$ErrorActionPreference = "Stop"

$root = $PSScriptRoot
$accepted = Join-Path $root "accepted"
$rejected = Join-Path $root "rejected"
$errors = New-Object System.Collections.Generic.List[string]

function Test-SourceProfile([System.IO.FileInfo]$file) {
    if ($file.BaseName.Length -gt 12) {
        $errors.Add("$($file.FullName): base name exceeds 12 characters")
    }

    $bytes = [IO.File]::ReadAllBytes($file.FullName)
    if ($bytes.Length -gt 18999) {
        $errors.Add("$($file.FullName): $($bytes.Length) bytes exceeds 18999")
    }

    $text = [Text.Encoding]::ASCII.GetString($bytes)
    $lines = $text -split "`r`n|`n|`r"
    if ($lines.Count -gt 599) {
        $errors.Add("$($file.FullName): $($lines.Count) lines exceeds 599")
    }
    for ($i = 0; $i -lt $lines.Count; $i++) {
        $count = [Text.Encoding]::ASCII.GetByteCount($lines[$i])
        if ($count -gt 80) {
            $errors.Add("$($file.FullName):$($i + 1): $count bytes exceeds 80")
        }
    }
}

$acceptedSources = @(Get-ChildItem -LiteralPath $accepted -Filter "*.n8" -File)
$rejectedSources = @(Get-ChildItem -LiteralPath $rejected -Filter "*.n8" -File)

if ($acceptedSources.Count -eq 0) { $errors.Add("no accepted fixtures found") }
if ($rejectedSources.Count -eq 0) { $errors.Add("no rejected fixtures found") }

foreach ($file in $acceptedSources) {
    Test-SourceProfile $file
    $sidecar = [IO.Path]::ChangeExtension($file.FullName, ".expect")
    if (Test-Path -LiteralPath $sidecar) {
        $errors.Add("${sidecar}: accepted fixtures must not have diagnostic sidecars")
    }
}

foreach ($file in $rejectedSources) {
    Test-SourceProfile $file
    $sidecar = [IO.Path]::ChangeExtension($file.FullName, ".expect")
    if (-not (Test-Path -LiteralPath $sidecar)) {
        $errors.Add("$($file.FullName): missing .expect sidecar")
        continue
    }
    $expect = Get-Content -Raw -LiteralPath $sidecar
    $matches = [regex]::Matches($expect, '(?m)^diagnostic: ([A-Z][A-Z0-9_]+)$')
    if ($matches.Count -ne 1) {
        $errors.Add("${sidecar}: expected exactly one symbolic diagnostic")
    }
}

$orphanSidecars = @(Get-ChildItem -LiteralPath $rejected -Filter "*.expect" -File |
    Where-Object { -not (Test-Path -LiteralPath ([IO.Path]::ChangeExtension($_.FullName, ".n8"))) })
foreach ($orphan in $orphanSidecars) {
    $errors.Add("$($orphan.FullName): orphan diagnostic sidecar")
}

if ($errors.Count -gt 0) {
    $errors | ForEach-Object { Write-Error $_ }
    exit 1
}

Write-Host ("grammar fixtures ok: {0} accepted, {1} rejected" -f
    $acceptedSources.Count, $rejectedSources.Count)