#include "error_dialog.h"

#include <QCheckBox>
#include <QDebug>
#include <QErrorMessage>
#include <QRegularExpression>
#include <QRegularExpressionMatch>

QErrorMessage *ErrorDialog::getDialog(QWidget *parent,
                                      const QString &errorMsg) {
  // Initialize the error dialog
  QErrorMessage *dialog =
      new QErrorMessage(parent); // parent is needed for the correct location
  dialog->setAttribute(Qt::WA_DeleteOnClose); // delete the dialog when closed

  // Hide the "don't show again" checkbox
#define ERROR_DIALOG_NEW_VERSION 0
#if (ERROR_DIALOG_NEW_VERSION == 1 && QT_VERSION >= QT_VERSION_CHECK(6, 3, 0))
  // You need to set DontShowAgainVisible to true in Qt 6.3
  errorDialog->setDontShowAgainVisible(false);
#else
  QCheckBox *cb = dialog->findChild<QCheckBox *>();
  if (cb) {
    cb->setEnabled(false);
    cb->hide();
  }
#endif
#undef ERROR_DIALOG_NEW_VERSION

  // Set the window title
  dialog->setWindowTitle(QObject::tr("Information messages"));

  // Set minimum width size
  dialog->setMinimumWidth(600);

  return dialog;
}

void ErrorDialog::displayError(QWidget *parent, const QString &errorMsg) {
  qDebug() << "Displaying error message:" << errorMsg;

  QErrorMessage *dialog = getDialog(parent, errorMsg);

  if (errorMsg.contains("constraint failed")) {
    QString detailedMessage = handleSqlConstraints(errorMsg);
    dialog->showMessage(detailedMessage);
    dialog->exec();
    return;
  }

  if (errorMsg.contains("not found")) {
    QString detailedMessage = handleNotFoundErrors(errorMsg);
    dialog->showMessage(detailedMessage);
    dialog->exec();
    return;
  }

  QRegularExpression regex("Error (\\d+):");
  QRegularExpressionMatch match = regex.match(errorMsg);

  if (!match.hasMatch()) {
    dialog->showMessage(QObject::tr(
        "An error occurred from an unknown source of the problem."));
    dialog->exec();
    return;
  }

  int errorCode = match.captured(1).toInt();
  QString detailedMessage = getDetailedMessage(errorCode);

  dialog->showMessage(detailedMessage);
  dialog->exec();
}

QString ErrorDialog::handleNotFoundErrors(const QString &errorMsg) {
  if (errorMsg.contains("Genre", Qt::CaseInsensitive)) {
    return QObject::tr("The specified genre was not found.");
  }
  if (errorMsg.contains("Hall", Qt::CaseInsensitive)) {
    return QObject::tr("The specified hall was not found.");
  }
  if (errorMsg.contains("Movie", Qt::CaseInsensitive)) {
    return QObject::tr("The specified movie was not found.");
  }
  if (errorMsg.contains("Refund", Qt::CaseInsensitive)) {
    return QObject::tr("The specified refund was not found.");
  }
  if (errorMsg.contains("Session", Qt::CaseInsensitive)) {
    return QObject::tr("The specified session was not found.");
  }
  if (errorMsg.contains("Ticket", Qt::CaseInsensitive)) {
    return QObject::tr("The specified ticket was not found.");
  }

  // If the specific error is not recognized, return a general message
  return QObject::tr("The requested object was not found in the database.");
}

QString ErrorDialog::handleSqlConstraints(const QString &errorMsg) {
  if (errorMsg.contains("UNIQUE constraint failed")) {
    return handleUniqueConstraint(errorMsg);
  }
  if (errorMsg.contains("FOREIGN KEY constraint failed")) {
    return handleForeignKeyConstraint(errorMsg);
  }
  if (errorMsg.contains("PRIMARY KEY constraint failed")) {
    return handlePrimaryKeyConstraint();
  }
  if (errorMsg.contains("CHECK constraint failed")) {
    return handleCheckConstraint(errorMsg);
  }
  if (errorMsg.contains("NOT NULL constraint failed")) {
    return tr("A required field is missing. Please fill all required fields.");
  }

  return tr("An SQL constraint violation occurred, but at the moment it has "
            "not been described in detail yet.");
}

