// manualDownloads provides functions to start and monitor manual downloads
// These are downloads that the user initiates through the GUI, such as downloading a profile/review/report
// The user is able to monitor the status of these downloads through the GUI
// These are different from the downloads that are called automatically in the background (see networkJobs.go)

package manualDownloads

// Types of downloads:
//	-Download a user's profile
//	-Download a specific message
//	-Download a review by reviewHash or reviewedHash
//	-Download a report by reportedHash
//	-Download all reviews by a reviewer
//	-Download all reviews for a reviewedHash
//	-Download all reports for a reportedHash
//	-Update a user's identity score/balance

import "seekia/internal/byteRange"
import "seekia/internal/encoding"
import "seekia/internal/helpers"
import "seekia/internal/identity"
import "seekia/internal/logger"
import "seekia/internal/moderation/trustedViewableStatus"
import "seekia/internal/network/eligibleHosts"
import "seekia/internal/network/hostRanges"
import "seekia/internal/network/peerClient"
import "seekia/internal/network/sendRequests"
import "seekia/internal/profiles/profileStorage"

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

// This object stores data about active processes
type processObject struct{

	// Set to true once process is complete. Will be true if we encounter an error
	isComplete bool

	// Set to true if we encounter an error
	encounteredError bool

	// The error we encountered
	errorEncountered error

	// Stores the number of hosts that have been successfully downloaded from
	numberOfSuccessfulDownloads int

	// Stores the number of hosts we tried to download from whom did not have the content
	numberOfHostsMissingContent int

	// Stores details about progress status, which are shown to user in GUI
	progressDetails string
}

var processObjectsMapMutex sync.RWMutex

var processObjectsMap map[[23]byte]processObject = make(map[[23]byte]processObject)


//Outputs:
//	-[23]byte: New process identifier
//	-error
func initializeNewProcessObject()([23]byte, error){

	processIdentifierBytes, err := helpers.GetNewRandomBytes(23)
	if (err != nil) { return [23]byte{}, err }

	processIdentifier := [23]byte(processIdentifierBytes)

	newProcessObject := processObject{
		isComplete: false,
		encounteredError: false,
		errorEncountered: nil,
		numberOfSuccessfulDownloads: 0,
		numberOfHostsMissingContent: 0,
		progressDetails: "",
	}

	processObjectsMapMutex.Lock()

	processObjectsMap[processIdentifier] = newProcessObject

	processObjectsMapMutex.Unlock()

	return processIdentifier, nil
}

func increaseProcessSuccessfulDownloadsCount(processIdentifier [23]byte)error{

	processObjectsMapMutex.Lock()
	defer processObjectsMapMutex.Unlock()

	processObject, exists := processObjectsMap[processIdentifier]
	if (exists == false){
		processIdentifierHex := encoding.EncodeBytesToHexString(processIdentifier[:])
		return errors.New("increaseProcessSuccessfulDownloadsCount called with uninitialized process: " + processIdentifierHex)
	}

	processObject.numberOfSuccessfulDownloads += 1

	processObjectsMap[processIdentifier] = processObject

	return nil
}

func increaseProcessHostsMissingContentCount(processIdentifier [23]byte)error{

	processObjectsMapMutex.Lock()
	defer processObjectsMapMutex.Unlock()

	processObject, exists := processObjectsMap[processIdentifier]
	if (exists == false){
		processIdentifierHex := encoding.EncodeBytesToHexString(processIdentifier[:])
		return errors.New("increaseProcessHostsMissingContentCount called with uninitialized process: " + processIdentifierHex)
	}

	processObject.numberOfHostsMissingContent += 1

	processObjectsMap[processIdentifier] = processObject

	return nil
}

func setProcessProgressDetails(processIdentifier [23]byte, newProgressDetails string)error{

	processObjectsMapMutex.Lock()
	defer processObjectsMapMutex.Unlock()

