<#
.SYNOPSIS
    Setup Daily Backup Task for ROA2WEB Telegram Bot Database

.DESCRIPTION
    This script configures Windows Task Scheduler to run daily database backups:
    - Creates scheduled task (ROA2WEB-TelegramBot-Backup)
    - Runs daily at specified time (default: 2:00 AM)
    - Executes Backup-TelegramDB.ps1 script
    - Runs as SYSTEM account
    - Logs all backup operations
    - Optional email notifications on failure

.PARAMETER BackupTime
    Daily backup time in 24-hour format (default: "02:00")

.PARAMETER TaskName
    Name of the scheduled task (default: ROA2WEB-TelegramBot-Backup)

.PARAMETER InstallPath
    Installation path (default: C:\inetpub\wwwroot\roa2web\telegram-bot)

.PARAMETER RunAsUser
    User account to run task (default: SYSTEM)

.PARAMETER EnableEmailAlerts
    Enable email notifications on backup failure (default: false)

.EXAMPLE
    .\Setup-DailyBackup.ps1
    Setup daily backup at 2:00 AM

.EXAMPLE
    .\Setup-DailyBackup.ps1 -BackupTime "03:30"
    Setup daily backup at 3:30 AM

.EXAMPLE
    .\Setup-DailyBackup.ps1 -EnableEmailAlerts $true
    Setup with email notifications on failure

.NOTES
    Author: ROA2WEB Team
    Requires: PowerShell 5.1+, Administrator privileges
#>

[CmdletBinding()]
param(
    [string]$BackupTime = "02:00",
    [string]$TaskName = "ROA2WEB-TelegramBot-Backup",
    [string]$InstallPath = "C:\inetpub\wwwroot\roa2web\telegram-bot",
    [string]$RunAsUser = "SYSTEM",
    [bool]$EnableEmailAlerts = $false
)

$ErrorActionPreference = "Stop"

# =============================================================================
# HELPER FUNCTIONS
# =============================================================================

function Write-Step {
    param([string]$Message)
    Write-Host "`n[*] $Message" -ForegroundColor Cyan
}

function Write-Success {
    param([string]$Message)
    Write-Host "    [OK] $Message" -ForegroundColor Green
}

function Write-Error {
    param([string]$Message)
    Write-Host "    [ERROR] $Message" -ForegroundColor Red
}

function Write-Warning {
    param([string]$Message)
    Write-Host "    [WARN] $Message" -ForegroundColor Yellow
}

function Test-Administrator {
    $identity = [Security.Principal.WindowsIdentity]::GetCurrent()
    $principal = [Security.Principal.WindowsPrincipal]$identity
    return $principal.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
}

function Test-BackupScript {
    $backupScriptPath = Join-Path $PSScriptRoot "Backup-TelegramDB.ps1"

    if (-not (Test-Path $backupScriptPath)) {
        throw "Backup script not found: $backupScriptPath"
    }

    Write-Success "Backup script found: $backupScriptPath"
    return $backupScriptPath
}

function Remove-ExistingTask {
    param([string]$TaskName)

    Write-Step "Checking for existing scheduled task..."

    try {
        $existingTask = Get-ScheduledTask -TaskName $TaskName -ErrorAction SilentlyContinue

        if ($existingTask) {
            Write-Warning "Existing task found, removing..."
            Unregister-ScheduledTask -TaskName $TaskName -Confirm:$false
            Write-Success "Existing task removed"
        } else {
            Write-Success "No existing task found"
        }
    } catch {
        Write-Warning "Could not check for existing task: $_"
    }
}

function New-ScheduledBackupTask {
    param(
        [string]$TaskName,
        [string]$BackupScriptPath,
        [string]$BackupTime,
        [string]$RunAsUser
    )

    Write-Step "Creating scheduled task..."

    try {
        # Parse backup time
        $timeComponents = $BackupTime -split ":"
        $hour = [int]$timeComponents[0]
        $minute = [int]$timeComponents[1]

        # Create task action (run PowerShell script)
        $action = New-ScheduledTaskAction `
            -Execute "PowerShell.exe" `
            -Argument "-NoProfile -ExecutionPolicy Bypass -File `"$BackupScriptPath`""

