import java.util.Random;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;

public class ChapattiStore {

    // Simple builder class for the store
    public static class Builder {
        private boolean verbose;
        private int chappatiToMake;
        private int bakers;
        private int bakeMeanTime;
        private int bakeStdDeviation;
        private int makers;
        private int makeMeanTime;
        private int makeStdDeviation;
        private int packageMeanTime;
        private int packageStdDeviation;

        public Builder verbose(boolean verbose) {
            this.verbose = verbose;
            return this;
        }

        public Builder chappatiToMake(int chappatiToMake) {
            this.chappatiToMake = chappatiToMake;
            return this;
        }

        public Builder bakers(int bakers) {
            this.bakers = bakers;
            return this;
        }

        public Builder bakeMeanTime(int bakeMeanTime) {
            this.bakeMeanTime = bakeMeanTime;
            return this;
        }

        public Builder bakeStdDeviation(int bakeStdDeviation) {
            this.bakeStdDeviation = bakeMeanTime;
            return this;
        }

        public Builder makers(int makers) {
            this.makers = makers;
            return this;
        }

        public Builder makeMeanTime(int makeMeanTime) {
            this.makeMeanTime = makeMeanTime;
            return this;
        }

        public Builder makeStdDeviation(int makeStdDeviation) {
            this.makeStdDeviation = makeStdDeviation;
            return this;
        }

        public Builder packageMeanTime(int packageMeanTime) {
            this.packageMeanTime = packageMeanTime;
            return this;
        }

        public Builder packageStdDeviation(int packageStdDeviation) {
            this.packageStdDeviation = packageStdDeviation;
            return this;
        }

        public ChapattiStore build() {
            ChapattiStore chapattiStore = new ChapattiStore();
            chapattiStore.verbose = this.verbose;
            chapattiStore.chappatiToMake = this.chappatiToMake;
            chapattiStore.bakers = this.bakers;
            chapattiStore.bakeMeanTime = this.bakeMeanTime;
            chapattiStore.bakeStdDeviation = this.bakeStdDeviation;
            chapattiStore.makers = this.makers;
            chapattiStore.makeMeanTime = this.makeMeanTime;
            chapattiStore.makeStdDeviation = this.makeStdDeviation;
            chapattiStore.packageMeanTime = this.packageMeanTime;
            chapattiStore.packageStdDeviation = this.packageStdDeviation;

            return chapattiStore;
        }
    }

    private boolean verbose; // True for thread progress logs
    private int chappatiToMake; // number of chappati to make
    private int bakers; // number of bakers
    private int bakeMeanTime; // mean time to prepare dough for one chappati  - in ms
    private int bakeStdDeviation; // standard deviation to prepare dough for one chappati - in ms
    private int makers; // number of chappati makers
    private int makeMeanTime; // mean time to make one chappati with baked dough- in ms
    private int makeStdDeviation; // standard deviation to make one chappati with baked dough - in ms
    private int packageMeanTime; // mean time to package one chapatti - in ms
    private int packageStdDeviation; // standard deviation top package one chapatti - in ms

    private BlockingQueue<Integer> dough;
    private BlockingQueue<Integer> baked;
    private BlockingQueue<Integer> made;


    /*
        work blocks the thread invoked for a period of time
        that is normally distributed around mean with a standard deviation of stddev.
     */
    private int work(int mean, int stdDeviation) throws InterruptedException {
        Random r = new Random();
        int delay = (int) r.nextGaussian() * stdDeviation + mean;
        if (delay < 0) delay = mean;
        Thread.sleep(delay);
        return delay;
    }

    // Bake a chappati and send it to the baked queue.
    private void baker() throws InterruptedException {
        // Take dough
        var d = dough.take();
        if (verbose) {
            System.out.println("baking " + d);
        }
        work(bakeMeanTime, bakeStdDeviation);
        // Send baked dough after work
        baked.put(d);
    }

    // Retrieve from the baked queue a dough and make a chappati with it.
    private void maker() throws InterruptedException {
        // Take a baked dough
        var bakedDough = baked.take();
        if (verbose) {
            System.out.println("making " + bakedDough);
        }
        work(makeMeanTime, makeStdDeviation);
        // Send a made chapatti after work
        made.put(bakedDough);
    }

    // Package chapatti and sell them
    private void packager() throws InterruptedException {
        for (int i = 0; i < chappatiToMake; i++) {
            var chapattiReady = made.take();
            if (verbose) {
                System.out.println("packaging " + chapattiReady);
            }
            work(packageMeanTime, packageStdDeviation);
            if (verbose) {
                System.out.println("selling " + chapattiReady);
            }
        }
    }

    public float run() throws InterruptedException {
        dough = new LinkedBlockingQueue<>();
        baked = new LinkedBlockingQueue<>();
        made = new LinkedBlockingQueue<>();

        for (int i = 0; i < chappatiToMake; i++) {
            dough.put(i);
        }

        long startTime = System.currentTimeMillis();
        for (int i = 0; i < bakers; i++) {
            Runnable bake = () -> {
                while (true) {
                    try {
                        baker();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            };
            Thread t = new Thread(bake);
            t.start();
        }

        for (int i = 0; i < makers; i++) {
            Runnable make = () -> {
                while (true) {
                    try {
                        maker();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            };
            Thread t = new Thread(make);
            t.start();
        }

        packager();
        return System.currentTimeMillis() - startTime;
    }

    @Override
    public String toString() {
        StringBuilder stringBuilder = new StringBuilder();
        stringBuilder.append(String.format("Baking{Bakers:%d,BakeStdDev:%dms,BakeMeanTime:%dms}\n",
                bakers, bakeStdDeviation, bakeMeanTime));
        stringBuilder.append(String.format("Making{Makers:%d,MakeStdDev:%dms,MakeMeanTime:%dms}\n",
                makers, makeStdDeviation, makeMeanTime));
        stringBuilder.append(String.format("Packaging{PackageMeanTime:%dms,PackageStdDev:%dms}\n",
                packageStdDeviation, packageMeanTime));
        return stringBuilder.toString();
    }

    public static void main(String[] args) throws InterruptedException {
        Builder builder = new Builder();
        // Change the below values - read the comments for attributes above
        builder.verbose(false).chappatiToMake(10)
                .bakers(5).bakeMeanTime(500).bakeStdDeviation(10)
                .makers(5).makeMeanTime(200).makeStdDeviation(10)
                .packageMeanTime(100).packageStdDeviation(10);
        ChapattiStore chapattiStore = builder.build();
        System.out.printf("We closed, took %.2fs to prepare %d chappatis.\n%n", chapattiStore.run() / 1000, chapattiStore.chappatiToMake);
        System.out.print(chapattiStore);
    }
}