# app/api/endpoints/events.py
import json
import os
import time
from datetime import datetime, timedelta, timezone
from typing import Dict, Tuple

import numpy as np
from dotenv import load_dotenv
from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy.orm import Session

from app.api.dependencies import get_db
from app.models.models import (
    ExtractedTopic,
    InfoSource,
    RankingLog,
    TargetType,
    TrendingEvent,
    UnifiedEvent,
    utcnow,
)
from app.schemas.event_schema import (
    PaginatedUnifiedEventResponse,
    PlatformTrendResponse,
    SearchTimelineResponse,
    TimelineDataPoint,
    UnifiedEventResponse,
)
from app.services.fetcher_service import embedder_model

load_dotenv()

SEARCH_EMBEDDING_THRESHOLD = float(os.getenv("SEARCH_EMBEDDING_THRESHOLD", "0.75"))
SEARCH_MAX_LIMIT = int(os.getenv("SEARCH_MAX_LIMIT", "30"))
SEARCH_DEFAULT_HOURS = int(os.getenv("SEARCH_DEFAULT_HOURS", "168"))
SEARCH_MAX_HOURS = int(os.getenv("SEARCH_MAX_HOURS", "168"))

router = APIRouter()

# 排名轨迹最多返回的点数，避免时间跨度过大时响应体过重。
MAX_RANKING_POINTS = 30

# 统一事件列表接口的短期缓存。
_UNIFIED_EVENTS_CACHE: Dict[str, Tuple[float, PaginatedUnifiedEventResponse]] = {}
CACHE_TTL_SECONDS = 60


def _load_vector(raw_embedding: str | None) -> np.ndarray | None:
    """将字符串形式的向量安全解析为 numpy 数组。"""
    if not raw_embedding:
        return None
    try:
        return np.asarray(json.loads(raw_embedding), dtype=np.float32)
    except (TypeError, ValueError, json.JSONDecodeError):
        return None


def _ensure_aware_datetime(dt: datetime) -> datetime:
    """确保 datetime 带时区；SQLite 返回无时区值时按 UTC 解释。"""
    if dt.tzinfo is None:
        return dt.replace(tzinfo=timezone.utc)
    return dt


@router.get("/unified", response_model=PaginatedUnifiedEventResponse)
def list_unified_events(
    min_hot: int = Query(5, ge=0, description="最低热度阈值"),
    hours: int = Query(48, ge=1, le=720, description="查询最近多少小时的数据"),
    sort_by: str = Query("hot_score", description="排序字段：hot_score | created_at"),
    skip: int = Query(0, ge=0, description="分页偏移量"),
    limit: int = Query(10, ge=1, le=50, description="每页条数"),
    db: Session = Depends(get_db),
):
    """查询统一事件列表，并附带平台趋势与标签信息。"""

    cache_key = f"{min_hot}:{hours}:{sort_by}:{skip}:{limit}"
    current_time = time.time()
    if cache_key in _UNIFIED_EVENTS_CACHE:
        expire_time, cached_data = _UNIFIED_EVENTS_CACHE[cache_key]
        if current_time < expire_time:
            return cached_data

    time_limit = utcnow() - timedelta(hours=hours)

    base_query = db.query(UnifiedEvent).filter(
        UnifiedEvent.hot_score >= min_hot,
        UnifiedEvent.created_at >= time_limit,
    )
    total = base_query.count()

    if sort_by == "created_at":
        base_query = base_query.order_by(UnifiedEvent.created_at.desc())
    else:
        base_query = base_query.order_by(UnifiedEvent.hot_score.desc(), UnifiedEvent.created_at.desc())

    events = base_query.offset(skip).limit(limit).all()
    if not events:
        return PaginatedUnifiedEventResponse(total=total, has_more=False, data=[])

    event_ids = [ev.id for ev in events]

    trend_rows = (
        db.query(TrendingEvent, InfoSource.source_name)
        .join(InfoSource, TrendingEvent.source_id == InfoSource.id)
        .filter(TrendingEvent.unified_event_id.in_(event_ids))
        .all()
    )

    trend_map: dict[int, list[tuple[TrendingEvent, str]]] = {}
    trend_ids: list[int] = []
    for trend, source_name in trend_rows:
        trend_map.setdefault(trend.unified_event_id, []).append((trend, source_name))
        trend_ids.append(trend.id)

