package main

import (
	"bufio"
	"bytes"
	"encoding/json"
	"flag"
	"log"
	"math/rand/v2"
	"os"
	"path/filepath"
	"sort"
	"time"
)

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

type shufflePattern struct {
	Index map[int][]int `json:"index"`
}

func main() {
	dictFile := flag.String("dict", "./dict/en_GB.dic", "dictionary of word to prep")
	outDir := flag.String("out", "./site/assets/data", "output directory")
	flag.Parse()

	r := rand.New(rand.NewPCG(uint64(time.Now().UnixNano()), uint64(time.Now().UnixNano())))

	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 k, word := range words.Words {
		log.Printf("Found %d words of length %v", len(word), k)
		sort.Strings(word)
	}

	var wordData bytes.Buffer
	if err := json.NewEncoder(&wordData).Encode(words); err != nil {
		log.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(*outDir, "words.json"), wordData.Bytes(), 0644); err != nil {
		log.Fatal(err)
	}

	// Generate a shuffle pattern
	shp := shufflePattern{Index: make(map[int][]int)}
	for k := range words.Words {
		pattern := make([]int, len(words.Words[k]))
		for i := range words.Words[k] {
			pattern[i] = i
		}

		for x := 4; x < r.IntN(8)+4; x++ {
			r.Shuffle(len(pattern), func(i, j int) {
				pattern[i], pattern[j] = pattern[j], pattern[i]
			})
		}

		// TODO: shuffle
		shp.Index[k] = pattern
	}

	var patternData bytes.Buffer
	if err := json.NewEncoder(&patternData).Encode(shp); err != nil {
		log.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(*outDir, "shuffle_pattern.json"), patternData.Bytes(), 0644); 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()
}