from rest_framework import serializers
from .models import User, Enterprise, Role, EnterpriseMember, Permission

class UserSerializer(serializers.ModelSerializer):
    roles = serializers.ReadOnlyField()
    permissions = serializers.SerializerMethodField()
    opc_certification = serializers.SerializerMethodField()
    enterprise_info = serializers.SerializerMethodField()

    class Meta:
        model = User
        fields = ['id', 'username', 'phone', 'email', 'nickname', 'avatar_url', 'face_url', 'bio', 'location', 'status', 'is_active', 'created_at', 'roles', 'permissions', 'is_staff', 'is_superuser', 'rating', 'completed_tasks', 'opc_certification', 'enterprise_info', 'is_recommended', 'recommend_priority']
        read_only_fields = ['id', 'status', 'is_active', 'created_at', 'roles', 'permissions', 'is_staff', 'is_superuser']

    def get_enterprise_info(self, obj):
        if 'ENTERPRISE' in obj.roles:
            from .models import Enterprise, EnterpriseMember
            ent = Enterprise.objects.filter(user=obj).first()
            if ent:
                return {'company_name': ent.company_name, 'role': 'OWNER'}
            member = EnterpriseMember.objects.filter(user=obj).first()
            if member:
                return {'company_name': member.enterprise.company_name, 'role': member.role}
        return None

    def get_opc_certification(self, obj):
        if 'OPC_USER' in obj.roles:
            from opc_cert.models import OpcCertification
            from opc_cert.serializers import OpcCertificationSerializer
            cert = OpcCertification.objects.filter(user=obj, status='APPROVED').first()
            if cert:
                return OpcCertificationSerializer(cert).data
        return None

    def get_permissions(self, obj):
        if obj.is_superuser:
            return ['*']
        from .models import RolePermission
        perms = RolePermission.objects.filter(role__userrole__user=obj).values_list('permission__code', flat=True).distinct()
        return list(perms)

    def validate(self, attrs):
        # Normalize empty strings to None to avoid unique constraint issues
        for field in ['phone', 'email']:
            if field in attrs and attrs[field] == '':
                attrs[field] = None
        return attrs

class RoleSerializer(serializers.ModelSerializer):
    permission_ids = serializers.SerializerMethodField()

    class Meta:
        model = Role
        fields = '__all__'

    def get_permission_ids(self, obj):
        return list(obj.role_permissions.values_list('permission_id', flat=True).distinct().values_list('permission_id', flat=True))

    def to_representation(self, instance):
        data = super().to_representation(instance)
        # Ensure permission_ids are strings for frontend comparison
        data['permission_ids'] = [str(pid) for pid in data.get('permission_ids', [])]
        return data

class PermissionSerializer(serializers.ModelSerializer):
    class Meta:
        model = Permission
        fields = '__all__'

class EnterpriseMemberSerializer(serializers.ModelSerializer):
    user_details = UserSerializer(source='user', read_only=True)
    
    class Meta:
        model = EnterpriseMember
        fields = ['id', 'user', 'user_details', 'role', 'joined_at']
        read_only_fields = ['id', 'joined_at']



import re
from django.core.validators import EmailValidator
from rest_framework.exceptions import ValidationError

class RegisterSerializer(serializers.ModelSerializer):
    password = serializers.CharField(write_only=True, min_length=6)

    username = serializers.CharField(
        error_messages={
            'unique': '该用户名已被占用，请尝试其他名称'
        }
    )
    phone = serializers.CharField(
        required=False,
        allow_blank=True,
        error_messages={
            'unique': '该手机号已注册，请直接登录'
        }
    )
    email = serializers.EmailField(
        required=False, 
        allow_blank=True,
        error_messages={
            'unique': '该邮箱已注册，请尝试其他邮箱'
        }
    )
    avatar_url = serializers.CharField(required=False, allow_blank=True)

    class Meta:


