// Package cache provides optional Redis cache support.
package cache

import (
    "fmt"
    "errors"
    "context"
    "time"
    redis "github.com/go-redis/redis/v8"
    "git.kirsle.net/apps/gophertype/pkg/settings"
)

// Global Redis configuration.
var (
    RedisHost = "localhost"
    RedisPort = 6379
    RedisDB = 0

    RedisClient *redis.Client
    ready bool
)

// Error codes
var (
    ErrNotReady = errors.New("RedisClient not ready")
)

// Connect to Redis after loading the details from the site's settings.json.
func Connect() error {
    set := settings.Current
    if set.RedisEnabled {
        RedisClient = redis.NewClient(&redis.Options{
            Addr: fmt.Sprintf("%s:%d", set.RedisHost, set.RedisPort),
            DB: set.RedisDB,
        })
        return nil
    }
    return errors.New("Redis not enabled in .settings.json")
}

// SetEx sets a cache key with expiration.
func SetEx(key string, value string, exp int64) error {
    if RedisClient == nil {
        return ErrNotReady
    }

    err := RedisClient.Set(context.Background(), key, value, time.Duration(exp) * time.Second).Err()
    return err
}

// Get a cache key.
func Get(key string) (string, error) {
    if RedisClient == nil {
        return "", ErrNotReady
    }

    val, err := RedisClient.Get(context.Background(), key).Result()
    return val, err
}