"""抖音视频解析多源轮询服务。

优先级（P0 最高）：
  P0: App Feed API 直连（零成本，不用 API Key，当前最稳定）
  P1: TikHub API（付费 $0.001/次起，稳定）
  P2: apizero.cn 极数本源（按量付费，国内延迟低）

任一源成功即返回 MP4 直链 + 标题/文案；所有源均失败时返回 None。
每个解析源独立超时（5-10s），总耗时不超过所有源超时之和（实际快速失败时远小于此）。
未配置 API Key 的源自动跳过；无任何 Key 时 P0 仍可使用。
"""

from __future__ import annotations

import logging
import os
import re
import time
from dataclasses import dataclass
from typing import Optional

import httpx

logger = logging.getLogger(__name__)

# ── API Keys from env ──────────────────────────────────────────────────
TIKHUB_API_KEY = os.environ.get("TIKHUB_API_KEY", "").strip()
APIZERO_API_KEY = os.environ.get("APIZERO_API_KEY", "").strip()

# ── Timeouts (seconds) ────────────────────────────────────────────────
_TIMEOUT_APP_FEED = 12
_TIMEOUT_TIKHUB = 6
_TIMEOUT_APIZERO = 6


@dataclass
class ResolveResult:
    video_url: str  # MP4 直链；图文视频时为空字符串
    desc: str  # 视频标题/描述文案
    source: str  # 解析源名称，用于日志/metrics


# ── URL preprocessing ─────────────────────────────────────────────────
_AWEME_ID_RE = re.compile(
    r"(?:douyin\.com/(?:video|note)/|iesdouyin\.com/share/video/|aweme_id=)(\d{15,25})",
    re.IGNORECASE,
)


def _extract_url_from_text(text: str) -> str:
    """从任意分享文本中提取首个 http(s) URL。"""
    if not text:
        return ""
    m = re.search(r"https?://\S+", text)
    return m.group(0).rstrip("。，！？!?,，；;\"'）)】") if m else ""  # noqa: B005


def _canonicalize_url(url: str, timeout: int = 8) -> str:
    """跟随 v.douyin.com 短链 302 重定向，返回完整 URL。失败时返回原 URL。"""
    if "v.douyin.com" not in url and "iesdouyin.com" not in url:
        return url
    try:
        with httpx.Client(
            timeout=timeout, follow_redirects=True, verify=False, headers={"User-Agent": "Mozilla/5.0"}
        ) as c:
            resp = c.get(url)
            return str(resp.url)
    except Exception as exc:
        logger.debug("短链解析失败: %s (%s)", url, exc)
        return url


# ── Provider P0: App Feed API (零成本直连) ────────────────────────────
def _resolve_app_feed(url: str, timeout: int = _TIMEOUT_APP_FEED) -> Optional[ResolveResult]:
    """抖音 Android App Feed API 直连 — 零依赖、无需 Key、目前最稳定。"""
    from packages.douyin_parser import fetch_douyin_video_url

    video_url, desc = fetch_douyin_video_url(url, timeout=timeout, max_retries=2)
    if video_url:
        return ResolveResult(video_url=video_url, desc=desc or "", source="app_feed")
    if desc:
        # 图文视频：video_url 为 None 但 desc 可用
        return ResolveResult(video_url="", desc=desc, source="app_feed_image")
    return None


# ── Provider P1: TikHub ───────────────────────────────────────────────
def _resolve_tikhub(url: str, api_key: str, timeout: int = _TIMEOUT_TIKHUB) -> Optional[ResolveResult]:
    """TikHub API: https://api.tikhub.io/
    两步：get_aweme_id → fetch_one_video
    """
    if not api_key:
        return None
    headers = {"Authorization": f"Bearer {api_key}"}
    aweme_id = _AWEME_ID_RE.search(url or "")
    aweme_id = aweme_id.group(1) if aweme_id else None

    if not aweme_id:
        try:
            with httpx.Client(timeout=timeout, verify=False) as c:
                r = c.get(
                    "https://api.tikhub.io/api/v1/douyin/web/get_aweme_id",
                    headers=headers,
                    params={"url": url},
                )
                data = r.json()
                aweme_id = (data.get("data") or {}).get("aweme_id")
        except Exception as exc:
            logger.warning("TikHub get_aweme_id 失败: %s", exc)
            return None
    if not aweme_id:
        return None

