._log_file, 'a', encoding='utf-8') as f:
                f.write(log_line + '\n')
    
    def _get_client(self) -> httpx.AsyncClient:
        """获取 HTTP 客户端实例"""
        if self._client is None:
            raise RuntimeError("ApiClient not initialized. Call 'await client.initialize()' first.")
        return self._client

    def _derive_op_kind(self, method: str, endpoint: str) -> str:
        endpoint_norm = endpoint.lower().strip()
        if endpoint_norm == "/push/result":
            return "poll"
        method_upper = method.upper()
        if method_upper == "GET":
            if endpoint_norm.endswith("/list"):
                return "load"
            return "get"
        if endpoint_norm.endswith("/create"):
            return "create"
        if endpoint_norm.endswith("/delete"):
            return "delete"
        if endpoint_norm.endswith("/update") or endpoint_norm.endswith("/plan"):
            return "update"
        if method_upper == "POST":
            return "create"
        if method_upper == "PUT":
            return "update"
        if method_upper == "DELETE":
            return "delete"
        return method.lower()

    def _derive_node_type_from_list_endpoint(self, endpoint: str) -> Optional[str]:
        endpoint_norm = endpoint.strip("/")
        if not endpoint_norm.endswith("/list"):
            return None
        prefix = endpoint_norm[:-5]
        if not prefix:
            return None
        return prefix.replace("/", "_")

    def _record_trace(
        self,
        *,
        method: str,
        endpoint: str,
        url: str,
        request_params: Optional[Dict[str, Any]],
        request_payload: Optional[Dict[str, Any]],
        response: Optional[Dict[str, Any]],
        elapsed_ms: int,
    ) -> None:
        self._trace_seq += 1
        op_kind = self._derive_op_kind(method, endpoint)
        payload = request_payload or {}
        response_view = self._build_trace_response_view(op_kind=op_kind, response=response)
        params_text = self._to_trace_text(request_params or {}, max_len=self._TRACE_TEXT_MAX_LEN)
        payload_text = self._to_trace_text(payload, max_len=self._TRACE_TEXT_MAX_LEN)
        response_text = self._to_trace_text(response_view, max_len=self._TRACE_TEXT_MAX_LEN)

        trace = {
            "trace_id": self._trace_seq,
            "op": op_kind,
            "method": method.upper(),
            "endpoint": endpoint,
            "url": url,
            "params": request_params or {},
            "payload": payload,
            "response": response_view,
            "params_text": params_text,
            "payload_text": payload_text,
            "response_text": response_text,
            "elapsed_ms": elapsed_ms,
            "ts": datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
        }

        push_id = payload.get("push_id")
        biz_id = payload.get("biz_id")
        if isinstance(push_id, str) and push_id:
            self._trace_by_push_id[push_id].append(trace)
        if isinstance(biz_id, str) and biz_id:
            self._trace_by_biz_id[biz_id].append(trace)
        self._trace_by_op[op_kind].append(trace)

        if op_kind == "load":
            node_type = self._derive_node_type_from_list_endpoint(endpoint)
            data = (response or {}).get("data") if isinstance(response, dict) else None
            if isinstance(data, list):
                items = data
            elif isinstance(data, dict):
                items = data.get("list", [])
            else:
                items = []
            if node_type and isinstance(items, list):
                for item in items:
                    if not isinstance(item, dict):
                        continue
                    item_id = item.get("id") or item.get("_id")
                    if not item_id:
                        continue
                    self._load_trace_by_item[(node_type, str(item_id))].append(trace)

    def _to_trace_text(self, value: Any, *, max_len: int) -> str:
        try:
            text = json_lib.dumps(value, ensure_ascii=False, separators=(",", ":"))
        except Exception:
            text = str(value)
        if len(text) > max_len:
            return f"{text[:max_len]}...(已截断)"
        return text

    def _build_trace_response_view(self, *, op_kind: str, response: Optional[Dict[str, Any]]) -> Any:
        return response or {}

    def consume_traces_by_push_id(self, push_id: str) -> List[Dict[str, Any]]:
        if not push_id:
            return []
        bucket = self._trace_by_push_id.get(push_id)
        if not bucket:
            return []
        traces = list(bucket)
        bucket.clear()
        return traces

