import os

from rest_framework import serializers

from .models import MediaItem, MediaLocation
from .services import VIDEO_EXTENSIONS


class MediaLocationSerializer(serializers.ModelSerializer):
    class Meta:
        model = MediaLocation
        fields = ["id", "path", "rel_path", "mtime"]


class MediaItemSerializer(serializers.ModelSerializer):
    tags = serializers.ListField(
        child=serializers.CharField(max_length=100), required=False
    )
    rating = serializers.ChoiceField(choices=["", "s", "q", "e"], required=False)
    locations = MediaLocationSerializer(many=True, read_only=True)
    j_id = serializers.SerializerMethodField()
    filename = serializers.SerializerMethodField()
    extension = serializers.SerializerMethodField()
    kind = serializers.SerializerMethodField()
    uploaded_by = serializers.SerializerMethodField()
    uploaded_by_id = serializers.IntegerField(read_only=True)

    class Meta:
        model = MediaItem
        fields = [
            "id",
            "j_id",
            "md5",
            "size",
            "rating",
            "tags",
            "notes",
            "filename",
            "extension",
            "kind",
            "uploaded_by",
            "uploaded_by_id",
            "locations",
            "created_at",
            "updated_at",
        ]
        read_only_fields = [
            "id",
            "j_id",
            "md5",
            "size",
            "filename",
            "extension",
            "kind",
            "uploaded_by",
            "uploaded_by_id",
            "locations",
            "created_at",
            "updated_at",
        ]

    def get_j_id(self, obj):
        return f"J-{obj.id}"

    def get_uploaded_by(self, obj):
        return obj.uploaded_by.username if obj.uploaded_by else None

    def _first_location(self, obj):
        locations = list(obj.locations.all())
        return locations[0] if locations else None

    def get_filename(self, obj):
        location = self._first_location(obj)
        return os.path.basename(location.rel_path) if location else obj.md5

    def get_extension(self, obj):
        return os.path.splitext(self.get_filename(obj))[1].lstrip(".").lower()

    def get_kind(self, obj):
        return "video" if "." + self.get_extension(obj) in VIDEO_EXTENSIONS else "image"