// backgroundJobs provides functions to start and stop the background jobs loop
// This is a loop that runs various jobs in the background periodically
// The backgroundJobs loop must be started when a user signs in, and stopped when they sign out

package backgroundJobs

// TODO: Add these jobs:
// -Remove old moderator reviews (where moderator has updated their review)(within reviews list)
// -Prune old profiles (if they are outdated and not reported/moderated with ban reviews)
// -Import broadcasted reviews and profiles into database (needed if restoring from old device/database is deleted)
// -Broadcast content (rebroadcast content in the background on a set period)
// -Find reviews with cipher keys that do not hash to the message cipherKeyHash, messages that are not decryptable
//		when using a cipherKey that hashes to the message's cipherKeyHash, and messages that are invalid upon being decrypted.
//		Ban the moderators who approved the messages (if ModeratorMode is enabled)
//		Also, automatically ban these kinds of messages.
// -Delete messages whose metadata we already have (for moderation, if HostMode is disabled and ModeratorMode is enabled)
// -Prune invalid message reports (whose cipher key's hash does not match message's cipherKeyHash)
// -Prune unfunded/expired identities/profiles/reports/messages
// -Prune old profiles/reviews once they have been replaced, if we know they are not reported or banned
//		We have to keep content that has been banned for some time, even if it has been replaced with newer content by its author
//		This is necessary so the moderators can review the content
//		An example is a mate user who shares unruleful content in a profile, then changes their profile to something ruleful	
// -Prune content we have already reviewed (in moderatorMode)
// Prune user profiles who no longer fulfill my downloads criteria (if space is running out and host/moderator mode is disabled)
// -Delete a mate user's older profiles if they have a newer profile that does not 
//		fulfill our criteria, even if that newer profile is not viewable yet (for users who are not within our host/moderator range)
// -Prune database of different networkType content
// -Moderators should automatically ban other moderators who review content from a different networkType
// 		For example, a review is created on Mainnet for a message which belongs to Testnet1
// 		The Seekia app will not allow this to happen, so any moderator who does it must be malicious.

//TODO: If a user disables a mode, we should be able to stop all of the jobs associated with that mode
// We will do this by using the checkIfStopped function which we will pass to all of the networkJobs
// We will also use the checkIfStopped function to stop networkJobs upon application closure and user signout.

import "seekia/internal/appMemory"
import "seekia/internal/databaseJobs"
import "seekia/internal/helpers"
import "seekia/internal/logger"
import "seekia/internal/moderation/bannedModeratorConsensus"
import "seekia/internal/moderation/enabledModerators"
import "seekia/internal/moderation/verdictHistory"
import "seekia/internal/myRanges"
import "seekia/internal/mySettings"
import "seekia/internal/network/appNetworkType/getAppNetworkType"
import "seekia/internal/network/enabledHosts"
import "seekia/internal/network/networkJobs"
import "seekia/internal/network/peerServer"

import "errors"
import "sync"
import "time"

var loopIsRunningMutex sync.RWMutex
var loopIsRunning bool

var taskCompletionTimesMapMutex sync.RWMutex
// Map Structure: Task name -> Last time task was completed
var taskCompletionTimesMap map[string]int64 = make(map[string]int64)

var runningTasksMapMutex sync.RWMutex
// Map Structure: Task Name -> Task is running
var runningTasksMap map[string]bool = make(map[string]bool)

func setLoopIsRunningStatus(newStatus bool){

	loopIsRunningMutex.Lock()
	loopIsRunning = newStatus
	loopIsRunningMutex.Unlock()
}

func StopBackgroundJobs()error{

	//TODO
	// This needs to be run whenever the user is changed
	// This will be tricky to implement, because some tasks take a long time
	// We need to add isStopped checking into many functions such as sendRequests
	// This function should wait for all tasks to stop.

