<#
.SYNOPSIS
  Validates, packages, and deploys this repository to its dedicated IIS site.

.DESCRIPTION
  The controller packages the complete repository, computes SHA-256, transfers
  the package and host installer over OpenSSH, and invokes the installer.
  -LocalPreflightOnly validates source provenance, XML, package layout, and
  archive safety without connecting. -PreflightOnly additionally streams the
  installer to the host and runs its read-only IIS preflight without writing a
  remote installer or package.
#>

[CmdletBinding()]
param(
  [ValidatePattern('^[A-Za-z0-9_. -]+$')]
  [string]$SiteName = 'AspClassicUnifiedFramework',
  [ValidatePattern('^[A-Za-z0-9_. -]+$')]
  [string]$AppPoolName = 'AspClassicUnifiedFramework',
  [string]$DeployRoot = 'D:\Deployments\AspClassicUnifiedFramework',
  [string]$BindingIpAddress = '100.97.39.23',
  [ValidateRange(1, 65535)]
  [int]$BindingPort = 8085,
  [AllowEmptyString()]
  [string]$HostHeader = '',
  [string]$InitialWebConfigPath = '',
  [string]$RemoteTarget = 'webserver-1',
  [ValidateRange(1, 65535)]
  [int]$RemotePort = 22,
  [string]$SourcePath = (Split-Path $PSScriptRoot -Parent),
  [string]$BaseUrl = '',
  [string]$ReleaseId = '',
  [string]$ExpectedBranch = 'master',
  [ValidateRange(2, 100)]
  [int]$KeepReleases = 5,
  [string]$SshExe = 'ssh',
  [string]$ScpExe = 'scp',
  [switch]$AllowAnyBranch,
  [switch]$AllowDirty,
  [switch]$RunMigrations,
  [switch]$SkipSmokeTest,
  [Alias('HostPreflightOnly', 'RemotePreflightOnly')]
  [switch]$PreflightOnly,
  [switch]$LocalPreflightOnly,
  [switch]$Rollback,
  [string]$RollbackTo = '',
  [switch]$DryRun,
  [switch]$KeepPackage
)

Set-StrictMode -Version 2.0
$ErrorActionPreference = 'Stop'

function Write-Step { param([string]$Message) Write-Host ('==> ' + $Message) }

function Assert-Command {
  param([string]$Name)
  if (-not (Get-Command $Name -ErrorAction SilentlyContinue)) {
    throw "$Name was not found on PATH."
  }
}

function ConvertTo-SingleQuotedPowerShell {
  param([string]$Value)
  return "'" + $Value.Replace("'", "''") + "'"
}

function Add-RemoteArgument {
  param(
    [System.Collections.Generic.List[string]]$Arguments,
    [string]$Name,
    [string]$Value
  )
  $Arguments.Add($Name)
  $Arguments.Add((ConvertTo-SingleQuotedPowerShell $Value))
}

function Assert-SafeNameValue {
  param([string]$Name, [string]$Value)
  if ([string]::IsNullOrWhiteSpace($Value) -or $Value -notmatch '^[A-Za-z0-9_. -]+$') {
    throw "$Name contains unsupported characters."
  }
  if ($Value -match '(?i)schedulicious') {
    throw "$Name must not identify a Schedulicious resource."
  }
}

function Assert-SafeDeploymentValues {
  Assert-SafeNameValue -Name 'SiteName' -Value $SiteName
  Assert-SafeNameValue -Name 'AppPoolName' -Value $AppPoolName
  if ($DeployRoot -match '(?i)schedulicious') {
    throw 'DeployRoot must not reference Schedulicious.'
  }
  if ([string]::IsNullOrWhiteSpace($BindingIpAddress)) {
    throw 'BindingIpAddress must not be empty.'
  }
  $parsedAddress = $null
  if (-not [System.Net.IPAddress]::TryParse($BindingIpAddress, [ref]$parsedAddress)) {
    throw "BindingIpAddress is not a valid IP address: $BindingIpAddress"
  }
  if ($HostHeader -match '[:/\\]') {
    throw 'HostHeader must be empty or a DNS host name without a scheme, port, slash, or backslash.'
  }
  if ($HostHeader -match '(?i)schedulicious') {
    throw 'HostHeader must not reference Schedulicious.'
  }
}

function Copy-ReleaseSource {
  param([string]$From, [string]$To)

