#!/usr/bin/env bash
# Installs Void Sector's launcher for this account on Linux, without sudo:
#
#   curl -fsSL https://playvoidsector.com/install.sh | bash
#
# It downloads the launcher, checks it against its published SHA-256, and runs it to install itself: with a display, on
# the launcher's install screen; without one (over SSH, say), in the terminal. Run it again to repair or update an
# install. VOID_SECTOR_UPDATES names another update server (for testing). Options go after "bash -s --":
#
#   --text                    install in the terminal even with a display
#   --folder DIR              install somewhere other than ~/.local/share/VoidSector
#   --no-menu, --no-shortcut, --no-command
#                             leave out the app menu entry, the desktop shortcut or the void-sector command
#
# Every line is inside a function, and the last line calls main: a download cut off part way does nothing at all.
set -euo pipefail

say() { printf '%s\n' "$*"; }
warn() { printf 'Warning: %s\n' "$*" >&2; }
fail() {
  printf 'Void Sector was not installed: %s\n' "$*" >&2
  exit 1
}

check_system() {
  [ "$(id -u)" -ne 0 ] || fail "run this as yourself, not as root or with sudo. It installs for your account only."
  [ "$(uname -s)" = Linux ] || fail "this installer is for Linux. Download the launcher for your system from https://playvoidsector.com"
  case "$(uname -m)" in
    x86_64 | amd64) ;;
    *) fail "Void Sector needs a 64-bit x86 PC (this one is $(uname -m))." ;;
  esac
  command -v tar >/dev/null || fail "tar is missing. Install it with your package manager, then run this again."
  command -v curl >/dev/null || command -v wget >/dev/null || fail "curl or wget is needed to download the launcher."
  command -v sha256sum >/dev/null || command -v shasum >/dev/null || fail "sha256sum is needed to check the download."
}

# Void Sector draws with Vulkan: a missing driver doesn't stop the install, but the game won't start without one.
check_vulkan() {
  if command -v vulkaninfo >/dev/null && vulkaninfo --summary >/dev/null 2>&1; then
    return
  fi
  local dir
  for dir in /usr/share/vulkan/icd.d /etc/vulkan/icd.d /usr/local/share/vulkan/icd.d "${XDG_DATA_HOME:-$HOME/.local/share}/vulkan/icd.d"; do
    if compgen -G "$dir/*.json" >/dev/null; then
      return
    fi
  done
  warn "no Vulkan driver was found. Void Sector needs one to run: install your graphics card's Vulkan driver (for example mesa-vulkan-drivers, vulkan-radeon, vulkan-intel or the NVIDIA driver)."
}

# fetch URL FILE
fetch() {
  if command -v curl >/dev/null; then
    curl -fsSL --retry 3 -o "$2" "$1"
  else
    wget -q -O "$2" "$1"
  fi
}

sha256_of() {
  if command -v sha256sum >/dev/null; then
    sha256sum "$1" | cut -d' ' -f1
  else
    shasum -a 256 "$1" | cut -d' ' -f1
  fi
}

# download DIR: the launcher's archive and its checksum, checked. Both are fetched with a cache-busting query, and fetched
# once more if they don't match, because right after a release a cached checksum can belong to the previous archive.
download() {
  local dir=$1 base=${VOID_SECTOR_UPDATES:-https://updates.playvoidsector.com}
  local archive="$dir/VoidSectorLauncher-linux.tar.gz" url="${base%/}/download/VoidSectorLauncher-linux.tar.gz"
  local attempt fresh expected actual
  for attempt in 1 2; do
    fresh="fresh=$(date +%s)$$$attempt"
    say "Downloading the Void Sector launcher..."
    fetch "$url?$fresh" "$archive" || fail "couldn't download $url. Check your connection and try again."
    fetch "$url.sha256?$fresh" "$archive.sha256" || fail "couldn't download the launcher's checksum ($url.sha256)."
    expected=$(cut -d' ' -f1 "$archive.sha256" | tr -d '[:space:]')
    actual=$(sha256_of "$archive")
    [[ $expected =~ ^[0-9a-f]{64}$ ]] || fail "the launcher's checksum file is malformed."
    if [ "$expected" = "$actual" ]; then
      return
    fi
    [ "$attempt" = 1 ] && sleep 5
  done
  fail "the download doesn't match its checksum (expected $expected, got $actual). It may be damaged or tampered with, so nothing was run. Try again in a few minutes."
}

installed_root() {
  local data=${XDG_DATA_HOME:-$HOME/.local/share} config=${XDG_CONFIG_HOME:-$HOME/.config}
  if [ -f "$data/VoidSector/install.json" ]; then
    printf '%s\n' "$data/VoidSector"
  elif [ -f "$config/VoidSector/install-folder" ]; then
    head -n1 "$config/VoidSector/install-folder"
  fi
}

main() {
  local text=
  local arg
  for arg in "$@"; do
    [ "$arg" = --text ] && text=1
  done
  if [ -z "${DISPLAY:-}${WAYLAND_DISPLAY:-}" ]; then
    text=1
  fi

  check_system
  check_vulkan
  # (a global, for the trap that runs after main returns; the launcher copies itself out before it hands over)
  scratch=$(mktemp -d "${TMPDIR:-/tmp}/void-sector-install.XXXXXX")
  trap 'rm -rf "${scratch:-}"' EXIT
  local dir=$scratch
  download "$dir"
  tar -xzf "$dir/VoidSectorLauncher-linux.tar.gz" -C "$dir" || fail "the download couldn't be unpacked."
  local launcher="$dir/VoidSector/VoidSectorLauncher.x86_64"
  [ -x "$launcher" ] || fail "the download has no launcher in it."
  # (another update server, for testing: the launcher installs itself from the same one)
  if [ -n "${VOID_SECTOR_UPDATES:-}" ]; then
    set -- "$@" --updates "${VOID_SECTOR_UPDATES%/}/"
  fi

  if [ -n "$text" ]; then
    say "Installing in the terminal (no display)."
    # (stdin is this script when it's piped to bash: the launcher asks its questions on the terminal instead)
    local status=0
    "$launcher" --headless --quiet -- --install "$@" </dev/null || status=$?
    [ "$status" -eq 0 ] || fail "the install didn't finish (status $status). Run this again to try once more."
    return
  fi

  say "Opening the installer..."
  local status=0
  # (in a session of its own, so the installed launcher it hands over to keeps running when this terminal closes)
  if command -v setsid >/dev/null; then
    setsid --wait "$launcher" -- --install "$@" </dev/null >"$dir/launcher.log" 2>&1 || status=$?
  else
    "$launcher" -- --install "$@" </dev/null >"$dir/launcher.log" 2>&1 || status=$?
  fi
  local root
  root=$(installed_root)
  if [ -z "$root" ] || [ ! -f "$root/install.json" ]; then
    [ "$status" -eq 0 ] || tail -n 20 "$dir/launcher.log" >&2
    fail "the installer closed before it finished. Run this again to install."
  fi
  say "Void Sector is installed. Start it from your app menu, or run: void-sector"
  case ":$PATH:" in
    *":${XDG_BIN_HOME:-$HOME/.local/bin}:"*) ;;
    *) say "(${XDG_BIN_HOME:-$HOME/.local/bin} isn't on your PATH yet, so until it is, run: ${XDG_BIN_HOME:-$HOME/.local/bin}/void-sector)" ;;
  esac
}

# (in braces: cut off anywhere before the closing brace, this line is a syntax error, so nothing runs)
{ main "$@"; }