#!/usr/bin/env bash

# gstack-gbrain-install — install the gbrain CLI on a local Mac.

#

# Usage:

# gstack-gbrain-install [--install-dir <dir>] [--pinned-commit <sha>] [--dry-run]

#

# D5 detect-first: before cloning anywhere, probe likely pre-existing

# locations (~/git/gbrain and ~/gbrain) and reuse a working clone if one

# exists. Falls back to a fresh clone of the pinned commit at ~/gbrain

# (override with GBRAIN_INSTALL_DIR or --install-dir).

#

# D19 PATH-shadowing: after `bun link`, compare `gbrain --version` output

# to the install-dir's package.json version. On mismatch, abort with an

# actionable error listing every gbrain on PATH. Never "silently fixes"

# PATH; setup skills should refuse broken environments.

#

# Prerequisites (checked before doing anything):

# - bun (install: curl -fsSL https://bun.sh/install | bash)

# - git

# - network reachability to https://github.com

#

# The pinned commit is declared here rather than resolved dynamically so

# upgrades are explicit and reviewable. Update PINNED_COMMIT when gstack

# verifies compatibility with a new gbrain release.

#

# Env:

# GBRAIN_INSTALL_DIR — override default install path (~/gbrain)

#

# Exit codes:

# 0 — success (or --dry-run printed the plan)

# 2 — prerequisite missing or invalid argument

# 3 — post-install validation failed (PATH shadow, broken binary, etc.)

set -euo pipefail

# --- defaults ---

PINNED_COMMIT="08b3698e90532b7b66c445e6b1d8cdfe71822802" # gbrain v0.18.2

PINNED_TAG="v0.18.2"

GBRAIN_REPO_URL="https://github.com/garrytan/gbrain.git"

DEFAULT_INSTALL_DIR="${GBRAIN_INSTALL_DIR:-$HOME/gbrain}"

INSTALL_DIR="$DEFAULT_INSTALL_DIR"

DRY_RUN=false

VALIDATE_ONLY=false

die() { echo "gstack-gbrain-install: $*" >&2; exit 2; }

fail() { echo "gstack-gbrain-install: $*" >&2; exit 3; }

log() { echo "gstack-gbrain-install: $*"; }

# --- parse args ---

while [ $# -gt 0 ]; do

case "$1" in

--install-dir) INSTALL_DIR="$2"; shift 2 ;;

--pinned-commit) PINNED_COMMIT="$2"; PINNED_TAG=""; shift 2 ;;

--dry-run) DRY_RUN=true; shift ;;

--validate-only) VALIDATE_ONLY=true; shift ;;

--help|-h) sed -n '2,30p' "$0" | sed 's/^# \{0,1\}//'; exit 0 ;;

*) die "unknown flag: $1" ;;

esac

done

# --- prerequisites ---

check_prereq() {

local bin="$1"

local hint="$2"

if ! command -v "$bin" >/dev/null 2>&1; then

fail "required tool '$bin' not found. $hint"

fi

}

if ! $VALIDATE_ONLY; then

check_prereq bun "Install: curl -fsSL https://bun.sh/install | bash"

check_prereq git "Install: xcode-select --install (macOS) or your package manager"

# GitHub reachability — fail fast if offline rather than hanging `git clone`.

# --max-time 10, --head (no body), quiet. Status code 200-4xx means we reached

# the server (even 404 is reachability proof).

if ! curl -s --head --max-time 10 https://github.com >/dev/null 2>&1; then

fail "cannot reach https://github.com. Check your network and try again."

fi

fi

# --- D5 detect-first: probe common locations before cloning fresh ---

# Accept any directory that looks like a gbrain clone: has package.json

# with name "gbrain" and a `bin.gbrain` entry. Don't accept version mismatches

# here — we'll let bun link run and then D19-validate.

is_valid_clone() {

local dir="$1"

[ -d "$dir" ] || return 1

[ -f "$dir/package.json" ] || return 1

local name

name=$(jq -r '.name // empty' "$dir/package.json" 2>/dev/null || true)

