#include "bibtexparser.h"
bool	BibTeXFileInfo::loadIfModified(const QFileInfo& fi){
	QDateTime fileLastModified = fi.lastModified();
	if (lastModified!=fileLastModified) { //load BibTeX iff modified
		lastModified=fileLastModified;
		load(fi);
		return true;
	}
	return false;
}
void BibTeXFileInfo::load(const QFileInfo& fi){
	//lastModified=lastModified; see above
	QFile f(fi.absoluteFilePath());
	if (!f.open(QFile::ReadOnly)) return; //ups...
	QByteArray data=f.readAll().trimmed();
	parse(data);
}

void BibTeXFileInfo::parse(QByteArray& data){
	ids.clear();
	linksTo.clear();
	if (data.startsWith("link ")) {
		//handle obscure bib tex feature, a just line containing "link fileName"
        linksTo  = QString::fromLatin1(data.constData(),data.count()).mid(5).trimmed();
	} else {
		enum BibTeXState {BTS_IN_SPACE,  //searches the first @, ignore everything before it
						  BTS_IN_TYPE,   //read until bracket ( or { e.g in @article{, reset if @comment
						  BTS_IN_ID,     //read everything until bracket close or , and ignore whitespace, reset when = or "
						  BTS_IN_DATA_KEY}; //read balanced bracket until all are closed, then reset
		enum BibTeXState state=BTS_IN_SPACE;
		const char* comment="comment\0"; const char* COMMENT="COMMENT\0";
		int typeLen = 0;
		bool commentPossible = false;
		int bracketBalance = 0;
		char bracketOpen = 0;
		char bracketClose = 0;
		QString curID;
		for (int j=0; j<data.count(); j++){
			char c = data.at(j);
			switch (state) {
				case BTS_IN_SPACE:
					if (c=='@') {
						state=BTS_IN_TYPE;
						commentPossible=true;
						typeLen=0;
					}
					break;
				case BTS_IN_TYPE:
					if (c=='(' || c=='{') {
						bracketOpen=c;
						if (c=='(') bracketClose=')';
						if (c=='{') bracketClose='}';
						bracketBalance=1;
						curID="";
						state=BTS_IN_ID;
					} else if (commentPossible && (comment[typeLen]==c || COMMENT[typeLen]==c)) {
						if (comment[typeLen+1]=='\0') state=BTS_IN_SPACE; //comment found
					} else commentPossible=false;
					typeLen++;
					break;
				case BTS_IN_ID:
					if (c!=' '&& c!='\t' && c!='\n' && c!='\r') {
						if (c==',' || c==bracketClose) {
							if (!curID.isEmpty())
								ids.append(curID); //**found id**
							state=BTS_IN_DATA_KEY;
						} else if (c=='=' || c=='"')
							state=BTS_IN_DATA_KEY; //@string or @preamble (don't cite that)
						else curID+=c;
					}
					break;
				case BTS_IN_DATA_KEY:
					if (c==bracketOpen) bracketBalance++;
					else if (c==bracketClose) {
						bracketBalance--;
						if (bracketBalance<=0) state=BTS_IN_SPACE;
					}
					break;
			}
		}
	}
}