    def consume_latest_trace_by_biz_id(self, biz_id: str, op_kind: Optional[str] = None) -> Optional[Dict[str, Any]]:
        if not biz_id:
            return None
        bucket = self._trace_by_biz_id.get(biz_id)
        if not bucket:
            return None
        if op_kind is None:
            return bucket.pop() if bucket else None
        for index in range(len(bucket) - 1, -1, -1):
            trace = bucket[index]
            if trace.get("op") == op_kind:
                del bucket[index]
                return trace
        return None

    def peek_latest_trace_by_biz_id(self, biz_id: str, op_kind: Optional[str] = None) -> Optional[Dict[str, Any]]:
        if not biz_id:
            return None
        bucket = self._trace_by_biz_id.get(biz_id)
        if not bucket:
            return None
        if op_kind is None:
            return bucket[-1] if bucket else None
        for index in range(len(bucket) - 1, -1, -1):
            trace = bucket[index]
            if trace.get("op") == op_kind:
                return trace
        return None

    def consume_latest_trace_by_op(self, op_kind: str) -> Optional[Dict[str, Any]]:
        bucket = self._trace_by_op.get(op_kind)
        if not bucket:
            return None
        return bucket.pop() if bucket else None

    def peek_latest_trace_by_op(self, op_kind: str) -> Optional[Dict[str, Any]]:
        bucket = self._trace_by_op.get(op_kind)
        if not bucket:
            return None
        return bucket[-1] if bucket else None

    def consume_load_traces(self, node_type: str, data_id: str) -> List[Dict[str, Any]]:
        key = (node_type, data_id)
        bucket = self._load_trace_by_item.get(key)
        if not bucket:
            return []
        traces = list(bucket)
        bucket.clear()
        return traces
    
    def _generate_signature(self, params: Dict[str, Any]) -> Dict[str, str]:
        """
        生成签名参数（兼容旧版签名算法）
        
        Args:
            params: 请求参数
            
        Returns:
            包含 timestamp, nonce, sign 的字典
        """
        timestamp = int(time.time() * 1000)  # 毫秒时间戳
        nonce = uuid.uuid4().hex[:16]  # 16位随机字符串
        
        # 构建签名参数
        sign_params = params.copy()
        sign_params['timestamp'] = timestamp
        sign_params['nonce'] = nonce
        
        # 按key排序
        sorted_items = sorted(sign_params.items())
        
        # 构建签名字符串
        items = []
        for k, v in sorted_items:
            if v is None:
                v_str = "null"
            elif isinstance(v, bool):
                v_str = "true" if v else "false"
            elif isinstance(v, str):
                v_str = v
            elif isinstance(v, (int, float)):
                v_str = str(v)
            elif isinstance(v, (list, dict)):
                v_str = json_lib.dumps(v, sort_keys=True, separators=(",", ":"), ensure_ascii=False)
            else:
                v_str = str(v)
            items.append(f"{k}={v_str}")
        
        sign_str = "&".join(items)
        
        # 使用 HMAC-SHA256 生成签名
        sign = hmac.new(self._secret.encode("utf-8"), sign_str.encode("utf-8"), hashlib.sha256).hexdigest()
        
        return {
            'timestamp': str(timestamp),
            'nonce': nonce,
            'sign': sign
        }
    
    async def request(
        self,
        method: str,
        endpoint: str,
        params: Optional[Dict[str, Any]] = None,
        data: Optional[Dict[str, Any]] = None,
        json_data: Optional[Dict[str, Any]] = None,
        json: Optional[Dict[str, Any]] = None
    ) -> Dict[str, Any]:
        """
        统一请求入口，自动签名
        
        Args:
            method: HTTP 方法（GET/POST/PUT/DELETE）
            endpoint: API 端点（如 /api/v2/project）
            params: URL 查询参数
            data: 请求体数据（form data）
            json_data: JSON 请求体数据
            json: JSON 请求体数据（兼容参数）
            
