[CmdletBinding()]
param(
    [string]$NodeVersion = '20.20.2',
    [int]$MaxOldSpaceSizeMB = 8192
)

$ErrorActionPreference = 'Stop'
$repoRoot = (Resolve-Path (Join-Path $PSScriptRoot '..')).Path
$toolRoot = Join-Path $env:LOCALAPPDATA 'CaiWuXiTong\tools'
$nodeFolderName = "node-v$NodeVersion-win-x64"
$nodeRoot = Join-Path $toolRoot $nodeFolderName
$nodeExe = Join-Path $nodeRoot 'node.exe'
$npmCmd = Join-Path $nodeRoot 'npm.cmd'
$archiveName = "$nodeFolderName.zip"
$archivePath = Join-Path $toolRoot $archiveName
$checksumPath = Join-Path $toolRoot 'SHASUMS256.txt'
$trackedCssPath = Join-Path $repoRoot 'public/css/app.css'
$frontendOutputRoot = Join-Path $repoRoot '.caiwu-build/public'
$fingerprintPath = Join-Path $repoRoot '.caiwu-build/frontend.sha'

function Invoke-Native {
    param(
        [Parameter(Mandatory = $true)]
        [scriptblock]$Command,
        [Parameter(Mandatory = $true)]
        [string]$FailureMessage
    )

    & $Command
    if ($LASTEXITCODE -ne 0) {
        throw $FailureMessage
    }
}

$fingerprintInputs = @(
    'HEAD:resources',
    'HEAD:package.json',
    'HEAD:package-lock.json',
    'HEAD:webpack.mix.js',
    'HEAD:tailwind.config.js'
)
$fingerprintHashes = @(& git -C $repoRoot rev-parse @fingerprintInputs)
if ($LASTEXITCODE -ne 0) {
    throw '无法计算前端输入指纹。'
}
$frontendFingerprint = "$NodeVersion|$($fingerprintHashes -join '|')"
$cachedOutputs = @(
    (Join-Path $frontendOutputRoot 'js/auth/common.min.js'),
    (Join-Path $frontendOutputRoot 'css/app.css'),
    (Join-Path $frontendOutputRoot 'mix-manifest.json'),
    $fingerprintPath
)
$cacheComplete = -not ($cachedOutputs | Where-Object { -not (Test-Path -LiteralPath $_) })
if ($cacheComplete -and (Get-Content -Raw -LiteralPath $fingerprintPath).Trim() -eq $frontendFingerprint) {
    Write-Host '前端输入未变化，复用已有构建产物。'
    return
}

if (-not (Test-Path -LiteralPath $nodeExe)) {
    New-Item -ItemType Directory -Force -Path $toolRoot | Out-Null

    try {
        $downloadRoot = "https://nodejs.org/dist/v$NodeVersion"
        Invoke-WebRequest -Uri "$downloadRoot/$archiveName" -OutFile $archivePath
        Invoke-WebRequest -Uri "$downloadRoot/SHASUMS256.txt" -OutFile $checksumPath

        $checksumLine = Select-String -Path $checksumPath -Pattern ([regex]::Escape($archiveName) + '$') |
            Select-Object -First 1
        if (-not $checksumLine) {
            throw 'Node 安装包缺少官方 SHA-256 校验值。'
        }

        $expectedHash = ($checksumLine.Line -split '\s+')[0].ToLowerInvariant()
        $actualHash = (Get-FileHash -Algorithm SHA256 -LiteralPath $archivePath).Hash.ToLowerInvariant()
        if ($actualHash -ne $expectedHash) {
            throw 'Node 安装包 SHA-256 校验失败。'
        }

        Expand-Archive -LiteralPath $archivePath -DestinationPath $toolRoot -Force
    }
    finally {
        if (Test-Path -LiteralPath $archivePath) {
            Remove-Item -LiteralPath $archivePath -Force
        }
        if (Test-Path -LiteralPath $checksumPath) {
            Remove-Item -LiteralPath $checksumPath -Force
        }
    }
}

if (-not (Test-Path -LiteralPath $nodeExe) -or -not (Test-Path -LiteralPath $npmCmd)) {
    throw "项目专用 Node $NodeVersion 安装不完整。"
}

$originalPath = $env:Path
$originalNodeOptions = $env:NODE_OPTIONS
$trackedCssBackup = if (Test-Path -LiteralPath $trackedCssPath) {
    [IO.File]::ReadAllBytes($trackedCssPath)
}
else {
    $null
}

Push-Location $repoRoot
try {
    $env:Path = "$nodeRoot;$originalPath"
    $env:NODE_OPTIONS = "--max-old-space-size=$MaxOldSpaceSizeMB"

    Invoke-Native { & $nodeExe --version } '项目专用 Node 无法运行。'
    Invoke-Native {
        & $npmCmd ci --prefer-offline --no-audit --no-fund
    } '前端依赖安装失败。'
    Invoke-Native { & $npmCmd run production } '前端资源构建失败。'

    $requiredOutputs = @(
        'public/js/auth/common.min.js',
        'public/css/app.css',
        'public/mix-manifest.json'
    )
    foreach ($output in $requiredOutputs) {
        if (-not (Test-Path -LiteralPath (Join-Path $repoRoot $output))) {
            throw "前端构建缺少产物：$output"
        }
    }

    if (Test-Path -LiteralPath $frontendOutputRoot) {
        Remove-Item -LiteralPath $frontendOutputRoot -Recurse -Force
    }
    New-Item -ItemType Directory -Force -Path (Join-Path $frontendOutputRoot 'css') | Out-Null
    Copy-Item -LiteralPath (Join-Path $repoRoot 'public/js') -Destination $frontendOutputRoot -Recurse
    Copy-Item -LiteralPath (Join-Path $repoRoot 'public/css/app.css') -Destination (Join-Path $frontendOutputRoot 'css/app.css')
    Copy-Item -LiteralPath (Join-Path $repoRoot 'public/mix-manifest.json') -Destination $frontendOutputRoot
    Set-Content -LiteralPath $fingerprintPath -Value $frontendFingerprint -NoNewline
}
finally {
    Pop-Location
    $env:Path = $originalPath
    $env:NODE_OPTIONS = $originalNodeOptions
    if ($null -ne $trackedCssBackup) {
        [IO.File]::WriteAllBytes($trackedCssPath, $trackedCssBackup)
    }
}