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

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

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


router = Router()


@router.get("results", response=ResultsOut)
def get_results(request: HttpRequest):
    cache_key = f"api:noita:results:{request.user.id}"
    cached_data = cache.get(cache_key)

    if cached_data is not None:
        return cached_data
    """
    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.
    """
    # Group objectives by objectiv_id and count occurrences
    user_objectives = (
        Objectiv.objects.filter(user=request.user)
        .values("objectiv_id")
        .annotate(count=Count("id"))
    )

    # Fetch points from ObjectivPoint using Subquery
    user_objectives = user_objectives.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"),
    )

    # Annotate seed + first-seen-at
    user_objectives = user_objectives.annotate(
        seed=F("seed"),
        first_seen_at=F("first_seen_at"),
    )

    # Build response with all objectives and compute total score
    total_score = 0
    with_points = {}
    for obj in ObjectivPoint.objects.all():
        with_points[obj.objectiv_id] = {
            "objectiv_id": obj.objectiv_id,
            "display_string": obj.display_string,
            "count": 0,
            "max_count": obj.max_count,
            "points_per_objectiv": obj.point,
            "total_points": 0,
            "first_seen_at": None,
            "seed": None,
        }

    for obj in user_objectives.order_by("-total_points"):
        points = obj["total_points"] or 0
        with_points[obj["objectiv_id"]].update(
            {
                "count": obj["count"],
                "total_points": points,
                "first_seen_at": obj["first_seen_at"],
                "seed": obj["seed"],
            }
        )
        total_score += points

    # Count deaths for the user
    deaths_count = DeathCounter.objects.filter(user=request.user).count()

    data = {
        "total_score": total_score,
        "deaths_count": deaths_count,
        "objectives": list(with_points.values()),
    }

    cache.set(f"api:noita:results:{request.user.id}", data, 300)
    return data


@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.
    """
    cache_key = "api:noita:leaderboard"
    cached_data = cache.get(cache_key)

    if cached_data is not None:
        return cached_data

    from django.contrib.auth import get_user_model

    User = get_user_model()

    # Get all objectives with calculated points (grouped by objectiv_id and user)
    all_objectives = (
        Objectiv.objects.values("user", "objectiv_id")
        .annotate(count=Count("id"))
        .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"),
        )
    )

    # Build user totals by iterating through objectives
    user_totals_dict = {}
    for obj in all_objectives:
        user_id = obj["user"]
        points = obj["total_points"] or 0
        if user_id not in user_totals_dict:
            user_totals_dict[user_id] = 0
        user_totals_dict[user_id] += points

    # Get unique users and their scores, then apply ranking
    users_with_scores = []
    for user_id, total_score in user_totals_dict.items():
        user = User.objects.get(id=user_id)
        objectives_count = (
            Objectiv.objects.filter(user_id=user_id)
            .values("objectiv_id")
            .distinct()
            .count()
        )
        deaths_count = DeathCounter.objects.filter(user_id=user_id).count()
        users_with_scores.append(
            {
                "user_id": user_id,
                "user": user,
                "total_score": total_score,
                "objectives_count": objectives_count,
                "deaths_count": deaths_count,
            }
        )

    # Sort by score and add rank
    users_with_scores.sort(key=lambda x: x["total_score"], reverse=True)
    leaderboard = [
        {
            "rank": idx + 1,
            "username": entry["user"].username,
            "is_staff": entry["user"].is_staff,
            "total_score": entry["total_score"],
            "objectives_count": entry["objectives_count"],
            "deaths_count": entry["deaths_count"],
        }
        for idx, entry in enumerate(users_with_scores)
    ]

    data = {"leaderboard": leaderboard}
    cache.set("api:noita:leaderboard", data, 300)
    return data


@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",
    ]

    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

        # Invalidate caches on successful submission
        if submission.user:
            cache.delete(f"api:noita:results:{submission.user.id}")
        cache.delete("api:noita:leaderboard")

        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)}"}