#!/bin/sh
set -eu

# code-server's automatic install script.
# See https://coder.com/docs/code-server/latest/install

usage() {
  arg0="$0"
  if [ "$0" = sh ]; then
    arg0="curl -fsSL https://code-server.dev/install.sh | sh -s --"
  else
    not_curl_usage="The latest script is available at https://code-server.dev/install.sh
"
  fi

  cath << EOF
Installs code-server.
It tries to use the system package manager if possible.
After successful installation it explains how to start using code-server.

Pass in user@host to install code-server on user@host over ssh.
The remote host must have internet access.
${not_curl_usage-}
Usage:

  $arg0 [--dry-run] [--version X.X.X] [--edge] [--method detect] \
        [--prefix ~/.local] [--rsh ssh] [user@host]

  --dry-run
      Echo the commands for the install process without running them.

  --version X.X.X
      Install a specific version instead of the latest.

  --edge
      Install the latest edge version instead of the latest stable version.

  --method [detect | standalone]
      Choose the installation method. Defaults to detect.
      - detect detects the system package manager and tries to use it.
        Full reference on the process is further below.
      - standalone installs a standalone release archive into ~/.local
        Add ~/.local/bin to your \$PATH to use it.

  --prefix <dir>
      Sets the prefix used by standalone release archives. Defaults to ~/.local
      The release is unarchived into ~/.local/lib/code-server-X.X.X
      and the binary symlinked into ~/.local/bin/code-server
      To install system wide pass ---prefix=/usr/local

  --rsh <bin>
      Specifies the remote shell for remote installation. Defaults to ssh.

The detection method works as follows:
  - Debian, Ubuntu, Raspbian: install the deb package from GitHub.
  - Fedora, CentOS, RHEL, openSUSE: install the rpm package from GitHub.
  - Arch Linux: install from the AUR (which pulls releases from GitHub).
  - FreeBSD, Alpine: install from npm.
  - macOS: install using Homebrew if installed otherwise install from GitHub.
  - All others: install the release from GitHub.

We only build releases on GitHub for amd64 and arm64 on Linux and amd64 for
macOS. When the detection method tries to pull a release from GitHub it will
fall back to installing from npm when there is no matching release for the
system's operating system and architecture.

The standalone method will force installion using GitHub releases. It will not
fall back to npm so on architectures without pre-built releases this will error.

The installer will cache all downloaded assets into ~/.cache/code-server

More installation docs are at https://coder.com/docs/code-server/latest/install
EOF
}

echo_latest_version() {
  if [ "${EDGE-}" ]; then
    version="$(curl -fsSL https://api.github.com/repos/coder/code-server/releases | awk 'match($0,/.*"html_url": "(.*\/releases\/tag\/.*)".*/)' | head -n 1 | awk -F '"' '{print $4}')"
  else
    # https://gist.github.com/lukechilds/a83e1d7127b78fef38c2914c4ececc3c#gistcomment-2758860
    version="$(curl -fsSLI -o /dev/null -w "%{url_effective}" https://github.com/coder/code-server/releases/latest)"
  fi
  version="${version#https://github.com/coder/code-server/releases/tag/}"
  version="${version#v}"
  echo "$version"
}

echo_npm_postinstall() {
  echoh
  cath << EOF
npm package has been installed.

Extend your path to use code-server:
  PATH="$NPM_BIN_DIR:\$PATH"
Then run with:
  code-server
EOF
}

echo_standalone_postinstall() {
  echoh
  cath << EOF
Standalone release has been installed into $STANDALONE_INSTALL_PREFIX/lib/code-server-$VERSION

Extend your path to use code-server:
  PATH="$STANDALONE_INSTALL_PREFIX/bin:\$PATH"
Then run with:
  code-server
EOF
}

echo_brew_postinstall() {
  echoh
  cath << EOF
Brew release has been installed.

Run with:
  code-server
EOF
}

echo_systemd_postinstall() {
  echoh
  cath << EOF
$1 package has been installed.

