package main

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

type Report struct {
	number    int
	levels    []int
	valid     bool
	direction string
}

// Reports stored one per line with levels in each column.
// In safe reports, the levels are either all increasing or all decreasing AND
// Any two adjacent levels differ by at least one and at most three.
func main() {
	input, err := os.ReadFile("input")
	if err != nil {
		fmt.Println(err)
	}
	var reports []Report

	lines := strings.Split(string(input), "\n")
	for idx, val := range lines[0 : len(lines)-1] {
		reportFields := strings.Fields(val)
		report := Report{
			number:    idx,
			valid:     true,
			direction: "ASC",
		}
		for _, field := range reportFields {
			reportVal, err := strconv.Atoi(field)
			if err != nil {
				break
			}

			report.valid = IsValidReport(&report, reportVal)

			report.levels = append(report.levels, reportVal)
		}
		reports = append(reports, report)
	}

	var valid int
	for _, report := range reports {
		fmt.Printf("%v\n", report)
		if report.valid {
			valid++
		}
	}

	fmt.Printf("Total: %v Valid %v\n", len(reports), valid)
}

func IsValidReport(report *Report, reportVal int) bool {
	if !report.valid {
		return false
	}
	valid := true
	if len(report.levels) >= 1 {
		fmt.Printf("===reportVal===: %v\n", reportVal)
		fmt.Printf("levels: %v\n", report.levels)
		last := report.levels[len(report.levels)-1]
		// if len(report.levels) == 1 {
		// 	last = 0
		// }
		fmt.Printf("last: %v\n", last)

		// Determine direction
		fmt.Printf("direction: %v\n", report.direction)
		if len(report.levels) == 1 {
			report.direction = DetermineDirection(report.levels[0], reportVal)
		}
		fmt.Printf("direction: %v\n", report.direction)

		fmt.Printf("valid: %v\n", valid)
		switch report.direction {
		case "ASC":
			if last > reportVal {
				valid = false
			}
		case "DESC":
			if last < reportVal {
				valid = false
			}
		}
		fmt.Printf("valid: %v\n", valid)
		// fmt.Printf("abs(%v-%v)=%v\n", reportVal, last, Abs(reportVal-last))
		// Check if our deltas are OK
		delta := Abs(reportVal - last)

		fmt.Printf("delta: %v\n", delta)
		// fmt.Printf("abs(%v-%v)=%v\n", reportVal, last, Abs(reportVal-last))
		if delta < 1 || delta > 3 {
			valid = false
		}
		fmt.Printf("valid: %v\n", valid)
		fmt.Printf("\n\n")
	}
	return valid
}

func DetermineDirection(one, two int) string {
	diff := one - two
	if diff < 0 {
		return "ASC"
	}
	return "DESC"
}

func Abs(input int) int {
	if input < 0 {
		return -input
	}
	return input
}