[ "$name" = "gbrain" ] || return 1

local bin

bin=$(jq -r '.bin.gbrain // empty' "$dir/package.json" 2>/dev/null || true)

[ -n "$bin" ] || return 1

return 0

}

DETECTED_CLONE=""

if ! $VALIDATE_ONLY; then

for candidate in "$HOME/git/gbrain" "$HOME/gbrain" "$INSTALL_DIR"; do

if is_valid_clone "$candidate"; then

DETECTED_CLONE="$candidate"

break

fi

done

fi

if $VALIDATE_ONLY; then

log "validate-only mode: skipping detect + clone + install + link"

elif [ -n "$DETECTED_CLONE" ]; then

log "detected existing gbrain clone at $DETECTED_CLONE — reusing"

INSTALL_DIR="$DETECTED_CLONE"

else

# Fresh clone path.

if $DRY_RUN; then

log "DRY RUN: would clone $GBRAIN_REPO_URL @ $PINNED_COMMIT → $INSTALL_DIR"

exit 0

fi

if [ -d "$INSTALL_DIR" ]; then

fail "install dir $INSTALL_DIR exists but is not a valid gbrain clone. Remove it or pass --install-dir <other>."

fi

log "cloning $GBRAIN_REPO_URL → $INSTALL_DIR"

git clone --quiet "$GBRAIN_REPO_URL" "$INSTALL_DIR"

( cd "$INSTALL_DIR" && git checkout --quiet "$PINNED_COMMIT" )

log "pinned to $PINNED_COMMIT${PINNED_TAG:+ ($PINNED_TAG)}"

fi

if $DRY_RUN; then

log "DRY RUN: would run bun install + bun link in $INSTALL_DIR"

exit 0

fi

# --- install + link ---

if ! $VALIDATE_ONLY; then

log "running bun install in $INSTALL_DIR"

( cd "$INSTALL_DIR" && bun install --silent )

log "running bun link in $INSTALL_DIR"

( cd "$INSTALL_DIR" && bun link --silent )

fi

# --- D19 PATH-shadowing validation ---

# Read the version from the install-dir's package.json; compare to

# `gbrain --version`. If they disagree, PATH is returning a DIFFERENT

# gbrain than the one we just linked. Fail hard with remediation.

expected_version=$(jq -r '.version // empty' "$INSTALL_DIR/package.json" 2>/dev/null || true)

if [ -z "$expected_version" ]; then

fail "cannot read version from $INSTALL_DIR/package.json (install may be broken)"

fi

if ! command -v gbrain >/dev/null 2>&1; then

fail "bun link completed but 'gbrain' is not on PATH. Ensure ~/.bun/bin is in your PATH."

fi

actual_version=$(gbrain --version 2>/dev/null | head -1 | awk '{print $NF}' | tr -d '[:space:]' || true)

if [ -z "$actual_version" ]; then

fail "gbrain is on PATH but 'gbrain --version' produced no output — the binary may be broken."

fi

# Tolerate a leading "v" (gbrain may print either "0.18.2" or "v0.18.2").

expected_norm="${expected_version#v}"

actual_norm="${actual_version#v}"

if [ "$actual_norm" != "$expected_norm" ]; then

echo "" >&2

echo "gstack-gbrain-install: PATH SHADOWING DETECTED" >&2

echo "" >&2

echo " We just linked gbrain $expected_version from $INSTALL_DIR," >&2

echo " but PATH is returning gbrain $actual_version." >&2

echo "" >&2

echo " All gbrain binaries on PATH:" >&2

type -a gbrain 2>&1 | sed 's/^/ /' >&2 || true

echo "" >&2

echo " Fix one of the following, then re-run /setup-gbrain:" >&2

echo " a) rm the shadowing binary: rm \$(which gbrain)" >&2

echo " b) prepend ~/.bun/bin to PATH in your shell rc" >&2

echo " c) point GBRAIN_INSTALL_DIR at the shadowing binary's install dir" >&2

echo "" >&2

exit 3

fi

log "installed gbrain $actual_version from $INSTALL_DIR"

echo ""

echo "Next: gbrain init --pglite (or run /setup-gbrain for the full setup flow)"