param(
    [string]$IlFile = "runs/offline-evidence-intake/zyl-qqfile-20260709/metadata/c28-il/IMPlatformClient.exe.il",
    [string]$OutDir = "runs/offline-chat-window"
)

$ErrorActionPreference = "Stop"
$repo = Resolve-Path -LiteralPath (Join-Path $PSScriptRoot "..")

function Resolve-RepoPath([string]$PathValue) {
    if ([System.IO.Path]::IsPathRooted($PathValue)) {
        return $PathValue
    }
    return (Join-Path $repo $PathValue)
}

$ilFull = Resolve-RepoPath $IlFile
$outFull = Resolve-RepoPath $OutDir
if (-not (Test-Path -LiteralPath $ilFull)) {
    throw "IL file not found: $ilFull"
}
New-Item -ItemType Directory -Force -Path $outFull | Out-Null

$lines = Get-Content -LiteralPath $ilFull
$endIndex = $null
for ($i = 0; $i -lt $lines.Count; $i++) {
    if ($lines[$i] -match 'end of method frmP2PChat::\.ctor') {
        $endIndex = $i
        break
    }
}
if ($null -eq $endIndex) {
    throw "frmP2PChat::.ctor end marker not found"
}

$startIndex = $null
for ($i = $endIndex; $i -ge 0; $i--) {
    if ($lines[$i] -match '^\s*\.method\s+public\s+hidebysig\s+specialname\s+rtspecialname') {
        $startIndex = $i
        break
    }
}
if ($null -eq $startIndex) {
    throw "frmP2PChat::.ctor method start not found before line $($endIndex + 1)"
}

$ctorIlFile = Join-Path $outFull "frmP2PChat-ctor.il.txt"
$riskCsvFile = Join-Path $outFull "frmP2PChat-ctor-null-risk.csv"
$riskMdFile = Join-Path $outFull "frmP2PChat-ctor-null-risk.md"

$ctorLines = New-Object System.Collections.Generic.List[string]
for ($i = $startIndex; $i -le $endIndex; $i++) {
    $ctorLines.Add(("{0}: {1}" -f ($i + 1), $lines[$i]))
}
$ctorLines | Set-Content -LiteralPath $ctorIlFile -Encoding UTF8

$riskRows = New-Object System.Collections.Generic.List[object]
foreach ($entry in $ctorLines) {
    if ($entry -notmatch '\b(callvirt|ldfld)\b') {
        continue
    }
    $offset = $null
    if ($entry -match '(IL_[0-9a-fA-F]{4})') {
        $offset = $matches[1].ToLowerInvariant().Replace("il_", "IL_")
    }
    $op = if ($entry -match '\b(callvirt|ldfld)\b') { $matches[1] } else { $null }
    $target = ($entry -replace '^.*?\b(callvirt|ldfld)\b\s+', '').Trim()
    $riskRows.Add([pscustomobject]@{
        source_line = [int]($entry -replace '^(\d+):.*$', '$1')
        il_offset = $offset
        opcode = $op
        target = $target
        null_risk = if ($op -eq "callvirt") { "receiver_null_possible" } else { "instance_field_owner_null_possible" }
        evidence = $entry.Trim()
    })
}

$riskRows | Sort-Object source_line | Export-Csv -LiteralPath $riskCsvFile -NoTypeInformation -Encoding UTF8

$topEvidence = $riskRows |
    Where-Object {
        $_.target -match 'Connection::add_OnConnectError|Connection::add_OnReConnectOk|P2PChat::get_OtherJid|Jid::getBareJid|IMPPManager::get_UserInfo|UCChatSendMessageBox::GetChatRichTextBox|UCChatSendMessageBox::GetReceiptCheckBox|MessageCenter::add_OnTcpMessageArrived|RosterManager::UpdateStrangerStatus|BaseConfig::VisualPhoneEnable'
    } |
    Select-Object -First 40

$md = New-Object System.Collections.Generic.List[string]
$md.Add("# frmP2PChat constructor IL NullRisk")
$md.Add("")
$md.Add("- Source IL: $ilFull")
$md.Add("- Constructor source lines: $($startIndex + 1)-$($endIndex + 1)")
$md.Add("- Constructor line count: $($ctorLines.Count)")
$md.Add("- callvirt / ldfld risk rows: $($riskRows.Count)")
$md.Add("")
$md.Add("## High-signal risks")
$md.Add("")
$md.Add("| source_line | il_offset | opcode | target |")
$md.Add("|---:|---|---|---|")
foreach ($row in $topEvidence) {
    $target = ($row.target -replace '\|', '\\|')
    $md.Add("| $($row.source_line) | $($row.il_offset) | $($row.opcode) | $target |")
}
$md.Add("")
$md.Add("## Files")
$md.Add("")
$md.Add("- Full constructor IL: $ctorIlFile")
$md.Add("- Full NullRisk CSV: $riskCsvFile")
$md | Set-Content -LiteralPath $riskMdFile -Encoding UTF8

[pscustomobject]@{
    ok = $true
    il_file = $ilFull
    ctor_line_start = $startIndex + 1
    ctor_line_end = $endIndex + 1
    ctor_line_count = $ctorLines.Count
    risk_count = $riskRows.Count
    ctor_il_file = $ctorIlFile
    risk_csv_file = $riskCsvFile
    risk_md_file = $riskMdFile
} | ConvertTo-Json -Compress