package main

import (
	"fmt"
	"os"

	h "git.bullercodeworks.com/brian/adventofcode/helpers"
)

func main() {
	inp := h.StdinToStringSlice()
	part1(inp)
	fmt.Println()
	part2(inp)
}

func part1(inp []string) {
	var ret int
	fresh, ing := parseDB(inp)
	for i := range ing {
		for j := range fresh {
			if fresh[j].Contains(ing[i]) {
				ret++
				break
			}
		}
	}
	fmt.Println("# Part 1")
	fmt.Println(ret)
}

func part2(inp []string) {
	fresh, _ := parseDB(inp)
	for {
		var toDel []*Range
		for i := 0; i < len(fresh)-1; i++ {
			for j := i + 1; j < len(fresh); j++ {
				if fresh[i].Overlaps(fresh[j]) {
					fresh[i].Merge(fresh[j])
					toDel = append(toDel, fresh[j])
				}
			}
			if len(toDel) > 0 {
				break
			}
		}
		if len(toDel) == 0 {
			break
		}
		for i := range toDel {
			for j := 0; j < len(fresh); j++ {
				if fresh[j] == toDel[i] {
					fresh = append(fresh[:j], fresh[j+1:]...)
					break
				}
			}
		}
	}

	// At this point, all ranges in 'fresh' should be non-overlapping
	var ret int
	for i := range fresh {
		ret += fresh[i].Size()
	}
	fmt.Println("# Part 2")
	fmt.Println(ret)
}

type Range struct {
	beg, end int
}

func NewRange(inp string) *Range {
	r := Range{}
	fmt.Sscanf(inp, "%d-%d", &r.beg, &r.end)
	return &r
}
func (r *Range) Contains(i int) bool { return r.beg <= i && i <= r.end }
func (r *Range) Overlaps(r2 *Range) bool {
	return r.Contains(r2.beg) || r.Contains(r2.end) || r2.Contains(r.beg) || r2.Contains(r.end)
}
func (r *Range) Merge(r2 *Range) {
	if !r.Overlaps(r2) {
		fmt.Println("Panic! Tried to merge non-overlapping ranges")
		os.Exit(1)
	}
	r.beg = h.Min(r.beg, r2.beg)
	r.end = h.Max(r.end, r2.end)
}
func (r *Range) Size() int     { return (r.end - r.beg) + 1 }
func (r Range) String() string { return fmt.Sprintf("%d to %d", r.beg, r.end) }

func parseDB(inp []string) ([]*Range, []int) {
	var retRng []*Range
	var retInt []int
	inRanges := true
	for i := range inp {
		if inp[i] == "" {
			inRanges = false
			continue
		}
		if inRanges {
			retRng = append(retRng, NewRange(inp[i]))
			continue
		}
		var ri int
		fmt.Sscanf(inp[i], "%d", &ri)
		retInt = append(retInt, ri)
	}
	return retRng, retInt
}