#include <QtCore/QRegExp>
#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"

const QLatin1String Board::CURRENT_DB_VERSION("testing2");

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();
		_db.setDatabaseName(QDir::toNativeSeparators(getTempDbPathFor(_slug)));
		if (!_db.open()) {
			qWarning() << "Could not open temp database file"
			           << _db.databaseName() << ":" << _db.lastError().text();
			return; // Give up
		}
	}
	if (!checkCompatibleDb()) {
		qDebug() << "Database version incompatible, reinitializing";
		eraseDb();
		initializeDb();
	}
	fetchConfigIfOutdated();
	fetchForumsIfOutdated();
	initializeBbCode(); // TODO This might depend on board config
}

Board::~Board()
{
	QSqlDatabase::removeDatabase(_slug);
}

void Board::enqueueAction(Action *action)
{
	// Let's find if a duplicate action is in there already.
	qDebug() << "Enqueing" << action;

	foreach (Action *a, _queue) {
		if (a->isSupersetOf(action)) {
			qDebug() << "Action superseded, ignoring";
			delete action;
			return;
		}
	}

	// Otherwise, enqueue the 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
{
	// Try config cache first
	QHash<QString, QString>::const_iterator i = _config.find(key);
	if (i != _config.end()) {
		// Cache hit
		return i.value();
	}

	// Try database
	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()) {
		QString value = query.value(1).toString();
		_config[key] = value; // Store in cache
		return value;
	}
	return QString();
}

void Board::setConfig(const QString &key, const QString &value)
{

	// Try config cache first
	QHash<QString, QString>::const_iterator i = _config.find(key);
	if (i != _config.end()) {
		QString old_value = i.value();
		if (old_value == value) {
			// It's in the cache, and it's the same value: don't change.
			return;
		}
	}

	// Update value in DB
	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();
	}
	_config.insert(key, value);
	notifyConfigChanged(key);
}

QString Board::removeHtml(QString text) const
{
	static const QRegExp regexp("<[a-zA-Z\\/][^>]*>");
	text.replace(regexp, "");
	return text;
}

QString Board::removeBbcode(QString text) const
{
	static const QRegExp regexp("\\[[a-zA-Z\\/][^]]*\\]");
	text.replace(regexp, "");
	return text;
}

QString Board::bbcodeToRichText(QString text) const
{
	typedef QPair<QRegExp, QString> Pair; // Workaround for ',' in Q_FOREACH
	foreach (const Pair& pair, _bbcodes) {
		text.replace(pair.first, pair.second);
	}

	return text;
}

QString Board::renderHumanDate(const QDateTime &dateTime)
{
	QDate date = dateTime.toLocalTime().date();
	QDate today = QDate::currentDate();
	if (date == today) {
		return tr("Today");
	} else if (date.daysTo(today) == 1) {
		return tr("Yesterday");
	} else if (date.daysTo(today) < 5) {
		return QDate::longDayName(date.dayOfWeek(), QDate::StandaloneFormat);
	} else {
		return date.toString(Qt::DefaultLocaleShortDate);
	}
}

QString Board::renderHumanTime(const QDateTime &dateTime)
{
	return dateTime.toLocalTime().time().toString(Qt::DefaultLocaleShortDate);
}

void Board::notifyConfigChanged(const QString& key)
{
	if (!key.isEmpty()) {
		_config.remove(key);
	} else {
		// Must assume all keys were changed
		_config.clear();
	}
	emit configChanged(key);
}

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);
}

void Board::notifyTopicPostsChanged(int topicId, int start, int end)
{
	qDebug() << "TopicPosts Changed" << topicId << start << end;
	emit topicPostsChanged(topicId, 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::getDbPathFor(const QString &slug)
{
	return board_manager->getCachePath() + "/" + slug + ".sqlite";
}