	processObject, exists := processObjectsMap[processIdentifier]
	if (exists == false){
		processIdentifierHex := encoding.EncodeBytesToHexString(processIdentifier[:])
		return errors.New("setProcessProgressDetails called with uninitialized process: " + processIdentifierHex)
	}

	processObject.progressDetails = newProgressDetails

	processObjectsMap[processIdentifier] = processObject

	return nil
}


func setProcessEncounteredError(processIdentifier [23]byte, errorEncountered error)error{

	processObjectsMapMutex.Lock()
	defer processObjectsMapMutex.Unlock()

	processObject, exists := processObjectsMap[processIdentifier]
	if (exists == false){
		processIdentifierHex := encoding.EncodeBytesToHexString(processIdentifier[:])
		return errors.New("setProcessEncounteredError called with uninitialized process: " + processIdentifierHex)
	}

	processObject.isComplete = true
	processObject.encounteredError = true
	processObject.errorEncountered = errorEncountered

	processObjectsMap[processIdentifier] = processObject

	return nil
}

func setProcessIsComplete(processIdentifier [23]byte)error{
	
	processObjectsMapMutex.Lock()
	defer processObjectsMapMutex.Unlock()

	processObject, exists := processObjectsMap[processIdentifier]
	if (exists == false){
		processIdentifierHex := encoding.EncodeBytesToHexString(processIdentifier[:])
		return errors.New("setProcessIsComplete called with uninitialized process: " + processIdentifierHex)
	}

	processObject.isComplete = true

	processObjectsMap[processIdentifier] = processObject

	return nil
}

//Outputs:
//	-bool: Process found
//	-bool: Process is complete status
//	-bool: Process encountered error
//	-error: Error encountered by process
//	-int: Number of hosts successfully downloaded from (These are hosts who gave us the content we are trying to download)
//	-int: Number of hosts missing content (These are hosts that have said they do not have the content)
//	-string: Process progress details
func GetProcessInfo(processIdentifier [23]byte)(bool, bool, bool, error, int, int, string){

	processObjectsMapMutex.RLock()
	defer processObjectsMapMutex.RUnlock()

	processObject, exists := processObjectsMap[processIdentifier]
	if (exists == false) {
		return false, false, false, nil, 0, 0, ""
	}

	processIsComplete := processObject.isComplete
	processEncounteredError := processObject.encounteredError
	processError := processObject.errorEncountered
	processNumberOfSuccessfulDownloads := processObject.numberOfSuccessfulDownloads
	processNumberOfHostsMissingContent := processObject.numberOfHostsMissingContent
	processProgressDetails := processObject.progressDetails

	return true, processIsComplete, processEncounteredError, processError, processNumberOfSuccessfulDownloads, processNumberOfHostsMissingContent, processProgressDetails
}

func EndProcess(processIdentifier [23]byte)error{

	err := setProcessIsComplete(processIdentifier)
	if (err != nil){ return err }

	err = setProcessProgressDetails(processIdentifier, "Download manually stopped.")
	if (err != nil) { return err }

	return nil
}

//Inputs:
//	-[16]byte: User identity hash whose profile we are downloading
//	-byte: Network type to retrieve from
//	-bool: Get viewable profiles only
//	-int: Number of hosts to query (This is the number of hosts to request a successful download from)
//		-A successful download is one where the host either offered a profile we already have, or we downloaded a new profile
//		-If they say they have no profile, the download is not successful
//	-int: Maximum number of hosts to query
//Outputs:
//	-bool: Any eligible hosts found to download from
//	-[23]byte: Process identifier
//	-error
func StartNewestUserProfileDownload(userIdentityHash [16]byte, networkType byte, getViewableOnly bool, numberOfHostsToDownloadFrom int, maximumHostsToContact int)(bool, [23]byte, error){

