// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use driver::session::Session;
use syntax::codemap;
use syntax::ast;
use syntax::ast_util::*;
use syntax::attr;

export maybe_inject_libcore_ref;

fn maybe_inject_libcore_ref(sess: Session,
                            crate: @ast::crate) -> @ast::crate {
    if use_core(crate) {
        inject_libcore_ref(sess, crate)
    } else {
        crate
    }
}

fn use_core(crate: @ast::crate) -> bool {
    !attr::attrs_contains_name(crate.node.attrs, ~"no_core")
}

fn inject_libcore_ref(sess: Session,
                      crate: @ast::crate) -> @ast::crate {

    fn spanned<T: Copy>(x: T) -> @ast::spanned<T> {
        return @{node: x,
            span: dummy_sp()};
    }

    let n1 = sess.next_node_id();
    let n2 = sess.next_node_id();

    let vi1 = @{node: ast::view_item_use(sess.ident_of(~"core"), ~[], n1),
                attrs: ~[],
                vis: ast::private,
                span: dummy_sp()};
    let vp = spanned(ast::view_path_glob(
        ident_to_path(dummy_sp(), sess.ident_of(~"core")),
        n2));
    let vi2 = @{node: ast::view_item_import(~[vp]),
                attrs: ~[],
                vis: ast::private,
                span: dummy_sp()};

    let vis = vec::append(~[vi1, vi2], crate.node.module.view_items);

    return @{node: {module: { view_items: vis,.. crate.node.module },
                 .. crate.node},.. *crate }
}