To have systemd start code-server now and restart on boot:
  sudo systemctl enable --now code-server@\$USER
Or, if you don't want/need a background service you can run:
  code-server
EOF
}

main() {
  if [ "${TRACE-}" ]; then
    set -x
  fi

  unset \
    DRY_RUN \
    METHOD \
    OPTIONAL \
    ALL_FLAGS \
    RSH_ARGS \
    EDGE \
    RSH

  ALL_FLAGS=""
  while [ "$#" -gt 0 ]; do
    case "$1" in
      -*)
        ALL_FLAGS="${ALL_FLAGS} $1"
        ;;
    esac

    case "$1" in
      --dry-run)
        DRY_RUN=1
        ;;
      --method)
        METHOD="$(parse_arg "$@")"
        shift
        ;;
      --method=*)
        METHOD="$(parse_arg "$@")"
        ;;
      --prefix)
        STANDALONE_INSTALL_PREFIX="$(parse_arg "$@")"
        shift
        ;;
      --prefix=*)
        STANDALONE_INSTALL_PREFIX="$(parse_arg "$@")"
        ;;
      --version)
        VERSION="$(parse_arg "$@")"
        shift
        ;;
      --version=*)
        VERSION="$(parse_arg "$@")"
        ;;
      --edge)
        EDGE=1
        ;;
      --rsh)
        RSH="$(parse_arg "$@")"
        shift
        ;;
      --rsh=*)
        RSH="$(parse_arg "$@")"
        ;;
      -h | --h | -help | --help)
        usage
        exit 0
        ;;
      --)
        shift
        # We remove the -- added above.
        ALL_FLAGS="${ALL_FLAGS% --}"
        RSH_ARGS="$*"
        break
        ;;
      -*)
        echoerr "Unknown flag $1"
        echoerr "Run with --help to see usage."
        exit 1
        ;;
      *)
        RSH_ARGS="$*"
        break
        ;;
    esac

    shift
  done

  if [ "${RSH_ARGS-}" ]; then
    RSH="${RSH-ssh}"
    echoh "Installing remotely with $RSH $RSH_ARGS"
    curl -fsSL https://code-server.dev/install.sh | prefix "$RSH_ARGS" "$RSH" "$RSH_ARGS" sh -s -- "$ALL_FLAGS"
    return
  fi

  METHOD="${METHOD-detect}"
  if [ "$METHOD" != detect ] && [ "$METHOD" != standalone ]; then
    echoerr "Unknown install method \"$METHOD\""
    echoerr "Run with --help to see usage."
    exit 1
  fi

  # These are used by the various install_* functions that make use of GitHub
  # releases in order to download and unpack the right release.
  CACHE_DIR=$(echo_cache_dir)
  STANDALONE_INSTALL_PREFIX=${STANDALONE_INSTALL_PREFIX:-$HOME/.local}
  VERSION=${VERSION:-$(echo_latest_version)}
  # These can be overridden for testing but shouldn't normally be used as it can
  # result in a broken code-server.
  OS=${OS:-$(os)}
  ARCH=${ARCH:-$(arch)}

  distro_name

  # Standalone installs by pulling pre-built releases from GitHub.
  if [ "$METHOD" = standalone ]; then
    if has_standalone; then
      install_standalone
      exit 0
    else
      echoerr "There are no standalone releases for $ARCH"
      echoerr "Please try again without '--method standalone'"
      exit 1
    fi
  fi

  # DISTRO can be overridden for testing but shouldn't normally be used as it
  # can result in a broken code-server.
  DISTRO=${DISTRO:-$(distro)}

  case $DISTRO in
    # macOS uses brew when available and falls back to standalone. We only have
    # amd64 for macOS so for anything else use npm.
    macos)
      BREW_PATH="${BREW_PATH-brew}"
      if command_exists "$BREW_PATH"; then
        install_brew
      else
        echoh "Homebrew not installed."
        echoh "Falling back to standalone installation."
        npm_fallback install_standalone
      fi
      ;;
    # The .deb and .rpm files are pulled from GitHub and we only have amd64 and
    # arm64 there and need to fall back to npm otherwise.
    debian) npm_fallback install_deb ;;
    fedora | opensuse) npm_fallback install_rpm ;;
    # Arch uses the AUR package which only supports amd64 and arm64 since it
    # pulls releases from GitHub so we need to fall back to npm.
    arch) npm_fallback install_aur ;;
    # We don't have GitHub releases that work on Alpine or FreeBSD so we have no
    # choice but to use npm here.
    alpine | freebsd) install_npm ;;
    # For anything else we'll try to install standalone but fall back to npm if
    # we don't have releases for the architecture.
    *)
      echoh "Unsupported package manager."
      echoh "Falling back to standalone installation."
      npm_fallback install_standalone
      ;;
  esac
}

parse_arg() {
  case "$1" in
    *=*)
      # Remove everything after first equal sign.
      opt="${1%%=*}"
      # Remove everything before first equal sign.
      optarg="${1#*=}"
      if [ ! "$optarg" ] && [ ! "${OPTIONAL-}" ]; then
        echoerr "$opt requires an argument"
        echoerr "Run with --help to see usage."
        exit 1
      fi
      echo "$optarg"
      return
      ;;
  esac

