Imports System.IO
Imports System.Net
Imports System.Net.Http

Imports ModpackUpdater.Model

Imports WebDav

Public Class UpdateInstaller

    Public Event InstallProgessUpdated(result As UpdateCheckResult, processedSyncs As Integer)
    Public Event CheckingProgressUpdated(toCheck As Integer, processed As Integer)

    Private ReadOnly updateConfig As ModpackConfig
    Private ReadOnly localPath As String
    Private webdavClient As WebDavClient = Nothing
    Private httpClient As New HttpClient

    Public Sub New(updateConfig As ModpackConfig, localPath As String)
        Me.updateConfig = updateConfig
        Me.localPath = localPath
    End Sub

    Protected Overrides Sub Finalize()
        httpClient.Dispose()
        MyBase.Finalize()
    End Sub

    Private Function CreateClient() As WebDavClient
        If webdavClient Is Nothing Then
            Dim params As New WebDavClientParams With {
                .BaseAddress = New Uri(updateConfig.WebdavURL),
                .Credentials = New NetworkCredential(updateConfig.WebdavUsername, updateConfig.WebdavPassword)
            }
            webdavClient = New WebDavClient(params)
        End If

        Return webdavClient
    End Function

    Private Async Function DownloadUpdateInfos() As Task(Of UpdateInfos)
        Dim content As String = Await httpClient.GetStringAsync(updateConfig.UpdateUrl)
        Return UpdateInfos.Parse(content)
    End Function

    Public Async Function CheckForUpdates(ignoreRevmoedFiles As Boolean) As Task(Of UpdateCheckResult)
        Dim infos As UpdateInfos = Await DownloadUpdateInfos()
        Dim result As New UpdateCheckResult

        If infos IsNot Nothing AndAlso infos.Updates.Any Then
            Dim updatesOrderes = infos.Updates.OrderByDescending(Function(n) n.Version)
            result.LatestVersion = updatesOrderes.First.Version

            If ModpackInfo.HasModpackInfo(localPath) Then
                Dim modpackInfo As ModpackInfo = ModpackInfo.Load(localPath)
                result.CurrentVersion = modpackInfo.Version

                Dim checkingVersionIndex As Integer = 0
                Dim checkingVersion As UpdateInfo = updatesOrderes(checkingVersionIndex)

                Do While checkingVersion IsNot Nothing AndAlso checkingVersion.Version > result.CurrentVersion
                    Dim actionsToAdd As New List(Of UpdateAction)

                    For Each action In checkingVersion.Actions
                        If Not result.UpdateActions.Any(Function(n) n.DestPath = action.DestPath) Then
                            actionsToAdd.Add(action)
                        End If
                    Next

                    result.UpdateActions.InsertRange(0, actionsToAdd)

                    checkingVersionIndex += 1
                    checkingVersion = updatesOrderes.ElementAtOrDefault(checkingVersionIndex)
                Loop
            Else
                Await CheckForUpdatesLegacy(result, ignoreRevmoedFiles)
            End If
        End If

        Return result
    End Function

    Private Async Function CheckForUpdatesLegacy(result As UpdateCheckResult, ignoreRevmoedFiles As Boolean) As Task
        Dim client As WebDavClient = CreateClient()
        Dim resTopFolder As WebDavResource = Nothing
        Dim checkedFiles = New List(Of String)()
        Dim responseSuccessfull As Boolean = False

        result.CurrentVersion = New Version("0.0.0.0")
        result.IsLegacy = True

        'Check for new & updated files
        Dim response = Await client.Propfind(String.Empty, New PropfindParameters() With {.ApplyTo = ApplyTo.Propfind.ResourceAndAncestors})
        If resTopFolder Is Nothing AndAlso response.IsSuccessful AndAlso response.Resources.Any() Then
            resTopFolder = response.Resources.ElementAtOrDefault(0)
            responseSuccessfull = True
        End If

        If responseSuccessfull AndAlso response.Resources.Count > 1 Then
            Dim i As Integer = 1
            Dim loopTo As Integer = response.Resources.Count - 1

            Do While i <= loopTo
                Dim res = response.Resources.ElementAtOrDefault(i)
                Dim isFolder As Boolean = res.Uri.EndsWith("/")

                If Not isFolder Then
                    Dim syncAction? As UpdateSyncAction = Nothing
                    Dim localFile As String
                    Dim remoteFile As String

                    'Get remote file path
                    remoteFile = res.Uri

                    'Get local file path
                    localFile = Path.Combine(localPath, Uri.UnescapeDataString(res.Uri.Substring(resTopFolder.Uri.Length)).Replace("/", "\"))

                    'Check action
                    If File.Exists(localFile) Then
                        If File.GetLastWriteTime(localFile) < res.LastModifiedDate = True Then
                            syncAction = UpdateSyncAction.UpdatedFile
                        End If
                    Else
                        syncAction = UpdateSyncAction.NewFile
                    End If

