package database;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Allows a prepared statement to contain named parameters instead of a question
 * mark position marker.
 *
 * @author Peter Wu
 */
public class NamedPreparedStatement {

    private final List<String> fields;
    private final PreparedStatement stmt;

    public NamedPreparedStatement(Connection conn, String query) throws SQLException {
        fields = new ArrayList<>();
        Pattern pattern = Pattern.compile(":(\\w+)");
        Matcher matcher = pattern.matcher(query);
        while (matcher.find()) {
            fields.add(matcher.group(1));
        }
        String sql = query.replaceAll(pattern.pattern(), "?");
        stmt = conn.prepareStatement(sql);
    }

    private List<Integer> getParamIndices(String fieldName) {
        List<Integer> indices = new ArrayList<>();
        int index = 0;
        for (String name : fields) {
            ++index;
            if (name.equals(fieldName)) {
                indices.add(index);
            }
        }
        if (indices.isEmpty()) {
            System.err.println(stmt);
            throw new RuntimeException("Missing " + fieldName + " in query!");
        }
        return indices;
    }

    public void setLong(String name, long l) throws SQLException {
        for (int paramIndex : getParamIndices(name)) {
            stmt.setLong(paramIndex, l);
        }
    }

    public void setString(String name, String str) throws SQLException {
        for (int paramIndex : getParamIndices(name)) {
            stmt.setString(paramIndex, str);
        }
    }

    public void setString(String name, int i) throws SQLException {
        for (int paramIndex : getParamIndices(name)) {
            stmt.setInt(paramIndex, i);
        }
    }

    public PreparedStatement getStmt() {
        return stmt;
    }

    public void executeUpdate() throws SQLException {
        try {
            getStmt().executeUpdate();
        } catch (SQLException ex) {
            System.err.println("Query error: " + ex.getMessage());
            System.err.println(stmt);
            throw ex;
        }
    }
}