/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is TransforMiiX XSLT processor.
 *
 * The Initial Developer of the Original Code is The MITRE Corporation.
 * Portions created by MITRE are Copyright (C) 1999 The MITRE Corporation.
 *
 * Portions created by Keith Visco as a Non MITRE employee,
 * (C) 1999 Keith Visco. All Rights Reserved.
 *
 * Contributor(s):
 * Keith Visco, kvisco@ziplink.net
 *   -- original author.
 *
 */

/**
 * StringFunctionCall
 * A representation of the XPath String funtions
**/

#include "FunctionLib.h"
#include "XMLUtils.h"
#include "XMLDOMUtils.h"
#include <math.h>

/**
 * Creates a StringFunctionCall of the given type
**/
StringFunctionCall::StringFunctionCall(short type) : FunctionCall() {
    this->type = type;
    switch ( type ) {
        case CONCAT:
            name = XPathNames::CONCAT_FN;
            break;
        case CONTAINS:
            name = XPathNames::CONTAINS_FN;
            break;
        case STARTS_WITH:
            name = XPathNames::STARTS_WITH_FN;
            break;
        case STRING_LENGTH:
            name = XPathNames::STRING_LENGTH_FN;
            break;
        case SUBSTRING:
            name = XPathNames::SUBSTRING_FN;
            break;
        case SUBSTRING_AFTER:
            name = XPathNames::SUBSTRING_AFTER_FN;
            break;
        case SUBSTRING_BEFORE:
            name = XPathNames::SUBSTRING_BEFORE_FN;
            break;
        case TRANSLATE:
            name = XPathNames::TRANSLATE_FN;
            break;
        default:
            name = XPathNames::STRING_FN;
            break;
    }
} //-- StringFunctionCall

/**
 * Evaluates this Expr based on the given context node and processor state
 * @param context the context node for evaluation of this Expr
 * @param ps the ContextState containing the stack information needed
 * for evaluation
 * @return the result of the evaluation
**/
ExprResult* StringFunctionCall::evaluate(Node* context, ContextState* cs) {
    ListIterator* iter = params.iterator();
    PRInt32 argc = params.getLength();
    String err;
    ExprResult* result = 0;
    switch ( type ) {
        case CONCAT :
            if ( requireParams(2, cs) ) {
                String resultStr;
                while(iter->hasNext()) {
                    evaluateToString((Expr*)iter->next(),context, cs, resultStr);
                }
                result  = new StringResult(resultStr);
            }
            else result = new StringResult("");
            break;
        case CONTAINS :
            if ( requireParams(2, 2, cs) ) {
                String arg1, arg2;
                evaluateToString((Expr*)iter->next(),context, cs, arg1);
                evaluateToString((Expr*)iter->next(),context, cs, arg2);
                result  = new BooleanResult((MBool)(arg1.indexOf(arg2) >= 0));
            }
            else result = new BooleanResult(MB_FALSE);
            break;

        case NORMALIZE_SPACE:
            if ( requireParams(0, 1, cs) ) {
                String resultStr;
                if ( argc == 1)
                    evaluateToString((Expr*)iter->next(),context, cs, resultStr);
                else
                    XMLDOMUtils::getNodeValue(context, &resultStr);
                // Leading & Trailing Whitespace
                resultStr.trim();
                MBool hasSpace = MB_FALSE;
                PRInt32 dest=0;
                String normed(resultStr.length());
                UNICODE_CHAR current;
                for (PRInt32 src=0; src<resultStr.length(); src++) {
                    current=resultStr.charAt(src);
                    if (current==' ' || current=='\n' ||
                            current=='\t' || current=='\r') {
                        if (!hasSpace) {
                            normed.replace(dest,' ');
                            dest++;
                            hasSpace=MB_TRUE;
                        }
                    }
                    else {
                        normed.replace(dest,current);
                        dest++;
                        hasSpace=MB_FALSE;
                    }
                }
                result  = new StringResult(normed);
            }
            else result = new StringResult("");
            break;
        case STARTS_WITH :
            if ( requireParams(2, 2, cs) ) {
                String arg1, arg2;
                evaluateToString((Expr*)iter->next(),context, cs, arg1);
                evaluateToString((Expr*)iter->next(),context, cs, arg2);
                result  = new BooleanResult((MBool)(arg1.indexOf(arg2) == 0));
            }
            else result = new BooleanResult(MB_FALSE);
            break;
        case STRING_LENGTH:
            if ( requireParams(0, 1, cs) ) {
                String resultStr;
                if ( argc == 1) {
                    evaluateToString((Expr*)iter->next(),context, cs, resultStr);
                }
                else XMLDOMUtils::getNodeValue(context, &resultStr);
                result  = new NumberResult( (double) resultStr.length());
            }
            else result = new NumberResult(0.0);
            break;
        case SUBSTRING:
            if ( requireParams(2, 3, cs) ) {
                String src;
                evaluateToString((Expr*)iter->next(),context, cs, src);
                double dbl = evaluateToNumber((Expr*)iter->next(), context, cs);