                    'Add to list
                    checkedFiles.Add(localFile)
                    If syncAction IsNot Nothing Then
                        result.SyncFiles.Add(New UpdateSyncFile(syncAction, localFile, remoteFile))
                    End If
                End If

                i += 1

                RaiseEvent CheckingProgressUpdated(loopTo, i)
            Loop
        End If

        'Find all old files to remove
        If responseSuccessfull Then
            Dim allLocalFiles = Directory.GetFiles(localPath, "*", SearchOption.AllDirectories)
            For Each lf As String In allLocalFiles
                Dim isKnown As Boolean = False

                For Each checkedFile As String In checkedFiles
                    If Not isKnown AndAlso If(checkedFile, "") = If(lf, "") Then
                        isKnown = True
                    End If
                Next

                If Not isKnown Then
                    result.SyncFiles.Add(New UpdateSyncFile(If(ignoreRevmoedFiles, UpdateSyncAction.None, UpdateSyncAction.RemovedFile), lf, String.Empty))
                End If
            Next
        End If
    End Function

    Public Async Function InstallUpdates(checkResult As UpdateCheckResult, Optional ignoreActions As UpdateSyncAction = UpdateSyncAction.None) As Task(Of Boolean?)
        Dim isSuccessfully As Boolean
        Dim modpackInfo As ModpackInfo

        If ModpackInfo.HasModpackInfo(localPath) Then
            modpackInfo = ModpackInfo.Load(localPath)
        Else
            modpackInfo = New ModpackInfo
        End If

        If checkResult.IsLegacy Then
            isSuccessfully = Await InstallUpdatesLegacy(checkResult, ignoreActions)
        Else
            Dim processed As Integer = 0
            For Each action As UpdateAction In checkResult.UpdateActions
                Dim destFilePath As String = Path.Combine(localPath, action.DestPath)

                Select Case action.Type
                    Case UpdateActionType.Update
                        Directory.CreateDirectory(Path.GetDirectoryName(destFilePath))
                        Dim sRemote As Stream = Await httpClient.GetStreamAsync(action.DownloadUrl)
                        Dim fs As New FileStream(destFilePath, FileMode.Create, FileAccess.ReadWrite)
                        Await sRemote.CopyToAsync(fs)
                        sRemote.Close()
                        fs.Close()
                    Case UpdateActionType.Delete
                        If action.IsDirectory Then
                            If Directory.Exists(destFilePath) Then
                                Directory.Delete(destFilePath, True)
                            End If
                        Else
                            If File.Exists(destFilePath) Then
                                File.Delete(destFilePath)
                            End If
                        End If
                    Case UpdateActionType.Copy
                        Dim srcFilePath As String = Path.Combine(localPath, action.SrcPath)
                        If File.Exists(srcFilePath) Then
                            Directory.CreateDirectory(Path.GetDirectoryName(destFilePath))
                            File.Copy(srcFilePath, destFilePath, True)
                        End If
                    Case UpdateActionType.Move
                        Dim srcFilePath As String = Path.Combine(localPath, action.SrcPath)
                        If File.Exists(srcFilePath) Then
                            Directory.CreateDirectory(Path.GetDirectoryName(destFilePath))
                            File.Move(srcFilePath, destFilePath, True)
                        End If
                End Select

                processed += 1
                RaiseEvent InstallProgessUpdated(checkResult, processed)
            Next

            isSuccessfully = True
        End If

        If isSuccessfully Then
            modpackInfo.Version = checkResult.LatestVersion
            modpackInfo.Save(localPath)
        End If

        Return isSuccessfully
    End Function

    Private Async Function InstallUpdatesLegacy(checkResult As UpdateCheckResult, Optional ignoreActions As UpdateSyncAction = UpdateSyncAction.None) As Task(Of Boolean?)
        Dim client As WebDavClient = CreateClient()
        Dim success As Boolean? = False
        Dim processed As Integer = 0

        'Init process update
        RaiseEvent InstallProgessUpdated(checkResult, processed)

        For Each syncFile In checkResult.SyncFiles
            If syncFile.SyncAction <> (ignoreActions And syncFile.SyncAction) Then
                If syncFile.SyncAction = UpdateSyncAction.UpdatedFile OrElse
                   syncFile.SyncAction = UpdateSyncAction.RemovedFile Then

                    If File.Exists(syncFile.LocalFile) Then
                        File.Delete(syncFile.LocalFile)
                    End If
                End If

                If syncFile.SyncAction = UpdateSyncAction.UpdatedFile OrElse
                   syncFile.SyncAction = UpdateSyncAction.NewFile Then

                    Dim response = Await client.GetProcessedFile(syncFile.RemoveFile)
                    Dim dirParent As New DirectoryInfo(Path.GetDirectoryName(syncFile.LocalFile))

                    If response.IsSuccessful Then
                        If Not dirParent.Exists Then
                            dirParent.Create()
                        End If

                        Dim fs As New FileStream(syncFile.LocalFile, FileMode.Create, FileAccess.Write)
                        response.Stream.CopyTo(fs)
                        fs.Close()

                        success = True
                    End If
                End If
            End If

            processed += 1
            RaiseEvent InstallProgessUpdated(checkResult, processed)
        Next

        Return success
    End Function

End Class