"""
收视分析 API — 提供收视走势和指标卡数据

端点：
  GET /api/analytics/years   → 有收视数据的年份列表（去重降序）
  GET /api/analytics/episodes?year=2026 → 指定年份所有期次的收视数据 + 年度目标
"""

from fastapi import APIRouter, Depends, Query
from sqlalchemy import extract
from sqlalchemy import distinct
from sqlmodel import Session, select

from app.core.deps import require_role
from app.db.session import get_session
from app.models.episode import Episode
from app.models.yearly_target import YearlyTarget
from app.models.user import UserRole

router = APIRouter(prefix="/api/analytics", tags=["收视分析"])


def _require_read():
    """三角色都可读"""
    return require_role(UserRole.zhipianren, UserRole.zebian, UserRole.biandao)


@router.get("/years")
def get_available_years(
    session: Session = Depends(get_session),
    current_user=Depends(_require_read()),
):
    """返回有收视数据的年份列表（去重，降序）。"""
    statement = (
        select(distinct(extract("year", Episode.air_date).label("year")))
        .where(Episode.audience_share.is_not(None))
        .order_by(extract("year", Episode.air_date).desc())
    )
    result = session.exec(statement).all()
    # extract 返回 float，转 int
    return [int(y) for y in result]


@router.get("/episodes")
def get_analytics_episodes(
    year: int | None = Query(None, description="年份，不传则取最近有数据的年份"),
    session: Session = Depends(get_session),
    current_user=Depends(_require_read()),
):
    """返回指定年份所有期次的收视数据（按 air_date 升序），附带该年年度目标。

    返回格式：
    {
      "year": 2026,
      "yearly_target": { "base_target": 0.6448, "stretch_target": 0.8989 } | null,
      "episodes": [ { id, episode_number, program_name, air_date, editor_name_snapshot,
                      audience_share, audience_rating }, ... ]
    }
    """
    # 如果没传 year，找最近有收视数据的年份
    if year is None:
        year_stmt = (
            select(extract("year", Episode.air_date).label("y"))
            .where(Episode.audience_share.is_not(None))
            .order_by(extract("year", Episode.air_date).desc())
            .limit(1)
        )
        latest_year = session.exec(year_stmt).first()
        if latest_year is None:
            return {"year": None, "yearly_target": None, "episodes": []}
        year = int(latest_year)

    # 查询该年份的期次（按 air_date 升序）
    ep_stmt = (
        select(Episode)
        .where(extract("year", Episode.air_date) == year)
        .order_by(Episode.air_date.asc())
    )
    episodes = session.exec(ep_stmt).all()

    # 查询该年份的年度目标
    target_stmt = select(YearlyTarget).where(YearlyTarget.year == year)
    target = session.exec(target_stmt).first()

    # 组装返回
    ep_list = [
        {
            "id": ep.id,
            "episode_number": ep.episode_number,
            "program_name": ep.program_name,
            "air_date": ep.air_date.isoformat() if ep.air_date else None,
            "editor_name_snapshot": ep.editor_name_snapshot,
            "audience_share": ep.audience_share,
            "audience_rating": ep.audience_rating,
            "program_format": ep.program_format,
            "narrative_structure": ep.narrative_structure,
            "opening_hook": ep.opening_hook,
            "equipment_domain": ep.equipment_domain,
        }
        for ep in episodes
    ]

    yearly_target = None
    if target:
        yearly_target = {
            "base_target": target.base_target,
            "stretch_target": target.stretch_target,
        }

    return {
        "year": year,
        "yearly_target": yearly_target,
        "episodes": ep_list,
    }