$ErrorActionPreference = 'Stop'

$repositoryRoot = Split-Path -Parent $PSScriptRoot
$installer = Join-Path $repositoryRoot 'scripts/install-tht.ps1'
if (-not (Test-Path -LiteralPath $installer)) {
    throw "installer is missing: $installer"
}

$isWindowsHost = $env:OS -eq 'Windows_NT'
if (-not $isWindowsHost) {
    $installerText = Get-Content -LiteralPath $installer -Raw
    foreach ($requiredText in @('THT_INSTALL_DIRECTORY', 'LOCALAPPDATA', 'SetEnvironmentVariable', 'build-tht.sh', 'Move-Item')) {
        if (-not $installerText.Contains($requiredText)) {
            throw "Windows installer is missing required behavior: $requiredText"
        }
    }
    Write-Output 'PowerShell installer behavior test skipped: requires Windows.'
    exit 0
}

$temporaryRoot = Join-Path ([System.IO.Path]::GetTempPath()) ("tht installer test {0}" -f [guid]::NewGuid())
$installDirectory = Join-Path $temporaryRoot 'command directory'
$artifact = Join-Path $temporaryRoot 'tht.exe'
$userPathStore = Join-Path $temporaryRoot 'user-path.txt'
New-Item -ItemType Directory -Path $temporaryRoot -Force | Out-Null
try {
    $program = @'
using System;
public static class Program {
    public static void Main(string[] args) {
        if (args.Length == 1 && args[0] == "--help") { Console.WriteLine("Usage: tht"); return; }
        if (args.Length == 1 && args[0] == "version") { Console.WriteLine("tht test version"); return; }
        Environment.Exit(2);
    }
}
'@
    Add-Type -TypeDefinition $program -OutputAssembly $artifact -OutputType ConsoleApplication
    [System.IO.File]::WriteAllText($userPathStore, 'C:\Existing Bin')

    $env:THT_INSTALL_DIRECTORY = $installDirectory
    $env:THT_BUILD_ARTIFACT = $artifact
    $env:THT_BUILD_ARTIFACT_SHA256 = (Get-FileHash -Algorithm SHA256 -LiteralPath $artifact).Hash.ToLowerInvariant()
    $env:THT_USER_PATH_FILE = $userPathStore
    & $installer

    $installed = Join-Path $installDirectory 'tht.exe'
    if (-not (Test-Path -LiteralPath $installed)) { throw 'installer did not create tht.exe' }
    if ((& $installed version) -ne 'tht test version') { throw 'installed tht.exe did not return version' }
    $firstBytes = [System.IO.File]::ReadAllBytes($installed)

    & $installer
    if ((& $installed version) -ne 'tht test version') { throw 'installer was not idempotent' }
    if (-not ([System.IO.File]::ReadAllBytes($installed).Length -eq $firstBytes.Length)) { throw 'replacement changed the unexpected binary' }

    $storedPath = [System.IO.File]::ReadAllText($userPathStore)
    $segments = $storedPath -split ';' | Where-Object { $_ -ne '' }
    if ((@($segments | Where-Object { $_ -ieq $installDirectory }).Count) -ne 1) {
        throw 'installer did not preserve a single destination PATH entry'
    }
    if (-not ($segments | Where-Object { $_ -ieq 'C:\Existing Bin' })) { throw 'installer did not preserve existing user PATH entries' }
    Write-Output 'PowerShell tht installer tests passed.'
}
finally {
    Remove-Item Env:THT_INSTALL_DIRECTORY -ErrorAction SilentlyContinue
    Remove-Item Env:THT_BUILD_ARTIFACT -ErrorAction SilentlyContinue
    Remove-Item Env:THT_BUILD_ARTIFACT_SHA256 -ErrorAction SilentlyContinue
    Remove-Item Env:THT_USER_PATH_FILE -ErrorAction SilentlyContinue
    Remove-Item -LiteralPath $temporaryRoot -Recurse -Force -ErrorAction SilentlyContinue
}