package ru.otus.stub.helper;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

public class SqlHelper {

    private final String jdbcUrl;
    private final String username;
    private final String password;

    public SqlHelper(String jdbcUrl, String username, String password) {
        this.jdbcUrl = jdbcUrl;
        this.username = username;
        this.password = password;
    }

    public int executeUpdate(String sql) {
        try (Connection connection = openConnection();
             PreparedStatement statement = connection.prepareStatement(sql)) {
            return statement.executeUpdate();
        } catch (SQLException exception) {
            throw new IllegalStateException("SQL update failed: " + sql, exception);
        }
    }

    public List<Map<String, Object>> selectRows(String sql) {
        try (Connection connection = openConnection();
             PreparedStatement statement = connection.prepareStatement(sql);
             ResultSet resultSet = statement.executeQuery()) {
            return mapRows(resultSet);
        } catch (SQLException exception) {
            throw new IllegalStateException("SQL query failed: " + sql, exception);
        }
    }

    private Connection openConnection() throws SQLException {
        return DriverManager.getConnection(jdbcUrl, username, password);
    }

    private List<Map<String, Object>> mapRows(ResultSet resultSet) throws SQLException {
        final List<Map<String, Object>> rows = new ArrayList<>();
        final ResultSetMetaData metaData = resultSet.getMetaData();
        final int columnsCount = metaData.getColumnCount();

        while (resultSet.next()) {
            final Map<String, Object> row = new LinkedHashMap<>();
            for (int column = 1; column <= columnsCount; column++) {
                row.put(metaData.getColumnLabel(column), resultSet.getObject(column));
            }
            rows.add(row);
        }
        return rows;
    }
}