/*
 * LuckyOccurrenceCounter.java
 *
 * Created on January 13, 2003, 7:35 PM
 */

package project1;

/** This oracle, and its omen, are written to take advantage of code
 *      already in LuckTester and LuckTesterOmen. 
 *
 * 
 */
public class LuckyOccurrenceCounter implements IOracle {
    
    /** Oracle will try this many times.
     */
    private static final int maxTrials = 1000000;
    
    /** Creates a new instance of LuckyOccurrenceCounter */
    public LuckyOccurrenceCounter() {
    }
    
    /** See if some data is suitable to be presented to the oracle.
     * For example, the God of Luck required initials (2 upper case characters)
     *    as request data.
     *  @param requestData the data, as a string; exact format and requirements
     *      are oracle-dependent.  For this oracle, the input must be a string
     *      of exactly two uppercase English letters.
     *  @return true iff the requestData is acceptable (can be processed without
     *      error) by the oracle.
     */
    public boolean checkRequestData(String requestData) {
        return LuckTester.checkInitials(requestData); // all the work is done there.
    }
    
    /** Tell the name of this oracle.
     *  @return A short string with the name of the oracle;  there should be
     *      no leading or trailing whitespace.
     */
    public String getName() {
        return "Lucky Occurrence Counter";
    }
    
    /** Search the entrails and return the omen found.
     *  It should never go into an infinite loop.
     *  @param requestData The information (typically a name) about which the oracle
     *      is searching for information (for an omen).
     *  @return an omen, or null if there is no omen at all.
     */
    public IOmen searchEntrailsForOmen(String initials) {
        final int matchesNeeded = maxTrials; //force it to keep going
        final int count = LuckTester.matchInitialsRandomly(initials, maxTrials, matchesNeeded);
        final String shortInterpretation = this.interpret(count);
        final IOmen retOmen = new LuckyOccurrencesOmen(count, 
                                                shortInterpretation);
        return retOmen;
    }
    
        /** Report on how lucky a result is.
        @param score a value representing the number of matches found.
     *  @return an English message explaining or evaluating the result.  For example,
     *  it could be "You are truly beloved of Fortuna" or "You need to increase
     *  your offerings or disaster will befall", as appropriate.
     */
    private String interpret(double score) {
        final double aSize = 26.0; //alphabet size
        final double trials = 1000000; // should probably be instance variables
        final double expectation = trials/(aSize*aSize); //expected number of matches
        if (score > 2 * expectation) {
            return "Incredible Luck!  You are truly beloved of the gods.";
        }
        if (score > expectation) {
            return "The gods smile upon you.";
        }
        if (score < expectation/5) {
            return "EXTREME DANGER -- the gods are wrathful unto thee.";
        }
        if (score < expectation/2) {
            return "Caution -- luck does not favor you.";
        }
        else {
            return "The gods of luck are just a tiny bit displeased.";
        }
    //end interpret   
    }

    
}