[CmdletBinding()]
param(
    [switch]$Clean,
    [switch]$SkipTests
)

$ErrorActionPreference = 'Stop'
$PSNativeCommandUseErrorActionPreference = $true

$projectRoot = Split-Path -Parent $PSScriptRoot
$n2nRoot = Join-Path $projectRoot 'third_party\n2n'
$cargoManifest = Join-Path $projectRoot 'src-tauri\Cargo.toml'
$packageScript = Join-Path $PSScriptRoot 'package-portable.ps1'
$n2nBuildScript = Join-Path $PSScriptRoot 'build-n2n.sh'
$archivePath = Join-Path $projectRoot 'release\super-n2n-portable.zip'
$checksumPath = $archivePath + '.sha256'

function Get-RequiredCommand {
    param(
        [string[]]$Names,
        [string]$Purpose
    )

    foreach ($name in $Names) {
        $command = Get-Command $name -CommandType Application -ErrorAction SilentlyContinue | Select-Object -First 1
        if ($command) {
            return $command.Source
        }
    }

    throw "Missing required tool for $Purpose. Expected one of: $($Names -join ', ')."
}

function Get-GitBash {
    param([string]$GitExecutable)

    $gitRoot = Split-Path -Parent (Split-Path -Parent $GitExecutable)
    $candidatePaths = @(
        (Join-Path $gitRoot 'bin\bash.exe')
    )
    $candidatePaths += Get-Command bash.exe -CommandType Application -All -ErrorAction SilentlyContinue | ForEach-Object Source

    foreach ($bashPath in $candidatePaths | Select-Object -Unique) {
        if (-not (Test-Path -LiteralPath $bashPath)) {
            continue
        }
        $bashDirectory = Split-Path -Parent $bashPath
        $gitUnixBinCandidates = @(
            $bashDirectory,
            (Join-Path (Split-Path -Parent $bashDirectory) 'usr\bin')
        )
        foreach ($gitUnixBin in $gitUnixBinCandidates) {
            if ((Test-Path -LiteralPath (Join-Path $gitUnixBin 'sh.exe')) -and
                (Test-Path -LiteralPath (Join-Path $gitUnixBin 'cygpath.exe'))) {
                return [pscustomobject]@{
                    Bash = $bashPath
                    UnixBin = $gitUnixBin
                }
            }
        }
    }

    throw 'Git Bash was not found. Install Git for Windows.'
}

function Invoke-Checked {
    param(
        [string]$Executable,
        [string[]]$Arguments
    )

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

if ($env:OS -ne 'Windows_NT') {
    throw 'This script builds the Windows portable package and must run on Windows.'
}

$git = Get-RequiredCommand -Names @('git.exe', 'git') -Purpose 'source checkout'
$npm = Get-RequiredCommand -Names @('npm.cmd', 'npm') -Purpose 'frontend dependency installation'
$cargo = Get-RequiredCommand -Names @('cargo.exe', 'cargo') -Purpose 'Tauri compilation'
$gitBash = Get-GitBash -GitExecutable $git
$make = Get-RequiredCommand -Names @('mingw32-make.exe', 'mingw32-make') -Purpose 'n2n compilation'
$null = Get-RequiredCommand -Names @('gcc.exe', 'gcc') -Purpose 'n2n compilation'
$null = Get-RequiredCommand -Names @('windres.exe', 'windres') -Purpose 'n2n Windows resource compilation'

# Make GNU utilities (rm, cp, gzip) available to n2n's Makefile on Windows.
$env:Path = "$($gitBash.UnixBin);$env:Path"
$env:SHELL = Join-Path $gitBash.UnixBin 'sh.exe'

Push-Location $projectRoot
try {
    Invoke-Checked $git @('submodule', 'sync')
    Invoke-Checked $git @('submodule', 'update', '--init')

    if (-not (Test-Path -LiteralPath $n2nRoot)) {
        throw "The n2n submodule was not initialized: $n2nRoot"
    }

    $cygpath = Join-Path $gitBash.UnixBin 'cygpath.exe'
    $n2nRootUnix = (& $cygpath -u $n2nRoot).Trim()
    $makeUnix = (& $cygpath -u $make).Trim()
    $n2nBuildScriptUnix = (& $cygpath -u $n2nBuildScript).Trim()
    Invoke-Checked $gitBash.Bash @($n2nBuildScriptUnix, $n2nRootUnix, $makeUnix, $(if ($Clean) { '1' } else { '0' }))

    foreach ($binary in @('edge.exe', 'supernode.exe')) {
        if (-not (Test-Path -LiteralPath (Join-Path $n2nRoot $binary))) {
            throw "n2n build did not produce $binary."
        }
    }

    Invoke-Checked $npm @('ci')

    if (-not $SkipTests) {
        Invoke-Checked $cargo @('test', '--manifest-path', $cargoManifest)
    }

    & $packageScript -Clean:$Clean
    if ($LASTEXITCODE -ne 0) {
        throw "Portable package script failed with exit code $LASTEXITCODE."
    }

    if (-not (Test-Path -LiteralPath $archivePath)) {
        throw "Portable archive was not created: $archivePath"
    }

    $stream = [System.IO.File]::OpenRead($archivePath)
    try {
        $sha256 = [System.Security.Cryptography.SHA256]::Create()
        try {
            $hashBytes = $sha256.ComputeHash($stream)
            $hash = -join ($hashBytes | ForEach-Object { $_.ToString('x2') })
        }
        finally {
            $sha256.Dispose()
        }
    }
    finally {
        $stream.Dispose()
    }
    "$hash *$(Split-Path -Leaf $archivePath)" | Set-Content -LiteralPath $checksumPath -Encoding ascii
    Write-Output "Build completed: $archivePath"
    Write-Output "SHA-256 checksum: $checksumPath"
}
finally {
    Pop-Location
}