package main

/**
 * Project 2: programming in Go lang
 * Using Go Lang, write a program that:
 *    - fills an array with random integers in the range 10 to 99.
 *    - builds a Singly LinkedList by inserting the integers in the array into the data structure.
 * 	  - finds the length of a given LinkedList.
 *    - finds the minimum value in a given LinkedList.
 * 	  - reverses the LinkedList
 *    - remove by value from the LinkedList
 *
 * author: Nicholas Adamou
 * date: 10/7/19
 * Class: CSC-315
 */


import (
	"fmt"
	"math/rand"
)

type Node struct {
	value int
	next *Node
}

func insert(LinkedList *Node, value int) *Node {
	if LinkedList == nil {
		return LinkedList
	}

	for node := LinkedList; node != nil; node = node.next {
		if node.next == nil {
			node.next = &Node{value, nil}

			return LinkedList
		}
	}

	return LinkedList
}

func findMinimum(LinkedList *Node) (minimum int) {
	for node := LinkedList; node != nil; node = node.next {
		if node.next != nil {
			if node.value < node.next.value {
				minimum = node.value
			}
		}
	}

	return
}

func length(LinkedList *Node) (count int) {
	for node := LinkedList; node != nil; node = node.next {
		count += 1
	}

	return
}

func reverse(LinkedList *Node) *Node {
	if LinkedList == nil {
		return LinkedList
	}

	node := LinkedList

	if node.next == nil {
		return node
	} else {
		newHead := reverse(node.next)

		node.next.next = node
		node.next = nil

		return newHead
	}
}

func removeByValue(LinkedList *Node, value int) *Node {
	if LinkedList == nil {
		return LinkedList
	}

	node := LinkedList

	if node.value == value {
		node = node.next

		return node
	}

	for node.next != nil {
		if node.next.value == value {
			node.next = node.next.next

			return LinkedList
		}

		node = node.next
	}

	return LinkedList
}

func print(LinkedList *Node) {
	for node := LinkedList; node != nil; node = node.next {
		if node.next == nil {
			fmt.Printf(" %d", node.value)
		} else {
			fmt.Printf(" %d ->", node.value)
		}
	}

	fmt.Println()
}

func random(max int, min int) int {
	return rand.Int() % (max - min + 1) + min
}

func main() {
	const MIN = 10
	const MAX = 99
	const SIZE = 10

	var LinkedList *Node = &Node{random(MAX, MIN), nil}

	for i := 1; i < SIZE; i++ {
		insert(LinkedList, random(MAX, MIN))
	}

	print(LinkedList)

	fmt.Printf("\nLength of LinkedList: %d\n", length(LinkedList))
	fmt.Printf("Minimum value: %d\n", findMinimum(LinkedList))

	fmt.Println()

	reversed := reverse(LinkedList)
	print(reversed)

	fmt.Printf("\nLength of LinkedList: %d\n", length(reversed))
	fmt.Printf("Minimum value: %d\n", findMinimum(reversed))

	node := removeByValue(reversed, findMinimum(reversed))

	fmt.Printf("\nRemoved %d\n\n", node.value)

	print(reversed)

	fmt.Printf("\nLength of LinkedList: %d\n", length(reversed))
}