	//TODO: Add to temporary downloads range so the profile doesn't get deleted automatically by backgroundJobs

	userIdentityType, err := identity.GetIdentityTypeFromIdentityHash(userIdentityHash)
	if (err != nil) {
		userIdentityHashHex := encoding.EncodeBytesToHexString(userIdentityHash[:])
		return false, [23]byte{}, errors.New("StartNewestUserProfileDownload called with invalid user identity hash: " + userIdentityHashHex)
	}

	isValid := helpers.VerifyNetworkType(networkType)
	if (isValid == false){
		networkTypeString := helpers.ConvertByteToString(networkType)
		return false, [23]byte{}, errors.New("StartNewestUserProfileDownload called with invalid networkType: " + networkTypeString)
	}

	allEligibleHostsList, err := eligibleHosts.GetEligibleHostsList(networkType)
	if (err != nil) { return false, [23]byte{}, err }

	hostsToContactList := make([][16]byte, 0)

	for _, hostIdentityHash := range allEligibleHostsList{

		exists, _, _, _, _, hostRawProfileMap, err := profileStorage.GetNewestUserProfile(hostIdentityHash, networkType)
		if (err != nil) { return false, [23]byte{}, err }
		if (exists == false){
			// Host profile was deleted, skip host	
			continue
		}

		hostIsHostingIdentityType, theirHostRangeStart, theirHostRangeEnd, err := hostRanges.GetHostedIdentityHashRangeFromHostRawProfileMap(hostRawProfileMap, userIdentityType)
		if (err != nil) { return false, [23]byte{}, err }
		if (hostIsHostingIdentityType == false){
			// Host is not hosting any profiles of this profileType. Skip to next host
			continue
		}

		isWithinRange, err := byteRange.CheckIfIdentityHashIsWithinRange(theirHostRangeStart, theirHostRangeEnd, userIdentityHash)
		if (err != nil) { return false, [23]byte{}, err }
		if (isWithinRange == true){
			hostsToContactList = append(hostsToContactList, hostIdentityHash)
		}
	}

	if (len(hostsToContactList) == 0){
		// No hosts exist who we can download this user's profile from
		// User needs to wait for Seekia to download more hosts
		return false, [23]byte{}, nil
	}

	processIdentifier, err := initializeNewProcessObject()
	if (err != nil) { return false, [23]byte{}, err }

	performDownloads := func(){

		var contactedHostsListMutex sync.RWMutex	

		//We use this list to prevent downloading from the same host twice
		contactedHostIdentityHashesList := make([][16]byte, 0)

		checkIfHostHasBeenContacted := func(hostIdentityHash [16]byte)bool{

			contactedHostsListMutex.RLock()			
			isContacted := slices.Contains(contactedHostIdentityHashesList, hostIdentityHash)
			contactedHostsListMutex.RUnlock()

			return isContacted
		}

		addContactedHostIdentityHashToList := func(contactedHostIdentityHash [16]byte){
			contactedHostsListMutex.Lock()
			contactedHostIdentityHashesList = append(contactedHostIdentityHashesList, contactedHostIdentityHash)
			contactedHostsListMutex.Unlock()
		}

		var activeDownloadsMutex sync.RWMutex
		numberOfActiveDownloads := 0	

		increaseActiveDownloads := func(){
			activeDownloadsMutex.Lock()
			numberOfActiveDownloads += 1
			activeDownloadsMutex.Unlock()
		}
		decreaseActiveDownloads := func(){
			activeDownloadsMutex.Lock()
			numberOfActiveDownloads -= 1
			activeDownloadsMutex.Unlock()
		}
		getNumberOfActiveDownloads := func()int{
			activeDownloadsMutex.RLock()
			result := numberOfActiveDownloads
			activeDownloadsMutex.RUnlock()
			return result
		}

