# Frey's servers: which one is on, which exist, and switching between them.
#
#   .\tools\server.ps1 status          # which server is on, and is it up
#   .\tools\server.ps1 list            # every server in this repo
#   .\tools\server.ps1 switch terror   # turn "terror" on (and the current one off)
#
# Run from the repo root. Only one server runs at a time; switching stops the
# current one (its world is kept) and starts the other at the same address,
# valls.dev. Written for Windows PowerShell 5.1: no &&, and the patch goes
# through a file because 5.1 mangles JSON quotes passed to kubectl.
param(
  [Parameter(Position = 0)][ValidateSet("status", "list", "switch")][string]$Command = "status",
  [Parameter(Position = 1)][string]$Name
)
# Not "Stop": on 5.1 that turns any stderr line from git/kubectl into a
# terminating error. Failures are checked through $LASTEXITCODE instead.
$ns = "game-servers"

function Get-ActiveServer {
  $json = kubectl -n $ns get statefulset minecraft -o json | Out-String
  if ($LASTEXITCODE -ne 0) { throw "kubectl could not read the server" }
  return ($json | ConvertFrom-Json).spec.template.metadata.annotations.'valls.dev/server'
}

$root = Split-Path -Parent $PSScriptRoot

switch ($Command) {
  "status" {
    $active = Get-ActiveServer
    Write-Output "Server on now: $active"
    kubectl -n $ns get pod minecraft-0
  }
  "list" {
    $active = Get-ActiveServer
    Get-ChildItem (Join-Path $root "servers") -Directory | ForEach-Object {
      $envFile = Join-Path $_.FullName "server.env"
      if (Test-Path $envFile) {
        $v = (Select-String -Path $envFile -Pattern '^(TYPE|VERSION)=(.*)$' | ForEach-Object { $_.Matches[0].Groups[2].Value }) -join " "
        $mark = if ($_.Name -eq $active) { "  <- on now" } else { "" }
        Write-Output ("{0,-20} {1}{2}" -f $_.Name, $v, $mark)
      }
    }
  }
  "switch" {
    if (-not $Name) { throw "Say which server: .\tools\server.ps1 switch <name>" }
    if ($Name -notmatch '^[a-z0-9][a-z0-9-]{0,39}$') { throw "Server names are lowercase letters, digits and dashes only" }

    # The server reads its definition from what has been pushed, not from this
    # folder, so refuse to switch to something that only exists locally.
    git -C $root fetch -q origin
    git -C $root cat-file -e "origin/main:servers/$Name/server.env" 2>$null
    if ($LASTEXITCODE -ne 0) { throw "servers/$Name/server.env is not pushed yet: commit and push it first" }

    $active = Get-ActiveServer
    if ($active -eq $Name) { Write-Output "$Name is already on."; return }

    $patch = Join-Path $env:TEMP "minecraft-switch.json"
    Set-Content -Path $patch -Encoding ASCII -Value ('{"spec":{"template":{"metadata":{"annotations":{"valls.dev/server":"' + $Name + '"}}}}}')
    kubectl -n $ns patch statefulset minecraft --type merge --patch-file $patch
    if ($LASTEXITCODE -ne 0) { throw "kubectl could not switch the server" }
    Write-Output "Switching $active -> $Name. Waiting for it to start (a brand-new server can take up to 15 minutes)..."
    kubectl -n $ns rollout status statefulset/minecraft --timeout=16m
    if ($LASTEXITCODE -ne 0) { throw "It did not start. Look at: kubectl -n $ns logs minecraft-0 -c minecraft --tail=100" }
    Write-Output "$Name is on."
  }
}