from rest_framework import serializers

from apps.transaction.models import TransactionParticipant, ParticipantInfo, TransactionReceipt
from apps.course.serializers import CourseDetailSerializer
from utils import FileFieldSerializer




class ParticipantInfoSerializer(serializers.ModelSerializer):
    phone_number = serializers.CharField(max_length=30)
    
    class Meta:
        model = ParticipantInfo
        fields = ['fullname', 'email', 'phone_number', 'gender', 'birthdate']

    def validate_phone_number(self, value):
        return value


class TransactionParticipantSerializer(serializers.ModelSerializer):
    participant_infos = ParticipantInfoSerializer(many=True)

    class Meta:
        model = TransactionParticipant
        fields = ['participant_infos']


    def create(self, validated_data):
        participant_infos_data = validated_data.pop('participant_infos', [])
        transaction_participant = TransactionParticipant.objects.create(**validated_data)
        
        for participant_info_data in participant_infos_data:
            ParticipantInfo.objects.create(transaction_participant=transaction_participant, **participant_info_data)
        
        return transaction_participant



class TransactionListSerializer(serializers.ModelSerializer):
    course = serializers.SerializerMethodField()
    receipts = serializers.SerializerMethodField()

    class Meta:
        model = TransactionParticipant
        fields = ['id', 'course', 'status', 'price', 'receipts', 'created_at', 'updated_at']

    def get_course(self, obj):
        return CourseDetailSerializer(obj.course, context=self.context).data

    def get_receipts(self, obj):
        receipts = obj.receipts.all()
        return TransactionReceiptSerializer(receipts, many=True, context=self.context).data


class TransactionReceiptSerializer(serializers.ModelSerializer):
    """
    Serializer for uploading payment receipts
    Uses FileFieldSerializer to handle pre-uploaded files from /upload-tmp-media/
    """
    file = FileFieldSerializer()

    class Meta:
        model = TransactionReceipt
        fields = ['id', 'file', 'description', 'uploaded_at']
        read_only_fields = ['id', 'uploaded_at']


class UploadReceiptsSerializer(serializers.Serializer):
    """
    Serializer for uploading multiple receipt files for a transaction.
    Files should be pre-uploaded using /upload-tmp-media/ endpoint,
    then their URLs should be sent here.
    """
    files = serializers.ListField(
        child=FileFieldSerializer(),
        allow_empty=False,
        max_length=10,
        help_text="List of file URLs (max 10 files) - files should be pre-uploaded via /upload-tmp-media/"
    )
    description = serializers.CharField(
        required=False,
        allow_blank=True,
        max_length=1000,
        help_text="Optional description for the receipts"
    )

    def validate_files(self, files):
        """
        Validate uploaded file URLs
        """
        if len(files) > 10:
            raise serializers.ValidationError("You can upload a maximum of 10 files.")

        return files


# =============================================================================
# Admin Panel Serializers
# =============================================================================

class AdminTransactionReceiptSerializer(serializers.ModelSerializer):
    file = serializers.SerializerMethodField()

    class Meta:
        model = TransactionReceipt
        fields = ['id', 'file', 'description', 'uploaded_at']

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


class AdminParticipantInfoSerializer(serializers.ModelSerializer):
    phone_number = serializers.CharField(read_only=True)

    class Meta:
        model = ParticipantInfo
        fields = ['id', 'fullname', 'email', 'phone_number', 'gender', 'birthdate']


class AdminTransactionSerializer(serializers.ModelSerializer):
    user_name = serializers.CharField(source='user.fullname', read_only=True)
    user_email = serializers.CharField(source='user.email', read_only=True)
    course_title = serializers.SerializerMethodField()
    receipts = AdminTransactionReceiptSerializer(many=True, read_only=True)
    participant_infos = AdminParticipantInfoSerializer(many=True, read_only=True)

    class Meta:
        model = TransactionParticipant
        fields = [
            'id', 'user', 'user_name', 'user_email',
            'course', 'course_title',
            'price', 'status', 'payment_method',
            'participant_infos', 'receipts',
            'created_at', 'updated_at'
        ]
        read_only_fields = [
            'id', 'user', 'user_name', 'user_email',
            'course', 'course_title', 'price', 'payment_method',
            'participant_infos', 'receipts', 'created_at', 'updated_at'
        ]

    def get_course_title(self, obj):
        if not obj.course:
            return None
        request = self.context.get('request')
        lang = getattr(request, 'LANGUAGE_CODE', None) or 'en'
        from apps.course.models.course import get_localized_field
        return get_localized_field(lang, obj.course.title)