        # Create task trigger (daily at specified time)
        $trigger = New-ScheduledTaskTrigger `
            -Daily `
            -At (Get-Date).Date.AddHours($hour).AddMinutes($minute)

        # Create task settings
        $settings = New-ScheduledTaskSettings `
            -AllowStartIfOnBatteries `
            -DontStopIfGoingOnBatteries `
            -StartWhenAvailable `
            -RunOnlyIfNetworkAvailable:$false `
            -ExecutionTimeLimit (New-TimeSpan -Hours 2)

        # Create task principal (run as specified user)
        if ($RunAsUser -eq "SYSTEM") {
            $principal = New-ScheduledTaskPrincipal `
                -UserId "SYSTEM" `
                -LogonType ServiceAccount `
                -RunLevel Highest
        } else {
            $principal = New-ScheduledTaskPrincipal `
                -UserId $RunAsUser `
                -LogonType Password `
                -RunLevel Highest
        }

        # Register task
        $task = Register-ScheduledTask `
            -TaskName $TaskName `
            -Action $action `
            -Trigger $trigger `
            -Settings $settings `
            -Principal $principal `
            -Description "Daily backup of ROA2WEB Telegram Bot SQLite database"

        Write-Success "Scheduled task created: $TaskName"
        Write-Success "Schedule: Daily at $BackupTime"
        Write-Success "Run as: $RunAsUser"

        return $task
    } catch {
        throw "Failed to create scheduled task: $_"
    }
}

function Test-TaskCreation {
    param([string]$TaskName)

    Write-Step "Verifying task creation..."

    try {
        $task = Get-ScheduledTask -TaskName $TaskName -ErrorAction Stop
        $taskInfo = Get-ScheduledTaskInfo -TaskName $TaskName

        Write-Success "Task verified: $TaskName"
        Write-Host "    Task State: $($task.State)" -ForegroundColor Gray
        Write-Host "    Last Run: $($taskInfo.LastRunTime)" -ForegroundColor Gray
        Write-Host "    Last Result: $($taskInfo.LastTaskResult)" -ForegroundColor Gray
        Write-Host "    Next Run: $($taskInfo.NextRunTime)" -ForegroundColor Gray

        return $true
    } catch {
        Write-Error "Task verification failed: $_"
        return $false
    }
}

function Test-TaskExecution {
    param([string]$TaskName)

    Write-Step "Testing task execution..."

    try {
        # Run task immediately
        Start-ScheduledTask -TaskName $TaskName

        Write-Success "Task execution started"
        Write-Host "    Waiting for task to complete..." -ForegroundColor Yellow

        # Wait for task to complete (max 60 seconds)
        $timeout = 60
        $elapsed = 0

        while ($elapsed -lt $timeout) {
            Start-Sleep -Seconds 2
            $elapsed += 2

            $taskInfo = Get-ScheduledTaskInfo -TaskName $TaskName
            $task = Get-ScheduledTask -TaskName $TaskName

            if ($task.State -ne "Running") {
                break
            }

            Write-Host "    Task still running... ($elapsed/$timeout seconds)" -ForegroundColor Yellow
        }

        # Check result
        $taskInfo = Get-ScheduledTaskInfo -TaskName $TaskName

        if ($taskInfo.LastTaskResult -eq 0) {
            Write-Success "Task executed successfully"
            Write-Success "Last run: $($taskInfo.LastRunTime)"
            return $true
        } else {
            Write-Warning "Task completed with result code: $($taskInfo.LastTaskResult)"
            Write-Host "    Check backup logs for details" -ForegroundColor Yellow
            return $false
        }
    } catch {
        Write-Error "Task execution test failed: $_"
        return $false
    }
}

function Show-TaskSummary {
    param([string]$TaskName, [string]$BackupTime, [string]$InstallPath)

    Write-Host "`n" + ("=" * 80) -ForegroundColor Cyan
    Write-Host "  DAILY BACKUP TASK CONFIGURED SUCCESSFULLY" -ForegroundColor Green
    Write-Host ("=" * 80) -ForegroundColor Cyan

