package storage

import (
	"context"
	"fmt"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/dynamodb/attributevalue"
	"github.com/aws/aws-sdk-go-v2/service/dynamodb"
	"github.com/aws/aws-sdk-go-v2/service/dynamodb/types"

	"custom-start-page/internal/models"
)

// UserRepository handles user data operations
type UserRepository struct {
	client    *DynamoDBClient
	tableName string
}

// NewUserRepository creates a new user repository
func NewUserRepository(client *DynamoDBClient, tableName string) *UserRepository {
	return &UserRepository{
		client:    client,
		tableName: tableName,
	}
}

// Create creates a new user in the database
func (r *UserRepository) Create(ctx context.Context, user *models.User) error {
	item, err := attributevalue.MarshalMap(user)
	if err != nil {
		return fmt.Errorf("failed to marshal user: %w", err)
	}

	_, err = r.client.GetClient().PutItem(ctx, &dynamodb.PutItemInput{
		TableName: aws.String(r.tableName),
		Item:      item,
	})
	if err != nil {
		return fmt.Errorf("failed to create user: %w", err)
	}

	return nil
}

// GetByID retrieves a user by their ID
func (r *UserRepository) GetByID(ctx context.Context, userID string) (*models.User, error) {
	result, err := r.client.GetClient().GetItem(ctx, &dynamodb.GetItemInput{
		TableName: aws.String(r.tableName),
		Key: map[string]types.AttributeValue{
			"user_id": &types.AttributeValueMemberS{Value: userID},
		},
	})
	if err != nil {
		return nil, fmt.Errorf("failed to get user: %w", err)
	}

	if result.Item == nil {
		return nil, fmt.Errorf("user not found")
	}

	var user models.User
	if err := attributevalue.UnmarshalMap(result.Item, &user); err != nil {
		return nil, fmt.Errorf("failed to unmarshal user: %w", err)
	}

	return &user, nil
}

// GetByOAuthID retrieves a user by their OAuth provider and OAuth ID
func (r *UserRepository) GetByOAuthID(ctx context.Context, provider, oauthID string) (*models.User, error) {
	// Use a scan with filter for now
	// In production, consider adding a GSI on oauth_provider + oauth_id
	result, err := r.client.GetClient().Scan(ctx, &dynamodb.ScanInput{
		TableName:        aws.String(r.tableName),
		FilterExpression: aws.String("oauth_provider = :provider AND oauth_id = :oauth_id"),
		ExpressionAttributeValues: map[string]types.AttributeValue{
			":provider":  &types.AttributeValueMemberS{Value: provider},
			":oauth_id": &types.AttributeValueMemberS{Value: oauthID},
		},
	})
	if err != nil {
		return nil, fmt.Errorf("failed to scan users: %w", err)
	}

	if len(result.Items) == 0 {
		return nil, fmt.Errorf("user not found")
	}

	var user models.User
	if err := attributevalue.UnmarshalMap(result.Items[0], &user); err != nil {
		return nil, fmt.Errorf("failed to unmarshal user: %w", err)
	}

	return &user, nil
}

// Update updates an existing user
func (r *UserRepository) Update(ctx context.Context, user *models.User) error {
	item, err := attributevalue.MarshalMap(user)
	if err != nil {
		return fmt.Errorf("failed to marshal user: %w", err)
	}

	_, err = r.client.GetClient().PutItem(ctx, &dynamodb.PutItemInput{
		TableName: aws.String(r.tableName),
		Item:      item,
	})
	if err != nil {
		return fmt.Errorf("failed to update user: %w", err)
	}

	return nil
}