import asyncio
import logging
import os
from abc import ABC, abstractmethod
from dataclasses import dataclass, field
from datetime import UTC, datetime
from enum import Enum
from typing import Any

import httpx

from app.services.api_key_manager import APIKeyManager

logger = logging.getLogger(__name__)

_MAX_RETRIES = 3
_RETRYABLE_STATUS = {429, 500, 502, 503}


class EngineType(str, Enum):
    CHATGPT = "chatgpt"
    PERPLEXITY = "perplexity"
    KIMI = "kimi"
    WENXIN = "wenxin"
    DOUBAO = "doubao"
    DEEPSEEK = "deepseek"
    QWEN = "qwen"
    GEMINI = "gemini"
    YUANBAO = "yuanbao"


@dataclass
class CitationInfo:
    source_url: str | None
    source_title: str | None
    citation_context: str
    confidence: float
    position: int


@dataclass
class AIQueryResult:
    engine_type: EngineType
    query: str
    raw_response: str
    citations: list[CitationInfo]
    has_brand_citation: bool
    has_competitor_citation: bool
    brand_context: str | None
    competitor_contexts: list[str]
    response_time_ms: int
    timestamp: datetime
    metadata: dict[str, Any] = field(default_factory=dict)
    input_tokens: int = 0
    output_tokens: int = 0

    @property
    def total_tokens(self) -> int:
        return self.input_tokens + self.output_tokens


class AIEngineAdapter(ABC):
    def __init__(
        self,
        api_key: str | None = None,
        rate_limiter=None,
        proxy: str | None = None,
        key_manager: APIKeyManager | None = None,
        user_id: str | None = None,
    ):
        self._key_manager = key_manager
        self._user_id = user_id
        self.api_key = self._resolve_api_key(api_key, key_manager, user_id)
        self.rate_limiter = rate_limiter
        self.proxy = proxy or self._load_proxy()
        self._client: httpx.AsyncClient | None = None

    def _load_proxy(self) -> str | None:
        return os.getenv("HTTPS_PROXY") or os.getenv("https_proxy")

    def _resolve_api_key(
        self,
        direct_key: str | None,
        key_manager: APIKeyManager | None,
        user_id: str | None,
    ) -> str:
        if direct_key and direct_key.strip():
            return direct_key

        if key_manager:
            key = key_manager.get_key(self.get_engine_type().value, user_id=user_id)
            if key:
                return key

        return self._get_env_key() or ""

    @abstractmethod
    def _get_env_key(self) -> str | None:
        pass

    @abstractmethod
    async def query(
        self,
        query: str,
        brand_name: str,
        competitor_names: list[str] | None = None,
    ) -> AIQueryResult:
        pass

    @abstractmethod
    def get_engine_type(self) -> EngineType:
        pass

    async def _get_client(self) -> httpx.AsyncClient:
        if self._client is None or self._client.is_closed:
            self._client = httpx.AsyncClient(**self._client_kwargs())
        return self._client

    def _client_kwargs(self) -> dict[str, Any]:
        kwargs: dict[str, Any] = {
            "timeout": httpx.Timeout(connect=10.0, read=120.0, write=10.0, pool=10.0),
        }
        if self.proxy:
            kwargs["proxy"] = self.proxy
        return kwargs

    def _detect_citations(
        self,
        response: str,
        brand_name: str,
        competitor_names: list[str] | None,
    ) -> tuple[bool, bool, str | None, list[str]]:
        has_brand = brand_name.lower() in response.lower()
        brand_context = None
        if has_brand:
            idx = response.lower().find(brand_name.lower())
            start = max(0, idx - 100)
            end = min(len(response), idx + len(brand_name) + 100)
            brand_context = response[start:end]

        has_competitor = False
        competitor_contexts = []
        if competitor_names:
            for name in competitor_names:
                if name.lower() in response.lower():
                    has_competitor = True
                    idx = response.lower().find(name.lower())
                    start = max(0, idx - 100)
                    end = min(len(response), idx + len(name) + 100)
                    competitor_contexts.append(response[start:end])

        return has_brand, has_competitor, brand_context, competitor_contexts

    async def _request_with_retry(self, payload: dict) -> dict:
        if self.rate_limiter:
            await self.rate_limiter.acquire()

        client = await self._get_client()
        engine_name = self.get_engine_type().value
        last_error: Exception | None = None

        for attempt in range(_MAX_RETRIES):
            try:
                response = await client.post(self._endpoint, json=payload)

                if response.status_code == 200:
                    return response.json()

                if response.status_code in _RETRYABLE_STATUS:
                    retry_after = response.headers.get("retry-after")
                    wait = float(retry_after) if retry_after else 2**attempt
                    logger.warning(
                        f"[{engine_name}] HTTP {response.status_code}, "
                        f"retry {attempt + 1}/{_MAX_RETRIES} in {wait:.1f}s"
                    )
                    last_error = Exception(
                        f"HTTP {response.status_code}: {response.text[:300]}"
                    )
                    await asyncio.sleep(wait)
                    continue

                raise Exception(
                    f"HTTP {response.status_code}: {response.text[:300]}"
                )

            except httpx.TransportError as exc:
                logger.warning(
                    f"[{engine_name}] Transport error: {exc}, "
                    f"retry {attempt + 1}/{_MAX_RETRIES}"
                )
                last_error = Exception(f"Network error: {exc}")
                await asyncio.sleep(2**attempt)
                continue

        raise last_error or Exception("Max retries exceeded")

    async def close(self) -> None:
        if self._client:
            await self._client.aclose()

    async def __aenter__(self) -> "AIEngineAdapter":
        return self

    async def __aexit__(self, *exc) -> None:
        await self.close()