def _generate_devtools_impl(ctx):
    outdir = ctx.actions.declare_directory("{}".format(ctx.attr.out))
    settings_template_file = ctx.actions.declare_file("generator_settings_{}.json".format(ctx.attr.protocol_version))

    ctx.actions.expand_template(
        template = ctx.attr._generator_settings_template.files.to_list()[0],
        output = settings_template_file,
        substitutions = {
            "{DEVTOOLS_VERSION}": ctx.attr.protocol_version.upper(),
        },
    )

    template_files = []
    for template_file in ctx.attr.templates:
        template_files.append(template_file.files.to_list()[0])

    args = ctx.actions.args()
    args.add_all("-s", [settings_template_file])
    args.add_all("-b", [ctx.attr.browser_protocol.files.to_list()[0]])
    args.add_all("-j", [ctx.attr.js_protocol.files.to_list()[0]])
    args.add_all("-t", [template_files[0]])
    args.add("-q")
    args.add_all("-o", [outdir.path])

    ctx.actions.run(
        executable = ctx.executable.generator,
        progress_message = "Generating {} DevTools Protocol bindings for .NET".format(ctx.attr.out),
        arguments = [args],
        outputs = [
            outdir,
        ],
        inputs = [
            settings_template_file,
            ctx.file.browser_protocol,
            ctx.file.js_protocol,
        ] + template_files,
    )

    return DefaultInfo(files = depset([
        outdir,
    ]))

generate_devtools = rule(
    implementation = _generate_devtools_impl,
    attrs = {
        "protocol_version": attr.string(
            mandatory = True,
            default = "",
        ),
        "browser_protocol": attr.label(
            allow_single_file = True,
        ),
        "js_protocol": attr.label(
            allow_single_file = True,
        ),
        "templates": attr.label_list(
            allow_files = True,
        ),
        "out": attr.string(
            doc = "File name, without extension, of the built assembly.",
        ),
        "generator": attr.label(
            default = Label("//third_party/dotnet/devtools/src/generator:generator"),
            executable = True,
            cfg = "exec",
        ),
        "deps": attr.label_list(),
        "_generator_settings_template": attr.label(
            default = Label("//third_party/dotnet/devtools:generator_settings_template.json"),
            allow_single_file = True,
        ),
    },
)