package hybridBackup

import (
	"log"
	"path/filepath"
	"strings"
	"time"
)

/*
	Hybrid Backup

	This module handle backup functions from the drive with Hieracchy labeled as "backup"
	Backup modes suport in this module currently consists of

	Denote P drive as parent drive and B drive as backup drive.
	1. Smart (smart):
		- Any new file created in P will be copied to B within 5 minutes
		- Any file removed in P will be delete from backup after 24 hours
	2. Nightly (nightly):
		- The whole P drive will be copied to N drive every night
	3. Append Only (append)
		- Any new file created in P will be copied to B within 5 minutes
		- No file will be removed from B unless drive is fulled (Similar to CCTV recorder)

*/

type BackupConfig struct {
	CycleCounter  int64  //The number of backup executed in the background
	LastCycleTime int64  //The execution time of the last cycle
	DiskUID       string //The UID of the target fsandlr
	DiskPath      string //The mount point for the disk
	ParentUID     string //Parent virtal disk UUID
	ParentPath    string //Parent disk path
	Mode          string //Backup mode
}

//Main handler function for hybrid backup
func HandleBackupProcess(backupConfig *BackupConfig) (string, error) {
	log.Println(">>>>>> Running backup process: ", backupConfig)
	rootPath := filepath.ToSlash(filepath.Clean(backupConfig.ParentPath))

	//Check if the target disk is writable and mounted
	if fileExists(filepath.Join(backupConfig.DiskPath, "aofs.db")) && fileExists(filepath.Join(backupConfig.DiskPath, "aofs.db.lock")) {
		//This filesystem is mounted

	} else {
		//File system not mounted. Skipping
		log.Println("*HybridBackup* Skipping backup cycle for " + backupConfig.ParentUID + ":/")
		return "Parent drive (" + backupConfig.ParentUID + ":/) not mounted. Skipping", nil
	}

	if backupConfig.Mode == "smart" {
		//Smart backup mode. Scan new files every minutes and compare creation time scan every hour minutes
		if backupConfig.CycleCounter%5 == 0 {
			//Perform deep backup, use walk function

		} else {
			//Perform shallow backup
			fastWalk(rootPath, func(filename string) error {
				rootAbs, _ := filepath.Abs(rootPath)
				fileAbs, _ := filepath.Abs(filename)

				rootAbs = filepath.ToSlash(filepath.Clean(rootAbs))
				fileAbs = filepath.ToSlash(filepath.Clean(fileAbs))

				relPath := strings.ReplaceAll(fileAbs, rootAbs, "")
				assumedTargetPosition := filepath.Join(backupConfig.DiskPath, relPath)
				if !fileExists(assumedTargetPosition) {
					//Target file not exists in backup disk. Make a copy
					//WIP
					log.Println("Copying ", assumedTargetPosition)
				}

				return nil
			})
		}
	} else if backupConfig.Mode == "nightly" {

	} else if backupConfig.Mode == "append" {

	}

	//Add one to the cycle counter
	backupConfig.CycleCounter++
	backupConfig.LastCycleTime = time.Now().Unix()

	//Return the log information
	return "", nil
}