from rest_framework import serializers
from django.contrib.auth import get_user_model
from django.contrib.auth.password_validation import validate_password
from django.core.exceptions import ValidationError as DjangoValidationError
from eox_tenant.models import TenantConfig

User = get_user_model()


class CreateTenantSerializer(serializers.Serializer):
    """Serializer for tenant creation request."""
    tenant_name = serializers.RegexField(
        regex=r'^[a-z0-9-]+$',
        max_length=63,
        help_text="Tenant name (lowercase alphanumeric and hyphens only)"
    )
    platform_name = serializers.CharField(max_length=255, required=False)
    theme_name = serializers.CharField(max_length=255, required=False, default='indigo')
    org_filter = serializers.ListField(
        child=serializers.CharField(),
        required=False,
        help_text="List of course organizations for this tenant"
    )

    # EDNX settings (all optional with sensible defaults)
    ednx_tenant_restrict_users = serializers.BooleanField(
        required=False,
        default=True,
        help_text="Restrict users to their assigned tenant (EDNX_TENANT_RESTRICT_USERS)"
    )
    ednx_tenant_user_filter_enabled = serializers.BooleanField(
        required=False,
        default=True,
        help_text="Enable user filtering by tenant (EDNX_TENANT_USER_FILTER_ENABLED)"
    )
    ednx_use_signal = serializers.BooleanField(
        required=False,
        default=True,
        help_text="Use signals for tenant context (EDNX_USE_SIGNAL)"
    )
    ednx_account_registration_sources = serializers.ListField(
        child=serializers.CharField(),
        required=False,
        help_text="Allowed account registration sources (auto-generated from tenant domain if not provided)"
    )

    def validate_tenant_name(self, value):
        """Ensure tenant name doesn't use reserved words."""
        reserved = ['local', 'studio', 'apps', 'meilisearch', 'www', 'api', 'admin']
        if value in reserved:
            raise serializers.ValidationError(f"'{value}' is a reserved name")
        return value


class TenantResponseSerializer(serializers.Serializer):
    """Serializer for tenant creation response."""
    status = serializers.CharField()
    tenant_id = serializers.IntegerField()
    tenant_name = serializers.CharField()
    lms_url = serializers.CharField()
    authn_url = serializers.CharField()
    learner_dashboard_url = serializers.CharField()


class TenantAdminCreateSerializer(serializers.Serializer):
    """Serializer for tenant admin creation request."""
    tenant_name = serializers.CharField(
        max_length=63,
        help_text="Tenant name (must exist)"
    )
    username = serializers.CharField(
        max_length=150,
        help_text="Username for the admin user"
    )
    email = serializers.EmailField(
        help_text="Email address for the admin user"
    )
    password = serializers.CharField(
        write_only=True,
        help_text="Password for the admin user"
    )
    org_name = serializers.CharField(
        max_length=255,
        help_text="Organization name for role assignment"
    )

    def validate_tenant_name(self, value):
        """Validate that tenant exists."""
        external_key = f"{value}.local.openedx.io"
        if not TenantConfig.objects.filter(external_key=external_key).exists():
            raise serializers.ValidationError("Tenant does not exist")
        return value

    def validate_username(self, value):
        """Validate username is unique."""
        if User.objects.filter(username=value).exists():
            raise serializers.ValidationError("Username already exists")
        return value

    def validate_email(self, value):
        """Validate email is unique."""
        if User.objects.filter(email=value).exists():
            raise serializers.ValidationError("Email already exists")
        return value

    def validate_password(self, value):
        """Validate password meets Django security requirements."""
        try:
            validate_password(value)
        except DjangoValidationError as e:
            raise serializers.ValidationError(list(e.messages))
        return value