/*
 * [The "BSD license"]
 * Copyright (c) 2011 Terence Parr
 * All rights reserved.
 *
 * Conversion to C#:
 * Copyright (c) 2011 Sam Harwell, Pixel Mine, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

namespace Antlr3.Runtime.Test.BuildOptions
{
    using System.Collections.Generic;
    using Antlr.Runtime.Tree;

    using BigInteger = System.Numerics.BigInteger;
    using Console = System.Console;

    partial class DebugTreeGrammar
    {
        /** Points to functions tracked by tree builder. */
        private List<CommonTree> functionDefinitions;

        /** Remember local variables. Currently, this is only the function parameter.
         */
        private readonly IDictionary<string, BigInteger> localMemory = new Dictionary<string, BigInteger>();

        /** Remember global variables set by =. */
        private IDictionary<string, BigInteger> globalMemory = new Dictionary<string, BigInteger>();

        /** Set up an evaluator with a node stream; and a set of function definition ASTs. */
        public DebugTreeGrammar(CommonTreeNodeStream nodes, List<CommonTree> functionDefinitions)
            : this(nodes)
        {
            this.functionDefinitions = functionDefinitions;
        }

        /** Set up a local evaluator for a nested function call. The evaluator gets the definition
         *  tree of the function; the set of all defined functions (to find locally called ones); a
         *  pointer to the global variable memory; and the value of the function parameter to be
         *  added to the local memory.
         */
        private DebugTreeGrammar(CommonTree function,
                     List<CommonTree> functionDefinitions,
                     IDictionary<string, BigInteger> globalMemory,
                     BigInteger paramValue)
            // Expected tree for function: ^(FUNC ID ( INT | ID ) expr)
            : this(new CommonTreeNodeStream(function.GetChild(2)), functionDefinitions)
        {
            this.globalMemory = globalMemory;
            localMemory[function.GetChild(1).Text] = paramValue;
        }

        /** Find matching function definition for a function name and parameter
         *  value. The first definition is returned where (a) the name matches
         *  and (b) the formal parameter agrees if it is defined as constant.
         */
        private CommonTree findFunction(string name, BigInteger paramValue)
        {
            foreach (CommonTree f in functionDefinitions)
            {
                // Expected tree for f: ^(FUNC ID (ID | INT) expr)
                if (f.GetChild(0).Text.Equals(name))
                {
                    // Check whether parameter matches
                    CommonTree formalPar = (CommonTree)f.GetChild(1);
                    if (formalPar.Token.Type == INT
                        && !BigInteger.Parse(formalPar.Token.Text).Equals(paramValue))
                    {
                        // Constant in formalPar list does not match actual value -> no match.
                        continue;
                    }
                    // Parameter (value for INT formal arg) as well as fct name agrees!
                    return f;
                }
            }
            return null;
        }

        /** Get value of name up call stack. */
        internal BigInteger getValue(string name)
        {
            BigInteger value;
            if (localMemory.TryGetValue(name, out value) && value != null)
            {
                return value;
            }
            if (globalMemory.TryGetValue(name, out value) && value != null)
            {
                return value;
            }
            // not found in local memory or global memory
            Console.Error.WriteLine("undefined variable " + name);
            return BigInteger.Zero;
        }
    }
}