#!/bin/sh
# Installs the opposable command line tool from getopposable.com.
#
#   curl -fsSL https://getopposable.com/install.sh | sh
#
# It downloads the build for this computer, checks it against the published SHA-256 sums, and puts `opposable` in
# ~/.local/bin (or /usr/local/bin when that is writable and ~/.local/bin isn't on your PATH). It never uses sudo.
# Settings: OPPOSABLE_INSTALL_DIR=/some/dir to choose the folder, OPPOSABLE_VERSION to pick another version.
set -eu

VERSION="${OPPOSABLE_VERSION:-0.3.0-preview.1}"
BASE="${OPPOSABLE_BASE_URL:-https://getopposable.com}"

say() { printf '%s\n' "$*"; }
die() { printf 'opposable install: %s\n' "$*" >&2; exit 1; }

fetch() { # url file
  if command -v curl >/dev/null 2>&1; then curl -fsSL --retry 2 -o "$2" "$1"
  elif command -v wget >/dev/null 2>&1; then wget -q -O "$2" "$1"
  else die "needs curl or wget"; fi
}

sha256() {
  if command -v sha256sum >/dev/null 2>&1; then sha256sum "$1" | cut -d ' ' -f 1
  elif command -v shasum >/dev/null 2>&1; then shasum -a 256 "$1" | cut -d ' ' -f 1
  else die "needs sha256sum or shasum to check the download"; fi
}

on_path() { case ":$PATH:" in *":$1:"*) return 0 ;; *) return 1 ;; esac; }

main() {
  os="$(uname -s)"
  arch="$(uname -m)"
  case "$os" in
    Darwin) os=darwin; site_os=macos ;;
    Linux) os=linux; site_os=linux ;;
    *) die "this script is for macOS and Linux. On Windows, in PowerShell: irm https://getopposable.com/install.ps1 | iex" ;;
  esac
  case "$arch" in
    arm64 | aarch64) arch=arm64 ;;
    x86_64 | amd64) arch=x64 ;;
    *) die "no build for $arch yet" ;;
  esac
  # An Intel shell on Apple silicon (Rosetta) still gets the native build.
  if [ "$os" = darwin ] && [ "$arch" = x64 ] && [ "$(sysctl -n sysctl.proc_translated 2>/dev/null || echo 0)" = 1 ]; then arch=arm64; fi
  if [ "$os" = linux ] && ldd --version 2>&1 | grep -qi musl; then
    die "this build needs glibc; Alpine and other musl systems aren't supported yet"
  fi

  name="opposable-$VERSION-$os-$arch.gz"
  if [ -n "${OPPOSABLE_INSTALL_DIR:-}" ]; then dir="$OPPOSABLE_INSTALL_DIR"
  elif on_path "$HOME/.local/bin"; then dir="$HOME/.local/bin"
  elif [ -d /usr/local/bin ] && [ -w /usr/local/bin ]; then dir=/usr/local/bin
  else dir="$HOME/.local/bin"; fi

  tmp="$(mktemp -d 2>/dev/null || mktemp -d -t opposable)"
  trap 'rm -rf "$tmp"' EXIT INT TERM

  say "Downloading opposable $VERSION for $os-$arch…"
  fetch "$BASE/download/cli/SHA256SUMS" "$tmp/SHA256SUMS" || die "couldn't download the checksums"
  if [ -n "${OPPOSABLE_VERSION:-}" ]; then url="$BASE/download/cli/$name"
  else url="$BASE/get/cli-$site_os-$arch?src=install-sh"; fi
  fetch "$url" "$tmp/$name" || die "couldn't download $name"

  want="$(grep " $name\$" "$tmp/SHA256SUMS" | cut -d ' ' -f 1)"
  [ -n "$want" ] || die "$name isn't listed in SHA256SUMS"
  got="$(sha256 "$tmp/$name")"
  [ "$want" = "$got" ] || die "checksum mismatch for $name (expected $want, got $got). Nothing was installed."

  gzip -dc "$tmp/$name" > "$tmp/opposable" || die "couldn't unpack $name"
  chmod 755 "$tmp/opposable"
  mkdir -p "$dir" || die "couldn't create $dir (set OPPOSABLE_INSTALL_DIR to another folder)"
  mv -f "$tmp/opposable" "$dir/opposable" || die "couldn't write to $dir (set OPPOSABLE_INSTALL_DIR to another folder)"

  say "Installed $("$dir/opposable" --version) to $dir/opposable"
  if ! on_path "$dir"; then
    say ""
    say "$dir isn't on your PATH yet. Add it, for example:"
    case "${SHELL:-}" in
      */zsh) say "  echo 'export PATH=\"$dir:\$PATH\"' >> ~/.zshrc && exec zsh" ;;
      */bash) say "  echo 'export PATH=\"$dir:\$PATH\"' >> ~/.bashrc && exec bash" ;;
      *) say "  export PATH=\"$dir:\$PATH\"" ;;
    esac
  fi
  say ""
  say "Next: in the Opposable app on your phone, tap Pair with computer, then run"
  say "  opposable connect CODE"
}

main "$@"