import core::{vec, str, int, option};
import option::{none, some};
import middle::ty;
import middle::ty::*;
import metadata::encoder;
import syntax::print::pprust;
import syntax::print::pprust::{path_to_str, constr_args_to_str, proto_to_str};
import syntax::{ast, ast_util};
import middle::ast_map;

fn mode_str(m: ty::mode) -> str {
    alt m {
      ast::by_ref. { "&&" }
      ast::by_val. { "++" }
      ast::by_mut_ref. { "&" }
      ast::by_move. { "-" }
      ast::by_copy. { "+" }
      _ { "" }
    }
}

fn ty_to_str(cx: ctxt, typ: t) -> str {
    fn fn_input_to_str(cx: ctxt, input: {mode: middle::ty::mode, ty: t}) ->
       str {
        let s = mode_str(input.mode);
        ret s + ty_to_str(cx, input.ty);
    }
    fn fn_to_str(cx: ctxt, proto: ast::proto, ident: option::t<ast::ident>,
                 inputs: [arg], output: t, cf: ast::ret_style,
                 constrs: [@constr]) -> str {
        let s = proto_to_str(proto);
        alt ident { some(i) { s += " "; s += i; } _ { } }
        s += "(";
        let strs = [];
        for a: arg in inputs { strs += [fn_input_to_str(cx, a)]; }
        s += str::connect(strs, ", ");
        s += ")";
        if struct(cx, output) != ty_nil {
            s += " -> ";
            alt cf {
              ast::noreturn. { s += "!"; }
              ast::return_val. { s += ty_to_str(cx, output); }
            }
        }
        s += constrs_str(constrs);
        ret s;
    }
    fn method_to_str(cx: ctxt, m: method) -> str {
        ret fn_to_str(cx, m.fty.proto, some(m.ident), m.fty.inputs,
                      m.fty.output, m.fty.ret_style, m.fty.constraints) + ";";
    }
    fn field_to_str(cx: ctxt, f: field) -> str {
        ret f.ident + ": " + mt_to_str(cx, f.mt);
    }
    fn mt_to_str(cx: ctxt, m: mt) -> str {
        let mstr;
        alt m.mut {
          ast::mut. { mstr = "mutable "; }
          ast::imm. { mstr = ""; }
          ast::maybe_mut. { mstr = "const "; }
        }
        ret mstr + ty_to_str(cx, m.ty);
    }
    alt ty_name(cx, typ) {
      some(cs) {
        alt struct(cx, typ) {
          ty_tag(_, tps) | ty_res(_, _, tps) {
            if vec::len(tps) > 0u {
                let strs = vec::map(tps, {|t| ty_to_str(cx, t)});
                ret *cs + "<" + str::connect(strs, ",") + ">";
            }
          }
          _ {}
        }
        ret *cs;
      }
      _ { }
    }
    ret alt struct(cx, typ) {
      ty_native(_) { "native" }
      ty_nil. { "()" }
      ty_bot. { "_|_" }
      ty_bool. { "bool" }
      ty_int(ast::ty_i.) { "int" }
      ty_int(ast::ty_char.) { "char" }
      ty_int(t) { ast_util::int_ty_to_str(t) }
      ty_uint(ast::ty_u.) { "uint" }
      ty_uint(t) { ast_util::uint_ty_to_str(t) }
      ty_float(ast::ty_f.) { "float" }
      ty_float(t) { ast_util::float_ty_to_str(t) }
      ty_str. { "str" }
      ty_box(tm) { "@" + mt_to_str(cx, tm) }
      ty_uniq(tm) { "~" + mt_to_str(cx, tm) }
      ty_ptr(tm) { "*" + mt_to_str(cx, tm) }
      ty_vec(tm) { "[" + mt_to_str(cx, tm) + "]" }
      ty_type. { "type" }
      ty_rec(elems) {
        let strs: [str] = [];
        for fld: field in elems { strs += [field_to_str(cx, fld)]; }
        "{" + str::connect(strs, ",") + "}"
      }
      ty_tup(elems) {
        let strs = [];
        for elem in elems { strs += [ty_to_str(cx, elem)]; }
        "(" + str::connect(strs, ",") + ")"
      }
      ty_fn(f) {
        fn_to_str(cx, f.proto, none, f.inputs, f.output, f.ret_style,
                  f.constraints)
      }
      ty_native_fn(inputs, output) {
        fn_to_str(cx, ast::proto_bare, none, inputs, output,
                  ast::return_val, [])
      }
      ty_var(v) { "<T" + int::str(v) + ">" }
      ty_param(id, _) {
        "'" + str::unsafe_from_bytes([('a' as u8) + (id as u8)])
      }
      _ { ty_to_short_str(cx, typ) }
    }
}

fn ty_to_short_str(cx: ctxt, typ: t) -> str {
    let s = encoder::encoded_ty(cx, typ);
    if str::byte_len(s) >= 32u { s = str::substr(s, 0u, 32u); }
    ret s;
}

fn constr_to_str(c: @constr) -> str {
    ret path_to_str(c.node.path) +
            pprust::constr_args_to_str(pprust::uint_to_str, c.node.args);
}

fn constrs_str(constrs: [@constr]) -> str {
    let s = "";
    let colon = true;
    for c: @constr in constrs {
        if colon { s += " : "; colon = false; } else { s += ", "; }
        s += constr_to_str(c);
    }
    ret s;
}

fn ty_constr_to_str<Q>(c: @ast::spanned<ast::constr_general_<@ast::path, Q>>)
   -> str {
    ret path_to_str(c.node.path) +
            constr_args_to_str::<@ast::path>(path_to_str, c.node.args);
}

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