package main

import (
	e "codeberg.org/pebbe/errors"

	"bufio"
	"fmt"
	"os"
	"regexp"
	"sort"
	"strconv"
	"strings"
)

type Item struct {
	text   string
	lctext string
	score  int
	isnew  bool
}

var (
	x          = e.ExitErr
	reYearWeek = regexp.MustCompile(`(.*)([12][0-9][0-9][0-9]-[0-5][0-9])(.*)`)
	count      = make(map[string]int)
	items      = make([]Item, 0)
)

func main() {
	filename := os.Args[1]
	prevname := getPrev(filename)

	fp, err := os.Open(prevname)
	x(err)
	scanner := bufio.NewScanner(fp)
	for scanner.Scan() {
		aa := strings.SplitN(scanner.Text(), "\t", 2)
		n, err := strconv.Atoi(strings.TrimSpace(aa[0]))
		x(err)
		count[aa[1]] = n
	}
	x(scanner.Err())
	x(fp.Close())

	fp, err = os.Open(filename)
	x(err)
	scanner = bufio.NewScanner(fp)
	for scanner.Scan() {
		aa := strings.SplitN(scanner.Text(), "\t", 2)
		n, err := strconv.Atoi(strings.TrimSpace(aa[0]))
		x(err)
		n1, ok := count[aa[1]]
		items = append(items, Item{
			text:   aa[1],
			lctext: strings.ToLower(aa[1]),
			score:  n - n1,
			isnew:  !ok,
		})
	}
	x(scanner.Err())
	x(fp.Close())

	sort.Slice(items, func(i, j int) bool {
		/*
			if items[i].isnew && !items[j].isnew {
				return true
			}
			if !items[i].isnew && items[j].isnew {
				return false
			}
		*/
		if items[i].score != items[j].score {
			return items[i].score > items[j].score
		}
		return items[i].lctext < items[j].lctext
	})

	for _, item := range items {
		/*
			if item.score < 2 {
				break
			}
		*/
		p := "."
		if item.isnew {
			p = "N"
		}
		fmt.Printf("%s\t%4d\t%s\n", p, item.score, item.text)
	}

}

func getPrev(filename string) string {
	mm := reYearWeek.FindStringSubmatch(filename)
	year, err := strconv.Atoi(mm[2][:4])
	x(err)
	week, err := strconv.Atoi(mm[2][5:])
	x(err)

	week--
	if week == 0 {
		week = 53
		year--
	}
	newname := fmt.Sprintf("%s%d-%02d%s", mm[1], year, week, mm[3])
	if week == 53 {
		_, err := os.Stat(newname)
		if err == nil {
			return newname
		}
		newname = fmt.Sprintf("%s%d-%02d%s", mm[1], year, week-1, mm[3])
	}
	return newname
}