  $excludedNames = @('.git', '.deployment', 'releases')
  $packageRoots = @(Get-ChildItem -LiteralPath $From -Force | Where-Object { $excludedNames -notcontains $_.Name })
  $unsafeSourceItem = $packageRoots |
    ForEach-Object {
      if (($_.Attributes -band [IO.FileAttributes]::ReparsePoint) -ne 0) { $_ }
      elseif ($_.PSIsContainer) { Get-ChildItem -LiteralPath $_.FullName -Recurse -Force }
    } |
    Where-Object { ($_.Attributes -band [IO.FileAttributes]::ReparsePoint) -ne 0 } |
    Select-Object -First 1
  if ($null -ne $unsafeSourceItem) {
    throw "Source contains a reparse point/symbolic link, which is not package-safe: $($unsafeSourceItem.FullName)"
  }

  New-Item -ItemType Directory -Force -Path $To | Out-Null
  $packageRoots | ForEach-Object {
    if ($excludedNames -contains $_.Name) { return }
    if (($_.Attributes -band [IO.FileAttributes]::ReparsePoint) -ne 0) {
      throw "Source contains a reparse point/symbolic link, which is not package-safe: $($_.FullName)"
    }
    Copy-Item -LiteralPath $_.FullName -Destination $To -Recurse -Force
  }

  $unsafeEntry = Get-ChildItem -LiteralPath $To -Recurse -Force |
    Where-Object { ($_.Attributes -band [IO.FileAttributes]::ReparsePoint) -ne 0 } |
    Select-Object -First 1
  if ($null -ne $unsafeEntry) {
    throw "Package staging contains a reparse point/symbolic link: $($unsafeEntry.FullName)"
  }
}

function Assert-ReleaseLayout {
  param([string]$Root)
  $required = @(
    'public\Default.asp',
    'public\web.config',
    'core\autoload_core.asp',
    'app\controllers\autoload_controllers.asp',
    'scripts\install-iis-release.ps1'
  )
  foreach ($relativePath in $required) {
    if (-not (Test-Path -LiteralPath (Join-Path $Root $relativePath) -PathType Leaf)) {
      throw "Package/source tree is incomplete; missing $relativePath"
    }
  }
  foreach ($xmlFile in Get-ChildItem -LiteralPath $Root -Recurse -Force -Filter 'web.config') {
    try {
      [xml](Get-Content -LiteralPath $xmlFile.FullName -Raw) | Out-Null
    } catch {
      throw "$($xmlFile.FullName) is not valid XML: $($_.Exception.Message)"
    }
  }
}

Assert-SafeDeploymentValues
$SourcePath = [System.IO.Path]::GetFullPath($SourcePath)
$installerPath = Join-Path $PSScriptRoot 'install-iis-release.ps1'
Assert-ReleaseLayout -Root $SourcePath

$directGitRoot = Test-Path -LiteralPath (Join-Path $SourcePath '.git')
$commit = 'nogit'
if ($directGitRoot) {
  Assert-Command 'git'
  $branch = (& git -C $SourcePath branch --show-current).Trim()
  if ($LASTEXITCODE -ne 0) { throw 'Could not determine the Git branch.' }
  if ((-not $AllowAnyBranch) -and $branch -ne $ExpectedBranch) {
    throw "Refusing to deploy branch '$branch'; expected '$ExpectedBranch'."
  }
  $dirty = & git -C $SourcePath status --porcelain
  if ($LASTEXITCODE -ne 0) { throw 'Could not inspect the Git worktree.' }
  if ((-not $AllowDirty) -and $null -ne $dirty -and @($dirty).Count -gt 0) {
    throw 'Refusing to deploy a dirty worktree. Use -AllowDirty only for a reviewed exception.'
  }
  $commit = (& git -C $SourcePath rev-parse --short=12 HEAD).Trim()
  if ($LASTEXITCODE -ne 0) { throw 'Could not determine the Git commit.' }
  Write-Host "Source branch: $branch"
  Write-Host "Source commit: $commit"
} else {
  Write-Warning 'SourcePath is not a standalone Git checkout; branch and dirty-worktree checks cannot be enforced.'
  if (-not $AllowAnyBranch) {
    throw 'Use a standalone checkout, or pass -AllowAnyBranch for a reviewed non-Git source tree.'
  }
}

