pub const IncludeDir = union(enum) {
    path: LazyPath,
    path_system: LazyPath,
    path_after: LazyPath,
    framework_path: LazyPath,
    framework_path_system: LazyPath,
    other_step: *Step.Compile,
    config_header_step: *Step.ConfigHeader,

    pub fn appendZigProcessFlags(
        include_dir: IncludeDir,
        b: *std.Build,
        zig_args: *std.ArrayList([]const u8),
        asking_step: ?*Step,
    ) !void {
        switch (include_dir) {
            .path => |include_path| {
                try zig_args.appendSlice(&.{ "-I", include_path.getPath2(b, asking_step) });
            },
            .path_system => |include_path| {
                try zig_args.appendSlice(&.{ "-isystem", include_path.getPath2(b, asking_step) });
            },
            .path_after => |include_path| {
                try zig_args.appendSlice(&.{ "-idirafter", include_path.getPath2(b, asking_step) });
            },
            .framework_path => |include_path| {
                try zig_args.appendSlice(&.{ "-F", include_path.getPath2(b, asking_step) });
            },
            .framework_path_system => |include_path| {
                try zig_args.appendSlice(&.{ "-iframework", include_path.getPath2(b, asking_step) });
            },
            .other_step => |other| {
                if (other.generated_h) |header| {
                    try zig_args.appendSlice(&.{ "-isystem", std.fs.path.dirname(header.getPath()).? });
                }
                if (other.installed_headers_include_tree) |include_tree| {
                    try zig_args.appendSlice(&.{ "-I", include_tree.generated_directory.getPath() });
                }
            },
            .config_header_step => |config_header| {
                const full_file_path = config_header.output_file.getPath();
                const header_dir_path = full_file_path[0 .. full_file_path.len - config_header.include_path.len];
                try zig_args.appendSlice(&.{ "-I", header_dir_path });
            },
        }
    }
}