#!/bin/sh
# POSTERM installer.
#
#   curl -fsSL https://posterm.sh/install | sh
#
# Linux: puts the static binary in ~/.local/bin (or /usr/local/bin as root),
#        checks tmux, tells you how to start. Nothing runs in the background.
# macOS: fetches the Mac package and runs its installer (tmux via Homebrew,
#        a LaunchAgent, Safari's Add to Dock as the app).
# Every download is checked against the release's SHA256SUMS.
#
# Read it before you pipe it: it's short on purpose.
# POSTERM_REPO=owner/name picks another GitHub repo, POSTERM_BASE another
# download URL (a mirror, or a local dir served over http for testing).

# Everything lives in main, called on the last line: a cut-off download runs
# nothing.
main() {
	set -eu
	repo=${POSTERM_REPO:-l3dlp/posterm.sh}
	base=${POSTERM_BASE:-https://github.com/$repo/releases/latest/download}

	say() { printf '\033[1m==> %s\033[0m\n' "$*"; }
	ok() { printf '    %s\n' "$*"; }
	die() { printf '\033[31mxx  %s\033[0m\n' "$*" >&2; exit 1; }

	command -v curl >/dev/null || die "curl not found."
	case $(uname -m) in
	x86_64 | amd64) arch=amd64 ;;
	aarch64 | arm64) arch=arm64 ;;
	*) die "No build for $(uname -m). Build from source: https://github.com/$repo" ;;
	esac
	os=$(uname -s)

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

	fetch() { # fetch <asset>: download it and check its sum
		curl -fsSL --proto '=https,http' -o "$tmp/$1" "$base/$1" || die "Download failed: $base/$1"
		want=$(grep " $1\$" "$tmp/SHA256SUMS" | cut -d' ' -f1)
		[ -n "$want" ] || die "$1 is not in SHA256SUMS."
		if command -v sha256sum >/dev/null; then
			got=$(sha256sum "$tmp/$1" | cut -d' ' -f1)
		else
			got=$(shasum -a 256 "$tmp/$1" | cut -d' ' -f1)
		fi
		[ "$got" = "$want" ] || die "Checksum mismatch for $1. Not installing."
	}

	say "POSTERM from $base"
	curl -fsSL --proto '=https,http' -o "$tmp/SHA256SUMS" "$base/SHA256SUMS" || die "Download failed: $base/SHA256SUMS"

	case $os in
	Darwin)
		fetch POSTERM-macos.zip
		ok "checksum ok"
		command -v unzip >/dev/null || die "unzip not found."
		unzip -q "$tmp/POSTERM-macos.zip" -d "$tmp"
		# The Mac installer asks questions: give it the terminal, not this pipe.
		if [ -r /dev/tty ]; then
			bash "$tmp/POSTERM/install.command" </dev/tty
		else
			bash "$tmp/POSTERM/install.command"
		fi
		;;
	Linux)
		asset=posterm-linux-$arch
		fetch "$asset"
		ok "checksum ok"
		if [ "$(id -u)" = 0 ]; then dir=/usr/local/bin; else dir=$HOME/.local/bin; fi
		mkdir -p "$dir"
		install -m 755 "$tmp/$asset" "$dir/posterm"
		say "Installed $dir/posterm"

		if command -v tmux >/dev/null; then
			v=$(tmux -V | sed 's/[^0-9.]//g')
			case $v in
			0.* | 1.* | 2.* | 3.0*) ok "tmux $v is too old: POSTERM needs 3.1 or later." ;;
			*) ok "tmux $v" ;;
			esac
		else
			ok "tmux is missing, and POSTERM is built on it. Install it:"
			if command -v apt-get >/dev/null; then ok "  sudo apt-get install tmux"
			elif command -v dnf >/dev/null; then ok "  sudo dnf install tmux"
			elif command -v pacman >/dev/null; then ok "  sudo pacman -S tmux"
			elif command -v apk >/dev/null; then ok "  sudo apk add tmux"
			elif command -v zypper >/dev/null; then ok "  sudo zypper install tmux"
			else ok "  (your package manager) tmux"
			fi
		fi

		case ":$PATH:" in
		*":$dir:"*) cmd=posterm ;;
		*)
			cmd=$dir/posterm
			ok "$dir is not on your PATH: add it, or call $cmd"
			;;
		esac
		cat <<EOF

Start the hub:     $cmd
Then open:         http://127.0.0.1:8206  (the token is printed at first start)
Run it as a service, add machines, lock it down:
                   https://github.com/$repo#readme
EOF
		;;
	*) die "No build for $os. Build from source: https://github.com/$repo" ;;
	esac
}

main "$@"