#
# Restic Windows Backup - Installation Script
#

# =========== start configuration =========== #

# load restic configuration parmeters (destination, passwords, etc.)
$SecretsScript = Join-Path $PSScriptRoot "secrets.ps1"

# load backup configuration variables
$ConfigScript = Join-Path $PSScriptRoot "config.ps1"

# initialize secrets
. $SecretsScript

# initialize config
. $ConfigScript

# apply global configuration
$ResticExe = Join-Path $InstallPath $ExeName
$LogPath = Join-Path $InstallPath "logs"

# make LASTEXITCODE global to enable error checking for Invoke-Expression commands
$global:LASTEXITCODE=0

# =========== end configuration =========== #

# download restic
if(-not (Test-Path $ResticExe)) {
    $url = $null
    if([Environment]::Is64BitOperatingSystem){
        $url = "https://github.com/restic/restic/releases/download/v0.17.3/restic_0.17.3_windows_amd64.zip"
    }
    else {
        $url = "https://github.com/restic/restic/releases/download/v0.17.3/restic_0.17.3_windows_386.zip"
    }
    try {
        $output = Join-Path $InstallPath "restic.zip"
        Invoke-WebRequest -Uri $url -OutFile $output
        Expand-Archive -LiteralPath $output $InstallPath
        Remove-Item $output
        Get-ChildItem *.exe | Rename-Item -NewName $ExeName
    }
    catch {
        Write-Error "[[Install]] restic.exe download failed. Check errors and resolve: $_"
        exit 1
    }
}

# Apply global paramters to $ResticExe, after the $ResticExe has been downloaded/confirmed to exist
if(-not [String]::IsNullOrEmpty($GlobalParameters)) {
    $ResticExe = "$ResticExe $GlobalParameters"
}

# Invoke restic self-update to check for a newer version
# This is enabled by default unless configuration disables self-update
if ([String]::IsNullOrEmpty($SelfUpdateEnabled) -or ($SelfUpdateEnabled -eq $true)) {
    Invoke-Expression "$ResticExe self-update"
    if($LASTEXITCODE) {
        Write-Warning "[[Update]] Restic self-update failed. Check errors and resolve."
    }
}

# Create log directory if it doesn't exit
if(-not (Test-Path $LogPath)) {
    New-Item -ItemType Directory -Force -Path $LogPath | Out-Null
    Write-Output "[[Init]] Created log directory: $LogPath"
}

# Create the local exclude file
if(-not (Test-Path $LocalExcludeFile)) {
    New-Item -Type File -Path $LocalExcludeFile | Out-Null
}

# Initialize the restic repository
Invoke-Expression "$ResticExe --verbose init"
if($LASTEXITCODE) {
    Write-Warning "[[Init]] Repository initialization failed. Check errors and resolve."
}
else {
    Write-Output "[[Init]] Repository successfully initialized."
}

# Scheduled Windows Task Scheduler to run the backup
$backup_task_name = "Restic Backup"
$backup_task = Get-ScheduledTask $backup_task_name -ErrorAction SilentlyContinue
if($null -eq $backup_task) {
    try {
        $task_action = New-ScheduledTaskAction -Execute 'powershell.exe' -Argument '-ExecutionPolicy Bypass -NonInteractive -NoLogo -NoProfile -Command ".\backup.ps1; exit $LASTEXITCODE"' -WorkingDirectory $InstallPath
        $task_user = New-ScheduledTaskPrincipal -UserId "NT AUTHORITY\SYSTEM" -LogonType ServiceAccount -RunLevel Highest
        $task_settings = New-ScheduledTaskSettingsSet -RestartCount 4 -RestartInterval (New-TimeSpan -Minutes 15) -ExecutionTimeLimit (New-TimeSpan -Days 3) -AllowStartIfOnBatteries -DontStopIfGoingOnBatteries -DontStopOnIdleEnd -MultipleInstances IgnoreNew -IdleDuration 0 -IdleWaitTimeout 0 -StartWhenAvailable -RestartOnIdle
        $task_trigger = New-ScheduledTaskTrigger -Daily -At 4:00am
        Register-ScheduledTask $backup_task_name -Action $task_action -Principal $task_user -Settings $task_settings -Trigger $task_trigger | Out-Null
        Write-Output "[[Scheduler]] Backup task scheduled."
    }
    catch {
        Write-Error "[[Scheduler]] Setting up backup task schedule failed: $_"
    }
}
else {
    Write-Warning "[[Scheduler]] Backup task not scheduled: there is already a task with the name '$backup_task_name'."
}

# Install NuGet and Send-MailKitMessage module (by force)
if ($PSVersionTable.PSVersion.Major -eq 5) {
    Install-PackageProvider -Name NuGet -Force
}
Install-Module Send-MailKitMessage -Repository PSGallery -Scope AllUsers -Force