/*
 *openPilot Log - A FOSS Pilot Logbook Application
 *Copyright (C) 2020  Felix Turowsky
 *
 *This program is free software: you can redistribute it and/or modify
 *it under the terms of the GNU General Public License as published by
 *the Free Software Foundation, either version 3 of the License, or
 *(at your option) any later version.
 *
 *This program is distributed in the hope that it will be useful,
 *but WITHOUT ANY WARRANTY; without even the implied warranty of
 *MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *GNU General Public License for more details.
 *
 *You should have received a copy of the GNU General Public License
 *along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
#include "db.h"
#include "dbinfo.h"

// Debug Makro
#define DEB(expr) \
    qDebug() << "db ::" << __func__ << "\t" << expr

db::db()
{

}

db::db(sql::tableName tn, int row_ID)
{
    switch (tn) {
    case sql::flights:
        table = "flights";
        break;
    case sql::pilots:
        table = "pilots";
        break;
    case sql::aircraft:
        table = "aircraft";
        break;
    case sql::tails:
        table = "tails";
        break;
    case sql::airports:
        table = "airports";
        break;
    }
    row_id = row_ID;


    QString statement = "SELECT COUNT(*) FROM " + table + " WHERE _rowid_="+QString::number(row_id);
    QSqlQuery q(statement);
    q.exec();
    q.next();
    int rows = q.value(0).toInt();
    if(rows==0){
        DEB("No entry found for row id: " << row_ID );
    }else{
        DEB("Retreiving data for row id: " << row_id);
        isValid = retreiveData();
    }
}

db::db(sql::tableName tn, QMap<QString, QString> newData)
{
    switch (tn) {
    case sql::flights:
        table = "flights";
        break;
    case sql::pilots:
        table = "pilots";
        break;
    case sql::aircraft:
        table = "aircraft";
        break;
    case sql::tails:
        table = "tails";
        break;
    case sql::airports:
        table = "airports";
        break;
    }
    //Do some checks
    auto in = dbInfo();
    auto columns = in.format.value(table);
    QMap<QString,QString>::iterator i;
    for (i = newData.begin(); i != newData.end(); ++i){
        if(!columns.contains(i.key())){
            DEB(newData);
            DEB(i.key()<< i.value() << "Not in column list for " << table <<". Removing.");
            newData.remove(i.key());
        }
    }
    data = newData;
}

void db::setData(const QMap<QString, QString> &value)
{
    data = value;
}

/*!
 * \brief db::connect connects to the database via the default connection.
 * Can then be accessed globally with QSqlDatabase::database("qt_sql_default_connection")
 */
void db::connect()
{
    const QString driver("QSQLITE");

    if(QSqlDatabase::isDriverAvailable(driver)){

        QDir directory("data");
        QString databaseLocation = directory.filePath("logbook.db");
        QSqlDatabase db = QSqlDatabase::addDatabase(driver);
        db.setDatabaseName(databaseLocation);

        if(!db.open()){
            DEB("DatabaseConnect - ERROR: " << db.lastError().text());
        }else{
            DEB("Database connection established.");
        }
    }else{
        DEB("DatabaseConnect - ERROR: no driver " << driver << " available");
    }
}

/*!
 * \brief db::retreiveData retreives data from the database.
 * \return
 */
bool db::retreiveData()
{
    const auto info = dbInfo();

    QString statement = "SELECT * FROM " + table + " WHERE _rowid_="+QString::number(row_id);
    DEB("Executing SQL...");
    DEB(statement);

    QSqlQuery q(statement);
    q.exec();
    q.next();
    for(int i=0; i < info.format.value(table).length(); i++){
        data.insert(info.format.value(table)[i],q.value(i).toString());
    }


    QString error = q.lastError().text();
    if(error.length() > 2){
        DEB("Error: " << q.lastError().text());
        return false;
    }else{return true;}
}


