"""趋势看板路由 — 论文统计图表页面和数据 API。"""

from __future__ import annotations

import logging
from datetime import date, timedelta

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

from app.config import settings
from app.database import get_db

logger = logging.getLogger(__name__)

router = APIRouter()
templates = Jinja2Templates(directory="app/templates")


@router.get("/trends")
def trends_page(request: Request, db: Session = Depends(get_db)):
    """趋势看板页面。"""
    stats = _get_trends_data(db)
    return templates.TemplateResponse(
        request,
        "trends.html",
        {
            "page_title": "趋势看板",
            "stats": stats,
            "today": _today_str(),
        },
    )


@router.get("/api/stats/trends")
def trends_api(db: Session = Depends(get_db)):
    """趋势数据 JSON API。"""
    return _get_trends_data(db)


def _get_trends_data(db: Session) -> dict:
    """从 DB 聚合趋势数据。"""
    thirty_days_ago = (date.today() - timedelta(days=30)).isoformat()

    # 1. 按日论文数量（近 30 天）
    daily_rows = db.execute(text("""
        SELECT paper_date, COUNT(*) as cnt
        FROM papers
        WHERE paper_date >= :start_date
        GROUP BY paper_date
        ORDER BY paper_date ASC
    """), {"start_date": thirty_days_ago}).fetchall()
    daily_counts = [
        {"date": str(row[0]), "count": row[1]}
        for row in daily_rows
    ]

    # 2. 热门标签 Top 20
    tag_rows = db.execute(text("""
        SELECT tag, COUNT(*) as cnt
        FROM paper_tags
        GROUP BY tag
        ORDER BY cnt DESC
        LIMIT 20
    """)).fetchall()
    top_tags = [
        {"tag": row[0], "count": row[1]}
        for row in tag_rows
    ]

    # 3. Upvotes 分布
    upvote_rows = db.execute(text("""
        SELECT
            CASE
                WHEN upvotes >= 100 THEN '100+'
                WHEN upvotes >= 50 THEN '50-99'
                WHEN upvotes >= 20 THEN '20-49'
                WHEN upvotes >= 10 THEN '10-19'
                WHEN upvotes >= 5 THEN '5-9'
                ELSE '0-4'
            END as bucket,
            COUNT(*) as cnt
        FROM papers
        GROUP BY bucket
        ORDER BY MIN(upvotes) DESC
    """)).fetchall()
    upvotes_dist = [
        {"range": row[0], "count": row[1]}
        for row in upvote_rows
    ]

    # 4. 总结完成率
    summary_rows = db.execute(text("""
        SELECT
            COALESCE(ss.status, 'none') as status,
            COUNT(*) as cnt
        FROM papers p
        LEFT JOIN summary_status ss ON ss.paper_id = p.id
        GROUP BY status
    """)).fetchall()
    summary_completion = [
        {"status": row[0], "count": row[1]}
        for row in summary_rows
    ]

    return {
        "daily_counts": daily_counts,
        "top_tags": top_tags,
        "upvotes_dist": upvotes_dist,
        "summary_completion": summary_completion,
    }


def _today_str() -> str:
    from datetime import datetime
    from zoneinfo import ZoneInfo
    tz = ZoneInfo(settings.APP_TIMEZONE)
    return datetime.now(tz).strftime("%Y-%m-%d")