<#
.SYNOPSIS
    check-update.ps1 - Check if a newer StudioBridge release exists on GitHub
    and compare it with the version bundled in this project.

.DESCRIPTION
    Used as Step 1 of the update procedure (see UPDATE.md).
    It reads the currently bundled version from the jar in portable-dist,
    queries the GitHub releases API for the latest release, and reports
    whether an update is available.

.EXAMPLE
    .\check-update.ps1
    .\check-update.ps1 -Repo "Rdiger-36/StudioBridge"

.NOTES
    Exit codes:
      0 - up to date (or no update available)
      1 - update available
      2 - error (offline, API failure, or version could not be determined)
#>
param(
    [string]$Repo = "Rdiger-36/StudioBridge",
    [string]$PortableDir = (Join-Path $PSScriptRoot "portable-dist")
)

$ErrorActionPreference = "Stop"

function Get-BundledVersion {
    # Bundled version = parsed from the deployed jar filename: StudioBridge-X.Y.Z.jar
    $jar = Get-ChildItem -Path $PortableDir -Filter "StudioBridge-*.jar" -File -ErrorAction SilentlyContinue |
        Where-Object { $_.Name -match 'StudioBridge-(\d+\.\d+\.\d+)\.jar$' } |
        Select-Object -First 1

    if ($jar) {
        if ($jar.Name -match 'StudioBridge-(\d+\.\d+\.\d+)\.jar$') {
            return $matches[1]
        }
    }

    # Fallback: read the version from the launcher script (JAR_FILE=...StudioBridge-X.Y.Z.jar)
    $bat = Join-Path $PortableDir "StudioBridge.bat"
    if (Test-Path $bat) {
        $line = Select-String -Path $bat -Pattern 'StudioBridge-(\d+\.\d+\.\d+)\.jar' | Select-Object -First 1
        if ($line -and $line.Matches[0].Groups[1]) {
            return $line.Matches[0].Groups[1].Value
        }
    }
    return $null
}

function Get-LatestVersion {
    $headers = @{ 'User-Agent' = 'StudioBridge-update-check' }
    $release = Invoke-RestMethod -Uri "https://api.github.com/repos/$Repo/releases/latest" -Headers $headers
    # Normalize tags like "v.2.1.3", "v2.1.3", "2.1.3" -> "2.1.3"
    return ($release.tag_name -replace '^v\.?', '')
}

function Test-Newer([string]$current, [string]$latest) {
    $a = $current -split '\.' | ForEach-Object { [int]$_ }
    $b = $latest  -split '\.' | ForEach-Object { [int]$_ }
    for ($i = 0; $i -lt [Math]::Max($a.Count, $b.Count); $i++) {
        $x = if ($i -lt $a.Count) { $a[$i] } else { 0 }
        $y = if ($i -lt $b.Count) { $b[$i] } else { 0 }
        if ($x -ne $y) { return $x -lt $y }
    }
    return $false
}

# --- Main ----------------------------------------------------------------
try {
    $bundled = Get-BundledVersion
    if (-not $bundled) {
        Write-Host "ERROR: Could not determine the bundled version in: $PortableDir" -ForegroundColor Red
        exit 2
    }

    Write-Host "Repo             : $Repo"
    Write-Host "Bundled version  : $bundled"

    $latest = Get-LatestVersion
    Write-Host "Latest on GitHub : $latest"

    if ($bundled -eq $latest) {
        Write-Host ""
        Write-Host "OK - You are up to date. No update needed." -ForegroundColor Green
        exit 0
    }

    if (Test-Newer $bundled $latest) {
        Write-Host ""
        Write-Host "UPDATE AVAILABLE: $bundled -> $latest" -ForegroundColor Yellow
        Write-Host "Follow the steps in UPDATE.md to download, rebuild and deploy."
        exit 1
    }

    Write-Host ""
    Write-Host "Note: bundled version ($bundled) is newer than the latest GitHub release ($latest)." -ForegroundColor Cyan
    exit 0
}
catch {
    Write-Host "ERROR: $($_.Exception.Message)" -ForegroundColor Red
    if ($_.ErrorDetails.Message) { Write-Host $_.ErrorDetails.Message -ForegroundColor Red }
    Write-Host "Check your internet connection, then retry." -ForegroundColor Yellow
    exit 2
}