	setLoopIsRunningStatus(false)

	return nil
}

func StartBackgroundJobs()error{

	exists, currentUserName := appMemory.GetMemoryEntry("AppUser")
	if (exists == false){
		return errors.New("StartBackgroundJobs called when appUser is not signed in.")
	}

	checkIfUserHasChanged := func()bool{

		exists, userName := appMemory.GetMemoryEntry("AppUser")
		if (exists == false || currentUserName != userName){
			return true
		}

		return false
	}

	appNetworkType, err := getAppNetworkType.GetAppNetworkType()
	if (err != nil) { return err }

	checkIfAppNetworkTypeHasChanged := func()(bool, error){

		currentAppNetworkType, err := getAppNetworkType.GetAppNetworkType()
		if (err != nil) { return false, err }
		if (appNetworkType != currentAppNetworkType){
			return true, nil
		}

		return false, nil
	}

	setLoopIsRunningStatus(true)

	runBackgroundJobsLoop := func(){

		//TODO: Stagger jobs, so we don't start them all at the same time
		// If we start them all at the same time, it could result in fingerprinting and privacy leaks

		for{

			userHasChanged := checkIfUserHasChanged()
			if (userHasChanged == true){
				// This should not happen
				// User should only be changed after this loop has stopped
				logger.AddLogError("BackgroundJobs", errors.New("App user changed before backgroundJobs loop is stopped."))
				return
			}

			appNetworkTypeHasChanged, err := checkIfAppNetworkTypeHasChanged()
			if (err != nil){
				logger.AddLogError("BackgroundJobs", err)
				return
			}
			if (appNetworkTypeHasChanged == true){
				// This should not happen
				// App network type should only be changed after this loop has stopped
				logger.AddLogError("BackgroundJobs", errors.New("App network type changed before backgroundJobs loop is stopped."))
				return
			}

			type taskStruct struct{

				// A task name is a jobName with a suffix representing the task process
				TaskName string

				// The name of the Job which this task will run
				JobName string

				// Seconds between each completed run of the task to wait before we run it again
				TimeBetweenTasks int
			}

			// For example, _1 is the first process, _2 is the second, etc...
			getTasksList := func()([]taskStruct, error){

				tasksList := make([]taskStruct, 0)

				addTasksToList := func(jobName string, timeBetweenTasks int, numberOfProcesses int){

					for i:=1; i <= numberOfProcesses; i++{

						processString := helpers.ConvertIntToString(i)

						taskName := jobName + "_" + processString

						newTaskObject := taskStruct{

							TaskName: taskName,
							JobName: jobName,
							TimeBetweenTasks: timeBetweenTasks,
						}

						tasksList = append(tasksList, newTaskObject)
					}
				}

				//TODO: Choose better timeBetweenTasks and numberOfProcesses values

				addTasksToList("UpdateEnabledHosts", 60, 1)

				addTasksToList("DownloadParameters", 120, 1)

				// Database Jobs:

				addTasksToList("UpdateDatabaseMateIdentityProfilesLists", 300, 1)
				addTasksToList("UpdateDatabaseHostIdentityProfilesLists", 300, 1)
				addTasksToList("UpdateDatabaseModeratorIdentityProfilesLists", 300, 1)

				addTasksToList("PruneMateProfileMetadata", 300, 1)
				addTasksToList("PruneHostProfileMetadata", 300, 1)
				addTasksToList("PruneModeratorProfileMetadata", 300, 1)
				addTasksToList("PruneMessageMetadata", 300, 1)

				// Host Jobs:

				getHostModeIsEnabledStatus := func()(bool, error){

					exists, hostModeStatus, err := mySettings.GetSetting("HostModeOnOffStatus")
					if (err != nil) { return false, err }
					if (exists == true && hostModeStatus == "On"){

						return true, nil
					}
					return false, nil
				}

				hostModeIsEnabled, err := getHostModeIsEnabledStatus()
				if (err != nil){ return nil, err }
				if (hostModeIsEnabled == true){

					addTasksToList("AdjustMyHostRanges", 120, 1)

					addTasksToList("DownloadMateProfilesToHost", 60, 1)
					addTasksToList("DownloadHostProfilesToHost", 60, 1)
					addTasksToList("DownloadModeratorProfilesToHost", 60, 1)

					addTasksToList("DownloadMessagesToHost", 60, 1)
					addTasksToList("DownloadReviewsToHost", 60, 1)
					addTasksToList("DownloadReportsToHost", 60, 1)

					addTasksToList("StartPeerServer", 3, 1)
				} else {
					addTasksToList("StopPeerServer", 3, 1)
				}

