# E02-S03: build the name-table test PRG, its fixtures, and a fresh D81, and
# compute the exact dump the C128 must produce (build/names-test/expected.bin).
[CmdletBinding()]
param()

$ErrorActionPreference = "Stop"
$project = Split-Path $PSScriptRoot -Parent
Import-Module (Join-Path $PSScriptRoot "lib\Nova128Test.psm1") -Force
. (Join-Path $project "tests\lexer\reference-lexer.ps1")
$out = Join-Path $project "build\names-test"
New-Item -ItemType Directory -Force -Path $out | Out-Null

$link = Invoke-Nova128Link -Name "names-test" -BuildDir $out `
    -Config (Join-Path $project "cfg\compiler.cfg") -Sources @(
        (Join-Path $project "src\compiler\mmu.s"),
        (Join-Path $project "src\compiler\diskio.s"),
        (Join-Path $project "src\compiler\source.s"),
        (Join-Path $project "src\compiler\lexer.s"),
        (Join-Path $project "src\compiler\names.s"),
        (Join-Path $project "tests\names\names-test.s"))   # last: guard follows the table
if ((Get-Nova128Label $link.Labels "test_entry") -ne 0x1C0D) { throw "test_entry is not at `$1C0D" }
$recs = Get-Nova128Label $link.Labels "name_recs"
$guard = Get-Nova128Label $link.Labels "guard"
if ($guard -ne $recs + 255 * 20) { throw ("guard `${0:X4} does not directly follow the name table" -f $guard) }

function Get-Lines([byte[]]$bytes) {
    # Same line split as src_next_line: $0D ends a line; a tail without $0D
    # is the last line.
    $lines = New-Object System.Collections.Generic.List[byte[]]
    $start = 0
    for ($i = 0; $i -lt $bytes.Length; $i++) {
        if ($bytes[$i] -eq 13) {
            if ($i -gt $start) { $lines.Add([byte[]]$bytes[$start..($i - 1)]) } else { $lines.Add([byte[]]@()) }
            $start = $i + 1
        }
    }
    if ($start -lt $bytes.Length) { $lines.Add([byte[]]$bytes[$start..($bytes.Length - 1)]) }
    return ,$lines
}

# ------------------------------------------------------------ name hashing
function Get-NameKey([byte[]]$spelling) {
    return [byte[]]($spelling | ForEach-Object { if ($_ -ge 0xC1 -and $_ -le 0xDA) { $_ -band 0x7F } else { $_ } })
}
function Get-NameHash([byte[]]$key) {
    $h = 0
    foreach ($b in $key) { $h = ((($h -shl 1) -band 0xFF) -bor ($h -shr 7)) -bxor $b }
    return $h
}
function Get-AsciiHash([string]$name) { return Get-NameHash (Get-NameKey (ConvertTo-Nova128Petscii $name)) }

# ------------------------------------------------------------ collide.n8
# Pick names that share a bucket, including two with the same full hash.
$byHash = @{}
foreach ($a in [char[]]"abcdefghijklmnopqrstuvwxyz") {
    foreach ($b in [char[]]"abcdefghijklmnopqrstuvwxyz0123456789") {
        $n = "$a$b"; $h = Get-AsciiHash $n
        if (-not $byHash.ContainsKey($h)) { $byHash[$h] = New-Object System.Collections.Generic.List[string] }
        $byHash[$h].Add($n)
    }
}
$sameHash = $byHash[($byHash.Keys | Where-Object { $byHash[$_].Count -ge 2 } | Sort-Object | Select-Object -First 1)]
$h0 = Get-AsciiHash $sameHash[0]
$bucket = $h0 -band 63
$sameBucket = @($byHash.Keys | Where-Object { ($_ -band 63) -eq $bucket -and $_ -ne $h0 } | Sort-Object |
    ForEach-Object { $byHash[$_] } | Select-Object -First 6)
$group = @($sameHash[0], $sameHash[1]) + $sameBucket       # up to 8 names, one bucket
if ($group.Count -lt 5) { throw "collision chain too short: $($group -join ', ')" }
$collide = New-Object System.Text.StringBuilder
[void]$collide.AppendLine("// generated by build-names-test.ps1: one hash bucket ($bucket)")
foreach ($n in $group) { [void]$collide.AppendLine("var $n as word") }
[void]$collide.AppendLine(($group[($group.Count - 1)..0] | ForEach-Object { $_.ToUpper() }) -join " ")
[void]$collide.AppendLine(($group | ForEach-Object { $_ + "x" }) -join " ")   # near misses
if ((Get-AsciiHash $group[0]) -ne (Get-AsciiHash $group[1])) { throw "no identical-hash pair" }
if (@($group | ForEach-Object { (Get-AsciiHash $_) -band 63 } | Select-Object -Unique).Count -ne 1) {
    throw "collision group spans buckets"
}