    ranking_map: dict[int, list[int]] = {}
    if trend_ids:
        ranking_rows = (
            db.query(RankingLog.event_id, RankingLog.ranking_position)
            .filter(
                RankingLog.event_id.in_(trend_ids),
                RankingLog.observed_at >= time_limit,
            )
            .order_by(RankingLog.event_id, RankingLog.observed_at.asc())
            .all()
        )
        for event_id, position in ranking_rows:
            ranking_map.setdefault(event_id, []).append(position)

    tag_map: dict[int, list[str]] = {}
    tag_rows = (
        db.query(ExtractedTopic.target_id, ExtractedTopic.topic_keyword)
        .filter(
            ExtractedTopic.target_type == TargetType.EVENT,
            ExtractedTopic.target_id.in_(event_ids),
        )
        .order_by(ExtractedTopic.relevance_score.desc(), ExtractedTopic.created_at.desc())
        .all()
    )
    for target_id, keyword in tag_rows:
        tag_map.setdefault(target_id, []).append(keyword)

    results: list[UnifiedEventResponse] = []
    for ev in events:
        platform_list: list[PlatformTrendResponse] = []
        trends_for_ev = trend_map.get(ev.id, [])

        for trend, source_name in trends_for_ev:
            history = ranking_map.get(trend.id, [])
            if len(history) > MAX_RANKING_POINTS:
                history = history[-MAX_RANKING_POINTS:]

            platform_list.append(
                PlatformTrendResponse(
                    source_id=trend.source_id,
                    platform_name=source_name,
                    headline=trend.current_headline,
                    url=trend.event_url,
                    current_ranking=trend.current_ranking,
                    ranking_history=history,
                )
            )

        last_active_at = max(t.updated_at for t, _ in trends_for_ev) if trends_for_ev else ev.updated_at

        results.append(
            UnifiedEventResponse(
                event_id=ev.id,
                unified_title=ev.unified_title if ev.unified_title else "Untitled",
                summary=ev.ai_comprehensive_summary,
                hot_score=ev.hot_score,
                created_at=ev.created_at,
                last_active_at=last_active_at,
                platforms=platform_list,
                tags=tag_map.get(ev.id, []),
            )
        )

    has_more = (skip + limit) < total
    response = PaginatedUnifiedEventResponse(total=total, has_more=has_more, data=results)

    if len(_UNIFIED_EVENTS_CACHE) > 1000:
        _UNIFIED_EVENTS_CACHE.clear()
    _UNIFIED_EVENTS_CACHE[cache_key] = (current_time + CACHE_TTL_SECONDS, response)

    return response


@router.get("/unified/{event_id}", response_model=UnifiedEventResponse)
def get_unified_event(
    event_id: int,
    db: Session = Depends(get_db),
):
    """按事件 ID 获取单个统一事件。"""
    ev = db.query(UnifiedEvent).filter(UnifiedEvent.id == event_id).first()
    if not ev:
        raise HTTPException(status_code=404, detail="Event not found")

    time_limit = utcnow() - timedelta(hours=720)

    trend_rows = (
        db.query(TrendingEvent, InfoSource.source_name)
        .join(InfoSource, TrendingEvent.source_id == InfoSource.id)
        .filter(TrendingEvent.unified_event_id == event_id)
        .all()
    )

    trend_ids = [t.id for t, _ in trend_rows]
    ranking_map: dict[int, list[int]] = {}
    if trend_ids:
        ranking_rows = (
            db.query(RankingLog.event_id, RankingLog.ranking_position)
            .filter(
                RankingLog.event_id.in_(trend_ids),
                RankingLog.observed_at >= time_limit,
            )
            .order_by(RankingLog.event_id, RankingLog.observed_at.asc())
            .all()
        )
        for eid, pos in ranking_rows:
            ranking_map.setdefault(eid, []).append(pos)

    tag_rows = (
        db.query(ExtractedTopic.topic_keyword)
        .filter(
            ExtractedTopic.target_type == TargetType.EVENT,
            ExtractedTopic.target_id == event_id,
        )
        .order_by(ExtractedTopic.relevance_score.desc())
        .all()
    )
    tags = [row[0] for row in tag_rows]

    platform_list: list[PlatformTrendResponse] = []
    for trend, source_name in trend_rows:
        history = ranking_map.get(trend.id, [])
        if len(history) > MAX_RANKING_POINTS:
            history = history[-MAX_RANKING_POINTS:]