if ([string]::IsNullOrWhiteSpace($ReleaseId)) {
  $ReleaseId = (Get-Date -Format 'yyyyMMdd-HHmmss') + '-' + $commit
}
if ($ReleaseId -notmatch '^[A-Za-z0-9._-]+$') { throw 'ReleaseId contains unsupported characters.' }
if ($Rollback -and [string]::IsNullOrWhiteSpace($RollbackTo)) { throw '-Rollback requires -RollbackTo.' }
if ((-not $Rollback) -and -not [string]::IsNullOrWhiteSpace($RollbackTo)) { throw '-RollbackTo requires -Rollback.' }
if ($RunMigrations -and $Rollback) { throw '-RunMigrations is not valid during rollback.' }
if (($PreflightOnly -or $LocalPreflightOnly) -and $Rollback) {
  throw 'Preflight modes cannot be combined with -Rollback.'
}
if ($PreflightOnly -and $LocalPreflightOnly) {
  throw '-PreflightOnly and -LocalPreflightOnly are mutually exclusive.'
}

$workRoot = Join-Path ([System.IO.Path]::GetTempPath()) ('asp-iis-deploy-' + [Guid]::NewGuid().ToString('N'))
$packageStage = Join-Path $workRoot 'package'
$packageExtract = Join-Path $workRoot 'verify'
$packagePath = Join-Path $workRoot ($ReleaseId + '.zip')
$remoteDirectory = 'C:\Windows\Temp\asp-iis-deploy-' + $ReleaseId
$remotePackage = $remoteDirectory + '\' + $ReleaseId + '.zip'
$remoteInstaller = $remoteDirectory + '\install-iis-release.ps1'

try {
  $sha256 = ''
  if (-not $Rollback) {
    Write-Step 'Staging the complete repository for packaging'
    Copy-ReleaseSource -From $SourcePath -To $packageStage
    Assert-ReleaseLayout -Root $packageStage
    Add-Type -AssemblyName System.IO.Compression.FileSystem
    [System.IO.Compression.ZipFile]::CreateFromDirectory($packageStage, $packagePath, [System.IO.Compression.CompressionLevel]::Optimal, $false)
    [System.IO.Compression.ZipFile]::ExtractToDirectory($packagePath, $packageExtract)
    Assert-ReleaseLayout -Root $packageExtract
    $sha256 = (Get-FileHash -LiteralPath $packagePath -Algorithm SHA256).Hash
    Write-Host "Package: $packagePath"
    Write-Host "SHA-256: $sha256"
  }

  if ($LocalPreflightOnly) {
    Write-Step 'Local/controller preflight passed; no network connection or host change was made'
    exit 0
  }

  $remoteArguments = New-Object 'System.Collections.Generic.List[string]'
  $remoteArguments.Add('&')
  $remoteArguments.Add((ConvertTo-SingleQuotedPowerShell $remoteInstaller))
  Add-RemoteArgument $remoteArguments '-SiteName' $SiteName
  Add-RemoteArgument $remoteArguments '-AppPoolName' $AppPoolName
  Add-RemoteArgument $remoteArguments '-DeployRoot' $DeployRoot
  Add-RemoteArgument $remoteArguments '-BindingIpAddress' $BindingIpAddress
  Add-RemoteArgument $remoteArguments '-BindingPort' $BindingPort.ToString()
  Add-RemoteArgument $remoteArguments '-HostHeader' $HostHeader
  Add-RemoteArgument $remoteArguments '-KeepReleases' $KeepReleases.ToString()
  if (-not [string]::IsNullOrWhiteSpace($InitialWebConfigPath)) { Add-RemoteArgument $remoteArguments '-InitialWebConfigPath' $InitialWebConfigPath }
  if (-not [string]::IsNullOrWhiteSpace($BaseUrl)) { Add-RemoteArgument $remoteArguments '-BaseUrl' $BaseUrl }

  if ($Rollback) {
    Add-RemoteArgument $remoteArguments '-RollbackTo' $RollbackTo
  } elseif ($PreflightOnly) {
    $remoteArguments.Add('-PreflightOnly')
  } else {
    Add-RemoteArgument $remoteArguments '-PackagePath' $remotePackage
    Add-RemoteArgument $remoteArguments '-ReleaseId' $ReleaseId
    Add-RemoteArgument $remoteArguments '-ExpectedSha256' $sha256
  }
  if ($RunMigrations) { $remoteArguments.Add('-RunMigrations') }
  if ($SkipSmokeTest) { $remoteArguments.Add('-SkipSmokeTest') }