				// Moderator Jobs:

				getModeratorModeIsEnabledStatus := func()(bool, error){

					exists, moderatorModeStatus, err := mySettings.GetSetting("ModeratorModeOnOffStatus")
					if (err != nil){ return false, err }
					if (exists == true && moderatorModeStatus == "On"){
						return true, nil
					}
	
					return false, nil
				}

				moderatorModeIsEnabled, err := getModeratorModeIsEnabledStatus()
				if (err != nil) { return nil, err }
				if (moderatorModeIsEnabled == true){

					addTasksToList("AdjustMyModeratorRanges", 120, 1)
				}

				if (hostModeIsEnabled == true || moderatorModeIsEnabled == true){

					addTasksToList("UpdateEnabledModerators", 60, 1)
					addTasksToList("UpdateBannedModerators", 60, 1)

					addTasksToList("RecordIdentityVerdictHistories", 120, 1)
					addTasksToList("RecordProfileVerdictHistories", 120, 1)
					addTasksToList("RecordMessageVerdictHistories", 120, 1)

				}

				addTasksToList("DownloadMyMateMessages", 1, 3)
				if (moderatorModeIsEnabled == true){
					addTasksToList("DownloadMyModeratorMessages", 1, 3)
				}

				//TODO: Add tasks from networkJobs.go, and more tasks:

				// networkJobs.DownloadAllNewestViewableUserProfiles
				// networkJobs.DownloadMateProfilesToBrowse
				// networkJobs.DownloadMateOutlierProfiles
				// networkJobs.DownloadProfilesToModerate
				// networkJobs.DownloadMessagesToModerate
				// networkJobs.DownloadMyInboxMessages
				// networkJobs.DownloadModeratorIdentityBanningReviews

				// networkJobs.DownloadIdentityReviewsToHost
				// networkJobs.DownloadMessageReviewsToHost
				// networkJobs.DownloadIdentityReviewsForModeration
				// networkJobs.DownloadMessageReviewsForModeration
				// networkJobs.DownloadIdentityReportsToHost
				// networkJobs.DownloadMessageReportsToHost
				// networkJobs.DownloadIdentityReportsForModeration
				// networkJobs.DownloadMessageReportsForModeration

				// networkJobs.DownloadHostViewableStatuses
				// networkJobs.DownloadModeratorProfileViewableStatuses
				// networkJobs.DownloadMateViewableStatusesForBrowsing
				// networkJobs.DownloadMateOutlierViewableStatuses

				// If local blockchain is not enabled and host/moderator mode is enabled:
				// networkJobs.DownloadModeratorIdentityDeposits

				// myMessageQueue.AttemptToSendMessagesInQueue

				// myBroadcasts.PruneMyBroadcastedReviews

				return tasksList, nil
			}

			tasksList, err := getTasksList()
			if (err != nil) {
				logger.AddLogError("BackgroundJobs", err)
				return
			}

			for _, taskObject := range tasksList{

				taskName := taskObject.TaskName
				jobName := taskObject.JobName
				taskWaitTime := taskObject.TimeBetweenTasks

				runningTasksMapMutex.RLock()
				taskIsRunning, exists := runningTasksMap[taskName]
				runningTasksMapMutex.RUnlock()
				if (exists == true && taskIsRunning == true){
					// Task is already running.
					// We skip it.
					continue
				}

				taskCompletionTimesMapMutex.RLock()
				taskLastCompletionTime, exists := taskCompletionTimesMap[taskName]
				taskCompletionTimesMapMutex.RUnlock()
				if (exists == true){

					currentTime := time.Now().Unix()
					timeElapsedFromLastCompletion := currentTime - taskLastCompletionTime
					if (timeElapsedFromLastCompletion < int64(taskWaitTime)){
						continue
					}
				}

				// Now we run the task
				// We get the task's job function

				//TODO: Add a CheckIfStoppedFunction that we pass to many jobs
				// This will return true if the user is signing out/closing Seekia

				getJobFunction := func()(func()error, error){

					if (jobName == "UpdateEnabledModerators"){

						jobFunction := func()error{

							err := enabledModerators.UpdateEnabledModeratorsList(appNetworkType)

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "UpdateBannedModerators"){

						jobFunction := func()error{

							err := bannedModeratorConsensus.UpdateBannedModeratorsList(appNetworkType)

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "UpdateEnabledHosts"){

						jobFunction := func()error{

							err := enabledHosts.UpdateEnabledHostsList(appNetworkType)

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "AdjustMyHostRanges"){

						jobFunction := func()error{

							err := myRanges.AdjustMyRanges("Host")

							return err
						}
						return jobFunction, nil
					}
					if (jobName == "AdjustMyModeratorRanges"){

						jobFunction := func()error{

							err := myRanges.AdjustMyRanges("Moderator")
				
							return err
						}
						return jobFunction, nil
					}

					if (jobName == "UpdateDatabaseMateIdentityProfilesLists"){

						jobFunction := func()error{

							err := databaseJobs.UpdateDatabaseIdentityProfilesLists("Mate")