QString ErrorDialog::handleUniqueConstraint(const QString &errorMsg) {
  if (errorMsg.contains("genres.genre_name")) {
    return tr("A genre with the same name already exists.");
  }
  if (errorMsg.contains("movies.title")) {
    return tr("A movie with the same title already exists.");
  }
  if (errorMsg.contains("halls.hall_name")) {
    return tr("A hall with the same name already exists.");
  }
  if (errorMsg.contains("tickets.session_id, tickets.seat_number")) {
    return tr("A ticket with the same session and seat number already exists.");
  }
  if (errorMsg.contains("refunds.ticket_id")) {
    return tr("A refund for the same ticket already exists.");
  }
  if (errorMsg.contains("sessions.hall_id, sessions.begin_at")) {
    return tr("A session is already scheduled in this hall at the same time.");
  }

  return tr("A unique constraint violation occurred, but at the moment it has "
            "not been described in detail yet.");
}

QString ErrorDialog::handleForeignKeyConstraint(const QString &errorMsg) {
  if (errorMsg.contains("sessions.movie_id")) {
    return tr("The movie ID for the session does not exist.");
  }
  if (errorMsg.contains("sessions.hall_id")) {
    return tr("The hall ID for the session does not exist.");
  }
  if (errorMsg.contains("movies.genre_id")) {
    return tr("The genre ID for the movie does not exist.");
  }
  if (errorMsg.contains("tickets.session_id")) {
    return tr("The session ID for the ticket does not exist.");
  }
  if (errorMsg.contains("refunds.ticket_id")) {
    return tr("The ticket ID for the refund does not exist.");
  }

  return tr("Operation violates a foreign key constraint, but at the moment it "
            "has not been described in detail yet.");
}

QString ErrorDialog::handlePrimaryKeyConstraint() {
  return tr("Duplicate primary key value. Ensure the primary key is unique.");
}

QString ErrorDialog::handleCheckConstraint(const QString &errorMsg) {
  if (errorMsg.contains("length(genre_name) > 0")) {
    return tr("Genre name must not be empty.");
  }
  if (errorMsg.contains("length(title) > 0")) {
    return tr("Movie title must not be empty.");
  }
  if (errorMsg.contains("duration > 0")) {
    return tr("Movie duration must be a positive value.");
  }
  if (errorMsg.contains("length(hall_name) > 0")) {
    return tr("Hall name must not be empty.");
  }
  if (errorMsg.contains("capacity > 0")) {
    return tr("Hall capacity must be a positive number.");
  }
  if (errorMsg.contains("ticket_price >= 0")) {
    return tr("Ticket price must be a non-negative value.");
  }
  if (errorMsg.contains("seat_number > 0")) {
    return tr("Seat number must be a positive value.");
  }
  if (errorMsg.contains("refund_amount >= 0")) {
    return tr("Refund amount must be a non-negative value.");
  }

  return tr("A value violates a CHECK constraint, but at the moment it has not "
            "been described in detail yet.");
}

QString ErrorDialog::getDetailedMessage(int errorCode) {
  switch (errorCode) {
  case 1001:
    return tr("Seat number exceeds hall capacity.");
  case 1002:
    return tr("Cannot purchase ticket after the session has started.");
  case 1003:
    return tr("Refunds cannot be made after the session has started.");
  case 1004:
    return tr("Refund amount cannot exceed the sale amount.");
  case 1005:
    return tr("Refund date cannot be earlier than the sale date.");
  case 1006:
    return tr("The new session overlaps with an ongoing movie in the hall.");
  default:
    return tr("A known error has occurred, but at the moment it has not been "
              "described in detail yet.");
  }
}