param(
    [Parameter(Mandatory = $true)]
    [string]$Path
)

$ErrorActionPreference = 'Stop'
$resolved = Resolve-Path -LiteralPath $Path
$item = Get-Item -LiteralPath $resolved
$file = if ($item.PSIsContainer) {
    Get-ChildItem -LiteralPath $item.FullName -Filter '*.jsonl' -File |
        Sort-Object LastWriteTime -Descending |
        Select-Object -First 1
}
else {
    $item
}
if (-not $file) { throw "No JSONL file found: $Path" }

$records = New-Object System.Collections.Generic.List[object]
$lineNumber = 0
Get-Content -LiteralPath $file.FullName | ForEach-Object {
    $lineNumber++
    try { $records.Add(($_ | ConvertFrom-Json)) }
    catch { throw "Invalid JSONL at line $lineNumber in $($file.FullName): $($_.Exception.Message)" }
}

$sequenceStrict = $true
for ($index = 1; $index -lt $records.Count; $index++) {
    if ([uint64]$records[$index].sequence -le [uint64]$records[$index - 1].sequence) {
        $sequenceStrict = $false
        break
    }
}

$immQueries = @($records | Where-Object recordType -eq 'imm_query')
$successfulResults = @($immQueries | Where-Object immQueryStatus -eq 'success')
$echoSummaries = @($records | Where-Object recordType -eq 'echo_correlation')
$textLeaks = @($records | Where-Object {
    $_.messageCategory -eq 'text' -and $_.wParamHex -ne $null
})
$lost = @($records | Where-Object recordType -eq 'records_lost')
$attach = $records | Where-Object recordType -eq 'window_attach' | Select-Object -First 1

$correlationCounts = [ordered]@{}
foreach ($entry in $echoSummaries) {
    $key = "$($entry.echoChannel):$($entry.correlationStatus)"
    if (-not $correlationCounts.Contains($key)) { $correlationCounts[$key] = 0 }
    $correlationCounts[$key]++
}

[pscustomobject]@{
    file = $file.FullName
    recordCount = $records.Count
    sequenceStrict = $sequenceStrict
    recordsLost = $lost.Count
    textRawWParamLeaks = $textLeaks.Count
    isWindowUnicode = $attach.isWindowUnicode
    ansiCodePage = $attach.ansiCodePage
    wndProcThreadIds = @($records | Where-Object sourceBackend -eq 'Win32WndProc' |
        Select-Object -ExpandProperty threadId -Unique)
    hostThreadIds = @($records | Where-Object sourceBackend -eq 'HostEventLoop' |
        Select-Object -ExpandProperty threadId -Unique)
    imeStartCount = @($records | Where-Object messageName -eq 'WM_IME_STARTCOMPOSITION').Count
    imeCompositionCount = @($records | Where-Object messageName -eq 'WM_IME_COMPOSITION').Count
    imeEndCount = @($records | Where-Object messageName -eq 'WM_IME_ENDCOMPOSITION').Count
    inputLanguageChangeRequestCount = @($records |
        Where-Object messageName -eq 'WM_INPUTLANGCHANGEREQUEST').Count
    inputLanguageChangeCount = @($records | Where-Object messageName -eq 'WM_INPUTLANGCHANGE').Count
    immQueryCount = $immQueries.Count
    successfulResultCount = $successfulResults.Count
    successfulUtf16Lengths = @($successfulResults | Select-Object -ExpandProperty utf16Length)
    successfulScalarCounts = @($successfulResults | Select-Object -ExpandProperty scalarCount)
    digestPresentCount = @($successfulResults | Where-Object sessionDigest -ne $null).Count
    correlationCounts = [pscustomobject]$correlationCounts
    closeObserved = @($records | Where-Object messageName -eq 'WM_CLOSE').Count -gt 0
    sessionEndObserved = @($records | Where-Object recordType -eq 'session_end').Count -gt 0
}