		executeDownloadFromHost := func(hostIdentityHash [16]byte){

			executeDownloadFromHostFunction := func()error{

				processFound, processIsComplete, errorEncountered, _, _, _, _ := GetProcessInfo(processIdentifier)
				if (processFound == false){
					return errors.New("executeDownloadFromHostFunction called with uninitialized process.")
				}
				if (processIsComplete == true || errorEncountered == true){
					// Error may have been encountered from a different broadcast goroutine				
					return nil
				}

				hostIdentityHashString, identityType, err := identity.EncodeIdentityHashBytesToString(hostIdentityHash)
				if (err != nil) { return err }
				if (identityType != "Moderator"){
					return errors.New("executeDownloadFromHost called with non-moderator identity hash.")
				}

				hostIdentityHashTrimmed, _, err := helpers.TrimAndFlattenString(hostIdentityHashString, 6)
				if (err != nil) { return err }

				hostProfileFound, connectionEstablished, connectionIdentifier, err := peerClient.EstablishNewConnectionToHost(false, hostIdentityHash, networkType)
				if (err != nil) { return err }
				if (hostProfileFound == false){
					return nil
				}
				if (connectionEstablished == false){

					err := setProcessProgressDetails(processIdentifier, "Failed to connect to host " + hostIdentityHashTrimmed)
					if (err != nil) { return err }

					return nil
				}

				err = setProcessProgressDetails(processIdentifier, "Downloading from host " + hostIdentityHashTrimmed)
				if (err != nil) { return err }

				minimumRange, maximumRange := byteRange.GetMinimumMaximumIdentityHashBounds()

				identityList := [][16]byte{userIdentityHash}

				successfulDownload, profilesInfoObjectsList, err := sendRequests.GetProfilesInfoFromHost(connectionIdentifier, hostIdentityHash, networkType, userIdentityType, minimumRange, maximumRange, identityList, nil, true, getViewableOnly)
				if (err != nil) { return err }
				if (successfulDownload == false){

					err := setProcessProgressDetails(processIdentifier, "Failed to download profile from host " + hostIdentityHashTrimmed)
					if (err != nil) { return err }

					return nil
				}

				if (len(profilesInfoObjectsList) == 0){
					// Host does not have profiles for this user.
					// We don't consider this a successful download
					// User profile we are trying to get may not exist anywhere
					// We need to make sure user is aware that they may never retrieve user's profile, and all downloads will fail

					err := increaseProcessHostsMissingContentCount(processIdentifier)
					if (err != nil) { return err }

					err = setProcessProgressDetails(processIdentifier, "Host " + hostIdentityHashTrimmed + " does not have the user's profile.")
					if (err != nil) { return err }

					return nil
				}

				if (len(profilesInfoObjectsList) != 1){
					return errors.New("GetProfilesInfoFromHost not validating profilesInfoObjectsList properly")
				}

				profilesInfoObject := profilesInfoObjectsList[0]

				profileHash := profilesInfoObject.ProfileHash
				profileBroadcastTime := profilesInfoObject.ProfileBroadcastTime

				// We check if we already have this profile
				alreadyExists, _, err := profileStorage.GetStoredProfile(profileHash)
				if (err != nil){ return err }
				if (alreadyExists == true){

					if (getViewableOnly == true){
						err := trustedViewableStatus.AddTrustedProfileIsViewableStatus(profileHash, hostIdentityHash, true)
						if (err != nil) { return err }
						err = trustedViewableStatus.AddTrustedIdentityIsViewableStatus(userIdentityHash, hostIdentityHash, networkType, true)
						if (err != nil) { return err }
					}

					err := increaseProcessSuccessfulDownloadsCount(processIdentifier)
					if (err != nil){ return err }

					err = setProcessProgressDetails(processIdentifier, "Host offered profile we already have.")
					if (err != nil){ return err }

					return nil
				}

				profileHashesToDownloadList := [][28]byte{profileHash}

				expectedProfileIdentityHashesMap := make(map[[28]byte][16]byte)
				expectedProfileIdentityHashesMap[profileHash] = userIdentityHash

