package solutions

import (
	"fmt"
	"strconv"
	"strings"
)

type InstructionStore struct {
	instruction    Instruction
	value          int
	executionCount int
}

type Instruction int

const (
	nop Instruction = iota
	acc
	jmp
)

func parseInstruction(line string) (Instruction, int) {
	instr := strings.Split(line, " ")[0]
	valueStr := line[4:]
	value, err := strconv.Atoi(valueStr)
	if err != nil {
		fmt.Println(err)
		panic("expected a number, got `" + valueStr + "`")
	}

	var instruction Instruction

	if instr == "nop" {
		instruction = nop
	} else if instr == "acc" {
		instruction = acc
	} else if instr == "jmp" {
		instruction = jmp
	} else {
		panic("Invalid instruction found: " + instr)
	}

	return instruction, value
}

func Day08Part01(isTest bool) int {
	input := ReadInput("08", isTest)
	groups := strings.Split(input, "\n")

	instructionArray := make([]*InstructionStore, len(groups))

	for idx, line := range groups {
		instr, value := parseInstruction(line)
		instructionArray[idx] = &InstructionStore{instruction: instr, value: value, executionCount: 0}
	}

	accumulator := 0
	instructionPointer := 0

	for {
		currentInstruction := instructionArray[instructionPointer]
		inst := currentInstruction.instruction
		value := currentInstruction.value
		executionCount := currentInstruction.executionCount

		if executionCount != 0 {
			return accumulator
		}

		switch inst {
		case nop:
			currentInstruction.executionCount += 1
			instructionPointer += 1
		case acc:
			currentInstruction.executionCount += 1
			accumulator += value
			instructionPointer += 1
		case jmp:
			currentInstruction.executionCount += 1
			instructionPointer += value
		default:
			panic("Found an invalid instruction while trying to execute it. " + strconv.Itoa(int(inst)))
		}
	}
}

func Day08Part02(isTest bool) int {
	return -1
}