from rest_framework import serializers
from django.contrib.auth import get_user_model
from .models import (
    Email, EmailFolder, EmailAttachment, EmailThread, EmailTemplate,
    EmailSignature, EmailRule, EmailSearch
)

User = get_user_model()


class EmailFolderSerializer(serializers.ModelSerializer):
    """Serializer for email folders."""
    
    email_count = serializers.SerializerMethodField()
    unread_count = serializers.SerializerMethodField()
    
    class Meta:
        model = EmailFolder
        fields = '__all__'
        read_only_fields = ('user', 'created_at', 'updated_at')
    
    def get_email_count(self, obj):
        return obj.emails.count()
    
    def get_unread_count(self, obj):
        return obj.emails.filter(is_read=False).count()


class EmailAttachmentSerializer(serializers.ModelSerializer):
    """Serializer for email attachments."""
    
    class Meta:
        model = EmailAttachment
        fields = '__all__'
        read_only_fields = ('created_at',)


class EmailSerializer(serializers.ModelSerializer):
    """Serializer for emails."""
    
    attachments = EmailAttachmentSerializer(many=True, read_only=True)
    folder_name = serializers.CharField(source='folder.name', read_only=True)
    from_name = serializers.SerializerMethodField()
    recipients = serializers.SerializerMethodField()
    thread_count = serializers.SerializerMethodField()
    
    class Meta:
        model = Email
        fields = '__all__'
        read_only_fields = ('uuid', 'user', 'message_id', 'created_at', 'updated_at')
    
    def get_from_name(self, obj):
        # Try to get name from contacts or use email
        return obj.from_email
    
    def get_recipients(self, obj):
        return {
            'to': obj.to_emails,
            'cc': obj.cc_emails,
            'bcc': obj.bcc_emails,
        }
    
    def get_thread_count(self, obj):
        return obj.threads.count()


class EmailCreateSerializer(serializers.ModelSerializer):
    """Serializer for creating emails."""
    
    attachments = serializers.ListField(
        child=serializers.FileField(),
        required=False,
        write_only=True
    )
    
    class Meta:
        model = Email
        fields = (
            'subject', 'to_emails', 'cc_emails', 'bcc_emails', 'reply_to',
            'body_text', 'body_html', 'priority', 'folder', 'attachments'
        )
    
    def validate_to_emails(self, value):
        if not value:
            raise serializers.ValidationError("At least one recipient is required.")
        return value
    
    def create(self, validated_data):
        attachments_data = validated_data.pop('attachments', [])
        user = self.context['request'].user
        
        # Set from_email to user's email
        validated_data['from_email'] = user.email
        
        # Create email
        email = Email.objects.create(user=user, **validated_data)
        
        # Handle attachments
        for attachment_file in attachments_data:
            EmailAttachment.objects.create(
                email=email,
                filename=attachment_file.name,
                content_type=attachment_file.content_type,
                size=attachment_file.size,
                file=attachment_file
            )
        
        return email


class EmailReplySerializer(serializers.ModelSerializer):
    """Serializer for replying to emails."""
    
    original_email = serializers.PrimaryKeyRelatedField(queryset=Email.objects.all())
    
    class Meta:
        model = Email
        fields = ('original_email', 'subject', 'body_text', 'body_html', 'priority')
    
    def create(self, validated_data):
        original_email = validated_data.pop('original_email')
        user = self.context['request'].user
        
        # Set reply headers
        validated_data.update({
            'user': user,
            'from_email': user.email,
            'to_emails': [original_email.from_email],
            'in_reply_to': original_email.message_id,
            'references': f"{original_email.references} {original_email.message_id}".strip(),
            'folder': EmailFolder.objects.get(user=user, folder_type='sent'),
        })
        
        # Add "Re: " prefix if not already present
        subject = validated_data.get('subject', '')
        if not subject.startswith('Re: '):
            validated_data['subject'] = f"Re: {subject}"
        
        return Email.objects.create(**validated_data)


class EmailForwardSerializer(serializers.ModelSerializer):
    """Serializer for forwarding emails."""
    
