#!/bin/sh
# babashka, which the scripts here are written in.
#
# A build script wants the things a shell is bad at — reading deps.edn, hashing
# a file set, holding a path in a variable without quoting it three times — and
# Clojure is already the language this repo is written in.
#
# This used to be a DotSlash manifest, pinning a release of babashka the way
# the native libraries are pinned. It is the flake's now, for the reason the
# flake exists: a bb from `nixpkgs` is one this tree already names a version
# of, so a checkout needs nix and nothing else. DotSlash still answers for the
# desktop libraries — those are jolt-native's releases, which no nixpkgs has —
# but nothing has to be installed to reach *them* any more either, because the
# script that fetches them starts here.
#
# Three answers, in order:
#
#   bb on PATH      the dev shell puts one there, and so does a machine that
#                   has its own; either is what the caller meant — as long as
#                   it is babashka. `bb` is also what bazel's own launcher
#                   calls itself, and a host with one of those ahead of the
#                   shell's answered every recipe here with "Command
#                   'scripts/tui.bb' not found. Try 'bb help'", which reads as
#                   a missing script rather than the wrong program
#   the flake       built once and kept alive by the symlink under build/,
#                   which is a gc root as well as a cache
#   the container   nix is not on every host this runs on — see CLAUDE.md —
#                   so a host without one re-enters this script where nix is,
#                   which is where the scripts want to be anyway
set -e

root=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)

# Asking it who it is, rather than trusting the name: the version line is the
# cheapest question babashka answers and the one nothing else answers the same
# way.
if command -v bb >/dev/null 2>&1 && bb --version 2>/dev/null | grep -qi '^babashka'; then
    exec bb "$@"
fi

link="$root/build/bb"

if command -v nix >/dev/null 2>&1; then
    # --out-link rather than --no-link: the path has to survive a gc, and the
    # symlink is what roots it. Rebuilt only when it is gone or dangling, so
    # the usual case is one readlink.
    [ -x "$link/bin/bb" ] || nix build "$root#bb" --out-link "$link" >&2
    exec "$link/bin/bb" "$@"
fi

if [ -n "$FRQ_BB_REENTERED" ]; then
    echo "scripts/bb: no bb and no nix, inside the container too." >&2
    echo "Install babashka, or put a nix on this machine." >&2
    exit 1
fi

exec distrobox enter arch -- bash -lc \
    "cd $root && FRQ_BB_REENTERED=1 exec scripts/bb \"\$@\"" -- "$@"