#!/bin/sh
# Geometer one-line installer (alpha). Served at https://geometer.dev/install.sh:
#
#   curl -fsSL https://geometer.dev/install.sh | sh
#   curl -fsSL https://geometer.dev/install.sh | sh -s -- --prefix "$HOME/tools"
#
# What it does, in order: looks at this computer (macOS on Apple silicon, or Linux on x86_64 or arm64),
# downloads the matching geo tarball and SHA256SUMS from the GitHub release, checks the tarball's
# SHA-256 against SHA256SUMS and stops if it differs, unpacks into a temporary folder and runs the
# tarball's own install.sh (which installs for you alone, under ~/.local by default). It never uses
# sudo and changes nothing outside the install folder and your Geometer records folder.
#
# Settings (environment): GEO_VERSION picks another release than the one named below;
# GEO_BASE_URL replaces the download address (for a mirror or a test; files are read from
# $GEO_BASE_URL/geo-<version>-<os>-<arch>.tar.gz and $GEO_BASE_URL/SHA256SUMS).
# The version below is written in when a release is made (tools/release/release.sh).
set -eu

DEFAULT_VERSION="0.1.0-alpha.2"
VERSION="${GEO_VERSION:-$DEFAULT_VERSION}"
case "$VERSION" in
  @*) echo "This copy of the installer has no release version written in. Set GEO_VERSION, for example GEO_VERSION=0.1.0-alpha.2." >&2; exit 2 ;;
esac
BASE="${GEO_BASE_URL:-https://github.com/GeometerLabs/geometer/releases/download/v$VERSION}"

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

# Show help without doing anything.
for a in "$@"; do
  case "$a" in
    -h|--help)
      say "Installs Geometer $VERSION for your user (no administrator rights)."
      say "Options are passed to the installer: --prefix DIR (default ~/.local), --home DIR."
      say "Set GEO_VERSION to install another release."
      exit 0 ;;
  esac
done

if [ "$(id -u)" = 0 ]; then
  die "Please run this as yourself, not as an administrator or with sudo: Geometer installs for one user."
fi

OS="$(uname -s)"
M="$(uname -m)"
case "$OS" in
  Darwin)
    case "$M" in
      arm64) PLATFORM="macos-arm64" ;;
      x86_64) die "This is an Intel Mac, and the alpha is built for Apple silicon only. Nothing was installed." ;;
      *) die "Geometer does not have a build for this Mac ($M). Nothing was installed." ;;
    esac ;;
  Linux)
    case "$M" in
      x86_64|amd64) PLATFORM="linux-x86_64" ;;
      aarch64|arm64) PLATFORM="linux-aarch64" ;;
      *) die "Geometer does not have a Linux build for this processor ($M); it is built for x86_64 and arm64. Nothing was installed." ;;
    esac ;;
  *) die "Geometer does not have a build for $OS; it is built for macOS on Apple silicon and for Linux. Nothing was installed." ;;
esac

if command -v sha256sum >/dev/null 2>&1; then
  sha_of() { sha256sum "$1" | awk '{print $1}'; }
elif command -v shasum >/dev/null 2>&1; then
  sha_of() { shasum -a 256 "$1" | awk '{print $1}'; }
else
  die "Neither sha256sum nor shasum is installed, so the download cannot be checked. Nothing was installed."
fi
if command -v curl >/dev/null 2>&1; then
  fetch() { curl -fsSL -o "$2" "$1"; }
elif command -v wget >/dev/null 2>&1; then
  fetch() { wget -q -O "$2" "$1"; }
else
  die "Neither curl nor wget is installed, so nothing can be downloaded. Nothing was installed."
fi

FILE="geo-$VERSION-$PLATFORM.tar.gz"
TMP="$(mktemp -d "${TMPDIR:-/tmp}/geometer-install.XXXXXX")"
trap 'rm -rf "$TMP"' EXIT INT TERM

say "Geometer $VERSION for $PLATFORM"
say "Downloading $FILE ..."
fetch "$BASE/$FILE" "$TMP/$FILE" || die "Could not download $BASE/$FILE. Check your connection and that release $VERSION exists. Nothing was installed."
fetch "$BASE/SHA256SUMS" "$TMP/SHA256SUMS" || die "Could not download $BASE/SHA256SUMS. Nothing was installed."

WANT="$(awk -v f="$FILE" '$2 == f || $2 == "*" f {print $1; exit}' "$TMP/SHA256SUMS")"
[ -n "$WANT" ] || die "$FILE is not listed in SHA256SUMS. Nothing was installed."
GOT="$(sha_of "$TMP/$FILE")"
if [ "$GOT" != "$WANT" ]; then
  die "The download does not match its published checksum (expected $WANT, got $GOT). It may be damaged or altered. Nothing was installed."
fi
say "Checksum matches ($GOT)."

mkdir "$TMP/unpacked"
tar -xzf "$TMP/$FILE" -C "$TMP/unpacked" || die "Could not unpack the download. Nothing was installed."
DIR="$TMP/unpacked/geo-$VERSION-$PLATFORM"
[ -f "$DIR/install.sh" ] || die "The download does not contain an installer. Nothing was installed."

say "Running the installer ..."
sh "$DIR/install.sh" "$@" || die "The installer stopped (see above). Anything already installed was left as it was."

PFX="$HOME/.local"
prev=""
for a in "$@"; do
  [ "$prev" = "--prefix" ] && PFX="$a"
  prev="$a"
done
say ""
say "Done. To see a first result on a practice agent, run: $PFX/bin/geo practice --check"
say "To remove Geometer: $PFX/lib/geometer/current/uninstall.sh --prefix $PFX   (add --purge-records to delete your records too)"
say "To go back to the previous version after an upgrade: run the installer again with --rollback."