#!/bin/sh
# Install the DUAL CLI.
#
#   curl -fsSL https://get.dual.network | sh
#
# Environment:
#   DUAL_VERSION       install a specific tag instead of the latest, e.g. v1.2.0
#   DUAL_INSTALL_DIR   where to put the binary (default: $HOME/.local/bin)
#   DUAL_REPO          release repository (default: DUALorg/dual-cli)

set -eu

REPO="${DUAL_REPO:-DUALorg/dual-cli}"
BIN=dual
INSTALL_DIR="${DUAL_INSTALL_DIR:-$HOME/.local/bin}"

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

command -v curl >/dev/null 2>&1 || die "curl is required"
command -v tar  >/dev/null 2>&1 || die "tar is required"

# Pick the checksum tool. Linux ships sha256sum, macOS ships shasum.
if command -v sha256sum >/dev/null 2>&1; then
  checksum() { sha256sum "$1" | awk '{print $1}'; }
elif command -v shasum >/dev/null 2>&1; then
  checksum() { shasum -a 256 "$1" | awk '{print $1}'; }
else
  die "need sha256sum or shasum to verify the download"
fi

os=$(uname -s | tr '[:upper:]' '[:lower:]')
case "$os" in
  darwin|linux) ;;
  *) die "unsupported operating system: $os" ;;
esac

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

version="${DUAL_VERSION:-}"
if [ -z "$version" ]; then
  version=$(curl -fsSL "https://api.github.com/repos/$REPO/releases/latest" \
    | sed -n 's/.*"tag_name"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p' | head -1)
  [ -n "$version" ] || die "could not find the latest release of $REPO"
fi

tarball="${BIN}_${version}_${os}_${arch}.tar.gz"
base="https://github.com/$REPO/releases/download/$version"

tmp=$(mktemp -d)
# shellcheck disable=SC2064
trap "rm -rf '$tmp'" EXIT INT TERM

printf 'downloading %s %s (%s/%s)\n' "$BIN" "$version" "$os" "$arch"
curl -fsSL -o "$tmp/$tarball"      "$base/$tarball"      || die "download failed: $base/$tarball"
curl -fsSL -o "$tmp/checksums.txt" "$base/checksums.txt" || die "download failed: $base/checksums.txt"

# Verifying is not optional: this script runs whatever it downloads.
expected=$(awk -v f="$tarball" '$2 == f || $2 == "*" f {print $1}' "$tmp/checksums.txt" | head -1)
[ -n "$expected" ] || die "checksums.txt has no entry for $tarball"
actual=$(checksum "$tmp/$tarball")
[ "$expected" = "$actual" ] || die "checksum mismatch for $tarball
  expected $expected
  got      $actual"

tar -xzf "$tmp/$tarball" -C "$tmp"
[ -f "$tmp/$BIN" ] || die "the archive does not contain $BIN"

mkdir -p "$INSTALL_DIR"
cp "$tmp/$BIN" "$INSTALL_DIR/$BIN.tmp"
chmod 0755 "$INSTALL_DIR/$BIN.tmp"
mv -f "$INSTALL_DIR/$BIN.tmp" "$INSTALL_DIR/$BIN"

printf 'installed %s to %s\n' "$BIN" "$INSTALL_DIR/$BIN"

case ":${PATH}:" in
  *":$INSTALL_DIR:"*) printf 'run "%s help" to get started\n' "$BIN" ;;
  *) printf '\n%s is not on your PATH. Add this to your shell profile:\n\n  export PATH="%s:$PATH"\n\n' "$INSTALL_DIR" "$INSTALL_DIR" ;;
esac