/*========================================================================
        Copyright (C) 2006 by Geir-Tore Lindsve, Torbjørn Meistad 
        and Yngve Raudberget, hereby refered to as "the authors".
                        All rights reserved

    Permission is hereby granted, without written agreement and without
    license or royalty fees, to use, reproduce, prepare derivative
    works, distribute, and display this software and its documentation
    for NONCOMMERCIAL RESEARCH AND EDUCATIONAL PURPOSES, provided 
    that (1) the above copyright notice and the following two paragraphs 
    appear in all copies of the source code and (2) redistributions, 
    including without limitation binaries, reproduce these notices in 
    the supporting documentation. 

    IN NO EVENT SHALL THE AUTHORS, OR DISTRIBUTORS OF THIS SOFTWARE 
    BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, 
    OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE 
    AND ITS DOCUMENTATION, EVEN IF THE AUTHORS OR ANY OF THE ABOVE 
    PARTIES HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    THE AUTHORS SPECIFICALLY DISCLAIM ANY WARRANTIES, INCLUDING,
    BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
    FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
    ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE NO
    OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
    MODIFICATIONS.
========================================================================*/

using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;

using Iesi.Collections;

using CLab.Data;
using CLab.Exceptions;

using Casper.Data;
using Casper;

namespace CLab.CSP
{
    /// <summary>
    /// Class for making Casper's CSP representation of the expressions. 
    /// <see cref="T:Casper.Data.CSPExpr"></see>.
    /// </summary>
    public class CSPExpressionBuilder
    {
        private CP cp;
        private CSPLayout layout;
        private CSPExpressions cspExpressions;
        private Symbols symbols;
        private Set variableSet;
        private ConstraintGraph constraintGraph;


        /// <summary>
        /// Initializes a new instance of the <see cref="T:CSPExpressionBuilder"/> class.
        /// </summary>
        /// <param name="layout">The <see cref="T:Casper.CSP"></see> layout.</param>
        /// <param name="cp">The <see cref="T:CLab.Data.CP"></see> instance for this problem.</param>
        /// <param name="symbols">The <see cref="T:CLab.Data.Symbols"></see> instance for this problem.</param>
        public CSPExpressionBuilder(CSPLayout layout, CP cp, Symbols symbols)
        {
            this.layout = layout;
            this.cp = cp;
            this.symbols = symbols;
            cspExpressions = new CSPExpressions();
            constraintGraph = new ConstraintGraph();
        }

        /// <summary>
        /// Gets the constraint graph.
        /// </summary>
        internal ConstraintGraph ConstraintGraph
        {
            get { return constraintGraph; }
        }

        /// <summary>
        /// Gets the CSP expressions.
        /// </summary>
        public CSPExpressions CSPExpressions
        {
            get { return cspExpressions; }
        }

        /// <summary>
        /// Builds the CSP expr for an <see cref="T:CLab.Data.ExpressionId"></see> expression.
        /// </summary>
        /// <param name="idexpr">The <see cref="T:CLab.Data.ExpressionId"></see> expression.</param>
        /// <returns>A <see cref="Casper.Data.CSPExpr"></see></returns>
        /// <exception cref="CLab.Exceptions.ClabInternalErrorException"/>
        public CSPExpr BuildCSPExpr(ExpressionId idexpr)
        {
            int variableID = (int)layout.CpVarToVarID[idexpr.Id];

            if (symbols.RangeVariables.Contains(idexpr.Id.ToLower()))
            {
                variableSet.Add(variableID);
                return new CSPExprVarInt(variableID);
            }
            else if (symbols.BoolVariables.Contains(idexpr.Id.ToLower()))
            {
                variableSet.Add(variableID);
                return new CSPExprVarBool(variableID);
            }
            else throw new ClabInternalErrorException("Unknown variable type");
        }

        /// <summary>
        /// Builds the CSP expr for an <see cref="T:CLab.Data.ExpressionInt"></see> expression.
        /// </summary>
        /// <param name="iExpr">The <see cref="T:CLab.Data.ExpressionInt"></see> expression.</param>
        /// <returns>A <see cref="Casper.Data.CSPExpr"></see></returns>
        public CSPExpr BuildCSPExpr(ExpressionInt iExpr)
        {
            return new CSPExprValueInt(iExpr.IntegerValue); 
        }

        /// <summary>
        /// Builds the CSP expr for an <see cref="T:CLab.Data.ExpressionNotNeg"></see> expression.
        /// </summary>
        /// <param name="nnExpr">The <see cref="T:CLab.Data.ExpressionNotNeg"></see> expression.</param>
        /// <returns>A <see cref="Casper.Data.CSPExpr"></see></returns>
        /// <exception cref="CLab.Exceptions.ClabInternalErrorException"/>
        public CSPExpr BuildCSPExpr(ExpressionNotNeg nnExpr)
        {
            CSPExpr resLeft = nnExpr.Left.RunCSPBuildExpr(this);
            if (nnExpr.Type.Equals(Common.ExprType.et_neg)) return new CSPExprNeg(resLeft);
            else if (nnExpr.Type.Equals(Common.ExprType.et_not)) return new CSPExprNot(resLeft);
            else throw new ClabInternalErrorException("Unknown notneg type");
        }

