#!/bin/sh
# nudge installer:  curl -fsSL https://nudge.reintelligence.live/install.sh | sh
#
# Installs the latest nudge into ~/.local/bin (no sudo needed). Run it again to upgrade.
#   NUDGE_VERSION=0.1.0       install that version instead of the latest
#   NUDGE_INSTALL_DIR=<dir>   install into another folder
#   NUDGE_NO_MODIFY_PATH=1    don't add the folder to your shell profile
#   NUDGE_DOWNLOAD_URL=<url>  download from a mirror instead of nudge.reintelligence.live
#
# Everything runs from main() at the very end, so a partly downloaded script does nothing.

set -eu

say() { printf '%s\n' "$*"; }
fail() { printf 'nudge install: %s\n' "$*" >&2; exit 1; }
fetch() { curl -fsSL --retry 2 "$1" || fail "download failed: $1"; }
tilde() { case $1 in "$HOME"/*) printf '~/%s' "${1#"$HOME"/}" ;; *) printf '%s' "$1" ;; esac; }

# Runs on every exit. bash 3.2 (macOS's /bin/sh) exits 0 after a shell error such as an unbound
# variable once a trap has run, and $? doesn't show it, so success is marked explicitly instead.
cleanup() {
	if [ -n "${tmp:-}" ]; then rm -rf "$tmp"; fi
	if [ -z "${installed:-}" ]; then exit 1; fi
}

check_mac() {
	[ "$(uname -s)" = Darwin ] || fail "nudge runs on macOS only."
	# hw.optional.arm64 is 1 on Apple Silicon even when this shell runs under Rosetta. Full paths:
	# agents often run with a minimal PATH that leaves out /usr/sbin.
	[ "$(/usr/sbin/sysctl -n hw.optional.arm64 2>/dev/null || echo 0)" = 1 ] ||
		fail "nudge needs a Mac with Apple Silicon (M1 or later)."
	macos=$(/usr/bin/sw_vers -productVersion)
	[ "${macos%%.*}" -ge 13 ] || fail "nudge needs macOS 13 or later; this Mac runs macOS $macos."
}

# Adds the install folder to PATH in the shell's profile, once. Prints what it did.
add_to_path() {
	dir=$1
	case ":$PATH:" in *":$dir:"*) return ;; esac
	[ -z "${NUDGE_NO_MODIFY_PATH:-}" ] || return 0
	shown=$dir
	[ "$dir" = "$HOME/.local/bin" ] && shown='$HOME/.local/bin'
	case $(basename "${SHELL:-zsh}") in
		zsh) profile=${ZDOTDIR:-$HOME}/.zshrc; line="export PATH=\"$shown:\$PATH\"" ;;
		bash) profile=$HOME/.bash_profile; line="export PATH=\"$shown:\$PATH\"" ;;
		fish) profile=$HOME/.config/fish/conf.d/nudge.fish; line="fish_add_path \"$dir\"" ;;
		*) say "Add $(tilde "$dir") to your PATH to run nudge by name."; return ;;
	esac
	if grep -qsF "$line" "$profile"; then
		say "$(tilde "$profile") already adds $(tilde "$dir") to your PATH. Open a new terminal if nudge isn't found."
		return
	fi
	mkdir -p "$(dirname "$profile")"
	printf '\n# added by the nudge installer\n%s\n' "$line" >>"$profile"
	say "Added $(tilde "$dir") to your PATH in $(tilde "$profile"). Open a new terminal to use it."
}

main() {
	trap cleanup EXIT
	base=${NUDGE_DOWNLOAD_URL:-https://nudge.reintelligence.live}
	dir=${NUDGE_INSTALL_DIR:-$HOME/.local/bin}
	check_mac

	version=${NUDGE_VERSION:-$(fetch "$base/latest" | tr -d '[:space:]')}
	case $version in ''|*[!0-9.]*) fail "couldn't read the latest version from $base/latest" ;; esac
	name=nudge-$version-macos-arm64.tar.gz

	tmp=$(mktemp -d)
	# Brace variables next to non-ASCII text: macOS's /bin/sh (bash 3.2) in a UTF-8 locale reads
	# the first byte of "…" as part of the name, and set -u then stops with "unbound variable".
	say "Downloading nudge ${version}…"
	fetch "$base/$version/$name" >"$tmp/$name"
	fetch "$base/$version/$name.sha256" >"$tmp/$name.sha256"
	(cd "$tmp" && shasum -a 256 -c "$name.sha256" >/dev/null 2>&1) ||
		fail "the download doesn't match its checksum; nothing was installed."
	tar -xzf "$tmp/$name" -C "$tmp"
	[ -f "$tmp/nudge" ] || fail "$name doesn't contain nudge; nothing was installed."

	previous=
	[ -x "$dir/nudge" ] && previous=$("$dir/nudge" --version 2>/dev/null | awk '{print $2}') || true
	# Builds can change without a new version number, so compare the binaries themselves.
	if [ -n "$previous" ] && cmp -s "$tmp/nudge" "$dir/nudge"; then
		installed=1
		say "nudge ${version} is already up to date."
		add_to_path "$dir"
		return
	fi
	mkdir -p "$dir" 2>/dev/null && [ -w "$dir" ] ||
		fail "can't write to $dir. Set NUDGE_INSTALL_DIR to a folder you own."
	# Move a fresh file into place instead of copying over the old one: macOS kills a signed
	# binary that was overwritten in place.
	cp "$tmp/nudge" "$dir/.nudge.new"
	chmod 755 "$dir/.nudge.new"
	xattr -d com.apple.quarantine "$dir/.nudge.new" 2>/dev/null || true
	mv -f "$dir/.nudge.new" "$dir/nudge"
	"$dir/nudge" --version >/dev/null 2>&1 || fail "installed $dir/nudge, but it doesn't run."
	installed=1

	if [ -z "$previous" ]; then
		say "Installed nudge $version to $(tilde "$dir/nudge")."
	elif [ "$previous" = "$version" ]; then
		say "Updated nudge ${version} to the latest build in $(tilde "$dir/nudge")."
	else
		say "Upgraded nudge ${previous} → ${version} in $(tilde "$dir/nudge")."
	fi
	add_to_path "$dir"
	[ -n "$previous" ] || say "Try it:  nudge -m \"Hello from nudge\""
}

main "$@"