package main

import (
	"fmt"
	"testing"
)

func assertEqual(t *testing.T, expected interface{}, actual interface{}) {
	if expected != actual {
		t.Fatalf("%v != %v", expected, actual)
	}
}

func insertionSort(A []int) []int {
	for j := 1; j < len(A); j++ {
		key := A[j]
		i := j - 1
		for i >= 0 && A[i] > key {
			A[i+1] = A[i]
			i = i - 1
		}
		A[i+1] = key
	}
	return A
}

func insertionSortDescending(A []int) []int {
	for j := 1; j < len(A); j++ {
		key := A[j]
		i := j - 1
		for i >= 0 && A[i] < key {
			A[i+1] = A[i]
			i = i - 1
		}
		A[i+1] = key
	}
	return A
}

func TestInsertionSort(t *testing.T) {
	t.Run("Ascending order", func(t *testing.T) {
		items := []int{31, 41, 59, 26, 41, 58}

		results := insertionSort(items)

		fmt.Printf("%v\n", results)

		assertEqual(t, 26, results[0])
		assertEqual(t, 31, results[1])
		assertEqual(t, 41, results[2])
		assertEqual(t, 41, results[3])
		assertEqual(t, 58, results[4])
		assertEqual(t, 59, results[5])
	})

	t.Run("Descending order", func(t *testing.T) {
		items := []int{31, 41, 59, 26, 41, 58}

		results := insertionSortDescending(items)

		fmt.Printf("%v\n", results)

		assertEqual(t, 26, results[5])
		assertEqual(t, 31, results[4])
		assertEqual(t, 41, results[2])
		assertEqual(t, 41, results[3])
		assertEqual(t, 58, results[1])
		assertEqual(t, 59, results[0])
	})
}