planner.cpp

#include <qapplication.h>
#include <QSqlDatabase>
#include <QSqlQuery>
#include <QSqlRecord>
#include <QSqlError>
#include <qfile.h>
#include <QtDebug>
#include <string>

#include "course.h"
#include "plannerview.h"

Course	*readCourse		(QSqlRecord course_cursor);
NumVect	*getSemesters	(QString number);
void	addDependencies (Course *course, CourseVect available);

int main(int argc, char **argv) {
	QApplication app(argc, argv);
	QString app_called_as(argv[0]);
	CourseVect	courses;
        
	// Decide on a DB name.
	QString dbname("courses3.db");
	if (argc > 1) {
		dbname = argv[1];
	}

	// Check if the db file exists, else abort.
	if ( ! QFile::exists(dbname) ) {
		qWarning() << app_called_as << ": " << dbname <<
			"does not exist. Aborting.";
		return FALSE;
	}
	
	// Open the Database or abort:
	auto courseDB = QSqlDatabase::addDatabase("QSQLITE");
	courseDB.setDatabaseName(dbname);
	
	if ( ! courseDB.open() ) {
		qWarning() << "Failed to open database" << dbname << ":  " 
			<< courseDB.lastError().text();
		return FALSE;
	}
	
	// Read courses and create their objects:
	auto course_cursor = QSqlQuery("SELECT * FROM courses;");
        
        while (course_cursor.next()) {
		courses.push_back( readCourse(course_cursor.record()) );
	}
	
	// Connect dependencies now. We do this only now that all of the course
	// objects are available.
	for (CourseVect::iterator course_iter = courses.begin();
		course_iter != courses.end(); course_iter++ ) {
		addDependencies( *course_iter, courses );
	}

	PlannerView *pv = new PlannerView(&courses);
	pv->show();
	// Set the widget's width to show al semesters.

	return app.exec();
}

// <readcourse> does all the dirty work of constructing
// a course from the DB info.
Course *readCourse(QSqlRecord course_cursor) {
	QString course_number( course_cursor.value("number").toString() );
	NumVect *semesters = getSemesters( course_number );
	
	//TODO: Type checking.
	Course* course = new Course( course_number, 
		course_cursor.value("title").toString(), *semesters,
		(float)course_cursor.value("hours").toDouble() );

	return course;
}

// <addDependencies> connects each course with its dependencies.
void addDependencies( Course *course, CourseVect available ) {
        auto deps_cursor = QSqlQuery("select * from deps where course=" 
            + course->getNumber() + ';');
        QSqlRecord rec = deps_cursor.record();
        
	CourseVect::iterator found;
	CourseByNum finder;
        int nameCol = rec.indexOf("depends_on");
	while ( deps_cursor.next() ) {
		finder.setNum(deps_cursor.value(nameCol).toString());
		if ( (found = std::find_if(available.begin(), 
			available.end(), finder)) != available.end() ) {
			course->addDependency(*found);
		}
	}
}

// This function constructs a list of semesters
// in which a course is given. Uses the default database.
NumVect *getSemesters(QString number) {
	NumVect *semesters = new NumVect;
        auto semesters_cursor = QSqlQuery("select * from times where course=" 
            + number + ';');
        QSqlRecord rec = semesters_cursor.record();
        int nameCol = rec.indexOf("semester");

	while ( semesters_cursor.next() ) {
		semesters->push_back(
			semesters_cursor.value(nameCol).toInt() );
	}
	
	return semesters;
}