    original_email = serializers.PrimaryKeyRelatedField(queryset=Email.objects.all())
    
    class Meta:
        model = Email
        fields = ('original_email', 'to_emails', 'cc_emails', 'bcc_emails', 'subject', 'body_text', 'body_html', 'priority')
    
    def create(self, validated_data):
        original_email = validated_data.pop('original_email')
        user = self.context['request'].user
        
        # Set forward headers
        validated_data.update({
            'user': user,
            'from_email': user.email,
            'in_reply_to': original_email.message_id,
            'folder': EmailFolder.objects.get(user=user, folder_type='sent'),
        })
        
        # Add "Fwd: " prefix if not already present
        subject = validated_data.get('subject', '')
        if not subject.startswith('Fwd: '):
            validated_data['subject'] = f"Fwd: {subject}"
        
        # Add original email content
        original_content = f"\n\n--- Forwarded message ---\nFrom: {original_email.from_email}\nDate: {original_email.sent_at}\nSubject: {original_email.subject}\n\n{original_email.body_text}"
        validated_data['body_text'] += original_content
        
        return Email.objects.create(**validated_data)


class EmailThreadSerializer(serializers.ModelSerializer):
    """Serializer for email threads."""
    
    emails = EmailSerializer(many=True, read_only=True)
    email_count = serializers.SerializerMethodField()
    
    class Meta:
        model = EmailThread
        fields = '__all__'
    
    def get_email_count(self, obj):
        return obj.emails.count()


class EmailTemplateSerializer(serializers.ModelSerializer):
    """Serializer for email templates."""
    
    class Meta:
        model = EmailTemplate
        fields = '__all__'
        read_only_fields = ('user', 'created_at', 'updated_at')


class EmailSignatureSerializer(serializers.ModelSerializer):
    """Serializer for email signatures."""
    
    class Meta:
        model = EmailSignature
        fields = '__all__'
        read_only_fields = ('user', 'created_at', 'updated_at')


class EmailRuleSerializer(serializers.ModelSerializer):
    """Serializer for email rules."""
    
    class Meta:
        model = EmailRule
        fields = '__all__'
        read_only_fields = ('user', 'created_at', 'updated_at')


class EmailSearchSerializer(serializers.ModelSerializer):
    """Serializer for email searches."""
    
    class Meta:
        model = EmailSearch
        fields = '__all__'
        read_only_fields = ('user', 'created_at')


class EmailBulkActionSerializer(serializers.Serializer):
    """Serializer for bulk email actions."""
    
    ACTION_CHOICES = [
        ('mark_read', 'Mark as read'),
        ('mark_unread', 'Mark as unread'),
        ('mark_starred', 'Mark as starred'),
        ('mark_unstarred', 'Mark as unstarred'),
        ('mark_important', 'Mark as important'),
        ('mark_unimportant', 'Mark as unimportant'),
        ('move_to_folder', 'Move to folder'),
        ('delete', 'Delete'),
    ]
    
    email_ids = serializers.ListField(
        child=serializers.IntegerField(),
        min_length=1
    )
    action = serializers.ChoiceField(choices=ACTION_CHOICES)
    folder_id = serializers.IntegerField(required=False)
    
    def validate_email_ids(self, value):
        user = self.context['request'].user
        # Verify all emails belong to the user
        email_count = Email.objects.filter(id__in=value, user=user).count()
        if email_count != len(value):
            raise serializers.ValidationError("Some emails don't exist or don't belong to you.")
        return value
    
    def validate(self, attrs):
        action = attrs.get('action')
        folder_id = attrs.get('folder_id')
        
        if action == 'move_to_folder' and not folder_id:
            raise serializers.ValidationError("folder_id is required for move_to_folder action.")
        
        return attrs