from marietje.utils import send_to_bertha
from queues.models import PlaylistSong
from songs.models import Song
from django.db.models.functions import Coalesce
from django.db.models import Sum, Value
from django.db import transaction
from mutagen import File


class UploadException(Exception):
    pass


def is_regular_queue(ps):
    if not ps.played_at:
        # Request is from the old times, assume good
        return True
    if not 0 <= ps.played_at.astimezone().weekday() <= 4:
        return False  # Queued in the weekend
    if not 7 <= ps.played_at.astimezone().hour <= 22:
        # Because of timezone shit, I allow for an extra hour of leeway
        return False  # Queued outside of regular opening hours
    return True


@transaction.atomic
def request_weight(ps):
    if is_regular_queue(ps):
        return float(ps.song.duration)
    # Count other requests for 10%
    return 0.10 * float(ps.song.duration)


def get_upload_stats(user):
    songs_queued = PlaylistSong.objects.select_related("song").filter(user=user, state=2, song__deleted=False)
    queued_score = sum(request_weight(x) for x in songs_queued)
    upload_score = Song.objects.filter(user=user, deleted=False).aggregate(x=Coalesce(Sum("duration"), Value(0)))["x"]
    return {"queued_score": queued_score, "upload_score": upload_score}


def get_reputation(user) -> float:
    try:
        stats = get_upload_stats(user)
        ratio = stats["queued_score"] / (2.0 * stats["upload_score"])
        return ratio
    except ZeroDivisionError:
        return 99999.0  # high enough


def check_upload_stats(user):
    # Allow upload if the user has a good reputation
    # Score function:
    #   - U = duration * songs uploaded
    #   - Q = duration * songs queued
    #   - If 2*U < Q: allow upload (otherwise don't)
    if user.is_superuser:
        return True

    ratio = get_reputation(user)
    return ratio >= 1.0


def upload_file(file, artist, title, user):
    duration = File(file).info.length
    bertha_hash = send_to_bertha(file).decode("ascii")
    if not bertha_hash:
        raise UploadException("Files not uploaded correctly.")
    return Song.objects.create(user=user, artist=artist, title=title, hash=bertha_hash, duration=duration)