/*
Copyright 2019 The KubeSphere Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package cache

import (
	"errors"
	"fmt"
	"time"

	"github.com/go-redis/redis"
	"github.com/mitchellh/mapstructure"
	"k8s.io/klog"
)

const typeRedis = "redis"

type redisClient struct {
	client *redis.Client
}

// redisOptions used to create a redis client.
type redisOptions struct {
	Host     string `json:"host" yaml:"host" mapstructure:"host"`
	Port     int    `json:"port" yaml:"port" mapstructure:"port"`
	Password string `json:"password" yaml:"password" mapstructure:"password"`
	DB       int    `json:"db" yaml:"db" mapstructure:"db"`
}

func NewRedisClient(option *redisOptions, stopCh <-chan struct{}) (Interface, error) {
	var r redisClient

	redisOptions := &redis.Options{
		Addr:     fmt.Sprintf("%s:%d", option.Host, option.Port),
		Password: option.Password,
		DB:       option.DB,
	}

	if stopCh == nil {
		klog.Fatalf("no stop channel passed, redis connections will leak.")
	}

	r.client = redis.NewClient(redisOptions)

	if err := r.client.Ping().Err(); err != nil {
		r.client.Close()
		return nil, err
	}

	// close redis in case of connection leak
	if stopCh != nil {
		go func() {
			<-stopCh
			if err := r.client.Close(); err != nil {
				klog.Error(err)
			}
		}()
	}

	return &r, nil
}

func (r *redisClient) Get(key string) (string, error) {
	return r.client.Get(key).Result()
}

func (r *redisClient) Keys(pattern string) ([]string, error) {
	return r.client.Keys(pattern).Result()
}

func (r *redisClient) Set(key string, value string, duration time.Duration) error {
	return r.client.Set(key, value, duration).Err()
}

func (r *redisClient) Del(keys ...string) error {
	return r.client.Del(keys...).Err()
}

func (r *redisClient) Exists(keys ...string) (bool, error) {
	existedKeys, err := r.client.Exists(keys...).Result()
	if err != nil {
		return false, err
	}

	return len(keys) == int(existedKeys), nil
}

func (r *redisClient) Expire(key string, duration time.Duration) error {
	return r.client.Expire(key, duration).Err()
}

type redisFactory struct{}

func (rf *redisFactory) Type() string {
	return typeRedis
}

func (rf *redisFactory) Create(options DynamicOptions, stopCh <-chan struct{}) (Interface, error) {
	var rOptions redisOptions
	if err := mapstructure.Decode(options, &rOptions); err != nil {
		return nil, err
	}
	if rOptions.Port == 0 {
		return nil, errors.New("invalid service port number")
	}
	if len(rOptions.Host) == 0 {
		return nil, errors.New("invalid service host")
	}
	client, err := NewRedisClient(&rOptions, stopCh)
	if err != nil {
		return nil, err
	}
	return client, nil
}

func init() {
	RegisterCacheFactory(&redisFactory{})
}