package main

import (
	"bufio"
	"encoding/json"
	"flag"
	"log"
	"os"
	"sort"
)

type wordList struct {
	Words map[int][]string `json:"words"`
}

func main() {
	dictFile := flag.String("dict", "", "dictionary of word to prep")
	flag.Parse()

	words := wordList{
		Words: make(map[int][]string),
	}

	if err := scanSuitableWords(*dictFile, func(word string) {
		if len(word) >= 4 && len(word) <= 6 {
			words.Words[len(word)] = append(words.Words[len(word)], word)
		}
	}); err != nil {
		log.Fatal(err)
	}

	for _, word := range words.Words {
		sort.Strings(word)
	}

	if err := json.NewEncoder(os.Stdout).Encode(words); err != nil {
		log.Fatal(err)
	}
}

func scanSuitableWords(dictFile string, withWord func(word string)) error {
	f, err := os.Open(dictFile)
	if err != nil {
		return err
	}
	defer f.Close()

	scanner := bufio.NewScanner(f)
	for scanner.Scan() {
		isSuitable := true
		breakpoint := len(scanner.Text())

		for i, r := range scanner.Text() {
			if r == '/' {
				breakpoint = i
				break
			}

			if r < 'a' || r > 'z' {
				isSuitable = false
				break
			}
		}

		if isSuitable {
			word := scanner.Text()[:breakpoint]
			withWord(word)
		} else {
		}
	}
	return scanner.Err()
}