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "UpdateDatabaseHostIdentityProfilesLists"){

						jobFunction := func()error{

							err := databaseJobs.UpdateDatabaseIdentityProfilesLists("Host")

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "UpdateDatabaseModeratorIdentityProfilesLists"){

						jobFunction := func()error{

							err := databaseJobs.UpdateDatabaseIdentityProfilesLists("Moderator")

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "PruneMateProfileMetadata"){

						jobFunction := func()error{

							err := databaseJobs.PruneProfileMetadata("Mate")

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "PruneHostProfileMetadata"){

						jobFunction := func()error{

							err := databaseJobs.PruneProfileMetadata("Host")

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "PruneModeratorProfileMetadata"){

						jobFunction := func()error{

							err := databaseJobs.PruneProfileMetadata("Moderator")

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "PruneMessageMetadata"){

						jobFunction := databaseJobs.PruneMessageMetadata

						return jobFunction, nil
					}

					if (jobName == "DownloadParameters"){

						jobFunction := func()error{

							err := networkJobs.DownloadParameters(appNetworkType)

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "DownloadMateProfilesToHost"){

						jobFunction := func()error{

							err := networkJobs.DownloadProfilesToHost("Mate", appNetworkType)

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "DownloadHostProfilesToHost"){

						jobFunction := func()error{

							err := networkJobs.DownloadProfilesToHost("Host", appNetworkType)

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "DownloadModeratorProfilesToHost"){

						jobFunction := func()error{

							err := networkJobs.DownloadProfilesToHost("Moderator", appNetworkType)

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "DownloadMessagesToHost"){

						jobFunction := func()error{

							err := networkJobs.DownloadMessagesToHost(appNetworkType)

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "StartPeerServer"){

						jobFunction := peerServer.StartPeerServer

						return jobFunction, nil
					}
					if (jobName == "StopPeerServer"){

						jobFunction := peerServer.StopPeerServer

						return jobFunction, nil
					}
					if (jobName == "RecordIdentityVerdictHistories"){

						jobFunction := func()error{

							err := verdictHistory.RecordIdentityVerdictsToHistoryMap(appNetworkType)

							return err
						}

						return jobFunction, nil
					}
					if (jobName == "RecordProfileVerdictHistories"){

						jobFunction := func()error{

							err := verdictHistory.RecordProfileVerdictsToHistoryMap(appNetworkType)

							return err
						}
						return jobFunction, nil
					}
					if (jobName == "RecordMessageVerdictHistories"){

						jobFunction := func()error{

							err := verdictHistory.RecordMessageVerdictsToHistoryMap(appNetworkType)

							return err
						}

						return jobFunction, nil
					}

					if (jobName == "DownloadMyMateMessages"){
		
						jobFunction := func()error{
	
							err := networkJobs.DownloadMyInboxMessages("Mate", appNetworkType)

							return err
						}

						return jobFunction, nil
					}

					if (jobName == "DownloadMyModeratorMessages"){
		
						jobFunction := func()error{
	
							err := networkJobs.DownloadMyInboxMessages("Moderator", appNetworkType)

							return err
						}

						return jobFunction, nil
					}

					return nil, errors.New("Tasks map contains unknown jobName: " + jobName)
				}

				jobFunction, err := getJobFunction()
				if (err != nil){
					logger.AddLogError("BackgroundJobs", err)
					return
				}

				runningTasksMapMutex.Lock()
				runningTasksMap[taskName] = true
				runningTasksMapMutex.Unlock()

				startTaskFunction := func(){

					err := jobFunction()
					if (err != nil){
						logger.AddLogError("BackgroundJobs", err)
					}

					runningTasksMapMutex.Lock()
					runningTasksMap[taskName] = false
					runningTasksMapMutex.Unlock()

					currentTime := time.Now().Unix()

					taskCompletionTimesMapMutex.Lock()
					taskCompletionTimesMap[taskName] = currentTime
					taskCompletionTimesMapMutex.Unlock()
				}

				go startTaskFunction()
			}

			loopIsRunningMutex.RLock()
			currentLoopIsRunningStatus := loopIsRunning
			loopIsRunningMutex.RUnlock()

			if (currentLoopIsRunningStatus == false){
				// Background jobs loop has been stopped.
				return
			}

			time.Sleep(time.Second)
		}
	}

	go runBackgroundJobsLoop()

	return nil
}