#include <QMessageBox>

#include<sqlite3.h>

#include "sqlitebackend.h"

SQLiteSaveFile::SQLiteSaveFile(QObject *parent, QString filename) :
    QObject(parent)
  , lastError(NoError)
  , lastErrorString(QString())
  , db(QSqlDatabase::addDatabase("QSQLITE", QUuid::createUuid().toString()))
  , filename(filename)
  , m_isOpen(false)
{
    connect();
}

bool SQLiteSaveFile::initDb(bool setCreationDate)
{
    for (auto const &q: {
         "CREATE TABLE IF NOT EXISTS metadata (key TEXT, value TEXT)",
         "CREATE TABLE IF NOT EXISTS tags (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, anchor_x REAL, anchor_y REAL, meta TEXT)",
         "CREATE TABLE IF NOT EXISTS blobs (name TEXT, data BLOB)"}) {
        if (!runSql(q))
            return false;
    }

    if (setCreationDate) {
        if (!setMetaLocked("creationTime", QDateTime::currentDateTimeUtc().toMSecsSinceEpoch()))
            return false;
    }

    return true;
}

bool SQLiteSaveFile::connect()
{
    QMutexLocker l(&dbMut);
    resetError();
    m_isOpen = false;
    imageData = QByteArray();

    bool newlyCreated = QFile(filename).exists();

    db.setDatabaseName(filename);
    if (!db.open()) {
        setDatabaseError(db);
        db.close();
        return false;
    }

    if (!initDb(newlyCreated)) {
        db.close();
        return false;
    }

    m_isOpen = true;

    /* Try to load image, ignore if image is unset */
    QSqlQuery q("SELECT data FROM blobs WHERE name = 'image'", db);
    if (!q.next())
        return setDatabaseError(q);

    imageData = q.value(0).toByteArray();
    return true;
}

static sqlite3 *getSqliteHandle(QSqlDatabase &db) {
    QVariant v = db.driver()->handle();
    assert (v.isValid());
    assert (!qstrcmp(v.typeName(), "sqlite3*"));
    return *static_cast<sqlite3 **>(v.data());
}

bool SQLiteSaveFile::saveAs(const QString &filename)
{
    QMutexLocker l(&dbMut);
    QFile f(filename);
    QSqlDatabase old_db = db;
    QSqlDatabase new_db(QSqlDatabase::addDatabase("QSQLITE", QUuid::createUuid().toString()));
    new_db.setDatabaseName(f.fileName());
    if (!new_db.open()) {
        setDatabaseError(new_db);
        new_db.close();
        return false;
    }

    sqlite3 *old_handle = getSqliteHandle(db);
    sqlite3 *new_handle = getSqliteHandle(new_db);
    sqlite3_backup *bck = sqlite3_backup_init(new_handle, "main", old_handle, "main");
    if (!bck)
        goto err_cleanup;

    if (sqlite3_backup_step(bck, -1) != SQLITE_DONE)
        goto err_cleanup;

    if (sqlite3_backup_finish(bck) != SQLITE_DONE)
        goto err_cleanup;

    db = new_db;
    old_db.close();
    return true;

err_cleanup:
    setDatabaseError(new_db);
    new_db.close();
    return false;
}

bool SQLiteSaveFile::clearNew()
{
    QMutexLocker l(&dbMut);

    QSqlDatabase new_db(QSqlDatabase::addDatabase("QSQLITE", QUuid::createUuid().toString()));
    new_db.setDatabaseName(":memory:");
    if (!new_db.open()) {
        setDatabaseError(new_db);
        new_db.close();
        return false;
    }

    if (!initDb()) {
        db.close();
        return false;
    }

    imageData = QByteArray();
    return true;
}

QList<Tag> SQLiteSaveFile::getAllTags()
{
    QMutexLocker l(&dbMut);
    resetError();
    QList<Tag> rv;
    QSqlQuery q("SELECT (id, name, anchor_x, anchor_y, meta) FROM tags", db);

    while (q.next()) {
        rv << Tag {
               q.value(0).toLongLong(),
               q.value(1).toString(),
               q.value(2).toFloat(),
               q.value(3).toFloat(),
               q.value(4).toByteArray()
        };
    }

    if (!setDatabaseError(q))
        return QList<Tag>();

    return rv;
}

bool SQLiteSaveFile::updateTag(Tag tag)
{
    QMutexLocker l(&dbMut);
    if (!runSql("UPDATE tags SET name=?, anchor_x=?, anchor_y=?, meta=? WHERE id=?", {
               tag.name, tag.anchor.x(), tag.anchor.y(), QJsonDocument::fromVariant(tag.metadata).toJson(), tag.id
           }))
        return false;

