# Copyright 2019 The ANGLE Project 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 file houses the build configuration for the ANGLE Metal back-end.

import("../../../../gni/angle.gni")
import("metal_backend.gni")

if (metal_internal_shader_compilation_supported) {
  import("//chromium/build/config/mac/mac_sdk.gni")
}

assert(is_mac || is_ios)
assert(angle_enable_metal)

config("angle_metal_backend_config") {
  defines = [ "ANGLE_ENABLE_METAL" ]
  ldflags = [
    "-weak_framework",
    "Metal",
  ]
  include_dirs = [ "$root_gen_dir/angle" ]
}

if (metal_internal_shader_compilation_supported) {
  template("run_metal_tool") {
    action(target_name) {
      forward_variables_from(invoker,
                             [
                               "deps",
                               "sources",
                               "outputs",
                               "metal_tool",
                             ])
      script = "shaders/metal_wrapper.py"
      if (use_system_xcode) {
        # System Xcode: run metal and metallib via xcrun. Since Xcode 26.0, the
        # Metal toolchain has been unbundled from Xcode, and must be installed
        # separately by running `xcodebuild -downloadComponent MetalToolchain`.
        # There is a vestigial metal executable in mac_bin_path, but it’s
        # incapable of running successfuly without the
        # rest of the Metal toolchain surrounding it. `xcrun` is able to find
        # and run the correct Metal toolchain when properly installed.
        #
        # If you’re using system Xcode and your build fails with this message:
        #   error: error: cannot execute tool 'metal' due to missing Metal Toolchain; use: xcodebuild -downloadComponent MetalToolchain
        # then do what the error message suggests, and then retry your build.
        args = [
          "xcrun",
          metal_tool,
        ]
      } else {
        # Hermetic Xcode: at least for now, the Metal toolchain is
        # “spliced” into the location in the hermetic toolchain where it lived
        # before Xcode 26.0, so it can be run directly from there.
        args = [ mac_bin_path + metal_tool ]
      }

      args += invoker.args
    }
  }

  _metal_internal_shaders_air_file =
      "$root_gen_dir/angle/mtl_internal_shaders_autogen.air"

  run_metal_tool("angle_metal_internal_shaders_to_air") {
    _metal_internal_shaders_metal_source =
        "shaders/mtl_internal_shaders_autogen.metal"
    sources = [ _metal_internal_shaders_metal_source ]

    outputs = [ _metal_internal_shaders_air_file ]

    metal_tool = "metal"

    args = [
      "-c",
      rebase_path(_metal_internal_shaders_metal_source, root_build_dir),
      "-o",
      rebase_path(_metal_internal_shaders_air_file, root_build_dir),
    ]

    if (is_mac) {
      args += [
        "--std=macos-metal2.1",
        "-mmacosx-version-min=10.14",
      ]
    } else if (is_ios) {
      args += [
        "--std=ios-metal2.1",
        "-mios-version-min=12",
      ]
    }
  }

  _metal_internal_shaders_metallib_file =
      "$root_gen_dir/angle/mtl_internal_shaders_autogen.metallib"

  run_metal_tool("angle_metal_internal_shaders_to_mtllib") {
    deps = [ ":angle_metal_internal_shaders_to_air" ]

    sources = [ _metal_internal_shaders_air_file ]

    outputs = [ _metal_internal_shaders_metallib_file ]

    metal_tool = "metallib"

    args = [
      rebase_path(_metal_internal_shaders_air_file, root_build_dir),
      "-o",
      rebase_path(_metal_internal_shaders_metallib_file, root_build_dir),
    ]
  }

  config("angle_metal_internal_shaders_config") {
    include_dirs = [ "$root_gen_dir/angle" ]
  }

  action("angle_metal_internal_shaders") {
    script = "shaders/embed_in_header.py"

    outputs = [ metal_internal_shaders_header ]

    sources = [ _metal_internal_shaders_metallib_file ]

    deps = [ ":angle_metal_internal_shaders_to_mtllib" ]

    args = [
      "--source",
      rebase_path(_metal_internal_shaders_metallib_file, root_build_dir),
      "--variable-name",
      "gDefaultMetallib",
      "--header",
      rebase_path(metal_internal_shaders_header, root_build_dir),
    ]

    public_configs = [ ":angle_metal_internal_shaders_config" ]
  }
}

angle_source_set("angle_metal_backend") {
  public_configs = [ ":angle_metal_backend_config" ]

  sources = metal_backend_sources

  cflags = []
  cflags_cc = []
  cflags_objc = []
  cflags_objcc = []
  ldflags = []
  libs = []
  defines = []

  public_deps = [
    "${angle_root}:angle_common",
    "${angle_root}:angle_gpu_info_util",
    "${angle_root}:angle_image_util",
    "${angle_root}:libANGLE_headers",
    "${angle_root}:translator",
  ]

  if (metal_internal_shader_compilation_supported) {
    public_deps += [ ":angle_metal_internal_shaders" ]
    defines += [ "ANGLE_METAL_HAS_PREBUILT_INTERNAL_SHADERS" ]
  }

  objc_flags = [
    "-Wno-nullability-completeness",
    "-Wno-unguarded-availability",
    "-fno-objc-arc",
  ]
  cflags_objc += objc_flags
  cflags_objcc += objc_flags

  if (is_apple) {
    frameworks = [
      "IOSurface.framework",
      "QuartzCore.framework",
    ]
    if (is_mac) {
      frameworks += [ "Cocoa.framework" ]
    }
  }
}