        /// <summary>
        /// Builds the CSP expr for an <see cref="T:CLab.Data.ExpressionBinary"></see> expression.
        /// </summary>
        /// <param name="bExpr">The <see cref="T:CLab.Data.ExpressionBinary"></see> expression.</param>
        /// <returns>A <see cref="Casper.Data.CSPExpr"></see></returns>
        public CSPExpr BuildCSPExpr(ExpressionBinary bExpr)
        {
            CSPExpr resLeft;
            CSPExpr resRight;

            if ((bExpr.Type.Equals(Common.ExprType.et_eq) || bExpr.Type.Equals(Common.ExprType.et_ne)) && (bExpr.Left.Type.Equals(Common.ExprType.et_id) && bExpr.Right.Type.Equals(Common.ExprType.et_id)))
            {
                ExpressionId idLeft = (ExpressionId)bExpr.Left;
                ExpressionId idRight = (ExpressionId)bExpr.Right;
                String var = "";
                String constant = "";
                Boolean varconst = false;
                if (symbols.EnumerationVariables.Contains(idLeft.Id.ToLower()))
                {
                    var = idLeft.Id;
                    constant = idRight.Id;
                    varconst = true;
                }
                else if (symbols.EnumerationVariables.Contains(idRight.Id.ToLower()))
                {
                    var = idRight.Id;
                    constant = idLeft.Id;
                    varconst = true;
                }

                if (varconst)
                {
                    int varID = (int)layout.CpVarToVarID[var];
                    int typeIndex = (int)layout.TypeNameToIndex[layout.VarIDToTypeName[varID]];
                    CSPTypeEnum te = (CSPTypeEnum)layout.Types[typeIndex];
                    int constantID = te.GetIntRepOfDomainString(constant);
                    resLeft = new CSPExprVarEnum(varID);
                    resRight = new CSPExprValueConst(constantID);
                    variableSet.Add(varID);
                }
                else
                {
                    resLeft = bExpr.Left.RunCSPBuildExpr(this);
                    resRight = bExpr.Right.RunCSPBuildExpr(this);
                }
            }
            else
            {
                resLeft = bExpr.Left.RunCSPBuildExpr(this);
                resRight = bExpr.Right.RunCSPBuildExpr(this);
            }
            StaticData.Operators oper = ConvertOperator(bExpr.Type);
            return new CSPExprBin(resLeft, resRight, oper);
        }

        /// <summary>
        /// Builds csp expressions of all clab expressions defined in the <see cref="T:CLab.Data.CP"/> instance.
        /// Also updates the Constraint graph of the problem.
        /// </summary>
        /// <returns><see cref="T:Casper.Data.CSPExpressions"> instance with all CSP expressions.</see></returns>
        /// <exception cref="CLab.Exceptions.ClabInternalErrorException"/>
        public CSPExpressions BuildCSPExpressions()
        {
            List<Expression> expressions = cp.Rules;
            for (int i = 0; i < expressions.Count; i++)
            {
                this.variableSet = new HybridSet();
                
                try
                {
                    CSPExpr exp = expressions[i].RunCSPBuildExpr(this);
                    ConstraintGraph.UpdateAdjacencyList(this.variableSet);
                    CSPExprWrapper wrapper = new CSPExprWrapper(exp, variableSet);
                    cspExpressions.AddWrappedExpr(wrapper);
                }
                catch (ClabInternalErrorException) { throw; }
            }
            for (int i = 0; i < cp.Variables.Count; i++)
            {
                int varID = (int) layout.CpVarToVarID[cp.Variables[i].VariableName];
                if (ConstraintGraph.CGraph[varID] == null)
                {
                    ConstraintGraph.CGraph[varID] = new AdjacencyList();
                }
            }
            return cspExpressions;
        }

        /// <summary>
        /// Builds a csp expression out of the passed in clab expression.
        /// Updates the constraint graph with new data from the current expression.
        /// </summary>
        /// <param name="expr">The clab expression.</param>
        /// <returns>The csp expression inside a <see cref="T:Casper.Data.CSPExprWrapper"></see> object.</returns>
        /// <exception cref="CLab.Exceptions.ClabInternalErrorException"/>
        public CSPExprWrapper BuildCSPExpression(Expression expr)
        {
            this.variableSet = new HybridSet();
            try
            {
                CSPExpr cspExp = expr.RunCSPBuildExpr(this);
                ConstraintGraph.UpdateAdjacencyList(this.variableSet);
                CSPExprWrapper wrapper = new CSPExprWrapper(cspExp, variableSet);
                return wrapper;
            }
            catch (ClabInternalErrorException) { throw; }
        }

        /// <summary>
        /// Converts a clab operator to a Casper operator. <see cref="F:Casper.StaticData.Operators"></see>.
        /// </summary>
        /// <param name="input">The input.</param>
        /// <returns></returns>
        public StaticData.Operators ConvertOperator(Common.ExprType input) 
        {
            if (input.Equals(Common.ExprType.et_and)) return StaticData.Operators.and;
            else if (input.Equals(Common.ExprType.et_div)) return StaticData.Operators.div;
            else if (input.Equals(Common.ExprType.et_eq)) return StaticData.Operators.eq;
            else if (input.Equals(Common.ExprType.et_gt)) return StaticData.Operators.gt;
            else if (input.Equals(Common.ExprType.et_gte)) return StaticData.Operators.gte;
            else if (input.Equals(Common.ExprType.et_impl)) return StaticData.Operators.impl;
            else if (input.Equals(Common.ExprType.et_lt)) return StaticData.Operators.lt;
            else if (input.Equals(Common.ExprType.et_lte)) return StaticData.Operators.lte;
            else if (input.Equals(Common.ExprType.et_minus)) return StaticData.Operators.minus;
            else if (input.Equals(Common.ExprType.et_mod)) return StaticData.Operators.mod;
            else if (input.Equals(Common.ExprType.et_ne)) return StaticData.Operators.ne;
            else if (input.Equals(Common.ExprType.et_or)) return StaticData.Operators.or;
            else if (input.Equals(Common.ExprType.et_plus)) return StaticData.Operators.plus;
            else return StaticData.Operators.times;
        }
    }
}