package main

import (
	"fmt"
	"sort"
)

func hasAverage(angles []int) (bool, int) {
	var differ bool // false
	if len(angles) == 0 {
		// We have no angles, return false and -1
		return false, -1
	}
	if len(angles) == 1 {
		// Only one angle, easy, return that one
		return true, angles[0]
	}
	// Check if the angles are different
	for _, a := range angles {
		if a != angles[0] {
			differ = true
			break
		}
	}
	// Only similar angles? Return the first one
	if !differ {
		return true, angles[0]
	}
	return false, 0
}

func average(angles []int) int {
	lastIndex := len(angles) - 1
	sort.SortInts(angles)
	for {
		if indeed, angle := hasAverage(angles); indeed {
			return angle
		}
		// There are more than one angle
		for i := lastIndex; i > 1; i-- {
			// Move all angles around, towards each other
			if angles[i] > angles[i - 1] {
				angles[i]--
			} else if angles[i] < angles[i - 1] {
				angles[i]++
			}
		}
		if angles[0] > angles[lastIndex] {
			angles[0]--
		} else if angles[0] < angles[lastIndex] {
			angles[0]++
		}
		//fmt.Println(angles)
	}
	return -1
}

func main() {
	var angles1 []int = []int{1, 359, 2, 358}
	var angles2 []int = []int{-180, 180}
	fmt.Println(average(angles1))
	fmt.Println(average(angles2))
}