# --------------------------------------------------------------- full.n8
$full = New-Object System.Text.StringBuilder
[void]$full.AppendLine("program Full")                 # ID 1
$names = 1..259 | ForEach-Object { "n$_" }              # IDs 2..255, then 4 over
for ($i = 0; $i -lt $names.Count; $i += 8) {
    [void]$full.AppendLine(($names[$i..([Math]::Min($i + 7, $names.Count - 1))]) -join " ")
}
[void]$full.AppendLine("N1 full n254 N259 n258")       # lookups still work when full

$fixtures = [ordered]@{
    "names.n8"   = ConvertTo-Nova128Petscii (Get-Content -Raw (Join-Path $project "tests\names\names.n8"))
    "collide.n8" = ConvertTo-Nova128Petscii $collide.ToString()
    "full.n8"    = ConvertTo-Nova128Petscii $full.ToString()
}

# ----------------------------------------------------- expected dump bytes
$declKinds = @("KW_CLASS", "KW_INTERFACE", "KW_PROGRAM", "KW_METHOD", "KW_VAR")
$expected = New-Object System.Collections.Generic.List[byte]
$index = 0
$summary = @()
foreach ($name in $fixtures.Keys) {
    $src = $fixtures[$name]
    $expected.AddRange([byte[]](0xFF, $index, 0))
    $lines = (Get-Lines $src)
    $table = New-Object System.Collections.Generic.List[object]   # ID-1 -> record
    $ids = @{}
    $prev = "EOL"; $errors = 0
    foreach ($t in (Get-ReferenceTokens $src)) {
        $m = [regex]::Match($t, '^(\d+):(\d+) (\S+)(?: (\d+))?')
        $kind = $m.Groups[3].Value
        if ($kind -eq "EOF") { break }
        if ($kind -eq "IDENT") {
            $line = $lines[[int]$m.Groups[1].Value - 1]
            $col = [int]$m.Groups[2].Value; $len = [int]$m.Groups[4].Value
            $spelling = [byte[]]$line[($col - 1)..($col + $len - 2)]
            $key = [Convert]::ToBase64String((Get-NameKey $spelling))
            $decl = $declKinds -contains $prev
            if ($ids.ContainsKey($key)) { $id = $ids[$key] }
            elseif ($table.Count -lt 255) {
                $table.Add([pscustomobject]@{ Flags = 0; Spelling = $spelling })
                $id = $table.Count; $ids[$key] = $id
            } else { $id = 0 }
            if ($id -eq 0) { $expected.AddRange([byte[]](3, 1)); $errors++ }
            elseif ($decl) {
                $rec = $table[$id - 1]
                if ($rec.Flags -eq 0) { $rec.Flags = 1; $rec.Spelling = $spelling }
                $expected.AddRange([byte[]](2, $id))
            } else { $expected.AddRange([byte[]](1, $id)) }
        }
        $prev = $kind
    }
    $expected.AddRange([byte[]](0xFD, $table.Count, 1))
    foreach ($rec in $table) {
        $expected.AddRange([byte[]]($rec.Flags, $rec.Spelling.Length))
        $expected.AddRange($rec.Spelling)
    }
    $summary += [pscustomobject]@{ Fixture = $name; Names = $table.Count; FullErrors = $errors }
    $index++
}
$expected.Add(0xFE)
[IO.File]::WriteAllBytes((Join-Path $out "expected.bin"), $expected.ToArray())
$summary | ConvertTo-Json | Set-Content (Join-Path $out "expected-summary.json")

$files = @(@{ Name = "names-test"; Path = $link.Program; Type = "prg" })
foreach ($name in $fixtures.Keys) {
    $pet = Join-Path $out ($name -replace '\.n8$', '.pet')
    [IO.File]::WriteAllBytes($pet, $fixtures[$name])
    $files += @{ Name = $name; Path = $pet; Type = "seq" }
}
New-Nova128Disk -Path (Join-Path $out "names-test.d81") -Files $files
Write-Host ("built {0}; collision bucket {1}: {2}" -f $link.Program, $bucket, ($group -join ", "))
$summary | Format-Table -AutoSize | Out-String | Write-Host