[CmdletBinding(SupportsShouldProcess)]
param(
    [Parameter(Mandatory=$true)][string]$WebglRoot,
    [string]$PatchZip = ''
)
$ErrorActionPreference = 'Stop'
if (-not $PatchZip) { $PatchZip = Join-Path $PSScriptRoot 'Client-BuddyDefense-15888.zip' }
$PatchZip = (Resolve-Path -LiteralPath $PatchZip).Path
$WebglRoot = (Resolve-Path -LiteralPath $WebglRoot).Path
if (-not (Test-Path -LiteralPath $WebglRoot -PathType Container)) { throw 'WebglRoot must be an existing website directory.' }
$versionPath = Join-Path $WebglRoot 'cdn/version.json'
if (-not (Test-Path -LiteralPath $versionPath) -and
    -not (Get-ChildItem -LiteralPath $WebglRoot -Filter '*.webgl.data.unityweb.bin.txt' -File | Select-Object -First 1)) {
    throw 'This does not look like the existing /game/Friends/webgl website folder. Choose the website folder, not the AIServer folder.'
}
Add-Type -AssemblyName System.IO.Compression.FileSystem
$archive = [IO.Compression.ZipFile]::OpenRead($PatchZip)
try {
    $contents = @{}
    foreach ($entry in $archive.Entries) {
        $name = $entry.FullName.Replace('\','/')
        if ($name -ne 'cdn/version.json' -and $name -notmatch '^yoo/DefaultPackage/[A-Za-z0-9_.-]+$') {
            throw "Unexpected patch entry: $name"
        }
        if ($contents.ContainsKey($name) -or $entry.Length -gt 5242880) { throw "Invalid patch entry: $name" }
        $reader = $entry.Open(); $memory = New-Object IO.MemoryStream
        try { $reader.CopyTo($memory); $contents[$name] = $memory.ToArray() }
        finally { $reader.Dispose(); $memory.Dispose() }
    }
} finally { $archive.Dispose() }
if ($contents.Count -ne 5 -or -not $contents.ContainsKey('cdn/version.json')) { throw 'Expected the five-file hot-update patch.' }
$version = [Text.Encoding]::UTF8.GetString($contents['cdn/version.json']) | ConvertFrom-Json
if ($version.packVersion -notmatch '^[a-f0-9]{32}$') { throw 'Invalid packVersion.' }
$indexName = "yoo/DefaultPackage/DefaultPackage_$($version.packVersion).bytes"
if (-not $contents.ContainsKey($indexName)) { throw 'Version refers to a missing manifest.' }
$md5 = [Security.Cryptography.MD5]::Create()
try { $indexHash = [BitConverter]::ToString($md5.ComputeHash($contents[$indexName])).Replace('-','').ToLowerInvariant() }
finally { $md5.Dispose() }
if ($indexHash -ne $version.packVersion) { throw 'Manifest MD5 does not match packVersion. Nothing published.' }
$changed = 0
if ($PSCmdlet.ShouldProcess($WebglRoot,"Publish pack $($version.packVersion); write cdn/version.json last")) {
    # Content-addressed resources must exist before exposing the new global version.
    $names = @($contents.Keys | Where-Object { $_ -ne 'cdn/version.json' } | Sort-Object) + @('cdn/version.json')
    foreach ($name in $names) {
        $target = Join-Path $WebglRoot $name
        if (Test-Path -LiteralPath $target) {
            $old = [IO.File]::ReadAllBytes($target)
            if ([Convert]::ToBase64String($old) -eq [Convert]::ToBase64String($contents[$name])) { continue }
        }
        New-Item -ItemType Directory -Path (Split-Path -Parent $target) -Force | Out-Null
        if ($name -eq 'cdn/version.json') {
            $temporary = "$target.publish-$([Guid]::NewGuid().ToString('N')).tmp"
            try {
                [IO.File]::WriteAllBytes($temporary,$contents[$name])
                if (Test-Path -LiteralPath $target) { [IO.File]::Replace($temporary,$target,"$target.previous") }
                else { [IO.File]::Move($temporary,$target) }
            } finally { if (Test-Path -LiteralPath $temporary) { Remove-Item -LiteralPath $temporary } }
        } else { [IO.File]::WriteAllBytes($target,$contents[$name]) }
        $changed++
        Write-Output "Published $name"
    }
    Write-Output "Done: packVersion=$($version.packVersion); changedFiles=$changed. Check the public cdn/version.json, then restart the mini game."
}