#include <QRegularExpression>
#include <QDebug>
#include <QSqlError>
#include <QStack>
#include "searchworker.h"
#include "../shared/sqlitesearch.h"
SearchWorker::SearchWorker()
{
}
SearchWorker::SearchWorker(const QString &dbpath)
{
	db = QSqlDatabase::addDatabase("QSQLITE");
	db.setDatabaseName(dbpath);
	if(!db.open())
	{
		qDebug() << "failed to open database";
	}
}

QVector<SearchWorker::Command> SearchWorker::tokenize(QString expression)
{
	if(!checkParanthesis(expression))
	{
		throw std::invalid_argument("Invalid paranthesis");
	}
	// TODO: merge lonewords
	QVector<Command> result;
	QRegularExpression rx("((?<filtername>(\\.|\\w)+):(?<args>\\((?<innerargs>[^\\)]+)\\)|(\\w)+)|(?<boolean>AND|OR|!)|"
						  "(?<bracket>\\(|\\))|(?<loneword>\\w+))");
	QRegularExpressionMatchIterator i = rx.globalMatch(expression);
	bool wasbool = true;
	while(i.hasNext())
	{
		QRegularExpressionMatch m = i.next();
		QString boolean = m.captured("boolean");
		QString filtername = m.captured("filtername");
		QString bracket = m.captured("bracket");
		QString loneword = m.captured("loneword");
		if(boolean != "")
		{
			/* if(wasbool)
			 {
				 throw new std::runtime_error("Bool after Bool is invalid");
			 }*/
			wasbool = true;
			result.append(Command(boolean));
		}

		if(bracket != "")
		{
			if(!wasbool)
			{
				if(bracket == "(")
				{
					result.append(Command("AND"));
				}
			}
			result.append(Command(bracket));
		}

		if(loneword != "")
		{
			if(!wasbool)
			{
				result.append(Command("AND"));
			}
			wasbool = false;
			result.append(Command("path.contains", loneword));
		}
		if(filtername != "")
		{
			if(!wasbool)
			{
				result.append(Command("AND"));
			}
			wasbool = false;
			QString value = m.captured("innerargs");
			if(value == "")
				value = m.captured("args");
			result.append(Command(filtername, value));
		}
	}
	return result;
}

QString SearchWorker::createSql(const SearchWorker::Command &cmd)
{
	QString key = cmd.key;
	QString value = cmd.value;
	value = value.replace("'", "\\'");
	if(key == "AND" || key == "OR" || key == "(" || key == ")")
	{
		return " " + key + " ";
	}
	if(key == "!")
	{
		return " NOT ";
	}
	if(key == "path.starts")
	{
		return " file.path LIKE '" + value + "%' ";
	}
	if(key == "path.ends")
	{
		return " file.path LIKE '%" + value + "' ";
	}
	if(key == "path.contains" || key == "inpath")
	{
		return " file.path LIKE '%" + value + "%' ";
	}
	if(key == "page")
	{
		return " content.page = " + value;
	}
	if(key == "contains" || key == "c")
	{
		return " content.id IN (SELECT content_fts.ROWID FROM content_fts WHERE content_fts.content MATCH '" + value +
			   "' )";
	}

	throw std::invalid_argument("Unknown filter: " + key.toStdString());
}

QString SearchWorker::makeSql(const QVector<SearchWorker::Command> &tokens)
{
	QString result;
	for(const Command &c : tokens)
	{
		result += createSql(c);
	}
	return result;
}

bool SearchWorker::checkParanthesis(QString expression)
{
	QStack<QChar> open;
	QStack<QChar> close;

	for(QChar &c : expression)
	{
		if(c == '(')
		{
			open.push(c);
		}
		if(c == ')')
		{
			close.push(c);
		}
	}
	if(open.size() != close.size())
	{
		return false;
	}
	while(!open.empty() && !close.empty())
	{
		QChar o = open.pop();
		QChar c = close.pop();
		if(o != '(' && c != ')')
		{
			return false;
		}
	}
	return true;
}

void SearchWorker::search(const QString &query)
{
	SqliteSearch searcher(db);
	emit searchResultsReady(searcher.search(query));
}