#!/bin/sh
#
# Installs the saasie CLI.
#
#   curl -fsSL https://saasie.io/install.sh | sh
#
# Options, as environment variables:
#
#   SAASIE_INSTALL_DIR   where to put it (default: the first writable of
#                        /usr/local/bin, ~/.local/bin)
#   SAASIE_BASE_URL      where to fetch it from (default: https://saasie.io)
#
# POSIX sh, no dependencies beyond curl (or wget) and a sha256 tool, because
# this runs on machines that have nothing else on them yet.
#
set -eu

BASE_URL="${SAASIE_BASE_URL:-https://saasie.io}"
DL_URL="$BASE_URL/dl"

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

# --- which build ------------------------------------------------------------

os="$(uname -s)"
case "$os" in
  Linux)  os=linux ;;
  Darwin) os=darwin ;;
  *)
    die "unsupported operating system: $os
Windows: download $DL_URL/saasie-windows-x64.exe by hand and put it on your PATH."
    ;;
esac

arch="$(uname -m)"
case "$arch" in
  x86_64 | amd64)  arch=x64 ;;
  arm64 | aarch64) arch=arm64 ;;
  *) die "unsupported architecture: $arch" ;;
esac

asset="saasie-$os-$arch"

# --- where it goes ----------------------------------------------------------

# Chosen before the download, so a permissions problem is reported before
# spending a minute on 40 MB.
if [ -n "${SAASIE_INSTALL_DIR:-}" ]; then
  install_dir="$SAASIE_INSTALL_DIR"
  mkdir -p "$install_dir" || die "cannot create $install_dir"
elif [ -w /usr/local/bin ]; then
  install_dir=/usr/local/bin
else
  install_dir="$HOME/.local/bin"
  mkdir -p "$install_dir" || die "cannot create $install_dir"
fi

[ -w "$install_dir" ] || die "cannot write to $install_dir
Pick somewhere else with: SAASIE_INSTALL_DIR=~/.local/bin"

# --- fetch ------------------------------------------------------------------

# The server stores the binaries gzipped and serves them under their plain
# names. `curl --compressed` unwraps that here; plain wget does not advertise
# gzip, so nginx expands them at its end instead. Either way what lands on
# disk is the executable.
if command -v curl >/dev/null 2>&1; then
  fetch() { curl -fsSL --compressed "$1" -o "$2"; }
elif command -v wget >/dev/null 2>&1; then
  fetch() { wget -q -O "$2" "$1"; }
else
  die "needs curl or wget"
fi

tmp="$(mktemp -d)"
trap 'rm -rf "$tmp"' EXIT INT TERM

fetch "$DL_URL/VERSION" "$tmp/VERSION" ||
  die "cannot reach $DL_URL — is $BASE_URL up?"
version="$(cat "$tmp/VERSION")"

say "downloading saasie $version for $os-$arch"
fetch "$DL_URL/$asset" "$tmp/saasie" || die "download failed: $DL_URL/$asset"

# --- verify -----------------------------------------------------------------

if command -v sha256sum >/dev/null 2>&1; then
  sum="$(sha256sum "$tmp/saasie" | cut -d' ' -f1)"
elif command -v shasum >/dev/null 2>&1; then
  sum="$(shasum -a 256 "$tmp/saasie" | cut -d' ' -f1)"
else
  sum=""
fi

if [ -n "$sum" ]; then
  fetch "$DL_URL/SHA256SUMS" "$tmp/SHA256SUMS" || die "cannot fetch checksums"
  expected="$(grep " $asset\$" "$tmp/SHA256SUMS" | cut -d' ' -f1)"

  [ -n "$expected" ] || die "no checksum published for $asset"
  [ "$sum" = "$expected" ] || die "checksum mismatch for $asset — refusing to install
  expected $expected
  got      $sum"
else
  say "! no sha256 tool found; skipping checksum verification"
fi

# --- install ----------------------------------------------------------------

chmod +x "$tmp/saasie"

# Move into place in one step: replacing a binary that is currently running
# fails on some systems if it is written to in place.
mv -f "$tmp/saasie" "$install_dir/saasie" 2>/dev/null ||
  die "cannot install into $install_dir"

say ""
say "saasie $version installed to $install_dir/saasie"

case ":$PATH:" in
  *":$install_dir:"*)
    say ""
    say "Next: saasie docs       — what the platform asks of your repo"
    say "      saasie otp <your email>"
    ;;
  *)
    say ""
    say "! $install_dir is not on your PATH. Add it:"
    say "    export PATH=\"$install_dir:\$PATH\""
    ;;
esac