/*!
 * \brief db::exists checks if a certain value exists in the database with a sqlite WHERE statement
 * \param table - Name of the table
 * \param column - Name of the column
 * \param value - The value to be checked
 * \return
 */
bool db::exists(QString column, QString table, QString checkColumn, QString value, sql::matchType match)
{
    bool output = false;
    QString statement = "SELECT " + column + " FROM " + table + " WHERE " + checkColumn;

    switch (match) {
    case sql::exactMatch:
        statement += " = '" + value + QLatin1Char('\'');
        break;
    case sql::partialMatch:
        value.append(QLatin1Char('%'));
        value.prepend(QLatin1Char('%'));
        statement.append(" LIKE '" + value + QLatin1Char('\''));
        break;
    }

    DEB(statement);

    QSqlQuery q(statement);
    q.exec();

    if(!q.first()){
        DEB("No result found. Check Query and Error.");
        DEB("Error: " << q.lastError().text());
    }else{
        DEB("Success. Found a result.");
        output = true;
        if(q.next()){
            DEB("More than one result in Database for your query");
        }
    }
// Debug:
    q.first();
    q.previous();
    while(q.next()){
            DEB("Query result: " << q.value(0).toString());
    }
// end of Debug
    return output;
}

/*!
 * \brief singleSelect Returns a single value from the database with a sqlite WHERE statement
 * \param table - Name of the table
 * \param column - Name of the column
 * \param value - Identifier for WHERE statement
 * \param match - enum sql::exactMatch or sql::partialMatch
 * \return QString
 */
QString db::singleSelect(QString column, QString table, QString checkColumn, QString value, sql::matchType match)
{
    QString statement = "SELECT " + column + " FROM " + table + " WHERE " + checkColumn;
    QString result;

    switch (match) {
    case sql::exactMatch:
        statement += " = '" + value + QLatin1Char('\'');
        break;
    case sql::partialMatch:
        value.append(QLatin1Char('%'));
        value.prepend(QLatin1Char('%'));
        statement.append(" LIKE '" + value + QLatin1Char('\''));
        break;
    }

    DEB(statement);

    QSqlQuery q(statement);
    q.exec();

    if(!q.first()){
        DEB("No result found. Check Query and Error.");
        DEB("Error: " << q.lastError().text());
        return QString();
    }else{
        DEB("Success. Found a result.");
        result.append(q.value(0).toString());
        if(q.next()){
            DEB("More than one result in Database for your query");
        }
        return result;
    }
}

/*!
 * \brief db::multiSelect Returns multiple values from the database with a sqlite WHERE statement
 * \param table - Name of the table
 * \param columns - QVector<QString> Names of the columns to be queried
 * \param value - Identifier for WHERE statement
 * \param checkColumn - column to match value to
 * \param match - enum sql::exactMatch or sql::partialMatch
 * \return QVector<QString>
 */
QVector<QString> db::multiSelect(QVector<QString> columns, QString table, QString checkColumn, QString value, sql::matchType match)
{
    QString statement = "SELECT ";
    for(const auto& column : columns)
    {
        statement.append(column);
        if(column != columns.last())
        {
            statement.append(QLatin1String(", "));
        }
    }
    statement.append(" FROM " + table + " WHERE " + checkColumn);

    switch (match) {
    case sql::exactMatch:
        statement += " = '" + value + QLatin1Char('\'');
        break;
    case sql::partialMatch:
        value.append(QLatin1Char('%'));
        value.prepend(QLatin1Char('%'));
        statement.append(" LIKE '" + value + QLatin1Char('\''));
        break;
    }

    DEB(statement);

