# LAN party bootstrap for Windows: installs Fjord Launcher Unlocked (DRM-free
# Prism fork), seeds a persistent offline account, drops in the pre-built
# modpack instance, and launches straight into it on the LAN server.
#
# Hosted from Gitea (git.mivanchenko.de), not a local http.server — see HOSTING.md.
# Participants run:    irm https://git.mivanchenko.de/mivanchenko/mc-lan-party/raw/branch/main/install.ps1 | iex

# ---- EDIT ME before hosting ----
$HostUrl      = "https://git.mivanchenko.de/mivanchenko/mc-lan-party/raw/branch/main"  # for this script + install.sh (small text files)
$ModpackUrl   = "https://minecraft.mivanchenko.de/modpack.zip"  # served directly by Caddy (static/ mount), NOT Gitea — modpack.zip is well over Gitea's 50MB upload cap
$InstanceName = "LANParty"
$ServerAddr   = "minecraft.mivanchenko.de:25565"  # always-on homelab box, same address for prep and the actual party
# ---------------------------------

$ErrorActionPreference = "Stop"  # fail loudly instead of printing an error and silently continuing

$InstallDir = Join-Path $env:USERPROFILE "mc-lan-party"
New-Item -ItemType Directory -Force -Path $InstallDir | Out-Null
Set-Location $InstallDir

Write-Host "==> Setting up in $InstallDir"

$release = Invoke-RestMethod -Uri "https://api.github.com/repos/hero-persson/FjordLauncherUnlocked/releases/latest"
$asset = $release.assets | Where-Object { $_.name -match "Windows-MSVC-Portable-.*\.zip$" } | Select-Object -First 1
if (-not $asset) {
    $asset = $release.assets | Where-Object { $_.name -match "Windows-MinGW-w64-Portable-.*\.zip$" } | Select-Object -First 1
}
if (-not $asset) { throw "Could not find a Windows portable build in the latest Fjord Launcher Unlocked release." }

Write-Host "==> Downloading $($asset.name)"
Invoke-WebRequest -Uri $asset.browser_download_url -OutFile "FjordLauncher.zip"
Expand-Archive -Path "FjordLauncher.zip" -DestinationPath "app" -Force
$LauncherBin = Get-ChildItem -Path "app" -Filter "fjordlauncher.exe" -Recurse | Select-Object -First 1 -ExpandProperty FullName
if (-not $LauncherBin) { throw "fjordlauncher.exe not found after extracting the portable build." }

# ---- offline account: compute Mojang-style offline UUID so playerdata persists across launches ----
$Nick = Read-Host "Minecraft nickname [$env:USERNAME]"
if ([string]::IsNullOrWhiteSpace($Nick)) { $Nick = $env:USERNAME }

function Get-OfflineUuid([string]$name) {
    $md5 = [System.Security.Cryptography.MD5]::Create()
    $bytes = $md5.ComputeHash([System.Text.Encoding]::UTF8.GetBytes("OfflinePlayer:$name"))
    $bytes[6] = ($bytes[6] -band 0x0f) -bor 0x30
    $bytes[8] = ($bytes[8] -band 0x3f) -bor 0x80
    $hex = -join ($bytes | ForEach-Object { $_.ToString("x2") })
    return "{0}-{1}-{2}-{3}-{4}" -f $hex.Substring(0,8), $hex.Substring(8,4), $hex.Substring(12,4), $hex.Substring(16,4), $hex.Substring(20,12)
}

$Uuid = Get-OfflineUuid $Nick
$md5 = [System.Security.Cryptography.MD5]::Create()
$clientTokenBytes = $md5.ComputeHash([System.Text.Encoding]::UTF8.GetBytes("ClientToken:$Nick"))
$ClientToken = -join ($clientTokenBytes | ForEach-Object { $_.ToString("x2") })
$Iat = [int][double]::Parse((Get-Date -UFormat %s))

$accounts = @{
    accounts = @(
        @{
            active      = $true
            type        = "Offline"
            profile     = @{ id = $Uuid; name = $Nick; capes = @(); skin = @{ id = ""; url = ""; variant = "" } }
            entitlement = @{ canPlayMinecraft = $true; ownsMinecraft = $true }
            ygg         = @{ token = "0"; extra = @{ clientToken = $ClientToken; userName = $Nick }; iat = $Iat }
        }
    )
    formatVersion = 3
}
$accounts | ConvertTo-Json -Depth 6 | Set-Content -Path "accounts.json" -Encoding UTF8
Write-Host "==> Offline account '$Nick' ready (UUID $Uuid)"

# ---- modpack instance ----
New-Item -ItemType Directory -Force -Path "instances" | Out-Null
if (-not (Test-Path (Join-Path "instances" $InstanceName))) {
    Write-Host "==> Downloading modpack from $ModpackUrl"
    try {
        Invoke-WebRequest -Uri $ModpackUrl -OutFile "modpack.zip"
        Expand-Archive -Path "modpack.zip" -DestinationPath "instances" -Force
    } catch {
        Write-Host "==> FAILED to fetch/extract the modpack from $ModpackUrl" -ForegroundColor Red
        Write-Host "    $($_.Exception.Message)" -ForegroundColor Red
        Write-Host "    (Fjord Launcher itself installed fine at $InstallDir\app — this just means modpack.zip isn't being served yet.)"
        exit 1
    }
    Write-Host "==> Modpack installed to instances\$InstanceName"
} else {
    Write-Host "==> Instance already present, skipping download"
}

Write-Host "==> Launching into $InstanceName as $Nick, joining $ServerAddr"
& $LauncherBin --dir $InstallDir --launch $InstanceName --profile $Nick --server $ServerAddr