// File   : hammurabi0/Kingdom.java
// Purpose: Represents a "kingdom".  Starting version.
// Author : Fred Swartz
// Source : www.roseindia.net/java/java-tips/oop/q-hammurabi/q-pr-hammurabi-1.shtml
// License: MIT
// Date   : 07 Oct 2005
// TODO   : * Add population instance variable.  Default value 100.
//          * Add a getter method for population.
//          * Compute the new population based on food in simulation..

class kingdom {
    //========================================================== constants
    private final static int MIN_GRAIN_TO_SURVIVE = 20;
    private final static int MAX_LAND_FARMABLE_PER_PERSON = 15;
    private final static int SEED_REQUIRED_PER_ACRE = 2;

    //================================================= instance variables
    private int myGrain = 4000; // Bushels of grain in storage.
    private int myArea  = 1500; // Area of kingdom.in acres.  Note that
                                // myArea isn't used yet, but will be if
                                // you add a check for the total amount
                                // of land that can be planted.
    private int myYear  = 0;    // Years since founding of kingdom.
    private int myHarvest = 0;  // Last harvest in bushels.

    //=========================================================== getGrain
    public int getGrain() {
        return myGrain;
    }

    //============================================================ getYear
    public int getYear() {
        return myYear;
    }

    //=========================================================== toString
    public String toString() {
        // TODO: Don't forget to add population here too.
        return "Kingdom status at year " + myYear
               + ", last harvest = " + myHarvest
               + ", total grain = " + myGrain;
    }

    //==================================================== simulateOneYear
    public void simulateOneYear(int food, int seed) {

        //TODO: Need to calculate new population.based on food.

        //... Reduce grain stockpile by amount used for food and seed
        myGrain = myGrain - food - seed;

        //... Calculate new harvest
        //    1. How many acres can be planted with seed.
        //    2. The yield per acre is random (2-6)
        //    3. Harvest is yield * area planted.
        int acresPlanted = seed / SEED_REQUIRED_PER_ACRE;
        // TODO: Check that there are enough people and there is
        //       enough land to actually plant that number of
        //       acres.
        int yieldPerAcre = 2 + (int)(5 * Math.random());
        myHarvest        = yieldPerAcre * acresPlanted;

        //... Compute new amount of grain in storage.
        myGrain += myHarvest;  // New amount of grain in storage.

        myYear++;              // Another year has passed.
    }
}