param(
    [string]$Output = "dist\factory_firmware"
)

$ErrorActionPreference = "Stop"
$toolRoot = Split-Path -Parent $MyInvocation.MyCommand.Path
$projectRoot = Split-Path -Parent $toolRoot
$audioImage = Join-Path $toolRoot "dist\factory_audio\customer_fs.bin"
$configuredImage = Join-Path $projectRoot "ql-config\config\EG800AKCN_11LG\customer_fs.bin"
$flashPackage = Join-Path $projectRoot "target\EG800AKCN_11LG\EG800AKCN_11LG.zip"
$outDir = Join-Path $toolRoot $Output
$backup = Join-Path $outDir "customer_fs.business-backup.bin"
$export = Join-Path $outDir "EG800AKCN_11LG-FT1-factory-test.zip"

if (-not (Test-Path -LiteralPath $audioImage)) {
    throw "Factory audio image is missing. Run build_factory_audio_package.py first."
}
if ((Get-Item -LiteralPath $audioImage).Length -ne 262144) {
    throw "Factory customer_fs.bin is not 262144 bytes."
}

New-Item -ItemType Directory -Force -Path $outDir | Out-Null
Copy-Item -LiteralPath $configuredImage -Destination $backup -Force
$originalHash = (Get-FileHash -LiteralPath $configuredImage -Algorithm SHA256).Hash
$audioHash = (Get-FileHash -LiteralPath $audioImage -Algorithm SHA256).Hash

try {
    Copy-Item -LiteralPath $audioImage -Destination $configuredImage -Force
    if ((Get-FileHash -LiteralPath $configuredImage -Algorithm SHA256).Hash -ne $audioHash) {
        throw "Temporary customer_fs.bin hash verification failed."
    }

    & cmd.exe /d /c "build.bat app"
    if ($LASTEXITCODE -ne 0) { throw "build.bat app failed with exit code $LASTEXITCODE" }
    & cmd.exe /d /c "build.bat firmware"
    if ($LASTEXITCODE -ne 0) { throw "build.bat firmware failed with exit code $LASTEXITCODE" }
    if (-not (Test-Path -LiteralPath $flashPackage)) {
        throw "Flashable inner package was not generated: $flashPackage"
    }
    Copy-Item -LiteralPath $flashPackage -Destination $export -Force
    $exportHash = (Get-FileHash -LiteralPath $export -Algorithm SHA256).Hash
    @{
        package = (Split-Path -Leaf $export)
        bytes = (Get-Item -LiteralPath $export).Length
        sha256 = $exportHash
        customer_fs_sha256 = $audioHash
        git_revision = (& git -C $projectRoot rev-parse HEAD).Trim()
        generated_at = (Get-Date).ToString("o")
    } | ConvertTo-Json | Set-Content -LiteralPath (Join-Path $outDir "firmware_manifest.json") -Encoding UTF8
    Write-Host "Factory firmware: $export"
    Write-Host "SHA256: $exportHash"
}
finally {
    Copy-Item -LiteralPath $backup -Destination $configuredImage -Force
    $restoredHash = (Get-FileHash -LiteralPath $configuredImage -Algorithm SHA256).Hash
    if ($restoredHash -ne $originalHash) {
        throw "Business customer_fs.bin restore verification failed. Backup: $backup"
    }
    Write-Host "Business customer_fs.bin restored: $restoredHash"
}