from rest_framework import serializers
from apps.support.models import SupportRoom, SupportMessage


class SupportMessageSerializer(serializers.ModelSerializer):
    sender_name = serializers.SerializerMethodField()
    timestamp_ms = serializers.SerializerMethodField()

    class Meta:
        model = SupportMessage
        fields = (
            'id',
            'room',
            'sender_type',
            'sender_name',
            'content',
            'is_read',
            'created_at',
            'timestamp_ms',
        )
        read_only_fields = fields

    def get_sender_name(self, obj: SupportMessage) -> str:
        if obj.sender_type == SupportMessage.SenderType.SUPPORT:
            if obj.sender and obj.sender.fullname:
                return obj.sender.fullname
            return 'Support Specialist'
        if obj.sender and obj.sender.fullname:
            return obj.sender.fullname
        return 'You'

    def get_timestamp_ms(self, obj: SupportMessage) -> int:
        if not obj.created_at:
            return 0
        return int(obj.created_at.timestamp() * 1000)


class SendSupportMessageSerializer(serializers.Serializer):
    content = serializers.CharField(
        required=True,
        allow_blank=False,
        max_length=4000,
        trim_whitespace=True,
    )


class SupportRoomSerializer(serializers.ModelSerializer):
    class Meta:
        model = SupportRoom
        fields = (
            'id',
            'status',
            'unread_by_user',
            'last_message_at',
            'created_at',
        )
        read_only_fields = fields