from collections import defaultdict
from typing import Optional

from fastapi import APIRouter, Depends, Request
from fastapi.responses import HTMLResponse
from sqlalchemy.sql.expression import func

from app.sql import models

from ..templates import jinja_templates
from ..sql.database import get_db

api_router = APIRouter(prefix="/stats", tags=["stats"])
html_router = APIRouter(
    prefix="/stats", include_in_schema=False, default_response_class=HTMLResponse
)


@api_router.get("/graph")
def stats_graph_api(deck_ids: Optional[str] = None, db=Depends(get_db)):
    # TODO - parallelize? (Probably not worth it :P )

    # SO Answer on row_number: https://stackoverflow.com/a/38160409/1040915
    # Docs: https://docs.sqlalchemy.org/en/20/core/sqlelement.html#sqlalchemy.sql.expression.over
    row_number_column = (
        func.row_number()
        .over(
            partition_by=[models.Deck.name, models.Game.date],
            order_by=models.EloScore.id.desc(),
        )
        .label("row_number")
    )
    sub_query = (
        db.query(models.Deck.name, models.EloScore.score, models.Game.date)
        .outerjoin(models.EloScore, models.Deck.id == models.EloScore.deck_id)
        .join(models.Game, models.EloScore.after_game_id == models.Game.id)
        .add_column(row_number_column)
    )
    if deck_ids is not None:
        sub_query = sub_query.filter(models.Deck.id.in_(deck_ids.split(",")))

    sub_query = sub_query.subquery()
    query = db.query(sub_query).filter(sub_query.c.row_number == 1)
    results = query.all()

    data_grouped_by_deck = defaultdict(list)
    for result in results:
        # TODO - how to index results by name instead of tuple-number
        data_grouped_by_deck[result[0]].append(
            {"score": result[1], "date": result[2].strftime("%Y-%m-%d")}
        )

    return {
        "datasets": [
            {"label": key, "data": data_grouped_by_deck[key]}
            for key in data_grouped_by_deck
        ]
    }


@html_router.get("/graph")
def stats_graph(request: Request, db=Depends(get_db)):
    return jinja_templates.TemplateResponse(request, "stats/graph.html")