# Copyright 2022 The Pigweed 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
#
#     https://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.

import("//build_overrides/pi_pico.gni")
import("//build_overrides/pigweed.gni")

import("$dir_pw_build/target_types.gni")

# Generates a pico/config_autogen.h file as part of a source set that provides
# the required include directory as a public config.
#
# Example contents:
#
#   // AUTO GENERATED BY A GN generate_config_header TARGET
#   #include "boards/pico.h"
#   #include "cmsis/rename_exceptions.h"
#
# Arguments:
#   config_header_files (required): Includes that should be written to the
#     generated header file.
template("generate_config_header") {
  assert(defined(invoker.config_header_files), "No headers provided")

  _generated_header_dir = "${target_gen_dir}/${target_name}_include"
  _generated_header_path = "${_generated_header_dir}/pico/config_autogen.h"

  # Provide the include path so the header is exposed when targets depend on
  # the generate_config_header target.
  config("${target_name}.public_include_dirs") {
    include_dirs = [ "${_generated_header_dir}" ]
  }

  # Actually generate config_autogen.h.
  generated_file("${target_name}.generated_header") {
    outputs = [ "${_generated_header_path}" ]
    _lines = [ "// AUTO GENERATED BY A GN generate_config_header TARGET" ]
    foreach(_header, invoker.config_header_files) {
      _lines += [ "#include \"${_header}\"" ]
    }

    # Join with newline.
    _NEWLINE_CHAR = "$0x0A"
    contents = string_join(_NEWLINE_CHAR, _lines)
  }

  # This source set bundles up the generated header such that depending on
  # this template will allow targets to include "pico/config_autogen.h".
  pw_source_set("${target_name}") {
    public_configs = [
      "${PICO_ROOT}/gn:disable_warnings",
      ":${target_name}.public_include_dirs",
    ]
    deps = [ ":${target_name}.generated_header" ]
    public = [ "${_generated_header_path}" ]
    forward_variables_from(invoker, "*", [ "config_header_files" ])
  }
}