    QSqlQuery q(statement);
    q.exec();

    if(!q.first()){
        DEB("No result found. Check Query and Error.");
        DEB("Error: " << q.lastError().text());
        return QVector<QString>();
    }else{
        q.first();
        q.previous();
        QVector<QString> result;
        while (q.next()) {
            for(int i = 0; i < columns.size() ; i++)
            {
                result.append(q.value(i).toString());
            }
        }
        return result;
    }
}
/*!
 * \brief db::multiSelect Returns a complete column(s) for a given table. Useful for creating
 * lists for QCompleter
 * \param column
 * \param table
 * \return
 */
QVector<QString> db::multiSelect(QVector<QString> columns, QString table)
{
    QString statement = "SELECT ";
    for(const auto& column : columns)
    {
        statement.append(column);
        if(column != columns.last())
        {
            statement.append(QLatin1String(", "));
        }
    }
    statement.append(" FROM " + table);

    DEB(statement);

    QSqlQuery q(statement);
    q.exec();

    if(!q.first()){
        DEB("No result found. Check Query and Error.");
        DEB("Error: " << q.lastError().text());
        return QVector<QString>();
    }else{
        q.first();
        q.previous();
        QVector<QString> result;
        while (q.next()) {
            for(int i = 0; i < columns.size() ; i++)
            {
                result.append(q.value(i).toString());
            }
        }
        return result;
    }
}

/*!
 * \brief db::singleUpdate Updates a single value in the database.
 * Query format: UPDATE table SET column = value WHERE checkcolumn =/LIKE checkvalue
 * \param table Name of the table to be updated
 * \param column Name of the column to be updated
 * \param checkColumn Name of the column for WHERE statement
 * \param value The value to be set
 * \param checkvalue The value for the WHERE statement
 * \param match enum sql::exactMatch or sql::partialMatch
 * \return true on success, otherwise error messages in debug out
 */
bool db::singleUpdate(QString table, QString column, QString value, QString checkColumn, QString checkvalue, sql::matchType match)
{
    QString statement = "UPDATE " + table;
    statement.append(QLatin1String(" SET ") + column + QLatin1String(" = '") + value);
    statement.append(QLatin1String("' WHERE "));

    switch (match) {
    case sql::exactMatch:
        statement.append(checkColumn + " = '" + checkvalue + QLatin1Char('\''));
        break;
    case sql::partialMatch:
        value.append(QLatin1Char('%'));
        value.prepend(QLatin1Char('%'));
        statement.append(checkColumn + " LIKE '" + checkvalue + QLatin1Char('\''));
        break;
    }

    DEB(statement);

    QSqlQuery q(statement);
    q.exec();
    QString error = q.lastError().text();

    if(error.length() > 1)
    {
        DEB("Errors have occured: " << error);
        return false;
    }else
    {
        DEB("Success!");
        return true;
    }
}

/*!
 * \brief db::deleteRow Deletes a single row from the database.
 * Query format: DELETE FROM table WHERE column =/LIKE value
 * \param table - Name of the table
 * \param column - Name of the column
 * \param value - Identifier for WHERE statement
 * \param match - enum sql::exactMatch or sql::partialMatch
 * \return true on success, otherwise error messages in debug out
 */
bool db::deleteRow(QString table, QString column, QString value, sql::matchType match)
{
    QString statement = "DELETE FROM " + table + " WHERE ";
    statement.append(column);


    switch (match) {
    case sql::exactMatch:
        statement += " = '" + value + QLatin1Char('\'');
        break;
    case sql::partialMatch:
        value.append(QLatin1Char('%'));
        value.prepend(QLatin1Char('%'));
        statement.append(" LIKE '" + value + QLatin1Char('\''));
        break;
    }

    DEB(statement);

    QSqlQuery q(statement);
    q.exec();
    QString error = q.lastError().text();

    if(error.length() > 1)
    {
        DEB("Errors have occured: " << error);
        return false;
    }else
    {
        DEB("Success!");
        return true;
    }
}

