<#
serial_capture.ps1 - Capture a serial boot log with serial-mcp-server CLI.

Workflow (deterministic boot-log capture after flashing):
1. Open COM via serial-mcp-server `read` CAPTURE mode and WAIT for the first
   byte (up to -InitialTimeoutMs). This starts BEFORE flashing.
2. Flash the target (download.bat) -> MCU resets and prints the boot log.
3. The running capture picks up the first byte, then collects for -DurationMs.
4. The process exits and writes a single structured JSON file at -OutFile.

Known trap (Adancurusul/serial-mcp-server, fixed here by retry):
  When COM is released by a previous process and reopened immediately,
  tokio-serial read returns 0 bytes and the project's capture.rs turns that
  into a fatal `UnexpectedEof` error (serial stream returned zero bytes).
  This is transient: a short backoff then reopening succeeds. This script
  detects that error, backs off, and restarts the capture.

Usage:
  powershell -ExecutionPolicy Bypass -File serial_capture.ps1 `
      -OutFile C:\temp\boot.json `
      [-Port COM6] [-BaudRate 115200] `
      [-DurationMs 20000] [-InitialTimeoutMs 60000] `
      [-IdleTimeoutMs 1500] [-MaxBytes 65536] `
      [-FlashCmd "D:\...\download.bat"] `
      [-MaxRetries 3] [-RetryDelayMs 1500]

Modes:
  -FlashCmd: orchestrates the whole sequence in ONE call: (retry-stable)
  start capture, run the flash/download command, then wait for capture to
  finish. Use this to avoid tool-call gaps letting the capture timeout before
  flashing.
  No -FlashCmd: starts the capture, waits for it to be stable (survives
  -StabilityCheckMs), prints the PID, and returns. Caller flashes, then calls
  with -WaitOnly to reap.

Exit codes:
  0 = capture completed (ok or clean timeout)
  1 = capture failed to start after retries
  2 = capture error status in JSON

NOTE: ASCII-only on purpose - project source files contain Chinese and must
never be rewritten by encoding-sensitive PowerShell. Keep this script ASCII.
#>

[CmdletBinding()]
param(
    [Parameter(Mandatory = $true)]
    [string]$OutFile,

    [string]$Port = "COM6",
    [int]$BaudRate = 115200,
    [int]$DurationMs = 20000,
    [int]$InitialTimeoutMs = 60000,
    [int]$IdleTimeoutMs = 1500,
    [int]$MaxBytes = 65536,
    [string]$FlashCmd = "",
    [int]$MaxRetries = 3,
    [int]$RetryDelayMs = 1500,
    [int]$StabilityCheckMs = 1500
)

$ErrorActionPreference = 'Stop'

$exe = "$env:LOCALAPPDATA\serial-mcp-server\serial-mcp-server.exe"
if (-not (Test-Path -LiteralPath $exe)) {
    Write-Output "CAPTURE_ERROR: serial-mcp-server binary not found: $exe"
    exit 1
}

$outDir = Split-Path -Parent $OutFile
if ($outDir -and -not (Test-Path -LiteralPath $outDir)) {
    New-Item -ItemType Directory -Path $outDir -Force | Out-Null
}

$baseArgs = @(
    "read",
    "--port", $Port,
    "--baud", ([string]$BaudRate),
    "--duration-ms", ([string]$DurationMs),
    "--start-trigger", "first-byte",
    "--initial-timeout-ms", ([string]$InitialTimeoutMs),
    "--idle-timeout-ms", ([string]$IdleTimeoutMs),
    "--max-bytes", ([string]$MaxBytes),
    "--json"
)

function Start-CaptureProcess {
    param([int]$attempt)
    $out = $OutFile
    $err = "$OutFile.err"
    if (Test-Path -LiteralPath $out) { Remove-Item -LiteralPath $out -Force }
    if (Test-Path -LiteralPath $err) { Remove-Item -LiteralPath $err -Force }
    if ($attempt -gt 0) {
        Write-Host "RETRY: capture attempt $attempt (backoff $RetryDelayMs ms)"
        Start-Sleep -Milliseconds $RetryDelayMs
    }
    $p = Start-Process -FilePath $exe -ArgumentList $baseArgs `
        -RedirectStandardOutput $out -RedirectStandardError $err `
        -WindowStyle Hidden -PassThru
    if ($p -eq $null -or $p.HasExited) {
        Write-Output "CAPTURE_ERROR: process failed to start (attempt $attempt)"
        return $null
    }
    return $p
}

function Test-CaptureErrored {
    $err = "$OutFile.err"
    if (Test-Path -LiteralPath $err) {
        $e = Get-Content -LiteralPath $err -Raw -ErrorAction SilentlyContinue
        if ($e -match "UnexpectedEof|zero bytes|Error:") { return $true }
    }
    return $false
}

$proc = $null
for ($i = 0; $i -le $MaxRetries; $i++) {
    $proc = Start-CaptureProcess -attempt $i
    if ($proc -eq $null) { continue }

    # Wait a moment: if the process died with EOF/error immediately, retry.
    Start-Sleep -Milliseconds $StabilityCheckMs
    if (-not $proc.HasExited) { break }  # stable, keep it
    if (-not (Test-CaptureErrored)) { break }  # exited cleanly, no error
    Write-Host "CAPTURE_EOF: transient EOF on attempt $i, retrying..."
    $proc = $null
}

if ($proc -eq $null) {
    Write-Output "CAPTURE_ERROR: could not start a stable capture after retries"
    exit 1
}

Write-Output "CAPTURE_PID: $($proc.Id)"

if ($FlashCmd) {
    if (-not (Test-Path -LiteralPath $FlashCmd)) {
        Stop-Process -Id $proc.Id -Force -ErrorAction SilentlyContinue
        Write-Output "CAPTURE_ERROR: flash command not found: $FlashCmd"
        exit 1
    }
    Write-Output "FLASH_START: $FlashCmd"
    & $FlashCmd
    $flashRc = $LASTEXITCODE
    Write-Output "FLASH_RC: $flashRc"
    $proc.WaitForExit()
    Write-Output "CAPTURE_DONE"
    if (Test-Path -LiteralPath $OutFile) {
        $content = Get-Content -LiteralPath $OutFile -Raw -ErrorAction SilentlyContinue
        if ($content -match '"status":\s*"error"') {
            Write-Output "CAPTURE_ERROR: capture returned error status"
            Write-Output $content
            exit 2
        }
    }
    exit 0
}

exit 0