  $remoteScript = $remoteArguments -join ' '
  $remoteEncodedCommand = [Convert]::ToBase64String([Text.Encoding]::Unicode.GetBytes($remoteScript))
  $remoteCommand = 'powershell.exe -NoProfile -NonInteractive -ExecutionPolicy RemoteSigned -EncodedCommand ' + $remoteEncodedCommand

  if ($DryRun) {
    Write-Step 'Dry-run complete; no network connection was made'
    Write-Host "Would use dedicated site '$SiteName' and app pool '$AppPoolName'."
    Write-Host "Would use binding ${BindingIpAddress}:$BindingPort with host header '$HostHeader'."
    if ($PreflightOnly) {
      Write-Host 'Would stream the installer over SSH for a read-only host preflight; no remote file would be written.'
    } else {
      Write-Host "Would create remote directory: $remoteDirectory"
      Write-Host "Would copy installer: $installerPath"
      if (-not $Rollback) { Write-Host "Would copy package: $packagePath" }
      Write-Host ('Would execute host script: ' + $remoteScript)
    }
    exit 0
  }

  Assert-Command $SshExe
  if ($PreflightOnly) {
    Write-Step 'Streaming the installer for read-only host preflight'
    $installerSource = Get-Content -LiteralPath $installerPath -Raw
    $argumentTail = @($remoteArguments | Select-Object -Skip 2) -join ' '
    $stdinScript = "& {`r`n" + $installerSource + "`r`n} " + $argumentTail
    $stdinScript | & $SshExe -p $RemotePort $RemoteTarget 'powershell.exe -NoProfile -NonInteractive -ExecutionPolicy RemoteSigned -Command -'
    if ($LASTEXITCODE -ne 0) { throw "Remote preflight failed with exit code $LASTEXITCODE." }
    Write-Step 'Remote host preflight completed successfully without persistent host changes'
    exit 0
  }

  Assert-Command $ScpExe
  Write-Step 'Creating remote temporary directory'
  $mkdirScript = "New-Item -ItemType Directory -Force -Path $(ConvertTo-SingleQuotedPowerShell $remoteDirectory) | Out-Null"
  $mkdirEncoded = [Convert]::ToBase64String([Text.Encoding]::Unicode.GetBytes($mkdirScript))
  & $SshExe -p $RemotePort $RemoteTarget ('powershell.exe -NoProfile -NonInteractive -EncodedCommand ' + $mkdirEncoded)
  if ($LASTEXITCODE -ne 0) { throw 'Remote directory creation failed.' }

  Write-Step 'Copying the host installer'
  & $ScpExe -P $RemotePort $installerPath ($RemoteTarget + ':' + $remoteDirectory.Replace('\', '/') + '/install-iis-release.ps1')
  if ($LASTEXITCODE -ne 0) { throw 'Installer copy failed.' }
  if (-not $Rollback) {
    Write-Step 'Copying the release package'
    & $ScpExe -P $RemotePort $packagePath ($RemoteTarget + ':' + $remoteDirectory.Replace('\', '/') + '/' + $ReleaseId + '.zip')
    if ($LASTEXITCODE -ne 0) { throw 'Package copy failed.' }
  }

  Write-Step 'Invoking the host-side installer'
  & $SshExe -p $RemotePort $RemoteTarget $remoteCommand
  if ($LASTEXITCODE -ne 0) { throw "Remote installer failed with exit code $LASTEXITCODE." }
  Write-Step 'Remote operation completed successfully'
} finally {
  if ($KeepPackage -and (Test-Path -LiteralPath $packagePath)) {
    $keptPath = Join-Path (Get-Location) ([System.IO.Path]::GetFileName($packagePath))
    Copy-Item -LiteralPath $packagePath -Destination $keptPath -Force
    Write-Host "Package retained at $keptPath"
  }
  if (Test-Path -LiteralPath $workRoot) { Remove-Item -LiteralPath $workRoot -Recurse -Force }
}