from django.db.models import Prefetch, Q
from rest_framework import viewsets
from rest_framework.decorators import api_view, permission_classes
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response

from .models import League, Player, PlayerSeasonStat, Team
from .serializers import (
    LeagueSerializer,
    PlayerDetailSerializer,
    PlayerListSerializer,
    TeamSerializer,
)

STAT_FILTERS = {
    "games_played": "season_stats__games_played",
    "minutes_per_game": "season_stats__minutes_per_game",
    "points_per_game": "season_stats__points_per_game",
    "assists_per_game": "season_stats__assists_per_game",
    "rebounds_per_game": "season_stats__rebounds_per_game",
    "steals_per_game": "season_stats__steals_per_game",
    "blocks_per_game": "season_stats__blocks_per_game",
    "turnovers_per_game": "season_stats__turnovers_per_game",
    "field_goal_percentage": "season_stats__field_goal_percentage",
    "three_point_percentage": "season_stats__three_point_percentage",
    "free_throw_percentage": "season_stats__free_throw_percentage",
    "efficiency_rating": "season_stats__efficiency_rating",
    "true_shooting_percentage": "season_stats__true_shooting_percentage",
    "usage_percentage": "season_stats__usage_percentage",
    "total_points": "season_stats__total_points",
    "total_assists": "season_stats__total_assists",
    "total_rebounds": "season_stats__total_rebounds",
}

PLAYER_FILTERS = {
    "position": "position__iexact",
    "role": "role__icontains",
    "nationality": "nationality__icontains",
    "height_cm": "height_cm",
    "weight_kg": "weight_kg",
    "birth_year": "birth_year",
}

LOOKUPS = {"exact", "gte", "lte", "gt", "lt"}


class PlayerViewSet(viewsets.ReadOnlyModelViewSet):
    permission_classes = [IsAuthenticated]

    def get_serializer_class(self):
        if self.action == "retrieve":
            return PlayerDetailSerializer
        return PlayerListSerializer

    def get_queryset(self):
        stats = PlayerSeasonStat.objects.select_related("league", "team", "season").order_by(
            "-efficiency_rating", "-points_per_game"
        )
        queryset = (
            Player.objects.select_related("current_team", "current_team__league")
            .prefetch_related(Prefetch("season_stats", queryset=stats, to_attr="prefetched_stats"))
            .distinct()
        )

        params = self.request.query_params
        if query := params.get("q"):
            queryset = queryset.filter(
                Q(first_name__icontains=query)
                | Q(last_name__icontains=query)
                | Q(role__icontains=query)
                | Q(nationality__icontains=query)
                | Q(current_team__name__icontains=query)
            )

        if league := params.get("league"):
            queryset = queryset.filter(
                Q(season_stats__league__code__iexact=league)
                | Q(season_stats__league__name__icontains=league)
                | Q(current_team__league__code__iexact=league)
            )

        if region := params.get("region"):
            queryset = queryset.filter(season_stats__league__region__iexact=region)

        if team := params.get("team"):
            queryset = queryset.filter(
                Q(season_stats__team__name__icontains=team) | Q(current_team__name__icontains=team)
            )

        if season := params.get("season"):
            queryset = queryset.filter(season_stats__season__label=season)

        for param, field in PLAYER_FILTERS.items():
            if params.get(param):
                queryset = queryset.filter(**{field: params[param]})
            for lookup in LOOKUPS - {"exact"}:
                key = f"{param}__{lookup}"
                if params.get(key):
                    queryset = queryset.filter(**{f"{param}__{lookup}": params[key]})

        for param, field in STAT_FILTERS.items():
            if params.get(param):
                queryset = queryset.filter(**{field: params[param]})
            for lookup in LOOKUPS - {"exact"}:
                key = f"{param}__{lookup}"
                if params.get(key):
                    queryset = queryset.filter(**{f"{field}__{lookup}": params[key]})

        return queryset.order_by("-season_stats__efficiency_rating", "-season_stats__points_per_game", "last_name")


class LeagueViewSet(viewsets.ReadOnlyModelViewSet):
    permission_classes = [IsAuthenticated]
    queryset = League.objects.all()
    serializer_class = LeagueSerializer


class TeamViewSet(viewsets.ReadOnlyModelViewSet):
    permission_classes = [IsAuthenticated]
    queryset = Team.objects.select_related("league").all()
    serializer_class = TeamSerializer


@api_view(["GET"])
@permission_classes([IsAuthenticated])
def me(request):
    role = getattr(request.user.profile, "role", "viewer")
    return Response({"username": request.user.username, "role": role})