"""
Serializers for file upload and sharing.
"""

from rest_framework import serializers
from django.utils import timezone

from .models import MediaFile, PublicShare, FileAccessLog, MemoryCard


class MediaFileSerializer(serializers.ModelSerializer):
    file_url = serializers.SerializerMethodField()
    share_count = serializers.SerializerMethodField()
    has_active_shares = serializers.SerializerMethodField()

    class Meta:
        model = MediaFile
        fields = [
            'id',
            'file',
            'file_url',
            'original_filename',
            'title',
            'description',
            'mime_type',
            'file_size',
            'file_hash',
            'tags',
            'extracted_text',
            'is_processed',
            'processing_error',
            'shared_space',
            'created_at',
            'updated_at',
            'share_count',
            'has_active_shares',
        ]
        read_only_fields = [
            'id',
            'file_url',
            'file_size',
            'file_hash',
            'is_processed',
            'processing_error',
            'created_at',
            'updated_at',
            'share_count',
            'has_active_shares',
        ]

    def get_file_url(self, obj):
        request = self.context.get('request')
        if obj.file and request:
            return request.build_absolute_uri(obj.file.url)
        return None

    def get_share_count(self, obj):
        return obj.get_public_shares().count()

    def get_has_active_shares(self, obj):
        return obj.get_public_shares().exists()


class MediaFileUploadSerializer(serializers.ModelSerializer):
    original_filename = serializers.CharField(required=False, allow_blank=True)
    mime_type = serializers.CharField(required=False, allow_blank=True)

    class Meta:
        model = MediaFile
        fields = [
            'file',
            'original_filename',
            'title',
            'description',
            'mime_type',
            'tags',
            'shared_space',
        ]

    def create(self, validated_data):
        file_obj = validated_data.get('file')
        if file_obj and not validated_data.get('original_filename'):
            validated_data['original_filename'] = file_obj.name

        if file_obj and not validated_data.get('mime_type'):
            validated_data['mime_type'] = getattr(file_obj, 'content_type', 'application/octet-stream')

        request = self.context.get('request')
        if request and request.user.is_authenticated:
            validated_data['uploaded_by'] = request.user

        return super().create(validated_data)


class PublicShareSerializer(serializers.ModelSerializer):
    public_url = serializers.SerializerMethodField()
    is_valid = serializers.SerializerMethodField()
    file_info = serializers.SerializerMethodField()

    class Meta:
        model = PublicShare
        fields = [
            'id',
            'token',
            'media_file',
            'public_url',
            'expires_at',
            'max_downloads',
            'download_count',
            'is_password_protected',
            'note',
            'is_active',
            'is_valid',
            'created_at',
            'file_info',
        ]
        read_only_fields = [
            'id',
            'token',
            'public_url',
            'download_count',
            'is_valid',
            'created_at',
            'file_info',
        ]
        extra_kwargs = {
            'media_file': {'required': True}
        }

    def get_public_url(self, obj):
        return obj.get_public_url()

    def get_is_valid(self, obj):
        return obj.is_valid

    def get_file_info(self, obj):
        return {
            'id': str(obj.media_file.id),
            'title': obj.media_file.title,
            'original_filename': obj.media_file.original_filename,
            'mime_type': obj.media_file.mime_type,
            'file_size': obj.media_file.file_size,
        }


class PublicShareCreateSerializer(serializers.ModelSerializer):
    password = serializers.CharField(
        write_only=True,
        required=False,
        allow_blank=True,
    )
    expires_in_hours = serializers.IntegerField(
        write_only=True,
        required=False,
        min_value=1,
        max_value=8760,
    )

    class Meta:
        model = PublicShare
        fields = [
            'media_file',
            'expires_at',
            'expires_in_hours',
            'max_downloads',
            'password',
            'note',
        ]

    def validate(self, data):
        if 'expires_in_hours' in data:
            hours = data.pop('expires_in_hours')
            data['expires_at'] = timezone.now() + timezone.timedelta(hours=hours)
        return data

    def create(self, validated_data):
        password = validated_data.pop('password', None)

        request = self.context.get('request')
        if request and request.user.is_authenticated:
            validated_data['created_by'] = request.user

        share = super().create(validated_data)

        if password:
            share.set_password(password)

        return share


class PublicShareInfoSerializer(serializers.ModelSerializer):
    file_info = serializers.SerializerMethodField()
    is_valid = serializers.SerializerMethodField()
    downloads_remaining = serializers.SerializerMethodField()

    class Meta:
        model = PublicShare
        fields = [
            'is_password_protected',
            'is_valid',
            'expires_at',
            'downloads_remaining',
            'file_info',
            'note',
        ]

    def get_is_valid(self, obj):
        return obj.is_valid

    def get_downloads_remaining(self, obj):
        if obj.max_downloads is None:
            return None
        return max(0, obj.max_downloads - obj.download_count)

    def get_file_info(self, obj):
        return {
            'title': obj.media_file.title,
            'original_filename': obj.media_file.original_filename,
            'file_size': obj.media_file.file_size,
            'mime_type': obj.media_file.mime_type,
        }


class MemoryCardSerializer(serializers.ModelSerializer):
    attachment_count = serializers.SerializerMethodField()

    class Meta:
        model = MemoryCard
        fields = [
            'id',
            'shared_space',
            'title',
            'body',
            'card_type',
            'tags',
            'media_files',
            'position',
            'docmost_page_id',
            'created_by',
            'created_at',
            'updated_at',
            'attachment_count',
        ]
        read_only_fields = [
            'id',
            'created_by',
            'created_at',
            'updated_at',
            'attachment_count',
        ]

    def get_attachment_count(self, obj):
        return obj.media_files.count()

    def create(self, validated_data):
        media_files = validated_data.pop('media_files', [])
        request = self.context.get('request')
        if request and request.user.is_authenticated:
            validated_data['created_by'] = request.user
        card = super().create(validated_data)
        if media_files:
            card.media_files.set(media_files)
        return card


class FileAccessLogSerializer(serializers.ModelSerializer):
    class Meta:
        model = FileAccessLog
        fields = [
            'id',
            'media_file',
            'share',
            'accessed_at',
            'ip_address',
            'access_type',
        ]
        read_only_fields = fields