# Copyright 2019 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.

import("$zx/public/gn/host_tool_action.gni")

# Run the FIDL compiler for a fidl_library().
#
# This is not really meant for general use.  It's used by FIDL support
# modules (see $zx/public/gn/fidl.gni for details).
#
# Parameters
#
#   deps
#     Required: List of exactly one fidl_library() target label.
#     Type: list(label_no_toolchain)
#
#   args
#     Required: Arguments for `fidlc` to generate the desired outputs.
#     Type: list(string)
#
#   outputs
#     Required: Files that `fidlc` will generate when given $args.
#     Type: list(file)
#
#   tool
#     Optional: Label of the host_tool() to run.
#     Type: label_no_toolchain
#     Default: "$zx/system/host/fidl:fidlc"
#
template("fidlc") {
  if (current_toolchain == default_toolchain) {
    fidlc_target = target_name

    fidl_deps = invoker.deps
    fidlc_outputs = invoker.outputs

    fidl_library = fidl_deps[0]
    assert(fidl_deps == [ fidl_library ],
           "fidlc() must list exactly one fidl_library() target in `deps`")
    fidl_label_dir = get_label_info(fidl_library, "dir")
    fidl_label_name = get_label_info(fidl_library, "name")

    # TODO(mcgrathr): temporary until everything is renamed with . names
    fidl_name = string_replace(fidl_label_name, "-", ".")

    # fidl_library() generates a response file of all the input arguments.
    fidl_gen_dir = get_label_info(fidl_library, "target_gen_dir")
    fidl_target_name = get_label_info(fidl_library, "name")
    files_rspfile = "$fidl_gen_dir/$fidl_target_name.rsp"
    files_rspfile_target =
        "$fidl_label_dir:_fidl_library.files.$fidl_label_name.rsp"

    # Next, combine that into a response file for the whole command.
    # At the same time, produce a depfile listing all the input files.
    fidlc_rspfile = "$target_out_dir/$fidlc_target.rsp"
    fidlc_depfile = "$target_out_dir/$fidlc_target.d"
    action("_fidlc.rsp.$target_name") {
      forward_variables_from(invoker, [ "testonly" ])
      visibility = [ ":$fidlc_target" ]
      deps = [
        files_rspfile_target,
      ]
      sources = [
        files_rspfile,
      ]
      outputs = [
        fidlc_rspfile,
        fidlc_depfile,
      ]
      script = "$zx/public/gn/fidl/gen-fidlc-rsp.sh"
      args = rebase_path(outputs + [ fidlc_outputs[0] ] + sources,
                         root_build_dir) +
             [
               "--name",
               fidl_name,
             ] + invoker.args
    }

    host_tool_action(fidlc_target) {
      forward_variables_from(invoker,
                             [
                               "visibility",
                               "testonly",
                             ])
      if (defined(invoker.tool)) {
        tool = invoker.tool
      } else {
        tool = "$zx/system/host/fidl:fidlc"
      }
      outputs = fidlc_outputs
      deps = [
        ":_fidlc.rsp.$target_name",
      ]
      sources = [
        fidlc_rspfile,
      ]
      depfile = fidlc_depfile
      args = [ "@" + rebase_path(fidlc_rspfile, root_build_dir) ]
    }
  } else {
    group(target_name) {
      forward_variables_from(invoker,
                             [
                               "visibility",
                               "testonly",
                             ])
      public_deps = [
        ":$target_name($default_toolchain)",
      ]
      not_needed(invoker, "*")
    }
  }
}