package io.trygvis.persistence.sql;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public abstract class SqlDao<Id, T, S extends SqlSession, Row> {

    protected final S session;

    protected SqlDao(S session) {
        this.session = session;
    }

    public abstract void insert(T o) throws SQLException;

    public abstract void delete(T o) throws SQLException;

    public abstract void deleteById(Id id) throws SQLException;

    public abstract T selectById(Id id) throws SQLException;

    public abstract void update(T entity) throws SQLException;

    public abstract List<T> selectWhere(String where) throws SQLException;

    public abstract String[] createTableSql();

    // -----------------------------------------------------------------------
    // Protected
    // -----------------------------------------------------------------------

    protected abstract Row newRow(ResultSet rs) throws SQLException;

    protected abstract T newEntity(Row row) throws SQLException;

    protected List<T> runQuery(final String sql) throws SQLException {
        return runQuery(new Preparator() {
            @Override
            public void prepare(PreparedStatement stmt) throws SQLException {
            }
        }, sql);
    }

    protected List<T> runQuery(final Preparator preparator, final String sql) throws SQLException {
        return session.query(new SqlExecutor.QueryCommand<T>() {
            @Override
            public List<T> run(Connection c) throws SQLException {
                try (PreparedStatement stmt = c.prepareStatement(sql)) {
                    preparator.prepare(stmt);
                    ResultSet rs = stmt.executeQuery();

                    List<Row> rows = new ArrayList<>();
                    while (rs.next()) {
                        rows.add(newRow(rs));
                    }

                    List<T> entities = new ArrayList<>(rows.size());
                    for (Row row : rows) {
                        entities.add(newEntity(row));
                    }

                    return entities;
                }
            }
        });
    }

    protected static interface Preparator {
        void prepare(PreparedStatement stmt) throws SQLException;
    }
}