import option;
import std::smallintmap;
import syntax::ast::*;
import syntax::ast_util;
import syntax::{visit, codemap};

tag ast_node {
    node_item(@item);
    node_obj_ctor(@item);
    node_obj_method(@method);
    node_native_item(@native_item);
    node_method(@method);
    node_expr(@expr);
    // Locals are numbered, because the alias analysis needs to know in which
    // order they are introduced.
    node_arg(arg, uint);
    node_local(uint);
    node_res_ctor(@item);
}

type map = std::map::hashmap<node_id, ast_node>;
type ctx = @{map: map, mutable local_id: uint};

fn map_crate(c: crate) -> map {
    // FIXME: This is using an adapter to convert the smallintmap
    // interface to the hashmap interface. It would be better to just
    // convert everything to use the smallintmap.
    let cx = @{map: new_smallintmap_int_adapter::<ast_node>(),
               mutable local_id: 0u};

    let v_map = visit::mk_simple_visitor
        (@{visit_item: bind map_item(cx, _),
           visit_native_item: bind map_native_item(cx, _),
           visit_expr: bind map_expr(cx, _),
           visit_fn: bind map_fn(cx, _, _, _, _, _),
           visit_local: bind map_local(cx, _),
           visit_arm: bind map_arm(cx, _)
           with *visit::default_simple_visitor()});
    visit::visit_crate(c, (), v_map);
    ret cx.map;
}

fn map_fn(cx: ctx, _fk: visit::fn_kind, decl: fn_decl, _body: blk,
          _sp: codemap::span, _id: node_id) {
    for a in decl.inputs {
        cx.map.insert(a.id, node_arg(a, cx.local_id));
        cx.local_id += 1u;
    }
}

fn map_local(cx: ctx, loc: @local) {
    ast_util::pat_bindings(loc.node.pat) {|p|
        cx.map.insert(p.id, node_local(cx.local_id));
        cx.local_id += 1u;
    };
}

fn map_arm(cx: ctx, arm: arm) {
    ast_util::pat_bindings(arm.pats[0]) {|p|
        cx.map.insert(p.id, node_local(cx.local_id));
        cx.local_id += 1u;
    };
}

fn map_item(cx: ctx, i: @item) {
    cx.map.insert(i.id, node_item(i));
    alt i.node {
      item_obj(ob, _, ctor_id) {
        cx.map.insert(ctor_id, node_obj_ctor(i));
        for m in ob.methods {
            cx.map.insert(m.id, node_obj_method(m));
        }
      }
      item_impl(_, _, _, ms) {
        for m in ms { cx.map.insert(m.id, node_method(m)); }
      }
      item_res(_, _, _, dtor_id, ctor_id) {
        cx.map.insert(ctor_id, node_res_ctor(i));
        cx.map.insert(dtor_id, node_item(i));
      }
      _ { }
    }
}

fn map_native_item(cx: ctx, i: @native_item) {
    cx.map.insert(i.id, node_native_item(i));
}

fn map_expr(cx: ctx, ex: @expr) {
    cx.map.insert(ex.id, node_expr(ex));
    alt ex.node {
      expr_anon_obj(ao) {
        for m in ao.methods {
            cx.map.insert(m.id, node_obj_method(m));
        }
      }
      _ {}
    }
}

fn new_smallintmap_int_adapter<copy V>() -> std::map::hashmap<int, V> {
    let key_idx = fn (&&key: int) -> uint { key as uint };
    let idx_key = fn (idx: uint) -> int { idx as int };
    ret new_smallintmap_adapter(key_idx, idx_key);
}

// This creates an object with the hashmap interface backed
// by the smallintmap type, because I don't want to go through
// the entire codebase adapting all the callsites to the different
// interface.
// FIXME: hashmap and smallintmap should support the same interface.
fn new_smallintmap_adapter<copy K, copy V>(key_idx: fn(K) -> uint,
                                           idx_key: fn(uint) -> K)
    -> std::map::hashmap<K, V> {

    obj adapter<copy K, copy V>(map: smallintmap::smallintmap<V>,
                                key_idx: fn(K) -> uint,
                                idx_key: fn(uint) -> K) {

        fn size() -> uint { fail }

        fn insert(key: K, value: V) -> bool {
            let exists = smallintmap::contains_key(map, key_idx(key));
            smallintmap::insert(map, key_idx(key), value);
            ret !exists;
        }

        fn contains_key(key: K) -> bool {
            ret smallintmap::contains_key(map, key_idx(key));
        }

        fn get(key: K) -> V { ret smallintmap::get(map, key_idx(key)); }

        fn find(key: K) -> option::t<V> {
            ret smallintmap::find(map, key_idx(key));
        }

        fn remove(_key: K) -> option::t<V> { fail }

        fn rehash() { fail }

        fn items(it: block(K, V)) {
            let idx = 0u;
            for item in map.v {
                alt item {
                  option::some(elt) {
                    it(idx_key(idx), elt);
                  }
                  option::none. { }
                }
                idx += 1u;
            }
        }
        fn keys(it: block(K)) {
            let idx = 0u;
            for item in map.v {
                if item != option::none { it(idx_key(idx)); }
                idx += 1u;
            }
        }
        fn values(it: block(V)) {
            for item in map.v {
                alt item { option::some(elt) { it(elt); } _ {} }
            }
        }
    }

    let map = smallintmap::mk::<V>();
    ret adapter(map, key_idx, idx_key);
}

fn node_span(node: ast_node) -> codemap::span {
    alt node {
      node_item(item) { item.span }
      node_obj_ctor(item) { item.span }
      node_native_item(nitem) { nitem.span }
      node_expr(expr) { expr.span }
    }
}

#[cfg(test)]
mod test {
    import syntax::ast_util;

    #[test]
    fn test_node_span_item() {
        let expected: codemap::span = ast_util::mk_sp(20u, 30u);
        let node =
            node_item(@{ident: "test",
                        attrs: [],
                        id: 0,
                        node: item_mod({view_items: [], items: []}),
                        span: expected});
        assert (node_span(node) == expected);
    }

    #[test]
    fn test_node_span_obj_ctor() {
        let expected: codemap::span = ast_util::mk_sp(20u, 30u);
        let node =
            node_obj_ctor(@{ident: "test",
                            attrs: [],
                            id: 0,
                            node: item_mod({view_items: [], items: []}),
                            span: expected});
        assert (node_span(node) == expected);
    }

    #[test]
    fn test_node_span_native_item() {
        let expected: codemap::span = ast_util::mk_sp(20u, 30u);
        let node =
            node_native_item(@{ident: "test",
                               attrs: [],
                               node: native_item_ty,
                               id: 0,
                               span: expected});
        assert (node_span(node) == expected);
    }

    #[test]
    fn test_node_span_expr() {
        let expected: codemap::span = ast_util::mk_sp(20u, 30u);
        let node = node_expr(@{id: 0, node: expr_break, span: expected});
        assert (node_span(node) == expected);
    }
}

// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End: