package main

import (
	"bufio"
	"errors"
	"log"
	"math"
	"os"
	"strconv"
	"strings"
)

func main() {
	file, err := os.Open("input.txt")
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	if !scanner.Scan() {
		log.Fatalln("Problem while read line.")
		return
	}

	stringarr := strings.Split(scanner.Text(), ",")
	var t2 = []int{}

	for _, i := range stringarr {
		j, err := strconv.Atoi(i)
		if err != nil {
			panic(err)
		}
		t2 = append(t2, j)
	}
	wip := make([]int, len(t2))
	wip2 := make([]int, len(t2))

	// ========= Finish now, we can solve the task ======
	copy(wip, t2)
	SolvePuzzle1(wip)
	copy(wip2, t2)
	SolvePuzzle2(wip2)
}

func SolvePuzzle1(list []int) {

	rawr := []int{0, 1, 2, 3, 4}
	combinations := permutations(rawr)
	highestOutput := math.MinInt32
	//highestInput := ""

	for _, combi := range combinations {
		output := RunAmplification(list, []int{int(combi[0]), int(combi[1]), int(combi[2]), int(combi[3]), int(combi[4])})
		if output > highestOutput {
			//highestInput = combi
			highestOutput = output
		}
	}
	log.Println("Part1: " + strconv.Itoa(highestOutput))
}

func SolvePuzzle2(list []int) {

	rawr := []int{9, 8, 7, 6, 5}
	combinations := permutations(rawr)
	highestOutput := math.MinInt32
	//highestInput := ""

	for _, combi := range combinations {
		output := RunRecursiveAmplification(list, []int{combi[0], combi[1], combi[2], combi[3], combi[4]})
		if output > highestOutput {
			//highestInput = combi
			highestOutput = output
		}
	}
	log.Println("Part2: " + strconv.Itoa(highestOutput))
}

func RunAmplification(list []int, phases []int) int {
	signal := []string{"0"}

	for i := 0; i < 5; i++ {
		wip := make([]int, len(list))
		copy(wip, list)

		inputs := make([]int, 0)
		inputs = append(inputs, phases[i])
		for j := 0; j < len(signal); j++ {
			inputStr, _ := strconv.Atoi(signal[j])
			inputs = append(inputs, inputStr)
		}

		output, err, _ := ParseArray(wip, inputs)

		if err != nil {
			log.Printf("Problem at Amplification: %d", i+1)
			log.Fatal(err)
		}

		signal = output
	}
	sigInt, _ := strconv.Atoi(signal[0])
	return sigInt
}

func RunRecursiveAmplification(list []int, phases []int) int {
	signal := []string{"0"}

	i := 0
	for true {
		wip := make([]int, len(list))
		copy(wip, list)

		inputs := make([]int, 0)
		inputs = append(inputs, phases[i])
		for j := 0; j < len(signal); j++ {
			inputStr, _ := strconv.Atoi(signal[j])
			inputs = append(inputs, inputStr)
		}

		output, err, cmdSuccess := ParseArray(wip, inputs)

		if err != nil {
			log.Printf("Problem at Amplification: %d", i+1)
			log.Fatal(err)
		}

		signal = output

		if cmdSuccess && i == 4 {
			break
		}

		if i == 4 {
			i = -1
		}
		i++
	}
	sigInt, _ := strconv.Atoi(signal[len(signal)-1])
	return sigInt
}

func ParseArray(list []int, inputs []int) (output []string, err error, cmdEnd bool) {
	inputIndex := 0
	output = make([]string, 0)

	for i := 0; i < len(list); i += 4 {
		//log.Println(strconv.Itoa(i) +  " -> "  + strconv.Itoa(list[i]))
		cmd := list[i]

		if cmd == 99 {
			return output, nil, true
		}
		sum := 0

		mode1 := 0
		mode2 := 0
		//mode3 := 0

		count := CountDigits(cmd)
		if count > 2 {
			cmdStr := strconv.Itoa(cmd)
			cmd, _ = strconv.Atoi(cmdStr[len(cmdStr)-2:])

			if count >= 3 {
				mode1, _ = strconv.Atoi(cmdStr[len(cmdStr)-3 : len(cmdStr)-2])
			}
			if count >= 4 {
				mode2, _ = strconv.Atoi(cmdStr[len(cmdStr)-4 : len(cmdStr)-3])
			}
			if count >= 5 {
				//mode3, _ = strconv.Atoi(cmdStr[len(cmdStr)-4:len(cmdStr)-3])
			}
		}

		if cmd == 1 {
			num1 := -1
			num2 := -1
			if mode1 == 1 {
				num1 = list[i+1]
			} else {
				num1 = list[list[i+1]]
			}
			if mode2 == 1 {
				num2 = list[i+2]
			} else {
				num2 = list[list[i+2]]
			}
			sum = num1 + num2
			list[list[i+3]] = sum

		} else if cmd == 2 {

			num1 := -1
			num2 := -1
			if mode1 == 1 {
				num1 = list[i+1]
			} else {
				num1 = list[list[i+1]]
			}
			if mode2 == 1 {
				num2 = list[i+2]
			} else {
				num2 = list[list[i+2]]
			}
			sum = num1 * num2
			list[list[i+3]] = sum
		} else if cmd == 3 {
			//log.Println(i)

			if len(inputs) > inputIndex {
				input := inputs[inputIndex]
				inputIndex++
				list[list[i+1]] = input
			} else {
				input := output[0]
				output = output[1:]
				inputInt, _ := strconv.Atoi(input)
				list[list[i+1]] = inputInt
			}
			i = i - 2
		} else if cmd == 4 {
			if mode1 == 1 {
				output = append(output, strconv.Itoa(list[i+1]))
			} else {
				output = append(output, strconv.Itoa(list[list[i+1]]))
			}
			i = i - 2
		} else if cmd == 5 {
			num1 := -1
			if mode1 == 1 {
				num1 = list[i+1]
			} else {
				num1 = list[list[i+1]]
			}
			num2 := -1
			if mode2 == 1 {
				num2 = list[i+2]
			} else {
				num2 = list[list[i+2]]
			}
			if num1 != 0 {
				i = num2 - 4
			} else {
				i -= 1
			}
		} else if cmd == 6 {
			num1 := -1
			if mode1 == 1 {
				num1 = list[i+1]
			} else {
				num1 = list[list[i+1]]
			}
			num2 := -1
			if mode2 == 1 {
				num2 = list[i+2]
			} else {
				num2 = list[list[i+2]]
			}
			if num1 == 0 {
				i = num2 - 4
			} else {
				i -= 1
			}
		} else if cmd == 7 {
			num1 := -1
			if mode1 == 1 {
				num1 = list[i+1]
			} else {
				num1 = list[list[i+1]]
			}
			num2 := -1
			if mode2 == 1 {
				num2 = list[i+2]
			} else {
				num2 = list[list[i+2]]
			}
			if num1 < num2 {
				list[list[i+3]] = 1
			} else {
				list[list[i+3]] = 0
			}
		} else if cmd == 8 {
			num1 := -1
			if mode1 == 1 {
				num1 = list[i+1]
			} else {
				num1 = list[list[i+1]]
			}
			num2 := -1
			if mode2 == 1 {
				num2 = list[i+2]
			} else {
				num2 = list[list[i+2]]
			}
			if num1 == num2 {
				list[list[i+3]] = 1
			} else {
				list[list[i+3]] = 0
			}
		} else {
			return output, errors.New("Wrong Command (" + strconv.Itoa(list[i]) + ") at position " + strconv.Itoa(i)), false
		}
	}
	return output, nil, false
}

func CountDigits(i int) int {
	count := 0
	for i != 0 {
		i /= 10
		count = count + 1
	}
	return count
}

func permutations(arr []int) [][]int {
	var helper func([]int, int)
	res := [][]int{}

	helper = func(arr []int, n int) {
		if n == 1 {
			tmp := make([]int, len(arr))
			copy(tmp, arr)
			res = append(res, tmp)
		} else {
			for i := 0; i < n; i++ {
				helper(arr, n-1)
				if n%2 == 1 {
					tmp := arr[i]
					arr[i] = arr[n-1]
					arr[n-1] = tmp
				} else {
					tmp := arr[0]
					arr[0] = arr[n-1]
					arr[n-1] = tmp
				}
			}
		}
	}
	helper(arr, len(arr))
	return res
}