        Returns:
            响应 JSON 数据
            
        Raises:
            httpx.HTTPStatusError: HTTP 错误
        """
        # 兼容json参数
        if json is not None and json_data is None:
            json_data = json
        
        client = self._get_client()
        url = f"{self._base_url}{endpoint}"
        await self._acquire_rate_limit_slot()
        self._request_total += 1
        
        # 记录请求信息
        self._log(f"\n{'='*60}", level="DEBUG")
        self._log(f"REQUEST: {method} {endpoint}", level="DEBUG")
        self._log(f"Full URL: {url}", level="DEBUG")
        if params:
            self._log(f"Params: {json_lib.dumps(params, ensure_ascii=False, indent=2)}", level="DEBUG")
        if data:
            self._log(f"Data: {json_lib.dumps(data, ensure_ascii=False, indent=2)}", level="DEBUG")
        if json_data:
            self._log(f"JSON: {json_lib.dumps(json_data, ensure_ascii=False, indent=2)}", level="DEBUG")
        
        # 准备签名参数
        if method.upper() == 'GET':
            # GET 请求：uid 放在 params 中
            if params is None:
                params = {}
            params['uid'] = self._uid

            # 转换所有参数值为字符串（除了 list/dict）
            params = {k: str(v) if not isinstance(v, (list, dict)) else v for k, v in params.items()}

            sign_params = params.copy()
            # 生成签名并附加到 params
            signature = self._generate_signature(sign_params)
            params.update(signature)
        else:
            # POST/PUT/DELETE：uid 和签名放在 body 中（符合 v2 schema）
            if data is None:
                data = {}
            if 'steps' not in data:
                data['steps'] = _build_default_push_steps()
            data['uid'] = self._uid
            sign_params = data.copy()
            if params:
                sign_params.update(params)
            signature = self._generate_signature(sign_params)
            data.update(signature)
        
        # 发送请求并增强异常处理
        start_time = time.time()
        try:
            response = await client.request(
                method=method,
                url=url,
                params=params,
                json=data if method.upper() in ['POST', 'PUT'] else None
            )
            
            # 记录响应时间
            elapsed = time.time() - start_time
            self._log_request_summary(method=method, endpoint=endpoint, elapsed_seconds=elapsed)
            self._log(f"Response Time: {elapsed:.3f}s", level="DEBUG")
            
            # 检查 HTTP 状态
            response.raise_for_status()
            
            # 记录响应
            result = response.json()
            self._log(f"Status Code: {response.status_code}", level="DEBUG")
            self._log(f"Response: {json_lib.dumps(result, ensure_ascii=False, indent=2)}", level="DEBUG")
            self._log(f"{'='*60}\n", level="DEBUG")

            self._record_trace(
                method=method,
                endpoint=endpoint,
                url=url,
                request_params=params,
                request_payload=data if method.upper() in ['POST', 'PUT', 'DELETE'] else None,
                response=result,
                elapsed_ms=int(elapsed * 1000),
            )
            self._request_success += 1
            
            return result
            
        except Exception as e:
            import traceback
            self._request_failure += 1
            
            # 记录错误
            elapsed = time.time() - start_time
            self._log_request_summary(method=method, endpoint=endpoint, elapsed_seconds=elapsed)
            error_msg = "\n========== [ApiClient HTTP Error] ==========\n"
            error_msg += f"Request: {method} {url}\n"
            error_msg += f"Params: {params}\n"
            if method.upper() in ['POST', 'PUT']:
                error_msg += f"JSON: {data}\n"
            error_msg += f"Exception: {type(e).__name__}: {e}\n"
            error_msg += f"Elapsed: {elapsed:.3f}s\n"
            
            response_obj = e.response if isinstance(e, httpx.HTTPStatusError) else None
            if response_obj is not None:
                error_msg += f"Status Code: {response_obj.status_code}\n"
                error_msg += f"Response Headers: {response_obj.headers}\n"
                try:
                    error_msg += f"Response Text: {response_obj.text}\n"
                except Exception:
                    pass
            
            error_msg += traceback.format_exc()
            error_msg += "============================================\n"
            
