package repository

import (
	"context"
	"fmt"
	"time"

	"github.com/redis/go-redis/v9"
)

const customerLoginAttemptKeyPrefix = "customer_login:attempts:"

// CustomerLoginAttemptRepository counts customer login attempts per phone number, so a
// password cannot be guessed by trying many.
type CustomerLoginAttemptRepository interface {
	// Hit counts one attempt for the phone number. It returns the attempts counted in
	// the current window, this one included, and how long the window still runs. A
	// window starts at the first attempt after the previous one ended.
	Hit(ctx context.Context, phoneNumber string, window time.Duration) (int64, time.Duration, error)
	// Reset forgets the attempts of the phone number.
	Reset(ctx context.Context, phoneNumber string) error
}

type customerLoginAttemptRepository struct {
	client *redis.Client
}

func NewCustomerLoginAttemptRepository(client *redis.Client) CustomerLoginAttemptRepository {
	return &customerLoginAttemptRepository{client: client}
}

func (r *customerLoginAttemptRepository) Hit(ctx context.Context, phoneNumber string, window time.Duration) (int64, time.Duration, error) {
	key := customerLoginAttemptKeyPrefix + phoneNumber
	// One transaction, so the key never exists without its expiry: concurrent attempts
	// all count, and a crash cannot leave a number locked for good.
	pipe := r.client.TxPipeline()
	pipe.SetNX(ctx, key, 0, window)
	count := pipe.Incr(ctx, key)
	left := pipe.PTTL(ctx, key)
	if _, err := pipe.Exec(ctx); err != nil {
		return 0, 0, fmt.Errorf("count login attempt: %w", err)
	}
	return count.Val(), left.Val(), nil
}

func (r *customerLoginAttemptRepository) Reset(ctx context.Context, phoneNumber string) error {
	if err := r.client.Del(ctx, customerLoginAttemptKeyPrefix+phoneNumber).Err(); err != nil {
		return fmt.Errorf("reset login attempts: %w", err)
	}
	return nil
}