package day10

import (
	"cmp"
	"fmt"
	"math"
	"slices"
	"strconv"
	"strings"

	"git.bizdoc.ro/gabi-public/Advent-of-Code.git/aoc"
	"git.bizdoc.ro/private/devkit.git/collections/dsa"
	"git.bizdoc.ro/private/devkit.git/gg"
)

func Part1(ctx aoc.Context) (int, error) {
	inputLines, err := ParseInput(ctx)
	if err != nil {
		return 0, fmt.Errorf("parse input: %w", err)
	}
	sum := 0
	for _, line := range inputLines {
		if line.IndicatorLight == 0 {
			continue // zero by default
		}

		cache2 := make([]int, 1<<line.indicatorSize)

		type Frame struct {
			indicator uint64
			step      int
			//history   *dsa.ImmutableList[uint64]
		}

		stack := dsa.NewList[Frame]()
		stack.Push(Frame{indicator: line.IndicatorLight, step: 0})

		solution := math.MaxInt
		for !stack.IsEmpty() {
			item := stack.PopFront()
			//if item.step != item.history.Len() {
			//	panic("stack overflow")
			//}
			if item.indicator == 0 {
				solution = min(solution, item.step)
			}
			if steps := cache2[item.indicator]; steps > 0 {
				if steps <= item.step {
					continue
				}
			}
			cache2[item.indicator] = item.step
			for _, button := range line.ButtonsNum {
				if item.step <= solution {
					stack.Push(Frame{
						indicator: item.indicator ^ button,
						step:      item.step + 1,
						//history:   dsa.NewImmutableList(button, item.history),
					})
				}
			}
		}
		sum += solution
	}

	return sum, nil
}

func compare[S ~[]E, E cmp.Ordered](s1, s2 S) (bool, bool) {
	isSolution := true

	for i := range len(s1) {
		canContinue := s1[i] >= s2[i]
		if !canContinue {
			return false, false
		}

		isSolution = isSolution && (s1[i] == s2[i])
	}
	return true, isSolution
}

func Part2(ctx aoc.Context) (int, error) {
	// does not work
	inputLines, err := ParseInput(ctx)
	if err != nil {
		return 0, fmt.Errorf("parse input: %w", err)
	}
	var sum int

	for _, line := range inputLines {
		type Frame struct {
			state   []byte
			step    int
			history [][]int
		}
		stack := dsa.NewStack[Frame]()

		startFrameJoltage := make([]byte, len(line.Joltages))
		for i, value := range line.Joltages {
			startFrameJoltage[i] = byte(value)
			if value > int(startFrameJoltage[i]) {
				panic("byte out of range")
			}
		}
		stack.Push(Frame{
			state: make([]byte, len(line.Joltages)),
			step:  0,
		})

		solution := math.MaxInt
		cache := make(map[string]int)

		for !stack.IsEmpty() {
			item := stack.Pop()
			if item.step > solution {
				continue
			}

			key := gg.UnsafeString(item.state)
			if steps, ok := cache[key]; ok {
				if steps < item.step {
					continue
				}
			}
			cache[key] = item.step

			canContinue, isSolution := compare(startFrameJoltage, item.state)
			if !canContinue {
				continue
			}
			if isSolution {
				//fmt.Println(item.state, item.step)
				solution = min(solution, item.step)
				//break
			}

			for _, button := range line.Buttons {
				state := slices.Clone(item.state)
				for _, val := range button {
					state[val] += 1
				}
				stack.Push(Frame{
					state: state,
					step:  item.step + 1,
					//history: append(slices.Clone(item.history), state),
				})
			}
		}
		ctx.Println(solution)
		sum += solution
	}

	return sum, nil
}

func ParseInput(ctx aoc.Context) ([]InputLine, error) {
	var inputLines []InputLine
	scanner := ctx.Scanner()
	for scanner.Scan() {
		line := scanner.Text()
		line = strings.TrimSpace(line)

		input, err := ParseInputLine([]rune(line))
		if err != nil {
			return nil, fmt.Errorf("parse input: %w", err)
		}
		inputLines = append(inputLines, input)
	}

	if err := scanner.Err(); err != nil {
		return nil, fmt.Errorf("scanner error: %w", err)
	}
	return inputLines, nil
}

type InputLine struct {
	indicatorSize     int
	IndicatorLight    uint64
	IndicatorLightRaw string
	Buttons           [][]int
	ButtonsNum        []uint64
	Joltages          []int
	RawLine           string
}

func ParseInputLine(line []rune) (input InputLine, err error) {
	// [...#.] (0,2,3,4) (2,3) (0,4) (0,1,2) (1,2,3,4) {7,5,12,7,2}
	for i, ch := range line {
		input.RawLine = string(line)
		switch ch {
		case '[': // indicator light
			if input.IndicatorLight != 0 {
				return input, fmt.Errorf("duplicate Indicator Light in line: %s", string(line))
			}

			size := i
		parseIndicatorLight:
			for i = i + 1; i < len(line); i++ {
				switch line[i] {
				case '#':
					input.IndicatorLight <<= 1
					input.IndicatorLight |= 1
				case ']':
					input.IndicatorLightRaw = string(line[size+1 : i])
					size = i - size - 1
					input.indicatorSize = size
					break parseIndicatorLight
				// done
				case '.':
					input.IndicatorLight <<= 1
				default:
					return input, fmt.Errorf("failed to parse Indicator Light. Unexpected character in IndicatorLight: %s", string(line))
				}
			}
		case '(':
			i += 1
			j := strings.IndexByte(string(line[i:]), ')')
			if j == -1 {
				return input, fmt.Errorf("failed to parse button in line: %s", string(line))
			}
			button := make([]int, 0)
			parts := strings.Split(string(line[i:i+j]), ",")
			for _, part := range parts {
				num, err := strconv.Atoi(part)
				if err != nil {
					return input, fmt.Errorf("failed to parse button in line: %s", string(line))
				}
				if num < 0 {
					return input, fmt.Errorf("negative button value in line: %s", string(line))
				}
				if num > input.indicatorSize {
					return input, fmt.Errorf("too many buttons in line: %s", string(line))
				}
				button = append(button, num)
			}
			input.Buttons = append(input.Buttons, button)
			i = j
		case '{':
			i += 1
			j := strings.IndexByte(string(line[i:]), '}')
			if j == -1 {
				return input, fmt.Errorf("failed to parse joltage in line: %s", string(line))
			}
			joltage := make([]int, 0)
			parts := strings.Split(string(line[i:i+j]), ",")
			for _, part := range parts {
				num, err := strconv.Atoi(part)
				if err != nil {
					return input, fmt.Errorf("failed to parse joltage in line: %s", string(line))
				}
				if num < 0 {
					return input, fmt.Errorf("negative joltage value in line: %s", string(line))
				}
				joltage = append(joltage, num)
			}
			input.Joltages = joltage
			i = j
		}
	}

	input.ButtonsNum = make([]uint64, len(input.Buttons))
	for i, button := range input.Buttons {
		for _, v := range button {
			input.ButtonsNum[i] |= 1 << uint64(input.indicatorSize-v-1)
		}
	}
	return input, nil
}