    tagChange(TagChange::CHANGED, tag);
    return true;
}

bool SQLiteSaveFile::deleteTag(Tag tag)
{
    QMutexLocker l(&dbMut);
    if (!runSql("DELETE FROM tags WHERE id=?", {tag.id}))
        return false;

    tagChange(TagChange::DELETED, tag);
    return true;
}

bool SQLiteSaveFile::createTag(Tag tag)
{
    QMutexLocker l(&dbMut);
    resetError();
    QSqlQuery q("INSERT INTO tags(name, anchor_x, anchor_y, meta) VALUES (?, ?, ?, ?)", db);
    q.addBindValue(tag.name);
    q.addBindValue(tag.anchor.x());
    q.addBindValue(tag.anchor.y());
    q.addBindValue(QJsonDocument::fromVariant(tag.metadata).toJson());
    if (!q.exec())
        return setDatabaseError(q);

    Tag created_tag(q.lastInsertId().toLongLong(), tag);
    tagChange(TagChange::CREATED, created_tag);
    return true;
}

bool SQLiteSaveFile::setMetaLocked(const QString &key, const QVariant &value)
{
    return runSql("INSERT OR REPLACE INTO metadata(key, value) VALUES (?, ?)", {key, value});
}

bool SQLiteSaveFile::setMetaLocked(std::initializer_list<QPair<QString, QVariant>> metas)
{
    for (const auto &meta : metas) {
        if (!setMetaLocked(meta.first, meta.second))
            return false;
    }
    return true;
}

bool SQLiteSaveFile::setMeta(const QString &key, const QVariant &value) {
    QMutexLocker l(&dbMut);
    return setMetaLocked(key, value);
}

bool SQLiteSaveFile::setMeta(std::initializer_list<QPair<QString, QVariant>> metas) {
    QMutexLocker l(&dbMut);
    return setMetaLocked(metas);
}

QVariant SQLiteSaveFile::getMeta(const QString &key) {
    QMutexLocker l(&dbMut);
    return getMetaLocked(key);
}

QVariant SQLiteSaveFile::getMetaLocked(const QString &key)
{
    resetError();
    QSqlQuery q("SELECT value FROM metadata WHERE key=?", db);
    q.addBindValue(key);
    if (!q.next()) {
        setDatabaseError(q);
        return QVariant();
    }

    return q.value(0);
}

bool SQLiteSaveFile::runSql(QString query, std::initializer_list<QVariant> bindings)
{
    resetError();
    QSqlQuery q(query, db);
    for (const QVariant &v : bindings)
        q.addBindValue(v);

    q.exec();
    return setDatabaseError(q);
}

bool SQLiteSaveFile::loadImageFromDisk(const QString &filename)
{
    QMutexLocker l(&dbMut);
    QFile f(filename);
    resetError();

    if (!f.open(QIODevice::ReadOnly)) {
        setError(ImageOpenError, QString("Failed to open image: %1").arg(f.errorString()));
        return false;
    }

    imageData = f.readAll();
    if (f.error() != QFileDevice::NoError) {
        setError(ImageReadError, QString("Failed to read image: %1").arg(f.errorString()));
        return false;
    }

    if (!setMetaLocked({
                 {"imagePathOriginal", f.fileName()},
                 {"imagePathAbsolute", QFileInfo(f).absoluteFilePath()},
                 {"imageLoadedTime", QDateTime::currentDateTimeUtc().toMSecsSinceEpoch()}}))
        return false;

    return runSql("INSERT OR REPLACE INTO blobs(name, data) VALUES ('image', ?)", {imageData});
}

bool SQLiteSaveFile::reloadImageFromDisk()
{
    const QString &p = getMeta("imagePathOriginal").toString();
    if (QFile(p).exists())
        return loadImageFromDisk(p);

    const QString &q = getMeta("imagePathAbsolute").toString();
    if (QFile(q).exists())
        return loadImageFromDisk(q);

    return false;
}

Tag::Tag(long long id, QString name, qreal anchor_x, qreal anchor_y, QByteArray metadata)
    : id(id)
    , name(name)
    , anchor(QPointF(anchor_x, anchor_y))
    , metadata(QJsonDocument::fromJson(metadata).object().toVariantMap())
{
}

Tag::Tag()
    : id(-1)
{
}

Tag::Tag(long long id, const Tag &other)
    : id(id)
    , name(other.name)
    , anchor(other.anchor)
    , metadata(other.metadata)
{
}

bool SQLiteSaveFile::setDatabaseError(const QSqlQuery &q)
{
    if (!q.lastError().isValid())
        return true;

    setError(SQLiteError, QString("Project file database error: %1").arg(q.lastError().text()));
    return false;
}

bool SQLiteSaveFile::setDatabaseError(const QSqlDatabase &db)
{
    if (!db.lastError().isValid())
        return true;

    setError(SQLiteError, QString("Project file database error: %1").arg(db.lastError().text()));
    return false;
}