        platform_list.append(
            PlatformTrendResponse(
                source_id=trend.source_id,
                platform_name=source_name,
                headline=trend.current_headline,
                url=trend.event_url,
                current_ranking=trend.current_ranking,
                ranking_history=history,
            )
        )

    last_active_at = max(t.updated_at for t, _ in trend_rows) if trend_rows else ev.updated_at

    return UnifiedEventResponse(
        event_id=ev.id,
        unified_title=ev.unified_title if ev.unified_title else "Untitled",
        summary=ev.ai_comprehensive_summary,
        hot_score=ev.hot_score,
        created_at=ev.created_at,
        last_active_at=last_active_at,
        platforms=platform_list,
        tags=tags,
    )


@router.get("/search_timeline", response_model=SearchTimelineResponse)
def search_events_timeline(
    keyword: str = Query(..., description="搜索关键词，支持正则表达式"),
    hours: int = Query(None, ge=1, le=SEARCH_MAX_HOURS, description="查询最近多少小时的数据"),
    mode: str = Query("hybrid", description="匹配模式：exact | semantic | hybrid"),
    semantic_threshold: float = Query(None, ge=0.0, le=1.0, description="语义匹配相似度阈值"),
    utc_offset_minutes: int | None = Query(None, ge=-840, le=840, description="客户端相对 UTC 的分钟偏移，东八区传 480"),
    db: Session = Depends(get_db),
):
    import re

    query_text = (keyword or "").strip()
    if not query_text:
        raise HTTPException(status_code=400, detail="keyword cannot be empty")

    if hours is None:
        hours = SEARCH_DEFAULT_HOURS
    if hours > SEARCH_MAX_HOURS:
        hours = SEARCH_MAX_HOURS

    match_mode = (mode or "hybrid").strip().lower()
    if match_mode not in {"exact", "semantic", "hybrid"}:
        match_mode = "hybrid"

    use_regex = match_mode in {"exact", "hybrid"}
    use_semantic = match_mode in {"semantic", "hybrid"}
    sim_threshold = semantic_threshold if semantic_threshold is not None else SEARCH_EMBEDDING_THRESHOLD

    pattern = None
    if use_regex:
        try:
            pattern = re.compile(query_text, re.IGNORECASE)
        except re.error:
            pattern = re.compile(re.escape(query_text), re.IGNORECASE)

    query_vec: np.ndarray | None = None
    if use_semantic:
        try:
            query_encoded = embedder_model.encode([query_text], normalize_embeddings=True, show_progress_bar=False)
            if len(query_encoded) > 0:
                query_vec = np.asarray(query_encoded[0], dtype=np.float32)
        except Exception:
            query_vec = None

    if match_mode == "semantic" and query_vec is None:
        use_regex = True
        if pattern is None:
            pattern = re.compile(re.escape(query_text), re.IGNORECASE)

    time_limit = utcnow() - timedelta(hours=hours)
    date_format = "%Y-%m-%d %H:00" if hours <= 48 else "%Y-%m-%d"

    display_timezone = timezone.utc
    if utc_offset_minutes is not None:
        display_timezone = timezone(timedelta(minutes=utc_offset_minutes))

    def _bucket_label(dt: datetime) -> str:
        aware_dt = _ensure_aware_datetime(dt)
        return aware_dt.astimezone(display_timezone).strftime(date_format)

    all_recent_unified = db.query(UnifiedEvent).filter(UnifiedEvent.created_at >= time_limit).all()
    all_recent_trends = db.query(TrendingEvent).filter(TrendingEvent.created_at >= time_limit).all()

    matched_event_ids: set[int] = set()
    matched_trend_points: list[tuple[int, str]] = []

    for ev in all_recent_unified:
        text_matched = False
        if use_regex and pattern is not None:
            text_to_search = f"{ev.unified_title or ''} {ev.ai_comprehensive_summary or ''}"
            text_matched = bool(pattern.search(text_to_search))

        semantic_matched = False
        if use_semantic and query_vec is not None:
            ev_vec = _load_vector(ev.center_embedding)
            if ev_vec is not None:
                semantic_matched = float(np.dot(query_vec, ev_vec)) >= sim_threshold

        if text_matched or semantic_matched:
            matched_event_ids.add(ev.id)

    for trend in all_recent_trends:
        text_matched = False
        if use_regex and pattern is not None and trend.current_headline:
            text_matched = bool(pattern.search(trend.current_headline))