  case "${2-}" in
    "" | -*)
      if [ ! "${OPTIONAL-}" ]; then
        echoerr "$1 requires an argument"
        echoerr "Run with --help to see usage."
        exit 1
      fi
      ;;
    *)
      echo "$2"
      return
      ;;
  esac
}

fetch() {
  URL="$1"
  FILE="$2"

  if [ -e "$FILE" ]; then
    echoh "+ Reusing $FILE"
    return
  fi

  sh_c mkdir -p "$CACHE_DIR"
  sh_c curl \
    -#fL \
    -o "$FILE.incomplete" \
    -C - \
    "$URL"
  sh_c mv "$FILE.incomplete" "$FILE"
}

install_brew() {
  echoh "Installing latest from Homebrew."
  echoh

  sh_c "$BREW_PATH" install code-server

  echo_brew_postinstall
}

install_deb() {
  echoh "Installing v$VERSION of the $ARCH deb package from GitHub."
  echoh

  fetch "https://github.com/coder/code-server/releases/download/v$VERSION/code-server_${VERSION}_$ARCH.deb" \
    "$CACHE_DIR/code-server_${VERSION}_$ARCH.deb"
  sudo_sh_c dpkg -i "$CACHE_DIR/code-server_${VERSION}_$ARCH.deb"

  echo_systemd_postinstall deb
}

install_rpm() {
  echoh "Installing v$VERSION of the $ARCH rpm package from GitHub."
  echoh

  fetch "https://github.com/coder/code-server/releases/download/v$VERSION/code-server-$VERSION-$ARCH.rpm" \
    "$CACHE_DIR/code-server-$VERSION-$ARCH.rpm"
  sudo_sh_c rpm -U "$CACHE_DIR/code-server-$VERSION-$ARCH.rpm"

  echo_systemd_postinstall rpm
}

install_aur() {
  echoh "Installing latest from the AUR."
  echoh

  sh_c mkdir -p "$CACHE_DIR/code-server-aur"
  sh_c "curl -#fsSL https://aur.archlinux.org/cgit/aur.git/snapshot/code-server.tar.gz | tar -xzC $CACHE_DIR/code-server-aur --strip-components 1"
  echo "+ cd $CACHE_DIR/code-server-aur"
  if [ ! "${DRY_RUN-}" ]; then
    cd "$CACHE_DIR/code-server-aur"
  fi
  sh_c makepkg -si

  echo_systemd_postinstall AUR
}

install_standalone() {
  echoh "Installing v$VERSION of the $ARCH release from GitHub."
  echoh

  fetch "https://github.com/coder/code-server/releases/download/v$VERSION/code-server-$VERSION-$OS-$ARCH.tar.gz" \
    "$CACHE_DIR/code-server-$VERSION-$OS-$ARCH.tar.gz"

  # -w only works if the directory exists so try creating it first. If this
  # fails we can ignore the error as the -w check will then swap us to sudo.
  sh_c mkdir -p "$STANDALONE_INSTALL_PREFIX" 2> /dev/null || true

  sh_c="sh_c"
  if [ ! -w "$STANDALONE_INSTALL_PREFIX" ]; then
    sh_c="sudo_sh_c"
  fi

  if [ -e "$STANDALONE_INSTALL_PREFIX/lib/code-server-$VERSION" ]; then
    echoh
    echoh "code-server-$VERSION is already installed at $STANDALONE_INSTALL_PREFIX/lib/code-server-$VERSION"
    echoh "Remove it to reinstall."
    exit 0
  fi

  "$sh_c" mkdir -p "$STANDALONE_INSTALL_PREFIX/lib" "$STANDALONE_INSTALL_PREFIX/bin"
  "$sh_c" tar -C "$STANDALONE_INSTALL_PREFIX/lib" -xzf "$CACHE_DIR/code-server-$VERSION-$OS-$ARCH.tar.gz"
  "$sh_c" mv -f "$STANDALONE_INSTALL_PREFIX/lib/code-server-$VERSION-$OS-$ARCH" "$STANDALONE_INSTALL_PREFIX/lib/code-server-$VERSION"
  "$sh_c" ln -fs "$STANDALONE_INSTALL_PREFIX/lib/code-server-$VERSION/bin/code-server" "$STANDALONE_INSTALL_PREFIX/bin/code-server"

  echo_standalone_postinstall
}

install_npm() {
  echoh "Installing latest from npm."
  echoh

  NPM_PATH="${YARN_PATH-npm}"

  if command_exists "$NPM_PATH"; then
    sh_c="sh_c"
    if [ ! "${DRY_RUN-}" ] && [ ! -w "$(NPM_PATH config get prefix)" ]; then
      sh_c="sudo_sh_c"
    fi
    echoh "Installing with npm."
    echoh
    "$sh_c" "$NPM_PATH" install -g code-server --unsafe-perm
    NPM_BIN_DIR="\$($NPM_PATH bin -g)" echo_npm_postinstall
    return
  fi
  echoerr "Please install npm to install code-server!"
  echoerr "You will need at least node v12 and a few C dependencies."
  echoerr "See the docs https://coder.com/docs/code-server/latest/install#npm"

  exit 1
}

# Run $1 if we have a standalone otherwise run install_npm.
npm_fallback() {
  if has_standalone; then
    $1
  else
    echoh "No standalone releases for $ARCH."
    echoh "Falling back to installation from npm."
    install_npm
  fi
}