        model = User
        fields = ['username', 'phone', 'email', 'password', 'nickname', 'avatar_url']

    def validate_phone(self, value):
        if value:
            if not re.match(r'^1[3-9]\d{9}$', value):
                raise ValidationError('请输入有效的11位手机号')
            if User.objects.filter(phone=value, is_deleted=False).exists():
                raise ValidationError('该手机号已注册，请直接登录')
        return value

    def validate_email(self, value):
        if value:
            if User.objects.filter(email=value, is_deleted=False).exists():
                raise ValidationError('该邮箱已注册，请尝试其他邮箱')
        return value

    def validate_username(self, value):
        if User.objects.filter(username=value, is_deleted=False).exists():
            raise ValidationError('该用户名已被占用，请尝试其他名称')
        return value

    def create(self, validated_data):
        phone = validated_data.get('phone')
        if phone == '':
            phone = None
        email = validated_data.get('email')
        if email == '':
            email = None

        user = User.objects.create_user(
            username=validated_data['username'],
            phone=phone,
            email=email,
            password=validated_data['password'],
            nickname=validated_data.get('nickname'),
            avatar_url=validated_data.get('avatar_url', '')
        )
        # Auto-assign USER role
        from .models import Role, UserRole
        user_role, _ = Role.objects.get_or_create(code='USER', defaults={'name': '普通用户'})
        UserRole.objects.get_or_create(user=user, role=user_role)
        return user

class AdminUserCreateSerializer(serializers.ModelSerializer):
    password = serializers.CharField(write_only=True, min_length=6)
    email = serializers.EmailField(required=False, allow_blank=True)
    username = serializers.CharField(
        error_messages={'unique': '该用户名已被占用'}
    )
    phone = serializers.CharField(
        required=False, allow_blank=True,
        error_messages={'unique': '该手机号已注册'}
    )
    
    class Meta:
        model = User
        fields = ['username', 'phone', 'email', 'password', 'nickname']
        
    def validate_phone(self, value):
        if value:
            if not re.match(r'^1[3-9]\d{9}$', value):
                raise ValidationError('请输入有效的11位手机号')
            if User.objects.filter(phone=value).exists():
                raise ValidationError('该手机号已注册')
        return value

    def validate_email(self, value):
        if value:
            if User.objects.filter(email=value).exists():
                raise ValidationError('该邮箱已注册')
        return value

    def create(self, validated_data):
        phone = validated_data.get('phone')
        if phone == '':
            phone = None
            
        user = User.objects.create_user(
            username=validated_data['username'],
            phone=phone,
            email=validated_data.get('email'),
            password=validated_data['password'],
            nickname=validated_data.get('nickname')
        )
        # Auto-assign USER role
        from .models import Role, UserRole
        user_role, _ = Role.objects.get_or_create(code='USER', defaults={'name': '普通用户'})
        UserRole.objects.get_or_create(user=user, role=user_role)
        return user



class EnterpriseSerializer(serializers.ModelSerializer):
    user_details = UserSerializer(source='user', read_only=True)
    credit_code = serializers.CharField(
        error_messages={
            'unique': '该统一社会信用代码已注册，请核对信息'
        }
    )

    class Meta:

        model = Enterprise
        fields = ['id', 'user', 'user_details', 'company_name', 'credit_code', 'business_license', 'contact_name', 'contact_phone', 'landline', 'contact_email', 'address', 'description', 'status', 'logo_url', 'created_at', 'updated_at']
        read_only_fields = ['id', 'user', 'user_details', 'status', 'created_at', 'updated_at']


    def validate_credit_code(self, value):
        if value:
            if not re.match(r'^[A-Z0-9]{18}$', value):
                raise ValidationError('请输入有效的18位统一社会信用代码')
        return value


