#Requires -Version 5.1

[CmdletBinding()]
param(
  [Parameter(Position = 0)]
  [ValidateSet('start', 'update')]
  [string]$Action = 'start',

  [ValidateNotNullOrEmpty()]
  [string]$ListenAddress = '0.0.0.0',

  [ValidateRange(1, 65535)]
  [int]$Port = 9000,

  [ValidateNotNullOrEmpty()]
  [string]$DataDir = 'C:\ProgramData\WebTools\data',

  [ValidateNotNullOrEmpty()]
  [string]$Remote = 'origin',

  [ValidateNotNullOrEmpty()]
  [string]$Branch = 'main',

  [switch]$NoStart
)

Set-StrictMode -Version 3.0
$ErrorActionPreference = 'Stop'

$projectRoot = $PSScriptRoot
$serverEntry = Join-Path $projectRoot 'server\index.mjs'
$distIndex = Join-Path $projectRoot 'dist\index.html'

function Resolve-Application {
  param(
    [Parameter(Mandatory = $true)]
    [string]$Name
  )

  $command = Get-Command $Name -CommandType Application -ErrorAction SilentlyContinue |
    Select-Object -First 1
  if ($null -eq $command) {
    throw "Required command '$Name' was not found in PATH."
  }

  return $command.Source
}

function Invoke-NativeCommand {
  param(
    [Parameter(Mandatory = $true)]
    [string]$Executable,

    [Parameter(Mandatory = $true)]
    [string[]]$Arguments
  )

  & $Executable @Arguments
  $exitCode = $LASTEXITCODE
  if ($exitCode -ne 0) {
    throw "Command '$Executable $($Arguments -join ' ')' failed with exit code $exitCode."
  }
}

function Assert-ProductionBuild {
  if (-not (Test-Path -LiteralPath $serverEntry -PathType Leaf)) {
    throw "Server entry was not found: $serverEntry"
  }

  if (-not (Test-Path -LiteralPath $distIndex -PathType Leaf)) {
    throw "Production build was not found: $distIndex. Run '.\web-tools.ps1 update' first."
  }
}

function Update-WebTools {
  $git = Resolve-Application 'git.exe'
  $npm = Resolve-Application 'npm.cmd'

  Push-Location $projectRoot
  try {
    $insideWorkTree = @(& $git rev-parse --is-inside-work-tree)
    if ($LASTEXITCODE -ne 0 -or ($insideWorkTree -join '').Trim() -ne 'true') {
      throw "Project directory is not a Git work tree: $projectRoot"
    }

    $statusLines = @(& $git status --porcelain --untracked-files=normal)
    if ($LASTEXITCODE -ne 0) {
      throw "Unable to inspect the Git work tree."
    }
    if ($statusLines.Count -gt 0) {
      throw "The Git work tree contains local changes. Update was stopped to avoid overwriting them:`n$($statusLines -join "`n")"
    }

    $currentBranchOutput = @(& $git branch --show-current)
    if ($LASTEXITCODE -ne 0) {
      throw "Unable to determine the current Git branch."
    }
    $currentBranch = ($currentBranchOutput -join '').Trim()
    if ($currentBranch -ne $Branch) {
      throw "Current branch is '$currentBranch'; expected '$Branch'."
    }

    Write-Host "Updating $Remote/$Branch..."
    Invoke-NativeCommand $git @('pull', '--ff-only', $Remote, $Branch)

    $previousNodeEnv = [Environment]::GetEnvironmentVariable('NODE_ENV', 'Process')
    try {
      [Environment]::SetEnvironmentVariable('NODE_ENV', $null, 'Process')

      Write-Host 'Installing locked dependencies (npm ci replaces node_modules automatically)...'
      Invoke-NativeCommand $npm @('ci', '--include=dev')

      Write-Host 'Building the production application...'
      Invoke-NativeCommand $npm @('run', 'build')
    }
    finally {
      [Environment]::SetEnvironmentVariable('NODE_ENV', $previousNodeEnv, 'Process')
    }

    Assert-ProductionBuild
    Write-Host 'Update and production build completed successfully.'
  }
  finally {
    Pop-Location
  }
}

function Start-WebTools {
  Assert-ProductionBuild
  $node = Resolve-Application 'node.exe'
  $dataDirectory = (New-Item -ItemType Directory -Force -Path $DataDir).FullName

  $previousEnvironment = @{
    NODE_ENV = [Environment]::GetEnvironmentVariable('NODE_ENV', 'Process')
    HOST = [Environment]::GetEnvironmentVariable('HOST', 'Process')
    PORT = [Environment]::GetEnvironmentVariable('PORT', 'Process')
    DATA_DIR = [Environment]::GetEnvironmentVariable('DATA_DIR', 'Process')
  }

  try {
    [Environment]::SetEnvironmentVariable('NODE_ENV', 'production', 'Process')
    [Environment]::SetEnvironmentVariable('HOST', $ListenAddress, 'Process')
    [Environment]::SetEnvironmentVariable('PORT', $Port.ToString(), 'Process')
    [Environment]::SetEnvironmentVariable('DATA_DIR', $dataDirectory, 'Process')

    Write-Host "Starting Web Tools on http://${ListenAddress}:$Port"
    Write-Host "Navigation config: $(Join-Path $dataDirectory 'navigation.json')"
    Write-Host 'Press Ctrl+C to stop.'

    Push-Location $projectRoot
    try {
      & $node $serverEntry
      $exitCode = $LASTEXITCODE
      if ($exitCode -ne 0) {
        throw "Web Tools exited with code $exitCode."
      }
    }
    finally {
      Pop-Location
    }
  }
  finally {
    foreach ($name in $previousEnvironment.Keys) {
      [Environment]::SetEnvironmentVariable($name, $previousEnvironment[$name], 'Process')
    }
  }
}

if ($Action -eq 'start' -and $NoStart) {
  throw "-NoStart can only be used with the 'update' action."
}

if ($Action -eq 'update') {
  Update-WebTools
  if ($NoStart) {
    return
  }
}

Start-WebTools