            # 记录到日志文件
            self._log(error_msg, level="ERROR")
            
            raise
    
    async def get(self, endpoint: str, params: Optional[Dict[str, Any]] = None) -> Dict[str, Any]:
        """
        GET 请求
        
        Args:
            endpoint: API 端点
            params: URL 查询参数
            
        Returns:
            响应 JSON 数据
        """
        return await self.request('GET', endpoint, params=params)
    
    async def post(self, endpoint: str, data: Dict[str, Any]) -> Dict[str, Any]:
        """
        POST 请求，data 中已包含 push_id/biz_id（由 Handler 生成）
        
        Args:
            endpoint: API 端点
            data: 请求体数据（包含业务数据和 push_id/biz_id）
            
        Returns:
            响应 JSON 数据
        """
        return await self.request('POST', endpoint, data=data)
    
    async def put(self, endpoint: str, data: Dict[str, Any]) -> Dict[str, Any]:
        """
        PUT 请求，data 中已包含 push_id/biz_id
        
        Args:
            endpoint: API 端点
            data: 请求体数据
            
        Returns:
            响应 JSON 数据
        """
        return await self.request('PUT', endpoint, data=data)
    
    async def delete(self, endpoint: str, data: Dict[str, Any]) -> Dict[str, Any]:
        """
        DELETE 请求，data 中已包含 push_id/biz_id
        
        Args:
            endpoint: API 端点
            data: 请求体数据
            
        Returns:
            响应 JSON 数据
        """
        return await self.request('DELETE', endpoint, data=data)
    
    async def get_push_logs(self, push_ids: List[str]) -> Dict[str, Dict[str, Any]]:
        """
        批量查询 Push Log
        
        注意：单个查询也传单元素列表
        当前实现：用 for 循环模拟，后续等后端实现批量接口
        
        Args:
            push_ids: Push ID 列表
            
        Returns:
            {push_id: push_log_data} 的映射
        """
        result: Dict[str, Dict[str, Any]] = {}

        if not push_ids:
            return result

        try:
            payload = PushIdsSchema(push_ids=','.join(push_ids)).model_dump(exclude_none=True)
            response = await self.request(
                method='POST',
                endpoint='/push/result',
                data=payload
            )
        except httpx.HTTPStatusError as e:
            return {push_id: {'error': str(e)} for push_id in push_ids}

        data_list: List[Dict[str, Any]] = []
        if isinstance(response, dict):
            raw_data = response.get('data')
            if isinstance(raw_data, list):
                data_list = [item for item in raw_data if isinstance(item, dict)]
            elif isinstance(raw_data, dict):
                data_list = [raw_data]
            elif 'push_id' in response and 'status' in response:
                data_list = [response]

        for item in data_list:
            push_id = item.get('push_id')
            if not push_id:
                continue

            poll_trace = {
                "trace_id": f"poll-{push_id}-{int(time.time() * 1000)}",
                "op": "poll",
                "method": "POST",
                "endpoint": "/push/result",
                "url": f"{self._base_url}/push/result",
                "params": {},
                "payload": {"push_ids": push_id},
                "response": item,
                "elapsed_ms": 0,
                "ts": datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
            }
            self._trace_by_push_id[push_id].append(poll_trace)

            status = (item.get('status') or '').lower()
            error_msg = item.get('error') or ''
            result_data = item.get('result') or {}

            if status == 'success':
                # result_data 的结构是 {"code": 200, "message": "OK", "data": {"biz_id": "..."}}
                # 需要提取 result_data["data"] 作为最终的 data
                inner_data = result_data.get('data', {}) if isinstance(result_data, dict) else {}
                result[push_id] = {
                    'code': 200,
                    'status': 'success',
                    'data': inner_data
                }
            elif status in {'failed', 'not_find'}:
                result[push_id] = {
                    'code': 500,
                    'status': 'failed',
                    'message': error_msg or status or 'Unknown error',
                    'error': error_msg or status or 'Unknown error'
                }
            else:
                result[push_id] = {
                    'status': status or 'processing'
                }

        for push_id in push_ids:
            if push_id not in result:
                result[push_id] = {'status': 'processing'}

        return result