package cache

import (
	"context"
	"fmt"
	"time"

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

type Redis struct {
	client *redis.Client
}

func NewRedis(url string) (*Redis, error) {
	opts, err := redis.ParseURL(url)
	if err != nil {
		return nil, fmt.Errorf("parse redis url: %w", err)
	}

	client := redis.NewClient(opts)

	if err := client.Ping(context.Background()).Err(); err != nil {
		return nil, fmt.Errorf("ping redis: %w", err)
	}

	return &Redis{client: client}, nil
}

func (r *Redis) Close() error {
	return r.client.Close()
}

func (r *Redis) SetTTL(ctx context.Context, remote, path string, ttl time.Duration) error {
	key := fmt.Sprintf("ttl:%s:%s", remote, path)
	return r.client.Set(ctx, key, "1", ttl).Err()
}

func (r *Redis) CheckTTL(ctx context.Context, remote, path string) (bool, error) {
	key := fmt.Sprintf("ttl:%s:%s", remote, path)
	exists, err := r.client.Exists(ctx, key).Result()
	if err != nil {
		return false, err
	}
	return exists > 0, nil
}

func (r *Redis) AcquireLock(ctx context.Context, remote, path string, ttl time.Duration) (bool, error) {
	key := fmt.Sprintf("lock:%s:%s", remote, path)
	ok, err := r.client.SetNX(ctx, key, "1", ttl).Result()
	return ok, err
}

func (r *Redis) ReleaseLock(ctx context.Context, remote, path string) error {
	key := fmt.Sprintf("lock:%s:%s", remote, path)
	return r.client.Del(ctx, key).Err()
}

func (r *Redis) SetETag(ctx context.Context, remote, path, etag string, ttl time.Duration) error {
	key := fmt.Sprintf("etag:%s:%s", remote, path)
	return r.client.Set(ctx, key, etag, ttl).Err()
}

func (r *Redis) GetETag(ctx context.Context, remote, path string) (string, error) {
	key := fmt.Sprintf("etag:%s:%s", remote, path)
	val, err := r.client.Get(ctx, key).Result()
	if err == redis.Nil {
		return "", nil
	}
	return val, err
}

func (r *Redis) IncrCircuitFailure(ctx context.Context, remote string, cooldown time.Duration) (int64, error) {
	key := fmt.Sprintf("circuit:%s", remote)
	pipe := r.client.Pipeline()
	incr := pipe.Incr(ctx, key)
	pipe.Expire(ctx, key, cooldown)
	_, err := pipe.Exec(ctx)
	if err != nil {
		return 0, err
	}
	return incr.Val(), nil
}

func (r *Redis) ResetCircuit(ctx context.Context, remote string) error {
	key := fmt.Sprintf("circuit:%s", remote)
	return r.client.Del(ctx, key).Err()
}

func (r *Redis) GetCircuitFailures(ctx context.Context, remote string) (int64, error) {
	key := fmt.Sprintf("circuit:%s", remote)
	val, err := r.client.Get(ctx, key).Int64()
	if err == redis.Nil {
		return 0, nil
	}
	return val, err
}

func (r *Redis) FlushRemote(ctx context.Context, remote string) error {
	iter := r.client.Scan(ctx, 0, fmt.Sprintf("*:%s:*", remote), 100).Iterator()
	for iter.Next(ctx) {
		r.client.Del(ctx, iter.Val())
	}
	return iter.Err()
}