package quota

/*
	ArOZ Online Storage Quota Limiting and Tracking Module
	author: tobychui

	This system track and limit the quota of the users.
*/

import (
	//"log"

	"os"
	"path/filepath"

	db "imuslab.com/arozos/mod/database"
	fs "imuslab.com/arozos/mod/filesystem"
)

//QuotaHandler Object
type QuotaHandler struct {
	database          *db.Database //System database for storing data
	username          string       //The current username for this handler
	fspool            []*fs.FileSystemHandler
	TotalStorageQuota int64
	UsedStorageQuota  int64
}

//Create a storage quotation handler for this user
func NewUserQuotaHandler(database *db.Database, username string, fsh []*fs.FileSystemHandler, defaultQuota int64) *QuotaHandler {
	//Create the quota table if not exists
	totalQuota := defaultQuota //Use defalt quota if init first time
	err := database.NewTable("quota")
	if err != nil {
		//Set this account to readonly.
		return &QuotaHandler{
			database:          database,
			username:          username,
			fspool:            fsh,
			TotalStorageQuota: 0,
			UsedStorageQuota:  0,
		}
	}

	//Get the user storage quota
	if !database.KeyExists("quota", username+"/quota") {
		//This user do not have a quota yet. Put in a default quota
		database.Write("quota", username+"/quota", defaultQuota)
	}

	//Load the user storage quota from database
	thisUserQuotaManager := QuotaHandler{
		database:          database,
		username:          username,
		fspool:            fsh,
		TotalStorageQuota: totalQuota,
		UsedStorageQuota:  0,
	}

	thisUserQuotaManager.CalculateQuotaUsage()
	return &thisUserQuotaManager
}

//Set and Get the user storage quota
func (q *QuotaHandler) SetUserStorageQuota(quota int64) {
	q.database.Write("quota", q.username+"/quota", quota)
	q.TotalStorageQuota = quota
}

func (q *QuotaHandler) GetUserStorageQuota() int64 {
	quota := int64(-2)
	q.database.Read("quota", q.username+"/quota", &quota)

	//Also update the one in memory
	q.TotalStorageQuota = quota
	return quota
}

//Check if the user's quota has been initialized
func (q *QuotaHandler) IsQuotaInitialized() bool {
	if q.GetUserStorageQuota() == int64(-2) {
		return false
	} else {
		return true
	}
}

func (q *QuotaHandler) RemoveUserQuota() {
	q.database.Delete("quota", q.username+"/quota")
}

func (q *QuotaHandler) HaveSpace(size int64) bool {
	remaining := q.TotalStorageQuota - q.UsedStorageQuota
	if q.TotalStorageQuota == -1 {
		return true
	}
	if size < remaining {
		return true
	} else {
		return false
	}
}

//Update the user's storage pool to new one
func (q *QuotaHandler) UpdateUserStoragePool(fsh []*fs.FileSystemHandler) {
	q.fspool = fsh
}

//Claim a space for the given file and set the file ownership to this user
func (q *QuotaHandler) AllocateSpace(filesize int64) error {
	q.UsedStorageQuota += filesize
	return nil
}

//Reclaim file occupied space (Call this before removing it)
func (q *QuotaHandler) ReclaimSpace(filesize int64) error {
	q.UsedStorageQuota -= filesize
	if q.UsedStorageQuota < 0 {
		q.UsedStorageQuota = 0
	}
	return nil
}

//Recalculate the user storage quota. This takes a lot of time and CPUs
func (q *QuotaHandler) CalculateQuotaUsage() {
	totalUsedVolume := int64(0)
	for _, thisfs := range q.fspool {
		if thisfs.Hierarchy == "user" {
			if !fs.FileExists(filepath.ToSlash(filepath.Clean(thisfs.Path)) + "/users/" + q.username) {
				//This folder not exists. Maybe not initialized
				continue
			}
			err := filepath.Walk(filepath.ToSlash(filepath.Clean(thisfs.Path))+"/users/"+q.username, func(path string, info os.FileInfo, err error) error {
				if info == nil || err != nil {
					//This file gone when quota is calculating. Ignore this
					return nil
				}
				if !info.IsDir() {
					totalUsedVolume += fs.GetFileSize(path)
				}
				return nil
			})
			if err != nil {
				continue
			}
		}
	}
	q.UsedStorageQuota = totalUsedVolume
}

func inSlice(slice []string, val string) (int, bool) {
	for i, item := range slice {
		if item == val {
			return i, true
		}
	}
	return -1, false
}