#
# This file introduces a template for calling download_file.py
#
# download_file behaves like CMake's file(DOWNLOAD) with the addtion
# of version checking the file against a build system defined version.
#
# Parameters:
#   url (required) [string]
#
#   output (required) [string]
#
#   version (required) [string]
#       Version of the file for caching purposes
#
#   version_file (reqiured) [string]
#       Filename to write the version to in the filesystem
#
#   cache [String]
#       Directory to clear on version mismatch
#
#   sha256 [String]
#       Expected SHA-256 hash of the downloaded file
#
# Example use:
#
#    download_file("my_tarball") {
#        url = "http://example.com/xyz.tar.gz"
#        output = "$root_gen_dir/MyModule/xyz.tar.gz"
#        version = "1.2.3"
#        version_file = "$root_gen_dir/MyModule/xyz_version.txt"
#    }
#

template("download_file") {
  assert(defined(invoker.url), "must set 'url' in $target_name")
  assert(defined(invoker.output), "must set 'output' in $target_name")
  assert(defined(invoker.version), "must set 'version' in $target_name")
  assert(defined(invoker.version_file),
         "must set 'version_file' in $target_name")

  action(target_name) {
    script = "//Meta/gn/build/download_file.py"

    sources = []
    if (defined(invoker.cache)) {
      outputs = [
        invoker.cache + "/" + invoker.output,
        invoker.cache + "/" + invoker.version_file,
      ]
    } else {
      outputs = [
        invoker.output,
        invoker.version_file,
      ]
    }
    args = [
      "-o",
      rebase_path(outputs[0], root_build_dir),
      "-f",
      rebase_path(outputs[1], root_build_dir),
      "-v",
      invoker.version,
      invoker.url,
    ]
    if (defined(invoker.cache)) {
      args += [
        "-c",
        rebase_path(invoker.cache, root_build_dir),
      ]
    }
    if (defined(invoker.sha256)) {
      args += [
        "-s",
        invoker.sha256,
      ]
    }

    forward_variables_from(invoker,
                           [
                             "configs",
                             "deps",
                             "public_configs",
                             "public_deps",
                             "testonly",
                             "visibility",
                           ])
  }
}