#!/bin/bash
# Copyright 2020 The Fuchsia Authors. All Rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# This script is a replacement for /usr/bin/env that adds Fuchsia-specific
# information and provides access to prebuilt tools in the source tree.
#
# This is not a subcommand of `fx` because multiple pieces of project
# infrastructure run outside of the build and need access to in-tree prebuilts.

set -e

# Filter out invalid FUCHSIA_DIR settings.
if [[ -n "${FUCHSIA_DIR}" ]]; then
  if [[ ! -d "${FUCHSIA_DIR}" ]]; then
    unset FUCHSIA_DIR
  elif [[ "${FUCHSIA_DIR#/}" == "${FUCHSIA_DIR}" ]]; then
    unset FUCHSIA_DIR
  else
    PWD="$(pwd)"
    if [[ "${PWD#${FUCHSIA_DIR}}" = "${PWD}" ]]; then
      # FUCHSIA_DIR does not contain the current directory
      unset FUCHSIA_DIR
    fi
  fi
fi

# Mimic `fx` behavior to set up a consistent root and get prebuilt paths.
fuchsia_dir="${FUCHSIA_DIR}"
if [[ -z "${fuchsia_dir}" ]]; then
  # We walk the parent directories looking for .jiri_root rather than using
  # BASH_SOURCE so that we find the fuchsia_dir enclosing the current working
  # directory instead of the one containing this file in case the user has
  # multiple source trees and is picking up this file from another one.
  fuchsia_dir="$(pwd)"
  while [[ ! -d "${fuchsia_dir}/.jiri_root" ]]; do
    fuchsia_dir="$(dirname "${fuchsia_dir}")"
    if [[ "${fuchsia_dir}" == "/" ]]; then
      echo "Cannot find Platform Source Tree containing $(pwd)"
      exit 1
    fi
  done
fi

export FUCHSIA_DIR="${fuchsia_dir}"
declare -r prebuilt_sh="${fuchsia_dir}/tools/devshell/lib/prebuilt.sh"
source "${prebuilt_sh}" || exit $?

if [[ "${PATH#${PREBUILT_ALL_PATHS}" == "${PATH}" ]]; then
  # Prebuilts have not been added to the path
  if [[ x"${FUCHSIA_HERMETIC_TOOLS}" == xy ]]; then
    readonly newpath="${PREBUILT_ALL_PATHS}:${FUCHSIA_DIR}/tools/system"
  else
    readonly newpath="${PREBUILT_ALL_PATHS}:${PATH}"
  fi
else
  readonly newpath="${PATH}"
fi

export PATH="${newpath}"

# Forward the args to the system `env`.
exec /usr/bin/env -S -i \
  "FUCHSIA_DIR=${fuchsia_dir}" \
  "TERM=${TERM}" \
  "PATH=${newpath}" \
  "FUCHSIA_HERMETIC_TOOLS=${FUCHSIA_HERMETIC_TOOLS}" \
  ${NINJA_STATUS+"NINJA_STATUS=${NINJA_STATUS}"} \
  ${GOMA_DISABLED+"GOMA_DISABLED=${GOMA_DISABLED}"} \
  ${TMPDIR+"TMPDIR=${TMPDIR}"} \
  "$@"