package db_updater

import (
	"github.com/robfig/cron/v3"
	"github.com/rs/zerolog/log"
	"sync/atomic"
	"thuanle.me/ip-info/configs"
	"thuanle.me/ip-info/internal/data"
	"time"
)

// DbUpdatedAt stores the DB last-updated time as unix milliseconds.
// Accessed concurrently by the cron goroutine (writer) and the /metrics
// handler (reader), so it must be synchronized — hence atomic.Int64.
var DbUpdatedAt atomic.Int64

// DbUpdatedAtMillis returns the last DB update time in unix milliseconds,
// or 0 if the DB has never been updated.
func DbUpdatedAtMillis() int64 {
	return DbUpdatedAt.Load()
}

func StartUpdateDbService() {
	c := cron.New()
	_, _ = c.AddFunc("@daily", fetchDbs)
	c.Start()
	fetchDbs()
}

func fetchDbs() {
	newFlag := false
	for _, url := range configs.GeoDbSourcePaths {
		newFlag = download(url) || newFlag
	}

	if newFlag {
		log.Info().Msg("New DB downloaded. Recreating mmdb")
		if err := mergeMmdb(); err != nil {
			// Keep the current (previous) DB rather than reloading a
			// potentially empty/corrupt merge output.
			log.Err(err).Msg("Failed to merge mmdb, keeping current DB")
			return
		}

		err := data.Ins().Reload()
		if err != nil {
			log.Err(err).Msg("Failed to reload mmdb")
			return
		}

		DbUpdatedAt.Store(time.Now().UnixMilli())
	}
}