/*!
 * \brief db::customQuery Can be used to send a complex query to the database.
 * \param query - the full sql query statement
 * \param returnValues - the number of expected return values
 * \return QVector<QString> of results
 */
QVector<QString> db::customQuery(QString query, int returnValues)
{
    QSqlQuery q(query);
    DEB(query);
    q.exec();

    if(!q.first()){
        DEB("No result found. Check Query and Error.");
        DEB("Error: " << q.lastError().text());
        return QVector<QString>();
    }else{
        q.first();
        q.previous();
        QVector<QString> result;
        while (q.next()) {
            for(int i = 0; i < returnValues ; i++)
            {
                result.append(q.value(i).toString());
            }
        }
        return result;
    }
}

/*!
 * \brief db::getColumnNames Looks up column names of a given table
 * \param table name of the table in the database

QVector<QString> db::getColumnNames(QString table)
{
    QSqlDatabase db = QSqlDatabase::database("qt_sql_default_connection");
    QVector<QString> columnNames;
    QSqlRecord fields = db.record(table);

    for(int i = 0; i < fields.count(); i++){
        columnNames << fields.field(i).name();
    }
    return columnNames;
}*/

/*!
 * \brief db::update updates the database with the values contained in the object.
 * \return True on Success
 */
bool db::update()
{
    //check prerequisites
    if(row_id == 0){
        DEB("Invalid Row ID: " << row_id);
        return false;
    }
    if(data.isEmpty()){
        DEB("Object Contains no data. Aborting.");
        return false;
    }
    //create query
    QString statement = "UPDATE " + table + " SET ";

    QMap<QString,QString>::const_iterator i;
    for (i = data.constBegin(); i != data.constEnd(); ++i){
        if(i.value()!=QString()){
            statement += i.key()+QLatin1String("='")+i.value()+QLatin1String("', ");
        }else{DEB(i.key() << "is empty. skipping.");}
    }
    statement.chop(2); // Remove last comma
    statement.append(QLatin1String(" WHERE _rowid_=")+QString::number(row_id));

    //execute query
    QSqlQuery q(statement);
    q.exec();
    //check result. Upon success, error should be " "
    QString error = q.lastError().text();
    if(error.length() < 2){
        return true;
    }else{
        DEB("Query Error: " << q.lastError().text());
        return false;
    }
}

bool db::commit()
{
    //check prerequisites
    if(row_id != 0){
        DEB("Row ID already set. Unable to commit as new, try update() for existing entries: " << row_id);
        return false;
    }
    if(data.isEmpty()){
        DEB("Object Contains no data. Aborting.");
        return false;
    }
    QString statement = "INSERT INTO " + table + QLatin1String(" (");
    QMap<QString,QString>::iterator i;
    for (i = data.begin(); i != data.end(); ++i){
        statement += i.key() + QLatin1String(", ");
    }
    statement.chop(2);
    statement += QLatin1String(") VALUES (");
    for (i = data.begin(); i != data.end(); ++i){
        statement += QLatin1String("'") + i.value() + QLatin1String("', ");
    }
    statement.chop(2);
    statement += QLatin1String(")");

    QSqlQuery q(statement);
    QString error = q.lastError().text();
    if(error.length() < 2){
        DEB("Entry successfully committed.");
        return true;
    }else{
        DEB("Unable to commit. Query Error: " << q.lastError().text());
        return false;
    }
}


//Debug
void db::print()
{
    QString v = "Object status:\t\033[38;2;0;255;0;48;2;0;0;0m VALID \033[0m\n";
    QString nv = "Object status:\t\033[38;2;255;0;0;48;2;0;0;0m INVALID \033[0m\n";
    QTextStream cout(stdout, QIODevice::WriteOnly);

    cout << "=========Database Object=========\n";
    if(isValid){cout << v;}else{cout << nv;}
    cout << "Record from table: " << table << ", row: " << row_id << "\n";
    cout << "=================================\n";
    QMap<QString,QString>::const_iterator i;
    for (i = data.constBegin(); i != data.constEnd(); ++i){
        cout << i.key() << ": " << i.value() << "\n";
    }
}

QString db::debug()
{
    print();
    return QString();
}