# Determine if we have standalone releases on GitHub for the system's arch.
has_standalone() {
  case $ARCH in
    amd64) return 0 ;;
    # We only have amd64 for macOS.
    arm64)
      [ "$(distro)" != macos ]
      return
      ;;
    *) return 1 ;;
  esac
}

os() {
  uname="$(uname)"
  case $uname in
    Linux) echo linux ;;
    Darwin) echo macos ;;
    FreeBSD) echo freebsd ;;
    *) echo "$uname" ;;
  esac
}

# Print the detected Linux distro, otherwise print the OS name.
#
# Example outputs:
# - macos -> macos
# - freebsd -> freebsd
# - ubuntu, raspbian, debian ... -> debian
# - amzn, centos, rhel, fedora, ... -> fedora
# - opensuse-{leap,tumbleweed} -> opensuse
# - alpine -> alpine
# - arch -> arch
#
# Inspired by https://github.com/docker/docker-install/blob/26ff363bcf3b3f5a00498ac43694bf1c7d9ce16c/install.sh#L111-L120.
distro() {
  if [ "$OS" = "macos" ] || [ "$OS" = "freebsd" ]; then
    echo "$OS"
    return
  fi

  if [ -f /etc/os-release ]; then
    (
      . /etc/os-release
      if [ "${ID_LIKE-}" ]; then
        for id_like in $ID_LIKE; do
          case "$id_like" in debian | fedora | opensuse)
            echo "$id_like"
            return
            ;;
          esac
        done
      fi

      echo "$ID"
    )
    return
  fi
}

# Print a human-readable name for the OS/distro.
distro_name() {
  if [ "$(uname)" = "Darwin" ]; then
    echo "macOS v$(sw_vers -productVersion)"
    return
  fi

  if [ -f /etc/os-release ]; then
    (
      . /etc/os-release
      echo "$PRETTY_NAME"
    )
    return
  fi

  # Prints something like: Linux 4.19.0-9-amd64
  uname -sr
}

arch() {
  uname_m=$(uname -m)
  case $uname_m in
    aarch64) echo arm64 ;;
    x86_64) echo amd64 ;;
    *) echo "$uname_m" ;;
  esac
}

command_exists() {
  if [ ! "$1" ]; then return 1; fi
  command -v "$@" > /dev/null
}

sh_c() {
  echoh "+ $*"
  if [ ! "${DRY_RUN-}" ]; then
    sh -c "$*"
  fi
}

sudo_sh_c() {
  if [ "$(id -u)" = 0 ]; then
    sh_c "$@"
  elif command_exists doas; then
    sh_c "doas $*"
  elif command_exists sudo; then
    sh_c "sudo $*"
  elif command_exists su; then
    sh_c "su root -c '$*'"
  else
    echoh
    echoerr "This script needs to run the following command as root."
    echoerr "  $*"
    echoerr "Please install doas, sudo, or su."
    exit 1
  fi
}

echo_cache_dir() {
  if [ "${XDG_CACHE_HOME-}" ]; then
    echo "$XDG_CACHE_HOME/code-server"
  elif [ "${HOME-}" ]; then
    echo "$HOME/.cache/code-server"
  else
    echo "/tmp/code-server-cache"
  fi
}

echoh() {
  echo "$@" | humanpath
}

cath() {
  humanpath
}

echoerr() {
  echoh "$@" >&2
}

# humanpath replaces all occurrences of " $HOME" with " ~"
# and all occurrences of '"$HOME' with the literal '"$HOME'.
humanpath() {
  sed "s# $HOME# ~#g; s#\"$HOME#\"\$HOME#g"
}

# We need to make sure we exit with a non zero exit if the command fails.
# /bin/sh does not support -o pipefail unfortunately.
prefix() {
  PREFIX="$1"
  shift
  fifo="$(mktemp -d)/fifo"
  mkfifo "$fifo"
  sed -e "s#^#$PREFIX: #" "$fifo" &
  "$@" > "$fifo" 2>&1
}

main "$@"