                //-- check for NaN
                if ( Double::isNaN(dbl)) {
                    result = new StringResult("");
                    break;
                }

                //-- check for -Infinity
                MBool startsNegInf = (dbl==Double::NEGATIVE_INFINITY);

                PRInt32 startIdx = startsNegInf?0:(PRInt32)floor(dbl+.5);
                PRInt32 endIdx = src.length()+1;
                if ( argc == 3) {
                    dbl = evaluateToNumber((Expr*)iter->next(),context, cs);
                    if (startsNegInf) {
                        result = new StringResult("");
                        break;
                    }
                    if (dbl == Double::POSITIVE_INFINITY) ; //already complete
                    else if ( Double::isNaN(dbl) || 
                              dbl == Double::NEGATIVE_INFINITY ||
                              dbl < 0 )
                        endIdx = 0;
                    else endIdx = startIdx+(PRInt32)floor(dbl+.5);
                }
                String resultStr;
                //-- strings are indexed starting at 1 for XSL
                //-- adjust to a 0-based index
                endIdx--;
                if (startIdx<1){
                    startIdx = 0;
                } else {
                    startIdx--;
                }

                src.subString(startIdx,endIdx,resultStr);
                result  = new StringResult(resultStr);
            }
            else result = new StringResult("");
            break;

        case SUBSTRING_AFTER:
            if ( requireParams(2, 2, cs) ) {
                String arg1, arg2;
                evaluateToString((Expr*)iter->next(),context, cs, arg1);
                evaluateToString((Expr*)iter->next(),context, cs, arg2);
                PRInt32 idx = arg1.indexOf(arg2);
                if ((idx >= 0)&&(idx<arg1.length())) {
                    PRInt32 len = arg2.length();
                    arg2.clear();
                    arg1.subString(idx+len,arg2);
                    result  = new StringResult(arg2);
                    break;
                }
            }
            result = new StringResult("");
            break;
        case SUBSTRING_BEFORE:
            if ( requireParams(2, 2, cs) ) {
                String arg1, arg2;
                evaluateToString((Expr*)iter->next(),context, cs, arg1);
                evaluateToString((Expr*)iter->next(),context, cs, arg2);
                PRInt32 idx = arg1.indexOf(arg2);
                if ((idx >= 0)&&(idx<arg1.length())) {
                    arg2.clear();
                    arg1.subString(0,idx,arg2);
                    result  = new StringResult(arg2);
                    break;
                }
            }
            result = new StringResult("");
            break;
        case TRANSLATE:
            if ( requireParams(3, 3, cs) ) {
                String src, oldChars, newChars;
                evaluateToString((Expr*)iter->next(),context, cs, src);
                evaluateToString((Expr*)iter->next(),context, cs, oldChars);
                evaluateToString((Expr*)iter->next(),context, cs, newChars);
                PRInt32 size = src.length();
                UNICODE_CHAR* chars = src.toUnicode(new UNICODE_CHAR[size]);
                src.clear();
                PRInt32 i;
                for (i = 0; i < size; i++) {
                    PRInt32 idx = oldChars.indexOf(chars[i]);
                    if (idx >= 0) {
                        if (idx<newChars.length())
                            src.append(newChars.charAt(idx));
                    }
                    else src.append(chars[i]);
                }
                delete chars;
                result = new StringResult(src);
            }
            else
                result = new StringResult("");
            break;

        default : //-- string( object? )
            if ( requireParams(0, 1, cs) ) {
                String resultStr;
                if (iter->hasNext()) {
                    evaluateToString((Expr*)iter->next(),context, cs, resultStr);
                }
                else {
                    XMLDOMUtils::getNodeValue(context, &resultStr);
                    if ( cs->isStripSpaceAllowed(context) &&
                         XMLUtils::shouldStripTextnode(resultStr))
                        resultStr = "";
                }
                result = new StringResult(resultStr);
            }
            else result = new StringResult("");
            break;
    }
    delete iter;
    return result;
} //-- evaluate