from django.contrib.auth import authenticate, get_user_model
from django.contrib.auth.password_validation import validate_password
from rest_framework import serializers

from .models import CompanyUser

User = get_user_model()


class SignupSerializer(serializers.ModelSerializer):
    password = serializers.CharField(
        write_only=True, required=True, validators=[validate_password]
    )
    password_confirm = serializers.CharField(write_only=True, required=True)

    class Meta:
        model = User
        fields = ('id', 'username', 'email', 'first_name', 'last_name', 'password', 'password_confirm')
        extra_kwargs = {
            'email': {'required': True},
            'first_name': {'required': False},
            'last_name': {'required': False},
        }

    def validate_email(self, value):
        if User.objects.filter(email__iexact=value).exists():
            raise serializers.ValidationError('A user with this email already exists.')
        return value.lower()

    def validate(self, attrs):
        if attrs['password'] != attrs.pop('password_confirm'):
            raise serializers.ValidationError({'password_confirm': 'Passwords do not match.'})
        return attrs

    def create(self, validated_data):
        user = User.objects.create_user(
            username=validated_data['username'],
            email=validated_data['email'],
            first_name=validated_data.get('first_name', ''),
            last_name=validated_data.get('last_name', ''),
            password=validated_data['password'],
        )
        return user


class LoginSerializer(serializers.Serializer):
    username = serializers.CharField(required=False)
    email = serializers.EmailField(required=False)
    password = serializers.CharField(write_only=True)

    def validate(self, attrs):
        username = attrs.get('username')
        email = attrs.get('email')
        password = attrs.get('password')

        if not username and not email:
            raise serializers.ValidationError('Either username or email is required.')

        # Resolve username from email if only email was supplied
        if not username and email:
            try:
                user_obj = User.objects.get(email__iexact=email)
                username = user_obj.username
            except User.DoesNotExist:
                raise serializers.ValidationError('No account found with this email address.')

        user = authenticate(
            request=self.context.get('request'),
            username=username,
            password=password,
        )
        if not user:
            raise serializers.ValidationError('Invalid credentials.')
        if not user.is_active:
            raise serializers.ValidationError('This account has been deactivated.')

        attrs['user'] = user
        return attrs


class UserDetailSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ('id', 'username', 'email', 'first_name', 'last_name', 'is_staff', 'date_joined')
        read_only_fields = fields


class SwitchCompanySerializer(serializers.Serializer):
    company_id = serializers.IntegerField(min_value=1)


class EmployeeCompanySerializer(serializers.ModelSerializer):
    company = serializers.SerializerMethodField()

    class Meta:
        model = CompanyUser
        fields = ('company', 'employment_number', 'user_type', 'status', 'work_email_address', 'phone_number')

    def get_company(self, obj):
        return {
            'id': obj.company.id,
            'company_name': obj.company.company_name,
            'company_description': obj.company.company_description,
            'company_logo': str(obj.company.company_logo) if obj.company.company_logo else None,
        }