/*
 * PCComponent.java
 */
import java.util.*; // for Vector
import java.sql.*;
import java.io.*; // for debug file writer

/** is a class for reading the contents of a database that describes
 * a Personal Computer system and its subcomponents.


 * History:


 *      2 Oct 2004 : initial version

 *      3 Oct 2004 : added indented recursive generation of
 *                  toString() data

 *      4 Oct 2004 : added ownCost data and special format marker
 *                  ^B in toString(). This requires the caller
 *                   of toString() to use the ConsoleFormatter
 *                   class to set the way toString() data will 
 *                   appear in a console session.
 * @author Timothy Paul Fox
 * @version 04 October 2004
 */
public class PCComponent {
    
    private String componentName;
    private String componentType;
    private Vector partsBin;
    private String tableName;
    private String tableKey;
    private double ownCost;
    private double aggregateCost;
    private String partsDescription;
    
    {
        partsBin = null;
        partsDescription = "";
    }
    
    /** Creates a new instance of PCComponent
     * @param dbTable names the database table that contains a row that 
     * describes this component.
     * @param dbKey is the primary key that identifies the row in dbTable 
     * that contains this component's data.
     * @param con is the connection to the database that contains dbTable.
     * @throws Exception is a catch-all for anything that can go wrong
     * when instantiating the object.
     */
    public PCComponent(String dbTable, String dbKey, Connection con) 
                                                throws Exception {
        Statement stmt = null;
        ResultSet rslt = null;
        ResultSetMetaData rsmd = null;
        String subTable, subKey, colName;
        Vector partFinder;
        StringBuffer sb;
        PCComponent subcomponent;
        int columns, xPos;
        
        if (dbTable == null || dbKey == null || con == null) {
            throw new IllegalArgumentException(
                                        "Bad arg to PCComponent()");
        }
        tableKey = dbKey;
        tableName = dbTable;
        try {
            stmt = con.createStatement();
            // look up the component type
            rslt = stmt.executeQuery("SELECT * FROM extrainfo" +
                                      " WHERE tname = " + 
                                      quoteForSQL(dbTable));
            rslt.first(); // if no data, throws SQLException.
            componentType = rslt.getString("classname");
            // read the home table
            rslt = stmt.executeQuery("SELECT * FROM " + dbTable +
                                      " WHERE prikey = " + 
                                      quoteForSQL(dbKey));
            rslt.first(); // if no data, throws SQLException.
            componentName = rslt.getString("name");
            ownCost = rslt.getDouble("owncost");
            partsBin = new Vector();
            sb = new StringBuffer(componentType + ": " + componentName);
            sb.append("\u0002" + getOwnCost());
            // get information about subcomponents, if any
            partFinder = new Vector();
            rsmd = rslt.getMetaData();
            columns = rsmd.getColumnCount();
            while (columns > 0) {
                colName = rsmd.getColumnName(columns).toLowerCase();
                if (colName.startsWith("fk")) {
                    subKey = rslt.getString(colName);
                    partFinder.insertElementAt(
                                colName.substring(2) + "\t" + subKey, 0);
                }
                columns--;
            }
            Enumeration en = partFinder.elements();
            aggregateCost = getOwnCost();
            while (en.hasMoreElements()) {
                subTable = (String) en.nextElement();
                xPos = subTable.indexOf('\t');
                subKey = subTable.substring(1 + xPos);
                subTable = subTable.substring(0, xPos);
                subcomponent = new PCComponent(subTable, subKey, con);
                aggregateCost += subcomponent.getCost();
                if (sb.charAt(sb.length() - 1) != '\n')
                    sb.append("\n");
                sb.append(subcomponent.toString());
                partsBin.add(subcomponent);
            }
            // build indented description string in sb 
            // to be used by toString()
            xPos = 0;
            do {
                xPos = sb.indexOf("\n", xPos);
                if (xPos >= 0) {
                    sb.insert(xPos + 1, '\t');
                    xPos++;
                }
                else
                    break;
                
            } while (true);
            partsDescription = sb.toString();
        }
        finally {
            if (stmt != null) stmt.close();
        }
    } // end constructor PCComponent
    
    /** describes this component and its subcomponents.
     * @return the name of this component and, if it has subcomponents,
     * the indented names of those subcomponents.
     */    
    public String toString() {
        return partsDescription;
    }
    
    /** Gets the name of this component from the database.
     * @return the name of this component.
     */    
    public String getName() {
        return componentName;
    }
    
    /** gets the cost of this component, without adding the cost 
     * of subcomponents.
     * @return the cost of this component.
     */    
    public double getOwnCost() {
        //ong tempL;
        //tempL = Math.round(ownCost * 1000.0);
        //return tempL / 1000.0;
        return ownCost;
    }
    
    /** gets the sum of the costs of this component and its
     * subcomponents.
     * @return the aggregate cost.
     */    
    public double getCost() {
        long tempL;
        tempL = Math.round(aggregateCost * 1000.0); 
        return tempL / 1000.0;
    }
    
    /** tells whether this component has subcomponents.
     * @return true if this component includes subcomponents.
     */    
    public boolean hasSubcomponents() {
        if (null == partsBin || partsBin.isEmpty())
            return false;
        return true;
    }
    
    /** gets the subcomponents, if any.
     * @return a Vector of PCComponents, or null.
     */    
    public Vector getSubcomponents() {
        return partsBin;
    }

    // NOTE : This method has only been tested with MySQL.
    private String quoteForSQL(String s) {
        StringBuffer sb = new StringBuffer(s);
        int qPos = -1;
        int lastQPos = 0;
        do { // escape any internal apostrophes
            //  O'Reilly --> O''Reilly
            qPos = sb.indexOf("'", lastQPos);
            if (qPos >= 0) {
                sb.insert(qPos,'\'');
                lastQPos = qPos + 2;
            }
        } while (qPos >= 0);
        sb.insert(0, '\'');
        sb.append('\'');
        return sb.toString();
    } // end quoteForSQL
} // end class PCComponent