from django.db import transaction

class EnterpriseRegisterSerializer(serializers.Serializer):
    email = serializers.EmailField()
    password = serializers.CharField(write_only=True, min_length=6)
    company_name = serializers.CharField(max_length=255)
    credit_code = serializers.CharField(max_length=18)
    business_license = serializers.CharField(required=False, allow_blank=True)
    logo_url = serializers.CharField(required=False, allow_blank=True)

    def validate_credit_code(self, value):
        if not re.match(r'^[A-Z0-9]{18}$', value):
            raise ValidationError('请输入有效的18位统一社会信用代码')
        if Enterprise.objects.filter(credit_code=value).exists():
            raise ValidationError('该社会信用代码已注册')
        return value

    def validate_email(self, value):
        if User.objects.filter(email=value).exists():
            raise ValidationError('该邮箱已注册')
        return value

    def create(self, validated_data):
        with transaction.atomic():
            # 1. Create User
            user = User.objects.create_user(
                username=validated_data['email'],
                email=validated_data['email'],
                password=validated_data['password'],
                nickname=validated_data['company_name'],
                avatar_url=validated_data.get('logo_url')
            )

            # 2. Create Enterprise
            enterprise = Enterprise.objects.create(
                user=user,
                company_name=validated_data['company_name'],
                credit_code=validated_data['credit_code'],
                business_license=validated_data.get('business_license', ''),
                logo_url=validated_data.get('logo_url')
            )

            # 3. Assign Role
            from .models import Role, UserRole
            role, created = Role.objects.get_or_create(code='ENTERPRISE', defaults={'name': '企业用户'})
            UserRole.objects.get_or_create(user=user, role=role)

            return enterprise

class AdminEnterpriseCreateSerializer(serializers.ModelSerializer):
    email = serializers.EmailField(write_only=True)
    password = serializers.CharField(write_only=True, min_length=6)

    class Meta:
        model = Enterprise
        fields = ['email', 'password', 'company_name', 'credit_code', 'business_license', 'contact_name', 'contact_phone', 'contact_email', 'address', 'description', 'logo_url']

    def validate_credit_code(self, value):
        if value:
            if not re.match(r'^[A-Z0-9]{18}$', value):
                raise ValidationError('请输入有效的18位统一社会信用代码')
            if Enterprise.objects.filter(credit_code=value).exists():
                raise ValidationError('该社会信用代码已注册')
        return value

    def validate_email(self, value):
        if User.objects.filter(email=value).exists():
            raise ValidationError('该邮箱已注册，无法创建企业账号')
        return value

    def create(self, validated_data):
        email = validated_data.pop('email')
        password = validated_data.pop('password')
        
        with transaction.atomic():
            user = User.objects.create_user(
                username=email,
                email=email,
                password=password,
                nickname=validated_data['company_name'],
                avatar_url=validated_data.get('logo_url')
            )
            
            enterprise = Enterprise.objects.create(
                user=user,
                status='VERIFIED', # Admins create pre-verified enterprises
                **validated_data
            )
            
            from .models import Role, UserRole
            role, _ = Role.objects.get_or_create(code='ENTERPRISE', defaults={'name': '企业用户'})
            UserRole.objects.get_or_create(user=user, role=role)
            
            return enterprise

from django.contrib.auth import authenticate

class EnterpriseLoginSerializer(serializers.Serializer):
    login_type = serializers.ChoiceField(choices=['ADMIN', 'EMPLOYEE'], default='ADMIN')
    enterprise_email = serializers.EmailField()
    username = serializers.CharField(required=False, allow_blank=True)
    password = serializers.CharField(write_only=True)

    def validate(self, data):
        login_type = data.get('login_type', 'ADMIN')
        enterprise_email = data.get('enterprise_email')
        username = data.get('username')
        password = data.get('password')

