#include "databaseview.h"
#include <QVBoxLayout>
#include <QPushButton>
#include <QSettings>
#include <QDialogButtonBox>
#include <QHeaderView>

const QStringList DEFAULT_COLUMNS = {"EXPTIME", "OBJECT", "RA", "DEC"};

SelectColumnsDialog::SelectColumnsDialog(QWidget *parent) : QDialog(parent)
{
    m_listWidget = new QListWidget(this);
    m_listWidget->setSelectionMode(QAbstractItemView::MultiSelection);
    QVBoxLayout *layout = new QVBoxLayout(this);
    setLayout(layout);
    layout->addWidget(m_listWidget);

    QDialogButtonBox *buttonBox = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel);
    connect(buttonBox, &QDialogButtonBox::accepted, this, &QDialog::accept);
    connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
    layout->addWidget(buttonBox);

    setWindowTitle(tr("Select columns"));
}

void SelectColumnsDialog::setColumns(QStringList columns)
{
    QSettings settings;
    m_listWidget->addItems(columns);
    QStringList selected = settings.value("databaseview/selectedColumns", DEFAULT_COLUMNS).toStringList();
    for(auto &sel : selected)
    {
        int i = columns.indexOf(sel);
        if(i>=0)
            m_listWidget->item(i)->setSelected(true);
    }
}

QStringList SelectColumnsDialog::selectedColumns()
{
    QStringList ret;
    for(auto &sel : m_listWidget->selectedItems())
        ret.append(sel->text());
    return ret;
}

DataBaseView::DataBaseView(Database *database, QWidget *parent) : QWidget(parent)
  ,m_database(database)
{
    QVBoxLayout *layout = new QVBoxLayout(this);
    setLayout(layout);

    m_tableView = new QTableView(this);
    m_tableView->verticalHeader()->setDefaultSectionSize(1);
    layout->addWidget(m_tableView);

    m_model = new QSqlQueryModel(this);

    QSettings settings;
    m_tableView->setModel(m_model);
    m_tableView->horizontalHeader()->restoreState(settings.value("databaseview/header").toByteArray());

    QHBoxLayout *hlayout = new QHBoxLayout(this);
    layout->addLayout(hlayout);

    QPushButton *selectColumnsButton = new QPushButton(tr("Select columns"), this);
    hlayout->addWidget(selectColumnsButton);
    connect(selectColumnsButton, &QPushButton::pressed, this, &DataBaseView::selectColumns);

    QPushButton *loadDatabaseButton = new QPushButton(tr("Load database"), this);
    hlayout->addWidget(loadDatabaseButton);
    connect(loadDatabaseButton, &QPushButton::pressed, this, &DataBaseView::loadDatabase);
}

DataBaseView::~DataBaseView()
{
    QSettings settings;
    settings.setValue("databaseview/header", m_tableView->horizontalHeader()->saveState());
}

void DataBaseView::selectColumns()
{
    SelectColumnsDialog dialog;
    QStringList columns = m_database->getFitsKeywords();
    dialog.setColumns(columns);
    if(dialog.exec() == QDialog::Accepted)
    {
        QSettings settings;
        QStringList columns = dialog.selectedColumns();
        settings.setValue("databaseview/selectedColumns", columns);
        prepareQuery(columns);
    }
}

void DataBaseView::loadDatabase()
{
    QSettings settings;
    prepareQuery(settings.value("databaseview/selectedColumns", DEFAULT_COLUMNS).toStringList());
}

void DataBaseView::prepareQuery(const QStringList &columns)
{
    QString sql = "SELECT file,";
    for(auto &column : columns)
    {
        sql += QString("GROUP_CONCAT(CASE WHEN key=\"%1\" THEN value END) AS \"%1\",").arg(column);
    }
    sql.chop(1);
    sql += " FROM fits_files LEFT JOIN fits_headers ON fits_files.id=id_file GROUP BY fits_files.id";
    m_model->setQuery(sql);
}