from collections import Counter
from datetime import date, timedelta

from fastapi import APIRouter, Depends, Request
from fastapi.responses import HTMLResponse
from fastapi.templating import Jinja2Templates
from sqlalchemy import func
from sqlalchemy.orm import Session

from app.database import get_db
from app.models import PlayHistory

router = APIRouter(prefix="/stats", tags=["stats"])
templates = Jinja2Templates(directory="app/templates")

_TOP_N = 10


def _stats_for_day(db: Session, selected: date) -> dict:
    records = (
        db.query(PlayHistory)
        .filter(func.date(PlayHistory.played_at) == selected.isoformat())
        .order_by(PlayHistory.played_at.asc())
        .all()
    )

    track_counts: Counter = Counter()
    artist_counts: Counter = Counter()
    genre_counts: Counter = Counter()

    for r in records:
        track_counts[(r.track_id, r.track_name)] += 1
        for artist in (a.strip() for a in r.artists.split(",") if a.strip()):
            artist_counts[artist] += 1
        for genre in (g.strip() for g in r.genres.split(",") if g.strip()):
            genre_counts[genre] += 1

    def _ranked(counter: Counter) -> list[dict]:
        top = counter.most_common(_TOP_N)
        max_val = top[0][1] if top else 1
        return [
            {"label": k if isinstance(k, str) else k[1], "count": v, "pct": round(v / max_val * 100)}
            for k, v in top
        ]

    return {
        "total_plays": len(records),
        "top_tracks": _ranked(track_counts),
        "top_artists": _ranked(artist_counts),
        "top_genres": _ranked(genre_counts),
    }


@router.get("/", response_class=HTMLResponse)
def stats_page(request: Request, day: str | None = None, db: Session = Depends(get_db)):
    try:
        selected_date = date.fromisoformat(day) if day else date.today()
    except ValueError:
        selected_date = date.today()

    data = _stats_for_day(db, selected_date)

    # Días con al menos una reproducción (para el selector)
    days_with_data = [
        str(r[0])
        for r in db.query(func.date(PlayHistory.played_at))
        .distinct()
        .order_by(func.date(PlayHistory.played_at).desc())
        .limit(30)
        .all()
    ]

    return templates.TemplateResponse(
        "admin/stats.html",
        {
            "request": request,
            "selected_date": selected_date.isoformat(),
            "prev_date": (selected_date - timedelta(days=1)).isoformat(),
            "next_date": (selected_date + timedelta(days=1)).isoformat(),
            "is_today": selected_date == date.today(),
            "days_with_data": days_with_data,
            **data,
        },
    )


@router.get("/api")
def stats_api(day: str | None = None, db: Session = Depends(get_db)):
    try:
        selected_date = date.fromisoformat(day) if day else date.today()
    except ValueError:
        selected_date = date.today()
    return {"date": selected_date.isoformat(), **_stats_for_day(db, selected_date)}