package day22

import (
	"fmt"
	"log"
	"os"
	"regexp"
	"strconv"
	"strings"
)

type XY struct {
	X, Y uint
}

type Block struct {
	XMin, XMax uint
	YMin, YMax uint
	Z          uint
	IsSettled  bool
	ZHeight    uint
	Supports   []*Block
}

func (b *Block) String() string {
	return fmt.Sprintf("[Block x:%d-%d, y:%d-%d, z:%d, h:%d, isSettled %t]",
		b.XMin, b.XMax, b.YMin, b.YMax, b.Z, b.ZHeight, b.IsSettled)
}

func AtoIOrPanic(a string) int {
	n, err := strconv.Atoi(a)
	if err != nil {
		panic(err)
	}
	return n
}

func ReadBlock(line string) (b Block) {
	re := regexp.MustCompile(`(\d+),(\d+),(\d+)~(\d+),(\d+),(\d+)`)
	matches := re.FindStringSubmatch(line)

	x1, x2 := AtoIOrPanic(matches[1]), AtoIOrPanic(matches[4])
	y1, y2 := AtoIOrPanic(matches[2]), AtoIOrPanic(matches[5])
	z1, z2 := AtoIOrPanic(matches[3]), AtoIOrPanic(matches[6])

	b.XMax = uint(max(x1, x2))
	b.XMin = uint(min(x1, x2))
	b.YMax = uint(max(y1, y2))
	b.YMin = uint(min(y1, y2))
	b.Z = uint(min(z1, z2))
	b.ZHeight = uint(max(z1, z2)) - b.Z

	return
}

func (b *Block) getXY() (coords []XY) {
	for x := b.XMin; x <= b.XMax; x++ {
		for y := b.YMin; y <= b.YMax; y++ {
			coords = append(coords, XY{X: x, Y: y})
		}
	}

	return
}

func ReadBlockFile(filename string) (blocks []*Block) {
	bytes, err := os.ReadFile(filename)
	if err != nil {
		panic(err)
	}

	text := strings.TrimSpace(string(bytes))
	for _, line := range strings.Split(text, "\n") {
		block := ReadBlock(line)
		blocks = append(blocks, &block)
	}

	return
}

func BlocksByZ(blocks []*Block) [][]*Block {
	maxZ := uint(0)
	for _, block := range blocks {
		if block.Z > maxZ {
			maxZ = block.Z
		}
	}
	log.Print("found max z: ", maxZ)

	result := make([][]*Block, maxZ+1)

	for _, block := range blocks {
		result[block.Z] = append(result[block.Z], block)
	}

	return result
}