[CmdletBinding()]
param(
    [string]$RomPath = (Join-Path $PSScriptRoot 'firmware\s5l8950x-secure-rom.bin'),
    [Alias('IbootPath')]
    [string]$DfuImagePath,
    [string]$MsysRoot = 'C:\msys64',
    [ValidateRange(1024, 65535)]
    [int]$UsbBridgePort = 26050,
    [switch]$NoWindowsUsb,
    [switch]$SkipBuild,
    [switch]$Trace,
    [ValidateRange(0, 65535)]
    [int]$GdbPort = 0,
    [switch]$Paused
)

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

if ([Environment]::OSVersion.Platform -ne [PlatformID]::Win32NT) {
    throw 'This launcher requires native Windows.'
}

$qemuSource = $PSScriptRoot
$buildDir = Join-Path $qemuSource 'build'
$mingwBin = Join-Path $MsysRoot 'mingw64\bin'
$msysBin = Join-Path $MsysRoot 'usr\bin'
$ninja = Join-Path $mingwBin 'ninja.exe'
$qemu = Join-Path $buildDir 'qemu-system-arm.exe'
$buildTemp = Join-Path $buildDir 'tmp'
$bridge = Join-Path $PSScriptRoot 'windows\QemuA6UsbBridge\build\Release\x64\QemuA6UsbBridge.exe'
$bridgeBuild = Join-Path $PSScriptRoot 'windows\QemuA6UsbBridge\build-bridge.ps1'
$bridgeStdout = Join-Path $buildDir 'a6-usb-bridge.log'
$bridgeStderr = Join-Path $buildDir 'a6-usb-bridge-error.log'

if (-not (Test-Path -LiteralPath $RomPath -PathType Leaf)) {
    throw "SecureROM not found: $RomPath"
}

$rom = Get-Item -LiteralPath $RomPath
if ($rom.Length -ne 0x10000) {
    throw "SecureROM must be exactly 65536 bytes (actual size: $($rom.Length))."
}

$dfuImage = $null
if ($DfuImagePath) {
    if (-not (Test-Path -LiteralPath $DfuImagePath -PathType Leaf)) {
        throw "DFU/iBSS image not found: $DfuImagePath"
    }
    $dfuImage = Get-Item -LiteralPath $DfuImagePath
    if ($dfuImage.Length -eq 0) {
        throw "The DFU/iBSS image is empty: $($dfuImage.FullName)"
    }
}

$windowsUsb = -not $NoWindowsUsb -and $null -eq $dfuImage

$env:Path = "$mingwBin;$msysBin;$env:Path"

if (-not $SkipBuild) {
    if (-not (Test-Path -LiteralPath $ninja -PathType Leaf)) {
        throw "MinGW64 Ninja not found: $ninja"
    }
    if (-not (Test-Path -LiteralPath (Join-Path $msysBin 'sort.exe') -PathType Leaf)) {
        throw "The MSYS2 tool set is incomplete: $msysBin"
    }
    if (-not (Test-Path -LiteralPath (Join-Path $buildDir 'build.ninja') -PathType Leaf)) {
        throw "qemu\build is not configured. Configure QEMU from MSYS2 MinGW64 with --target-list=arm-softmmu."
    }

    [IO.Directory]::CreateDirectory($buildTemp) | Out-Null
    $env:TMP = $buildTemp
    $env:TEMP = $buildTemp
    $env:TMPDIR = $buildTemp

    & $ninja -C $buildDir qemu-system-arm.exe
    if ($LASTEXITCODE -ne 0) {
        throw "The QEMU build failed with exit code $LASTEXITCODE."
    }
}

if (-not (Test-Path -LiteralPath $qemu -PathType Leaf)) {
    throw "QEMU binary not found: $qemu"
}

$machines = & $qemu -machine help 2>&1
if ($LASTEXITCODE -ne 0 -or -not ($machines -match '^iphone5\s')) {
    throw 'This QEMU binary does not include the iphone5 machine.'
}

$qemuArgs = @(
    '-machine', 'iphone5',
    '-bios', $rom.FullName,
    '-no-reboot',
    '-no-shutdown'
)

if ($dfuImage) {
    $qemuArgs += @(
        '-global',
        "s5l8950x-usb-otg.dfu-image=$($dfuImage.FullName)"
    )
}

if ($windowsUsb) {
    $qemuArgs += @(
        '-chardev', "socket,id=a6usb,host=127.0.0.1,port=$UsbBridgePort,server=on,wait=off",
        '-global', 's5l8950x-usb-otg.usb-bridge=a6usb'
    )
}

if ($Paused -and $GdbPort -eq 0) {
    $GdbPort = 1234
}
if ($GdbPort -gt 0) {
    $qemuArgs += @('-gdb', "tcp:127.0.0.1:$GdbPort")
}
if ($Paused) {
    $qemuArgs += '-S'
}

# UART0 and the monitor stay multiplexed on the native console, including
# while the CPU is stopped for a debugger (Ctrl+A C toggles the monitor).
$qemuArgs += @('-display', 'none', '-serial', 'mon:stdio')

if ($Trace) {
    $tracePath = Join-Path $buildDir 'a6-boot.log'
    $qemuArgs += @(
        '-d', 'in_asm,cpu_reset,guest_errors,unimp',
        '-D', $tracePath
    )
    Write-Host "QEMU trace           : $tracePath"
}

Write-Host "Native Windows QEMU  : $qemu"
Write-Host "SecureROM           : $($rom.FullName)"
if ($dfuImage) {
    Write-Host "DFU/iBSS image       : $($dfuImage.FullName)"
}
if ($windowsUsb) {
    if (-not (Test-Path -LiteralPath $bridge -PathType Leaf)) {
        & $bridgeBuild -Configuration Release
    }
    Write-Host 'Windows USB          : Apple DFU VID_05AC&PID_1227 through UDE'
    Write-Host "QEMU bridge          : 127.0.0.1:$UsbBridgePort"
    Write-Host "USB bridge log       : $bridgeStdout"
}
if ($dfuImage) {
    Write-Host 'The USB cable and DFU transfer are simulated internally.'
} elseif ($windowsUsb) {
    Write-Host 'Windows exposes the virtual DFU phone to unmodified host tools.'
} else {
    Write-Host 'Recovery and the USB cable are simulated; the ROM is waiting in DFU mode.'
}
Write-Host 'A6 UART              : this console (Ctrl+A C = monitor)'
Write-Host 'Press Ctrl+A, then X to quit.'
if ($GdbPort -gt 0) {
    Write-Host "Debugger             : remote GDB at 127.0.0.1:$GdbPort"
    Write-Host "LLDB                 : lldb -o 'gdb-remote 127.0.0.1:$GdbPort'"
}
if ($Paused) {
    Write-Host 'CPU                  : paused until the debugger issues continue'
}

$bridgeProcess = $null
$exitCode = 1
try {
    if ($windowsUsb) {
        $bridgeProcess = Start-Process -FilePath $bridge `
            -ArgumentList @('127.0.0.1', $UsbBridgePort.ToString()) `
            -WindowStyle Hidden -PassThru `
            -RedirectStandardOutput $bridgeStdout `
            -RedirectStandardError $bridgeStderr
    }

    & $qemu @qemuArgs
    $exitCode = $LASTEXITCODE
} finally {
    if ($null -ne $bridgeProcess -and -not $bridgeProcess.HasExited) {
        Stop-Process -Id $bridgeProcess.Id
        $bridgeProcess.WaitForExit()
    }
}
exit $exitCode