QString Board::getTempDbPathFor(const QString& slug)
{
	return QDir::tempPath() + "/" + slug + ".sqlite";
}

bool Board::checkCompatibleDb()
{
	QString version = getConfig("tapasboard_db_version");
	return version == CURRENT_DB_VERSION;
}

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)")) {
		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_parent index:" << q.lastError().text();
		return false;
	}
	if (!q.exec("CREATE UNIQUE INDEX IF NOT EXISTS forums_order ON forums (sort_index ASC)")) {
		qWarning() << "Could not create forums_order index:" << 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, reply_number INT, 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;
	}

	if (!q.exec("CREATE TABLE IF NOT EXISTS posts (forum_id INTEGER, topic_id INTEGER, post_id INTEGER PRIMARY KEY, post_title TEXT, post_content TEXT, post_author_id INTEGER, post_author_name TEXT, can_edit BOOL, icon_url TEXT, post_time TEXT, last_update_time TEXT)")) {
		qWarning() << "Could not create posts table:" << q.lastError().text();
		return false;
	}
	if (!q.exec("CREATE INDEX IF NOT EXISTS posts_topic ON posts (topic_id)")) {
		qWarning() << "Could not create posts_topic index:" << q.lastError().text();
		return false;
	}
	if (!q.exec("CREATE INDEX IF NOT EXISTS posts_time ON posts (post_time)")) {
		qWarning() << "Could not create posts_time index:" << q.lastError().text();
		return false;
	}

	return true;
}

bool Board::eraseDb()
{
	QSqlQuery q(_db);

	if (!q.exec("DROP TABLE IF EXISTS config")) {
		qWarning() << "Could not drop config table:" << q.lastError().text();
		return false;
	}
	if (!q.exec("DROP TABLE IF EXISTS forums")) {
		qWarning() << "Could not drop forums table:" << q.lastError().text();
		return false;
	}
	if (!q.exec("DROP TABLE IF EXISTS topics")) {
		qWarning() << "Could not drop topics table:" << q.lastError().text();
		return false;
	}
	if (!q.exec("DROP TABLE IF EXISTS posts")) {
		qWarning() << "Could not drop posts table:" << q.lastError().text();
		return false;
	}
	if (!q.exec("VACUUM")) {
		qWarning() << "Could not vacuum database:" << q.lastError().text();
		return false;
	}

	return true;
}

bool Board::cleanDb()
{
	QSqlQuery q(_db);
	// TODO: Delete old posts from cache
	if (!q.exec("VACUUM")) {
		qWarning() << "Could not vacuum database:" << 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::initializeBbCode()
{
	_bbcodes.clear();
	_bbcodes << qMakePair(QRegExp("\\[(/?[bius])\\]", Qt::CaseInsensitive), QString("<\\1>"));

	_bbcodes << qMakePair(QRegExp("\\[(/?)quote\\]", Qt::CaseInsensitive), QString("<\\1blockquote>"));

	_bbcodes << qMakePair(QRegExp("\\[url\\]([^[]*)\\[/url\\]", Qt::CaseInsensitive), QString("<a href=\"\\1\">\\1</a>"));
	_bbcodes << qMakePair(QRegExp("\\[url=([^]]*)\\]", Qt::CaseInsensitive), QString("<a href=\"\\1\">"));
	_bbcodes << qMakePair(QRegExp("\\[/url\\]", Qt::CaseInsensitive), QString("</a>"));

	_bbcodes << qMakePair(QRegExp("\\[img\\]([^[]*)\\[/img\\]", Qt::CaseInsensitive), QString("<img src=\"\\1\" />"));

	_bbcodes << qMakePair(QRegExp("\\[hr\\]", Qt::CaseInsensitive), QString("<hr>"));

	_bbcodes << qMakePair(QRegExp("\n"), QString("<br>"));
}

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)
{
	qDebug() << action << "finished";
	bool ok = removeFromActionQueue(action);
	if (!ok) {
		qWarning() << "Finished action not in queue";
	}
}

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