from django.http import HttpRequest
from django.core.files.base import ContentFile
from django.db.models import (
    F,
    Case,
    When,
    Sum,
    Count,
    IntegerField,
    Subquery,
    OuterRef,
    Window,
)
from django.db.models.functions import Rank
from ninja import Router, File
from ninja.files import UploadedFile

from noita.schemas import ObjectivOut, ResultsOut, LeaderboardOut
from noita.services.objectives import parse_objectives_and_store

from .models import LogfileSubmission, Objectiv, ObjectivPoint
from .schemas import NoitaSubmissionOut


router = Router()


@router.get("objectives", response=list[ObjectivOut])
def get_my_objectives(request: HttpRequest):
    return Objectiv.objects.order_by("-count").filter(user=request.user)


@router.get("results", response=ResultsOut)
def get_results(request: HttpRequest):
    """
    Get the user's score based on their objectives.

    Calculates points as: ObjectivPoint.point * min(max_count, count) for each objective
    Uses Django ORM annotate for efficient queryset computation.
    """
    # Fetch points from ObjectivPoint using Subquery
    user_objectives = Objectiv.objects.filter(user=request.user).annotate(
        # Get points per objective from ObjectivPoint
        points_per_objectiv=Subquery(
            ObjectivPoint.objects.filter(objectiv_id=OuterRef("objectiv_id")).values(
                "point"
            )[:1],
            output_field=IntegerField(),
        ),
        # Get max_count from ObjectivPoint
        max_objectives=Subquery(
            ObjectivPoint.objects.filter(objectiv_id=OuterRef("objectiv_id")).values(
                "max_count"
            )[:1],
            output_field=IntegerField(),
        ),
    )

    # Handle negative max_count (means unlimited)
    user_objectives = user_objectives.annotate(
        effective_max=Case(
            When(max_objectives__lt=0, then=F("count")),
            default=F("max_objectives"),
            output_field=IntegerField(),
        )
    )

    # Calculate capped count and total points
    user_objectives = user_objectives.annotate(
        capped_count=Case(
            When(effective_max__lt=F("count"), then=F("effective_max")),
            default=F("count"),
            output_field=IntegerField(),
        ),
        total_points=F("points_per_objectiv") * F("capped_count"),
    )

    # Get total score
    total_score_result = user_objectives.aggregate(Sum("total_points"))[
        "total_points__sum"
    ]
    total_score = total_score_result or 0

    # Build response with all objectives
    objectives_with_points = [
        {
            "objectiv_id": obj.objectiv_id,
            "count": obj.count,
            "points_per_objectiv": obj.points_per_objectiv or 0,
            "total_points": obj.total_points or 0,
        }
        for obj in user_objectives.order_by("-total_points")
    ]

    return {
        "total_score": total_score,
        "objectives": objectives_with_points,
    }


@router.get("leaderboard", response=LeaderboardOut)
def get_leaderboard(request: HttpRequest):
    """
    Get the global leaderboard for all users ranked by total score.

    Uses Window functions to rank users by their total score in descending order.
    """
    from django.contrib.auth import get_user_model

    User = get_user_model()

    # Get all objectives with calculated points
    all_objectives = (
        Objectiv.objects.annotate(
            # Fetch points from ObjectivPoint using Subquery
            points_per_objectiv=Subquery(
                ObjectivPoint.objects.filter(
                    objectiv_id=OuterRef("objectiv_id")
                ).values("point")[:1],
                output_field=IntegerField(),
            ),
            # Get max_count from ObjectivPoint
            max_objectives=Subquery(
                ObjectivPoint.objects.filter(
                    objectiv_id=OuterRef("objectiv_id")
                ).values("max_count")[:1],
                output_field=IntegerField(),
            ),
        )
        .annotate(
            # Handle negative max_count (means unlimited)
            effective_max=Case(
                When(max_objectives__lt=0, then=F("count")),
                default=F("max_objectives"),
                output_field=IntegerField(),
            )
        )
        .annotate(
            # Calculate capped count and total points
            capped_count=Case(
                When(effective_max__lt=F("count"), then=F("effective_max")),
                default=F("count"),
                output_field=IntegerField(),
            ),
            total_points=F("points_per_objectiv") * F("capped_count"),
        )
    )

    # Get user totals using subquery
    user_totals = (
        all_objectives.values("user")
        .annotate(total_score=Sum("total_points"))
        .values("user", "total_score")
    )

    # Get unique users and their scores, then apply ranking
    leaderboard = (
        User.objects.filter(objectiv__isnull=False)
        .distinct()
        .annotate(
            total_score=Subquery(
                user_totals.filter(user=OuterRef("id")).values("total_score")[:1],
                output_field=IntegerField(),
            )
        )
        .annotate(objectives_count=Count("objectiv", distinct=True))
        .annotate(
            rank=Window(
                expression=Rank(),
                order_by=F("total_score").desc(),
            )
        )
        .values("rank", "username", "total_score", "objectives_count")
        .order_by("rank")
    )

    return {
        "leaderboard": [
            {
                "rank": entry["rank"],
                "username": entry["username"],
                "total_score": entry["total_score"] or 0,
                "objectives_count": entry["objectives_count"],
            }
            for entry in leaderboard
        ]
    }


@router.post("submit", response={200: NoitaSubmissionOut, 400: dict})
def submit_log_file(request: HttpRequest, file: UploadedFile = File(...)):
    """
    Submit a Noita run file (log file, screenshot, or video).

    Accepts:
    - Text files (.txt) for polylan_mod_log.txt
    - Images (.png, .jpg, .gif)
    - Videos (.mp4, .webm)

    Max file size: 256 MB
    """
    # Validate file type
    allowed_types = [
        "text/plain",
        "text/x-log",
        "image/jpeg",
        "image/jpg",
        "image/png",
        "image/gif",
        "video/mp4",
        "video/webm",
    ]

    if file.content_type not in allowed_types:
        return 400, {
            "detail": f"Invalid file type: {file.content_type}. Allowed types: {', '.join(allowed_types)}"
        }

    # Validate file size (256MB limit)
    if file.size > 256 * 1024 * 1024:
        return 400, {"detail": "File too large (max 256MB)"}

    try:
        # Create submission
        submission = LogfileSubmission.objects.create(
            user=request.user if request.user.is_authenticated else None,
            content_type=file.content_type,
            file_size=file.size,
        )

        # Save the file
        submission.file.save(file.name, ContentFile(file.read()), save=True)

        try:
            parse_objectives_and_store(submission)
            submission.processed = True
            submission.save(update_fields=["processed"])
        except Exception:
            pass

        return {
            "id": str(submission.id),
            "user_id": submission.user_id,
            "username": submission.user.username if submission.user else None,
            "file_size": submission.file_size,
            "content_type": submission.content_type,
            "created_at": submission.created_at,
            "processed": submission.processed,
        }

    except Exception as e:
        return 500, {"detail": f"Error creating submission: {str(e)}"}