package localcache

import (
	"fmt"
	"os"
	"time"

	"gitee.com/chenhonghua/ginorigin/log"
	"gitee.com/chenhonghua/ginorigin/timezone"

	"github.com/robfig/cron"

	"github.com/patrickmn/go-cache"
)

var (
	localCache             *cache.Cache
	localCacheConfig       LocalCacheConfig
	defaultExpiration      time.Duration
	defaultCleanupInterval time.Duration
)

type LocalCacheConfig struct {
	Expiration      int         `mapstructure:"expiration" json:"expiration" yaml:"expiration"`                  // 过期时间，如果为0，则永不过期
	CleanupInterval int         `mapstructure:"cleanup-interval" json:"cleanupInterval" yaml:"cleanup-interval"` // 清理间隔，如果为0，则不执行自动清理
	Persistence     Persistance `mapstructure:"persistance" json:"persistance" yaml:"persistance"`               // 持久化
}

type Persistance struct {
	Enable              bool   `mapstructure:"enable" json:"enable" yaml:"enable"`                                            // 是否启用
	PersistanceOnChange bool   `mapstructure:"persistance_on_change" json:"persistanceOnChange" yaml:"persistance_on_change"` // 数据发生改变时保存
	File                string `mapstructure:"file" json:"file" yaml:"file"`                                                  // 文件路径
	Spec                string `mapstructure:"spec" json:"spec" yaml:"spec"`                                                  // 持久化定时调度表达式，"0 */1 * * * *"
	ShowPersistanceLog  bool   `mapstructure:"show_persistance_log" json:"showPersistanceLog" yaml:"show_persistance_log"`    // 是否记录持久化的日志
}

func (lc LocalCacheConfig) Load() {
	if localCache != nil {
		return
	}
	localCacheConfig = lc
	log.Infof("启用本地缓存:%v\n", localCacheConfig)
	defaultExpiration = time.Duration(lc.Expiration) * time.Second
	defaultCleanupInterval = time.Duration(lc.CleanupInterval) * time.Second
	localCache = cache.New(defaultExpiration, defaultCleanupInterval)
	if lc.Persistence.Enable { // 启用缓存持久化
		// if len(lc.Persistence.Spec) == 0 { // 无效的表达式
		// 	log.PanicIfErr(fmt.Errorf("缓存持久化表达式错误：%s", lc.Persistence.Spec))
		// }
		go lc.persistanceSchedule()
		if fi, err := os.Stat(lc.Persistence.File); err != nil {
			return
		} else if fi.IsDir() {
			log.Fatal(fmt.Errorf("路径[%s]是文件夹，无法作为缓存持久化文件", lc.Persistence.File))
		}
		log.Info(fmt.Sprintf("开始从文件[%s]加载缓存\n", lc.Persistence.File))
		if err := localCache.LoadFile(lc.Persistence.File); err != nil { // 从文件加载缓存
			log.Errorf("从文件[%s]加载缓存错误：%v\n", lc.Persistence.File, err)
		}
	}
}

// 缓存持久化
func (lc LocalCacheConfig) persistanceSchedule() {
	if len(lc.Persistence.Spec) == 0 {
		return
	}
	i := 0
	log.Infof("开始启动本地缓存持久化定时任务：spec = %s \n", lc.Persistence.Spec)
	c := cron.NewWithLocation(timezone.LOCATION)
	c.AddFunc(lc.Persistence.Spec, func() {
		if lc.Persistence.ShowPersistanceLog {
			i++
			log.Debugf("第%d次执行，开始持久化本地缓存到文件[%s]\n", i, lc.Persistence.File)
		}
		if err := Default.SaveFile(lc.Persistence.File); err != nil {
			log.Errorf("本地缓存持久化失败：%v\n", err)
		}
	})
	c.Start()
	defer c.Stop()
	select {}
}