#!/usr/bin/env bash
# prplsp -- launch the Pyrope/LiveHD LSP server (lhd pyrope lsp)
#
# Picks which lhd to run based on the CURRENT WORKING DIRECTORY (the dir the
# editor launched in), so neovim can use a single command everywhere:
#
#   1. If $PWD is inside a livehd checkout, use that repo's freshly-built
#      bazel-bin/lhd/lhd -- no copying/installing while hacking on the LSP.
#   2. Otherwise fall back to the `lhd` found in $PATH (the default install).
#
# A livehd checkout is identified by an ancestor MODULE.bazel declaring
# name = "livehd". Extra arguments are forwarded to lhd after `pyrope lsp`.

set -euo pipefail

# Walk up from $PWD looking for the livehd repo root (MODULE.bazel naming the
# "livehd" module). Prints the root on success; empty if not inside a checkout.
find_livehd_root() {
  local dir
  dir=$(pwd -P)
  while [[ -n "${dir}" ]]; do
    if [[ -f "${dir}/MODULE.bazel" ]] &&
      grep -Eq 'name[[:space:]]*=[[:space:]]*"livehd"' "${dir}/MODULE.bazel"; then
      printf '%s\n' "${dir}"
      return 0
    fi
    [[ "${dir}" == "/" ]] && break
    dir=$(dirname "${dir}")
  done
  return 1
}

if repo_root=$(find_livehd_root); then
  repo_lhd="${repo_root}/bazel-bin/lhd/lhd"
  if [[ -x "${repo_lhd}" ]]; then
    lhd="${repo_lhd}"
  else
    echo "prplsp: inside livehd (${repo_root}) but no built lhd at" >&2
    echo "  ${repo_lhd}" >&2
    echo "  build it with: bazel build //lhd:lhd" >&2
    echo "  falling back to 'lhd' in \$PATH" >&2
  fi
fi

# Fall back to PATH if not inside a checkout, or inside but not yet built.
if [[ -z "${lhd:-}" ]]; then
  if ! lhd=$(command -v lhd 2>/dev/null); then
    echo "prplsp: could not find lhd (not in a livehd checkout, and none in \$PATH)" >&2
    exit 1
  fi
fi

exec "${lhd}" pyrope lsp "$@"