				expectedProfileBroadcastTimesMap := make(map[[28]byte]int64)
				expectedProfileBroadcastTimesMap[profileHash] = profileBroadcastTime

				processFound, processIsComplete, errorEncountered, _, _, _, _ = GetProcessInfo(processIdentifier)
				if (processFound == false){
					// This should not happen
					return errors.New("Process not found after being found already.")
				}
				if (processIsComplete == true || errorEncountered == true){
					// Error may have been encountered from a different download goroutine	
					return nil
				}

				downloadSuccessful, listOfProfiles, err := sendRequests.GetProfilesFromHost(connectionIdentifier, hostIdentityHash, networkType, userIdentityType, profileHashesToDownloadList, expectedProfileIdentityHashesMap, expectedProfileBroadcastTimesMap, nil)
				if (err != nil) { return err }
				if (downloadSuccessful == false){

					err := setProcessProgressDetails(processIdentifier, "Failed to download profile from host " + hostIdentityHashTrimmed)
					if (err != nil){ return err }

					return nil
				}

 				if (len(listOfProfiles) == 0){
					// Host does not have profiles for this user (after saying they did)
					// We don't consider this a successful download
					// User profile we are trying to get may not exist anywhere
					// We need to make sure user is aware that they may never retrieve user profile, and all downloads will fail

					err := increaseProcessHostsMissingContentCount(processIdentifier)
					if (err != nil) { return err }

					err = setProcessProgressDetails(processIdentifier, "Host " + hostIdentityHashTrimmed + " does not have the user's profile.")
					if (err != nil) { return err }

					return nil
				}

				if (len(listOfProfiles) != 1){
					return errors.New("sendRequests.GetProfilesFromHost not verifying list of profiles matches requested profile hashes list.")
				}

				profileBytes := listOfProfiles[0]
	
				profileIsWellFormed, _, err := profileStorage.AddUserProfile(profileBytes)
				if (err != nil) { return err }
				if (profileIsWellFormed == false){
					return errors.New("GetProfilesFromHost not verifying profile is well formed")
				}
				if (getViewableOnly == true){

					err := trustedViewableStatus.AddTrustedProfileIsViewableStatus(profileHash, hostIdentityHash, true)
					if (err != nil) { return err }

					err = trustedViewableStatus.AddTrustedIdentityIsViewableStatus(userIdentityHash, hostIdentityHash, networkType, true)
					if (err != nil) { return err }
				}

				err = increaseProcessSuccessfulDownloadsCount(processIdentifier)
				if (err != nil){ return err }

				err = setProcessProgressDetails(processIdentifier, "Successfully downloaded profile from " + hostIdentityHashTrimmed)
				if (err != nil) { return err }

				return nil
			}

			err := executeDownloadFromHostFunction()
			if (err != nil){				
				logger.AddLogError("General", err)
				err := setProcessEncounteredError(processIdentifier, err)
				if (err != nil){
					logger.AddLogError("General", err)
				}
			}
	
			decreaseActiveDownloads()
		}

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

		for {

			processFound, processIsComplete, errorEncountered, _, numberOfSuccessfulDownloads, numberOfHostsMissingContent, _ := GetProcessInfo(processIdentifier)
			if (processFound == false){
				// This should not happen
				logger.AddLogError("General", errors.New("Process not found during manualDownloads loop 1"))
				return
			}
			if (processIsComplete == true || errorEncountered == true){
				return
			}

			if (numberOfSuccessfulDownloads >= numberOfHostsToDownloadFrom){
				// We have completed the required number of downloads
				// Nothing left to do
				break
			}

			totalAttemptedDownloads := numberOfSuccessfulDownloads + numberOfHostsMissingContent
			if (totalAttemptedDownloads >= maximumHostsToContact){
				// We have contacted enough hosts
				// We are done
				break
			}

			activeDownloads := getNumberOfActiveDownloads()

			pendingAndCompletedDownloads := numberOfSuccessfulDownloads + activeDownloads

			if (pendingAndCompletedDownloads >= numberOfHostsToDownloadFrom || (numberOfHostsMissingContent + pendingAndCompletedDownloads) >= maximumHostsToContact){