        # 1. Find enterprise
        try:
            enterprise_user = User.objects.get(email=enterprise_email)
            enterprise = Enterprise.objects.get(user=enterprise_user)
        except (User.DoesNotExist, Enterprise.DoesNotExist):
            raise ValidationError({'detail': '企业邮箱未注册'})

        if login_type == 'ADMIN':
            # 2. Find and authenticate the admin
            if not enterprise_user.is_active or enterprise_user.is_deleted:
                raise ValidationError({'detail': '您的账号已被禁用，可能因为违规操作或安全风险。如有疑问请联系平台管理员。'})
            if not enterprise_user.check_password(password):
                raise ValidationError({'detail': '管理员邮箱或密码错误'})
            
            # Check if user is the enterprise owner
            user = enterprise_user
                
        else:
            # EMPLOYEE login
            if not username:
                raise ValidationError({'detail': '员工账号不能为空'})
                
            namespaced_username = f"{enterprise_email}_{username}"
            user = User.objects.filter(username=namespaced_username).first()
            
            if not user:
                raise ValidationError({'detail': '员工账号未注册'})
            if not user.is_active or user.is_deleted:
                raise ValidationError({'detail': '您的账号已被禁用，可能因为违规操作或安全风险。如有疑问请联系平台管理员。'})
            if not user.check_password(password):
                raise ValidationError({'detail': '员工账号或密码错误'})
                
            # Check if user is a member of the enterprise
            if not EnterpriseMember.objects.filter(enterprise=enterprise, user=user).exists():
                raise ValidationError({'detail': '该员工不属于此企业团队'})

        data['user'] = user
        return data

class EnterpriseMemberAddSerializer(serializers.Serializer):
    username = serializers.CharField()
    password = serializers.CharField(write_only=True, min_length=6)
    nickname = serializers.CharField(required=False, allow_blank=True)
    role = serializers.ChoiceField(choices=EnterpriseMember.MemberRole.choices, default=EnterpriseMember.MemberRole.MEMBER)
    enterprise_id = serializers.UUIDField(required=False)

    def _get_enterprise(self):
        request_user = self.context['request'].user
        enterprise_id = self.initial_data.get('enterprise_id')
        
        if enterprise_id and (request_user.is_staff or request_user.is_superuser):
            try:
                return Enterprise.objects.get(id=enterprise_id)
            except Enterprise.DoesNotExist:
                raise ValidationError('指定的企业不存在')
                
        try:
            return Enterprise.objects.get(user=request_user)
        except Enterprise.DoesNotExist:
            raise ValidationError('当前用户没有关联的企业主体')

    def validate_username(self, value):
        enterprise = self._get_enterprise()
            
        namespaced_username = f"{enterprise.user.email}_{value}"
        if User.objects.filter(username=namespaced_username).exists():
            raise ValidationError('该用户名已被占用')
        return value

    def create(self, validated_data):
        enterprise = self._get_enterprise()

        with transaction.atomic():
            namespaced_username = f"{enterprise.user.email}_{validated_data['username']}"
            user = User.objects.create_user(
                username=namespaced_username,
                password=validated_data['password'],
                nickname=validated_data.get('nickname', validated_data['username'])
            )

            # Assign ENTERPRISE role so they can access enterprise portal
            from .models import Role, UserRole
            role, _ = Role.objects.get_or_create(code='ENTERPRISE', defaults={'name': '企业用户'})
            UserRole.objects.get_or_create(user=user, role=role)

            member = EnterpriseMember.objects.create(
                enterprise=enterprise,
                user=user,
                role=validated_data.get('role', EnterpriseMember.MemberRole.MEMBER)
            )

        return member

class ChangePasswordSerializer(serializers.Serializer):
    old_password = serializers.CharField(required=True)
    new_password = serializers.CharField(required=True, min_length=6)

class PasswordResetRequestSerializer(serializers.Serializer):
    email = serializers.EmailField(required=True)

class PasswordResetConfirmSerializer(serializers.Serializer):
    email = serializers.EmailField(required=True)
    verification_code = serializers.CharField(required=True, min_length=6, max_length=6)
    new_password = serializers.CharField(required=True, min_length=6)