#!/usr/bin/env bash
# Copyright 2022 The Tint Authors
#
# 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 -e # Fail on any error.

SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd )"
ROOT_DIR="$( cd "${SCRIPT_DIR}/.." >/dev/null 2>&1 && pwd )"
BUILD_SYSTEM=$(echo "$1" | tr '[:upper:]' '[:lower:]') # lowercase
BUILD_TYPE=$(echo "$2" | tr '[:upper:]' '[:lower:]') # lowercase
BUILD_DIR="${BUILD_SYSTEM}-${BUILD_TYPE}"

function show_usage() {
  echo "setup-build [gn|cmake] [debug|release]"
  echo
  echo "creates a build directory in <dawn>/out using either GN or CMake, then"
  echo "updates the '<dawn>/out/active' symlink to point to the build directory"
  exit 1
}

function generate() {
  CMD=$1
  pushd "$ROOT_DIR" > /dev/null
    mkdir -p "out/$BUILD_DIR"
    rm -fr "out/active" || true
    ln -s "$BUILD_DIR" "out/active"
    ${CMD}
  popd > /dev/null
}

case $BUILD_SYSTEM in
  "gn")
    case $BUILD_TYPE in
      "debug")
        generate "gn gen out/active --args=is_debug=true"
      ;;
      "release")
        generate "gn gen out/active"
      ;;
      *)
        echo "invalid build type '${BUILD_TYPE}'"
        show_usage
      ;;
    esac
  ;;
  "cmake")
    CMAKE_FLAGS=""
    if [[ -x $(command -v ccache) ]]; then
      CMAKE_FLAGS+="-DCMAKE_CXX_COMPILER_LAUNCHER=ccache"
    fi
    case $BUILD_TYPE in
      "debug")
        generate "cmake -S . -B out/active -GNinja -DCMAKE_BUILD_TYPE=Debug ${CMAKE_FLAGS}"
      ;;
      "release")
        generate "cmake -S . -B out/active -GNinja -DCMAKE_BUILD_TYPE=RelWithDebInfo ${CMAKE_FLAGS}"
      ;;
      *)
        echo "invalid build type '${BUILD_TYPE}'"
        show_usage
      ;;
    esac
  ;;
  "--help" | "-help" | "-h")
    show_usage
  ;;
  *)
    echo "invalid build system '${BUILD_SYSTEM}'"
    show_usage
  ;;
esac