        semantic_matched = False
        if use_semantic and query_vec is not None:
            trend_vec = _load_vector(trend.title_embedding)
            if trend_vec is not None:
                semantic_matched = float(np.dot(query_vec, trend_vec)) >= sim_threshold

        if (text_matched or semantic_matched) and trend.unified_event_id:
            matched_event_ids.add(trend.unified_event_id)
            matched_trend_points.append((trend.unified_event_id, _bucket_label(trend.created_at)))

    matched_unified_events = [ev for ev in all_recent_unified if ev.id in matched_event_ids]
    matched_unified_events.sort(key=lambda x: x.created_at, reverse=True)

    display_events = matched_unified_events[:100]
    display_event_ids = [ev.id for ev in display_events]
    display_event_id_set = set(display_event_ids)

    trend_map: dict[int, list[tuple[TrendingEvent, str]]] = {}
    trend_ids: list[int] = []
    if display_event_ids:
        trend_rows = (
            db.query(TrendingEvent, InfoSource.source_name)
            .join(InfoSource, TrendingEvent.source_id == InfoSource.id)
            .filter(TrendingEvent.unified_event_id.in_(display_event_ids))
            .all()
        )
        for trend, source_name in trend_rows:
            trend_map.setdefault(trend.unified_event_id, []).append((trend, source_name))
            trend_ids.append(trend.id)

    ranking_map: dict[int, list[int]] = {}
    if trend_ids:
        ranking_rows = (
            db.query(RankingLog.event_id, RankingLog.ranking_position)
            .filter(
                RankingLog.event_id.in_(trend_ids),
                RankingLog.observed_at >= time_limit,
            )
            .order_by(RankingLog.event_id, RankingLog.observed_at.asc())
            .all()
        )
        for event_id, position in ranking_rows:
            ranking_map.setdefault(event_id, []).append(position)

    timeline_event_map: dict[str, set[int]] = {}
    for ev in display_events:
        timeline_event_map.setdefault(_bucket_label(ev.created_at), set()).add(ev.id)

    for event_id, time_label in matched_trend_points:
        if event_id in display_event_id_set:
            timeline_event_map.setdefault(time_label, set()).add(event_id)

    timeline_data = [
        TimelineDataPoint(time_label=time_label, count=len(event_ids), event_ids=sorted(event_ids))
        for time_label, event_ids in sorted(timeline_event_map.items())
    ]

    results: list[UnifiedEventResponse] = []
    if display_event_ids:
        tag_map: dict[int, list[str]] = {}
        tag_rows = (
            db.query(ExtractedTopic.target_id, ExtractedTopic.topic_keyword)
            .filter(
                ExtractedTopic.target_type == TargetType.EVENT,
                ExtractedTopic.target_id.in_(display_event_ids),
            )
            .order_by(ExtractedTopic.relevance_score.desc(), ExtractedTopic.created_at.desc())
            .all()
        )
        for target_id, kw in tag_rows:
            tag_map.setdefault(target_id, []).append(kw)

        for ev in display_events:
            trends_for_ev = trend_map.get(ev.id, [])
            platform_list: list[PlatformTrendResponse] = []
            seen_platforms = set()

            for trend, source_name in trends_for_ev:
                uniq_key = f"{source_name}_{trend.current_headline}"
                if uniq_key in seen_platforms:
                    continue
                seen_platforms.add(uniq_key)

                history = ranking_map.get(trend.id, [])
                if len(history) > MAX_RANKING_POINTS:
                    history = history[-MAX_RANKING_POINTS:]

                platform_list.append(
                    PlatformTrendResponse(
                        source_id=trend.source_id,
                        platform_name=source_name,
                        headline=trend.current_headline,
                        url=trend.event_url,
                        current_ranking=trend.current_ranking,
                        ranking_history=history,
                    )
                )

            last_active_at = max(t.updated_at for t, _ in trends_for_ev) if trends_for_ev else ev.updated_at

            results.append(
                UnifiedEventResponse(
                    event_id=ev.id,
                    unified_title=ev.unified_title if ev.unified_title else "Untitled",
                    summary=ev.ai_comprehensive_summary,
                    hot_score=ev.hot_score,
                    created_at=ev.created_at,
                    last_active_at=last_active_at,
                    platforms=platform_list,
                    tags=tag_map.get(ev.id, []),
                )
            )

    return SearchTimelineResponse(keyword=query_text, timeline=timeline_data, events=results)