package build.selsort;

import org.openjdk.jmh.annotations.*;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;

import java.util.Random;
import java.util.concurrent.TimeUnit;

@State(Scope.Thread)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@Fork(1)
@Warmup(iterations = 2, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)

public class Timeselsort {

    static Boolean checkorder(int[] A) {
        for (int i=1; i<A.length; i++)
            if (A[i] < A[i-1]) {
                return false;
            }
        return true;
    }

    // JMH will run the benchmark for arrays of size 10 to 1,000,000
    // @Param({"10", "100", "1000", "10000", "100000", "1000000"})
    // @Param({"10", "100", "1000", "10000", "100000"})
    @Param({"10000"})
    private int testsize;

    @Param({"regular", "up", "down"})
    private String testtype;
    
    private int maxval = 1000000;

    private int[] originalArray;
    private int[] arrayToSort;

    // Generated once per benchmark trial run
    @Setup(Level.Trial)
    public void setupData() {
        originalArray = new int[testsize];
        Random random = new Random(42); // Fixed seed makes tests reproducible
        if (testtype.equals("regular")) {
            for (int i = 0; i < testsize; i++) {
                originalArray[i] = random.nextInt(maxval);
            }
        }
        else if (testtype.equals("up")) {
            for (int i = 0; i < testsize; i++) {
                originalArray[i] = i + 1;
            }
        }
        else if (testtype.equals("down")) {
            for (int i = 0; i < testsize; i++) {
                originalArray[i] = maxval - i;
            }
        }
        else System.out.println("++++++++++++++++ ERROR!! BAD TEST TYPE!!");
    }

    // Generated right before every single iteration execution
    @Setup(Level.Invocation)
    public void copyArray() {
        // Crucial for sorting algorithms so we never benchmark an already-sorted array
        arrayToSort = originalArray.clone();
    }

    @Benchmark
    public int[] benchmarkselsort() {
        if (!testtype.equals("regular") && (testsize != 10000)) {
            throw new RuntimeException("Up/down only 10,000");
        }
        /* ========== CALL THE SORT ============== */
        //        if (checkorder(arrayToSort)) {
        //            throw new RuntimeException("ARRAY SHOULD NOT START SORTED!!");
        //        }
        selsort(arrayToSort);
        //        if (!checkorder(arrayToSort)) {
        //            throw new RuntimeException("ARRAY DID NOT SORT PROPERLY!!");
        //        }
        return arrayToSort; // Returning prevents Dead Code Elimination optimization
    }

    // =============== HERE IS THE BENCHMARKED CODE =======================
    // Swap for int arrays
    public static void swap(int[] A, int i, int j) {
        int temp = A[i];
        A[i] = A[j];
        A[j] = temp;
    }

    void selsort(int[] A) {
        for (int i=0; i<A.length-1; i++) {       // Select i'th biggest record
            int bigindex = 0;                      // Current biggest index
            for (int j=1; j < A.length-i; j++) {     // Find the max value
                if (A[j] > A[bigindex])              // Found something bigger  
                    bigindex = j;                      // Remember bigger index
            }
            swap(A, bigindex, A.length-i-1);       // Put it into place
        }
    }
    // =============== END THE BENCHMARKED CODE =======================

    // Built-in main method so you can kick it off easily from your command line execution
    public static void main(String[] args) throws Exception {
        Options opt = new OptionsBuilder()
            .include(Timeselsort.class.getSimpleName())
            .build();

        new Runner(opt).run();
    }
}