#!/bin/bash

# Copyright 2015 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

set -eu

# This is a script which is installed instead of the real Bazel binary.
# It looks for a tools/bazel executable next to the containing WORKSPACE
# file and runs that. If that's not found, it runs the real Bazel binary which
# is installed next to this script as bazel-real.

# `readlink -f` that works on OSX too.
function get_realpath() {
  if [ "$(uname -s)" == "Darwin" ]; then
    local queue="$1"
    if [[ "${queue}" != /* ]] ; then
      # Make sure we start with an absolute path.
      queue="${PWD}/${queue}"
    fi
    local current=""
    while [ -n "${queue}" ]; do
      # Removing a trailing /.
      queue="${queue#/}"
      # Pull the first path segment off of queue.
      local segment="${queue%%/*}"
      # If this is the last segment.
      if [[ "${queue}" != */* ]] ; then
        segment="${queue}"
        queue=""
      else
        # Remove that first segment.
        queue="${queue#*/}"
      fi
      local link="${current}/${segment}"
      if [ -h "${link}" ] ; then
        link="$(readlink "${link}")"
        queue="${link}/${queue}"
        if [[ "${link}" == /* ]] ; then
          current=""
        fi
      else
        current="${link}"
      fi
    done

    echo "${current}"
  else
    readlink -f "$1"
  fi
}

WORKSPACE_DIR="${PWD}"
while [[ "${WORKSPACE_DIR}" != / ]]; do
  if [[ -e "${WORKSPACE_DIR}/WORKSPACE" ]]; then
    break;
  fi
  WORKSPACE_DIR="$(dirname "${WORKSPACE_DIR}")"
done
readonly WORKSPACE_DIR

if [[ -e "${WORKSPACE_DIR}/WORKSPACE" ]]; then
  readonly WRAPPER="${WORKSPACE_DIR}/tools/bazel"

  if [[ -x "${WRAPPER}" ]]; then
    exec -a "$0" "${WRAPPER}" "$@"
  fi
fi

SYSTEM_BAZEL=$(command -v bazel-real)
if [[ ! -x "${SYSTEM_BAZEL}" ]]; then
  echo "Failed to find a bazel-real binary in your path." >&2
  exit 1
fi

exec -a "$0" "${SYSTEM_BAZEL}" "$@"
