#include <QtGui>

#include "highlighter.h"

Highlighter::Highlighter(QTextDocument *parent)
    : QSyntaxHighlighter(parent)
{
    HighlightingRule rule;

    keywordFormat.setForeground(Qt::darkBlue);
    keywordFormat.setFontWeight(QFont::Bold);
    QStringList keywordPatterns;
    QString keys="SELECT,FROM,WHERE,GROUP BY,ORDER BY,UNION,UNION ALL ALTER TABLE ADD DROP DELETE UPDATE COLUMN INSERT INTO";
    

    keywordPatterns= keys.toUpper().split(",");
    foreach (QString pattern, keywordPatterns) {
    	  pattern=pattern.trimmed();
        QString strPattern="\\b"+pattern.toUpper()+"\\b";
        rule.pattern = QRegExp(strPattern);
        rule.format = keywordFormat;
        highlightingRules.append(rule);
        strPattern="\\b"+pattern.toLower()+"\\b";
        rule.pattern = QRegExp(strPattern);
        rule.format = keywordFormat;
        highlightingRules.append(rule);
    }

    //classFormat.setFontWeight(QFont::Bold);
    classFormat.setForeground(Qt::darkMagenta);
    //rule.pattern = QRegExp("\\bQ[A-Za-z]+\\b");
    rule.pattern = QRegExp("\\b[0-9]+\\b");
    rule.format = classFormat;
    highlightingRules.append(rule);

    singleLineCommentFormat.setForeground(Qt::red);
    rule.pattern = QRegExp("--[^\n]*");
    rule.format = singleLineCommentFormat;
    highlightingRules.append(rule);

    multiLineCommentFormat.setForeground(Qt::red);

    quotationFormat.setForeground(Qt::magenta);
    rule.pattern = QRegExp("\".*\"");
    rule.format = quotationFormat;
//    highlightingRules.append(rule);

    rule.pattern = QRegExp("\'.*\'");
    rule.format = quotationFormat;
    //highlightingRules.append(rule);


    //functionFormat.setFontItalic(false);
    functionFormat.setForeground(Qt::blue);
    rule.pattern = QRegExp("\\b[A-Za-z0-9_]+(?=\\()");
    rule.format = functionFormat;
    highlightingRules.append(rule);


    commentStartExpression = QRegExp("/\\*");
    commentEndExpression = QRegExp("\\*/");
    
}

void Highlighter::highlightBlock(const QString &text)
{
    foreach (HighlightingRule rule, highlightingRules) {
        QRegExp expression(rule.pattern);
        int index = text.indexOf(expression);
        while (index >= 0) {
            int length = expression.matchedLength() ;
            setFormat(index, length, rule.format);
            index = text.indexOf(expression, index + length );
        }
    }
    setCurrentBlockState(0);

   int times=0;
   int length=0;
   int preIndex=0;
   int index=text.indexOf("\"");   
   while (index>=0)
   {
   	  times++;
   	  
   	  if(times%2==0)
   	  {
   	  	length=index-preIndex;
   	  	setFormat(preIndex, length+1, quotationFormat);
   	  }
   	  preIndex=index;
   	  index=text.indexOf("\"",index+1);
   }
   if(index==-1 && times%2)
   	 setFormat(preIndex, text.length()-preIndex, quotationFormat);


   times=0;
   preIndex=0;
   index=text.indexOf("\'");   
   while (index>=0)
   {
   	  times++;
   	  
   	  if(times%2==0)
   	  {
   	  	length=index-preIndex;
   	  	setFormat(preIndex, length+1, quotationFormat);
   	  }
   	  preIndex=index;
   	  index=text.indexOf("\'",index+1);
   }
   if(index==-1 && times%2)
   	setFormat(preIndex, text.length()-preIndex, quotationFormat);


    int startIndex = 0;
    if (previousBlockState() != 1)
        startIndex = text.indexOf(commentStartExpression);

    while (startIndex >= 0) {
        int endIndex = text.indexOf(commentEndExpression, startIndex);
        int commentLength;
        if (endIndex == -1) {
            setCurrentBlockState(1);
            commentLength = text.length() - startIndex;
        } else {
            commentLength = endIndex - startIndex
                            + commentEndExpression.matchedLength();
        }
        setFormat(startIndex, commentLength, multiLineCommentFormat);
        startIndex = text.indexOf(commentStartExpression,
                                                startIndex + commentLength);
    }
}