				// We are actively downloading from the required/maximum number of hosts
				// Wait to see if we need to retry to another host

				currentTime := time.Now().Unix()
				secondsElapsed := currentTime - startTime

				if (secondsElapsed > 150){
					// Something has gone wrong. Downloads should timeout before this.
					err := setProcessEncounteredError(processIdentifier, errors.New("Profile download failed: Reached timeout."))
					if (err != nil) {
						logger.AddLogError("General", err)
					}
					return
				}

				time.Sleep(time.Second)

				continue
			}

			// We need to start another download
			// We find a host we have not contacted yet

			//Outputs:
			//	-bool: We found a host
			startNewDownload := func()bool{

				for _, hostIdentityHash := range hostsToContactList{

					isContacted := checkIfHostHasBeenContacted(hostIdentityHash)
					if (isContacted == false){

						addContactedHostIdentityHashToList(hostIdentityHash)
						
						increaseActiveDownloads()

						go executeDownloadFromHost(hostIdentityHash)

						return true
					}
				}
				return false
			}

			foundHost := startNewDownload()
			if (foundHost == false){
				// There are not enough hosts to contact the requested numberOfHostsToDownloadFrom
				break
			}
		}

		// We wait for downloads to complete
		secondsElapsed := 0
		for {

			processFound, processIsComplete, errorEncountered, _, _, _, _ := GetProcessInfo(processIdentifier)
			if (processFound == false){
				// This should not happen
				logger.AddLogError("General", errors.New("Process not found while waiting for manual download to complete"))
				return
			}
			if (processIsComplete == true || errorEncountered == true){
				// Error may have been encountered from a different broadcast goroutine				
				return
			}

			activeDownloads := getNumberOfActiveDownloads()
			if (activeDownloads <= 0){
				// We are done waiting for downloads to complete
				break
			}

			time.Sleep(time.Second)

			secondsElapsed += 1

			if (secondsElapsed > 100){
				// Something has gone wrong.
				err := setProcessEncounteredError(processIdentifier, errors.New("Download failed: reached timeout."))
				if (err != nil){
					logger.AddLogError("General", err)
				}
				return
			}
		}

		err := setProcessIsComplete(processIdentifier)
		if (err != nil){
			logger.AddLogError("General", err)
			return
		}

		processFound, processIsComplete, errorEncountered, _, numberOfSuccessfulDownloads, numberOfHostsMissingContent, _ := GetProcessInfo(processIdentifier)
		if (processFound == false){
			// This should not happen
			return
		}
		if (processIsComplete == false){
			// This should not happen
			err := setProcessEncounteredError(processIdentifier, errors.New("setProcessIsComplete is not working."))
			if (err != nil) {
				logger.AddLogError("General", err)
			}
			return
		}
		if (errorEncountered == true){
			return
		}

		getFinalDownloadStatus := func()string{

			if (numberOfSuccessfulDownloads != 0){

				numberOfSuccessfulDownloadsString := helpers.ConvertIntToString(numberOfSuccessfulDownloads)

				return "Downloaded profile from " + numberOfSuccessfulDownloadsString + " hosts."
			}
			if (numberOfHostsMissingContent == 0){
				// We were unable to download from any hosts
				return "Download failed: Hosts unavailable."
			}
			// We downloaded from hosts, but none of them had the user's profile
			return "Download failed: Content unavailable."
		}
	
		finalDownloadStatus := getFinalDownloadStatus()

		err = setProcessProgressDetails(processIdentifier, finalDownloadStatus)
		if (err != nil){
			logger.AddLogError("General", err)
			return
		}
	}

	go performDownloads()

	return true, processIdentifier, nil
}