package confg

import (
	"bytes"
	"github.com/fsnotify/fsnotify"
	"github.com/goccy/go-json"
	"github.com/spf13/viper"
	"go.uber.org/zap"
	"path/filepath"
	"sync"
)

type RWLock interface {
	sync.Locker
	RLock()
	RUnlock()
}

type Config interface {
	RWLock
}

func WriteConf(path string, conf any) (err error) {
	var data []byte
	data, err = json.Marshal(conf)

	v := newViper(path)
	if err = v.ReadConfig(bytes.NewBuffer(data)); err != nil {
		return
	}
	v.SetConfigType(filepath.Ext(path))
	err = v.WriteConfig()
	return
}

func ReadConf(path string, conf any) error {
	return updateConfig(newViper(path), conf)
}

func ReadConfAndWatch(path string, conf Config, up func()) (err error) {
	v := newViper(path)

	if err = updateConfig(v, conf); err != nil {
		return
	}

	onUpdate := func(in fsnotify.Event) {
		zap.L().Info("watch file", zap.Any("event", in))
		if in.Name == "WRITE" {
			conf.Lock()
			defer conf.Unlock()
			err = updateConfig(v, conf)
		}

		if err != nil {
			zap.L().Error("auto update config err", zap.String("path", path), zap.Error(err))
			return
		}

		if up != nil {
			up()
		}
	}

	// watch config WRITE event reread config
	v.OnConfigChange(onUpdate)
	v.WatchConfig()
	return
}

func newViper(path string) (v *viper.Viper) {
	v = viper.New()
	v.SetConfigFile(path)
	ext := filepath.Ext(path)
	v.SetConfigType(ext[1:])
	return
}

func updateConfig(v *viper.Viper, conf any) (err error) {
	if err = v.ReadInConfig(); err != nil {
		return
	}

	if err = v.Unmarshal(conf); err != nil {
		return
	}
	return
}