#include <QtCore/QRegExp>
#include <QtCore/QDateTime>
#include <QtCore/QDir>
#include <QtCore/QDebug>
#include <QtSql/QSqlQuery>
#include <QtSql/QSqlError>

#include "global.h"
#include "action.h"
#include "fetchboardconfigaction.h"
#include "fetchforumsaction.h"
#include "xmlrpcinterface.h"
#include "board.h"

Board::Board(const QString& forumUrl, QObject *parent) :
    QObject(parent), _url(forumUrl), _slug(createSlug(forumUrl)),
    _db(QSqlDatabase::addDatabase("QSQLITE", _slug)),
    _iface(new XmlRpcInterface(QUrl(_url), this))
{
	_db.setDatabaseName(QDir::toNativeSeparators(getDbPathFor(_slug)));
	qDebug() << "Opening database file" << _db.databaseName() << "for" << _url;
	if (!_db.open()) {
		qWarning() << "Could not open database file" << _db.databaseName() << ":"
		           << _db.lastError().text();
	}
	initializeDb();
	fetchConfigIfOutdated();
	fetchForumsIfOutdated();
}

void Board::enqueueAction(Action *action)
{
	connect(action, SIGNAL(finished(Action*)), SLOT(handleActionFinished(Action*)));
	connect(action, SIGNAL(error(Action*,QString)), SLOT(handleActionError(Action*,QString)));

	_queue.enqueue(action);

	if (_queue.size() == 1) {
		// There were no actions queued, so start by executing this one.
		executeActionFromQueue();
	}
}

QString Board::getConfig(const QString &key) const
{
	QSqlQuery query(_db);
	query.prepare("SELECT key, value FROM config WHERE key = :key");
	query.bindValue(":key", key);
	if (!query.exec()) {
		qWarning() << "Could not get configuration key:" << key;
		return QString();
	}
	if (query.next()) {
		return query.value(1).toString();
	}
	return QString();
}

void Board::setConfig(const QString &key, const QString &value)
{
	QSqlQuery query(_db);
	query.prepare("INSERT OR REPLACE INTO config (key, value) VALUES (:key, :value)");
	query.bindValue(":key", key);
	query.bindValue(":value", value);
	if (!query.exec()) {
		qWarning() << "Could not set configuration key" << key << ":" << query.lastError().text();
	}
	notifyConfigChanged();
}

int Board::rootForumId() const
{
	QSqlQuery query(_db);
	query.exec("SELECT forum_id FROM forums WHERE parent_id = -1");
	if (query.next()) {
		return query.value(0).toInt();
	} else {
		return -1;
	}
}

void Board::notifyConfigChanged()
{
	emit configChanged();
}

void Board::notifyForumsChanged()
{
	emit forumsChanged();
}

void Board::notifyForumTopicsChanged(int forumId, int start, int end)
{
	qDebug() << "ForumTopics Changed" << forumId << start << end;
	emit forumTopicsChanged(forumId, start, end);
}

QString Board::createSlug(const QString &forumUrl)
{
	static const QRegExp regexp("[^a-z0-9]+");
	QString url = forumUrl.toLower();
	url.replace(regexp, "_");
	return url;
}

QString Board::getDbDir()
{
	QString path;

#ifdef Q_OS_LINUX
	char * xdg_cache_dir = getenv("XDG_CACHE_HOME");
	if (xdg_cache_dir) {
		path = QString::fromLocal8Bit(xdg_cache_dir) + "/tapasboard";
	} else {
		path = QDir::homePath() + "/.cache/tapasboard";
	}
	if (!QDir().mkpath(path)) {
		qWarning() << "Failed to create directory for databases:" << path;
	}
#endif

	return path;
}

QString Board::getDbPathFor(const QString &slug)
{
	return getDbDir() + "/" + slug + ".sqlite";
}

bool Board::initializeDb()
{
	QSqlQuery q(_db);
	if (!q.exec("CREATE TABLE IF NOT EXISTS config (key TEXT PRIMARY KEY, value TEXT)")) {
		qWarning() << "Could not create config table:" << q.lastError().text();
		return false;
	}

	if (!q.exec("CREATE TABLE IF NOT EXISTS forums (forum_id INTEGER PRIMARY KEY, forum_name TEXT, description TEXT, parent_id INT, logo_url TEXT, new_post BOOL, is_protected BOOL, is_subscribed BOOL, can_subscribe BOOL, url TEXT, sub_only BOOL, sort_index INT UNIQUE)")) {
		qWarning() << "Could not create forums table:" << q.lastError().text();
		return false;
	}
	if (!q.exec("CREATE INDEX IF NOT EXISTS forums_parent ON forums (parent_id)")) {
		qWarning() << "Could not create forums table:" << q.lastError().text();
		return false;
	}

	if (!q.exec("CREATE TABLE IF NOT EXISTS topics (forum_id INTEGER, topic_id INTEGER PRIMARY KEY, topic_title TEXT, topic_author_id INTEGER, topic_author_name TEXT, is_subscribed BOOL, is_closed BOOL, icon_url TEXT, last_reply_time TEXT, new_post BOOL, last_update_time TEXT)")) {
		qWarning() << "Could not create topics table:" << q.lastError().text();
		return false;
	}
	if (!q.exec("CREATE INDEX IF NOT EXISTS topics_forum ON topics (forum_id)")) {
		qWarning() << "Could not create topics_forum index:" << q.lastError().text();
		return false;
	}
	if (!q.exec("CREATE INDEX IF NOT EXISTS topics_time ON topics (last_reply_time)")) {
		qWarning() << "Could not create topics_time index:" << q.lastError().text();
		return false;
	}

	return true;
}

bool Board::removeFromActionQueue(Action *action)
{
	if (_queue.isEmpty()) return false;
	Action *head = _queue.head();
	if (_queue.removeOne(action)) {
		if (!_queue.isEmpty() && head != _queue.head()) {
			// The head action was removed; advance the queue.
			executeActionFromQueue();
		}
		action->deleteLater();
		return true;
	}
	return false;
}

void Board::executeActionFromQueue()
{
	if (!_queue.empty()) {
		Action *head = _queue.head();
		head->execute();
	}
}

void Board::fetchConfigIfOutdated()
{
	if (_iface->isAccessible()) {
		// Only fetch if network is accessible and data is >48h old.
		QDateTime last_fetch = QDateTime::fromString(
		            getConfig("last_config_fetch"), Qt::ISODate);
		if (!last_fetch.isValid() || last_fetch.daysTo(QDateTime::currentDateTimeUtc()) >= BOARD_CONFIG_TTL) {
			enqueueAction(new FetchBoardConfigAction(this));
		}
	}

}

void Board::fetchForumsIfOutdated()
{
	if (_iface->isAccessible()) {
		// Only fetch if network is accessible and data is >48h old.
		QDateTime last_fetch = QDateTime::fromString(
		            getConfig("last_forums_fetch"), Qt::ISODate);
		if (!last_fetch.isValid() || last_fetch.daysTo(QDateTime::currentDateTimeUtc()) >= BOARD_LIST_TTL) {
			enqueueAction(new FetchForumsAction(this));
		}
	}
}

void Board::handleActionFinished(Action *action)
{
	removeFromActionQueue(action);
}

void Board::handleActionError(Action *action, const QString& message)
{
	qWarning() << "Action failed:" << message;
	removeFromActionQueue(action);
}