    try:
        with httpx.Client(timeout=timeout, verify=False) as c:
            r = c.get(
                "https://api.tikhub.io/api/v1/douyin/app/v3/fetch_one_video",
                headers=headers,
                params={"aweme_id": aweme_id},
            )
            data = r.json()
            video = (data.get("data") or {}).get("video") or {}
            urls = []
            for k in ("download_addr", "play_addr_h264", "play_addr"):
                urls = (video.get(k) or {}).get("url_list") or []
                if urls:
                    break
            if not urls:
                # bit_rate 兜底
                for br in video.get("bit_rate") or []:
                    urls = (br.get("play_addr") or {}).get("url_list") or []
                    if urls:
                        break
            if not urls:
                return None
            # 优先 CDN 直链
            video_url = urls[0]
            for u in urls:
                if any(h in u for h in ("douyinvod.com", "bytecdn.com", "365yg.com")):
                    video_url = u
                    break
            desc = (data.get("data") or {}).get("desc", "")
            # 检测图文
            images = (data.get("data") or {}).get("images") or []
            if images and not any(h in video_url for h in ("douyinvod.com", "bytecdn.com", "amemv.com")):
                # 图文且无视频直链
                if desc:
                    return ResolveResult(video_url="", desc=desc, source="tikhub_image")
                return None
            return ResolveResult(video_url=video_url, desc=desc or "", source="tikhub")
    except Exception as exc:
        logger.warning("TikHub fetch_one_video 失败: %s", exc)
        return None


# ── Provider P2: apizero.cn ──────────────────────────────────────────
def _resolve_apizero(url: str, api_key: str, timeout: int = _TIMEOUT_APIZERO) -> Optional[ResolveResult]:
    """apizero.cn 极数本源: https://v1.apizero.cn/api/video-parse?url=...&flat=2"""
    if not api_key:
        return None
    headers = {"Authorization": f"Bearer {api_key}"}
    try:
        with httpx.Client(timeout=timeout, verify=False) as c:
            r = c.get(
                "https://v1.apizero.cn/api/video-parse",
                headers=headers,
                params={"url": url, "flat": 2},
            )
            data = r.json()
            d = data.get("data") or {}
            video_list = d.get("video_list") or []
            if not video_list:
                return None
            video_url = video_list[0].get("url", "")
            desc = d.get("title", "") or d.get("desc", "") or d.get("author", "")
            if not video_url:
                return None
            return ResolveResult(video_url=video_url, desc=desc, source="apizero")
    except Exception as exc:
        logger.warning("apizero 解析失败: %s", exc)
        return None


# ── Main API ──────────────────────────────────────────────────────────
def resolve_douyin_video(page_url: str) -> Optional[ResolveResult]:
    """按 P0→P1→P2 顺序轮询解析抖音视频。

    Args:
        page_url: 抖音 URL 或含 URL 的分享文本。

    Returns:
        ResolveResult 或 None（所有源均失败）。
        图文视频时 video_url 为空字符串、desc 为文案。
    """
    url = _extract_url_from_text(page_url) or page_url
    url = _canonicalize_url(url)

    providers = [
        ("app_feed", lambda: _resolve_app_feed(url)),
        ("tikhub", lambda: _resolve_tikhub(url, TIKHUB_API_KEY)),
        ("apizero", lambda: _resolve_apizero(url, APIZERO_API_KEY)),
    ]

    enabled_count = 0
    for name, fn in providers:
        if name == "tikhub" and not TIKHUB_API_KEY:
            continue
        if name == "apizero" and not APIZERO_API_KEY:
            continue
        enabled_count += 1
        t0 = time.time()
        try:
            result = fn()
            elapsed = time.time() - t0
            if result:
                domain = result.video_url.split("/")[2] if result.video_url and "/" in result.video_url else "(image)"
                logger.info(
                    "抖音解析成功: source=%s url_domain=%s desc_len=%d time=%.2fs",
                    result.source,
                    domain,
                    len(result.desc),
                    elapsed,
                )
                return result
            logger.debug("解析源 %s 返回空 (%.2fs)", name, elapsed)
        except Exception as exc:
            logger.warning("解析源 %s 异常 (%.2fs): %s", name, time.time() - t0, exc)

    if enabled_count == 0:
        logger.error("无任何抖音解析源可用：请检查 App Feed API 网络连通性")
    else:
        logger.warning("所有 %d 个抖音解析源均失败: url=%s", enabled_count, url)
    return None


def available_providers() -> list[str]:
    """返回当前可用的解析源列表（用于诊断）。"""
    provs = ["app_feed"]
    if TIKHUB_API_KEY:
        provs.append("tikhub")
    if APIZERO_API_KEY:
        provs.append("apizero")
    return provs