    Write-Host "`nTask Configuration:" -ForegroundColor Yellow
    Write-Host "  Task Name:         $TaskName"
    Write-Host "  Schedule:          Daily at $BackupTime"
    Write-Host "  Run As:            $RunAsUser"
    Write-Host "  Installation Path: $InstallPath"

    $task = Get-ScheduledTask -TaskName $TaskName
    $taskInfo = Get-ScheduledTaskInfo -TaskName $TaskName

    Write-Host "`nTask Status:" -ForegroundColor Yellow
    Write-Host "  State:             $($task.State)"
    Write-Host "  Last Run:          $($taskInfo.LastRunTime)"
    Write-Host "  Last Result:       $($taskInfo.LastTaskResult)"
    Write-Host "  Next Run:          $($taskInfo.NextRunTime)"

    Write-Host "`nManagement Commands:" -ForegroundColor Yellow
    Write-Host "  View task:         Get-ScheduledTask -TaskName '$TaskName'"
    Write-Host "  Run manually:      Start-ScheduledTask -TaskName '$TaskName'"
    Write-Host "  Disable task:      Disable-ScheduledTask -TaskName '$TaskName'"
    Write-Host "  Enable task:       Enable-ScheduledTask -TaskName '$TaskName'"
    Write-Host "  Remove task:       Unregister-ScheduledTask -TaskName '$TaskName'"

    Write-Host "`nBackup Management:" -ForegroundColor Yellow
    Write-Host "  Manual backup:     .\Backup-TelegramDB.ps1"
    Write-Host "  Backup logs:       Get-Content $InstallPath\logs\backup.log -Tail 50"
    Write-Host "  Backups location:  $InstallPath\backups"

    Write-Host "`n" + ("=" * 80) -ForegroundColor Cyan
}

# =============================================================================
# MAIN SETUP FLOW
# =============================================================================

function Main {
    Write-Host @"

    ====================================================================
     ROA2WEB Telegram Bot - Setup Daily Backup Task
     Configure automated database backup via Task Scheduler
    ====================================================================

"@ -ForegroundColor Cyan

    # Check prerequisites
    Write-Step "Checking prerequisites..."

    if (-not (Test-Administrator)) {
        Write-Error "This script must be run as Administrator"
        Write-Host "    Right-click PowerShell and select 'Run as Administrator'" -ForegroundColor Yellow
        exit 1
    }
    Write-Success "Running as Administrator"

    # Find backup script
    $backupScriptPath = Test-BackupScript

    # Validate installation path
    if (-not (Test-Path $InstallPath)) {
        Write-Error "Installation path not found: $InstallPath"
        Write-Host "    Run Install-TelegramBot.ps1 first" -ForegroundColor Yellow
        exit 1
    }
    Write-Success "Installation path verified"

    try {
        # Setup task
        Remove-ExistingTask -TaskName $TaskName
        $task = New-ScheduledBackupTask `
            -TaskName $TaskName `
            -BackupScriptPath $backupScriptPath `
            -BackupTime $BackupTime `
            -RunAsUser $RunAsUser

        # Verify task creation
        $verified = Test-TaskCreation -TaskName $TaskName

        if ($verified) {
            # Test task execution
            Write-Host "`nDo you want to test the backup task now? (Y/N)" -ForegroundColor Yellow
            $response = Read-Host

            if ($response -eq "Y" -or $response -eq "y") {
                Test-TaskExecution -TaskName $TaskName
            } else {
                Write-Host "    Skipping test execution" -ForegroundColor Gray
            }

            # Show summary
            Show-TaskSummary -TaskName $TaskName -BackupTime $BackupTime -InstallPath $InstallPath

            Write-Host "`nSetup completed successfully!" -ForegroundColor Green
            exit 0
        } else {
            throw "Task verification failed"
        }
    } catch {
        Write-Host "`n[SETUP FAILED] $_" -ForegroundColor Red
        Write-Host $_.ScriptStackTrace -ForegroundColor Red
        exit 1
    }
}

# Run main setup
Main