package main

import (
	"path/filepath"
	"os"
	"database/sql"
	"fmt"
	"flag"
	"io/ioutil"
	"math/rand"
	"log"
	"strings"

	_ "github.com/mattn/go-sqlite3"
)

var version = "0.0.1"

var topEnglishWords = []string{
	"the", "and", "of", "to", "a", "in", "is", "it", "you", "that",
	"he", "was", "for", "on", "are", "with", "as", "I", "his", "they",
	"be", "at", "one", "have", "this", "from", "or", "had", "by", "hot",
	"word", "but", "what", "some", "we", "can", "out", "other", "were",
	"all", "there", "when", "up", "use", "your", "how", "said", "an",
	"each", "she", "which", "do", "their", "time", "if", "will", "way",
	"about", "many", "then", "them", "write", "would", "like", "so", "these",
	"here", "me", "make", "where", "give", "now", "just",
}

var commonSymbols = []string{
	".", ",", "!", ";", "?", "(", ")", "'", "\"", "...", ":", "*", "$", "@", "#", "%",
}

func insertSymbols(db *sql.DB) {
		// Insert symbols into the database
		tx, err := db.Begin()
		if err != nil {
			log.Fatal(err)
		}

		stmt, err := tx.Prepare("INSERT INTO words(word) VALUES(?)")
		if err != nil {
			log.Fatal(err)
		}
		defer stmt.Close()

		for _, word := range commonSymbols {
			_, err = stmt.Exec(word)
			if err != nil {
				log.Fatal(err)
			}
		}

		// Commit the transaction
		tx.Commit()

		fmt.Println("Common symbols inserted into the database.")
}

func insertCommonEnglishWords(db *sql.DB) {
		// Insert top English words into the database
		tx, err := db.Begin()
		if err != nil {
			log.Fatal(err)
		}

		stmt, err := tx.Prepare("INSERT INTO words(word) VALUES(?)")
		if err != nil {
			log.Fatal(err)
		}
		defer stmt.Close()

		for _, word := range topEnglishWords {
			_, err = stmt.Exec(word)
			if err != nil {
				log.Fatal(err)
			}
		}

		// Commit the transaction
		tx.Commit()

		fmt.Println("Top English words inserted into the database.")
}

func insertEnglishWords(db *sql.DB, dictFilePtr *string) {
	// Read the contents of the shuf american-english file
	content, err := ioutil.ReadFile(*dictFilePtr)
	if err != nil {
		log.Fatal(err)
	}

	// Split content into words
	words := strings.Fields(string(content))

	// Insert american-english words into the database
	tx, err := db.Begin()
	if err != nil {
		log.Fatal(err)
	}

	stmt, err := tx.Prepare("INSERT INTO words(word) VALUES(?)")
	if err != nil {
		log.Fatal(err)
	}
	defer stmt.Close()

	for _, word := range words {
		_, err = stmt.Exec(word)
		if err != nil {
			log.Fatal(err)
		}
	}

	// Commit the transaction
	tx.Commit()

	fmt.Println("American-English words inserted into the database.")
}

func main() {
	help := flag.Bool("help", false, "print a short usage message")
	dbPtr := flag.String("db", "./english_words.db", "SQLite3 DB file to use")
	dictFilePtr := flag.String("dict", "./rnd-english", "Dictionary file to use")
	bDbUpdatePtr := flag.Bool("db-update", false, "Only update the database")
	bSkipShufflePtr := flag.Bool("skip-shuffle", false, "Skip shuffle")
	bCompressionPtr := flag.Bool("compression", false, "Use High Freq Words to compress")
	bSymbolsLastPtr := flag.Bool("symbols-last", false, "Use symbols last")
	flag.Parse()
	
	if *help {
		usage()
		return
	}
	
	// Open SQLite database file
	db, err := sql.Open("sqlite3", *dbPtr)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	// Create table
	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS words (id INTEGER PRIMARY KEY, word TEXT);`)
	if err != nil {
		log.Fatal(err)
	}

	if *bDbUpdatePtr {
		insertEnglishWords(db, dictFilePtr)
		return
	}
	
	if ! *bSkipShufflePtr {
		fmt.Println("Shuffling.....")
		// Randomize high Freq. words
		shuffleArray(topEnglishWords)
		shuffleArray(commonSymbols)
	}

	if ! *bSymbolsLastPtr {
		insertSymbols(db)
	}

	if *bCompressionPtr {
		insertCommonEnglishWords(db)
	}

	insertEnglishWords(db, dictFilePtr)
	
	if *bSymbolsLastPtr {
		insertSymbols(db)
	}
	
}

func shuffleArray(arr []string) {
	n := len(arr)
	for i := n - 1; i > 0; i-- {
		// Generate a random index between 0 and i (inclusive)
		j := rand.Intn(i + 1)

		// Swap the elements at indices i and j
		arr[i], arr[j] = arr[j], arr[i]
	}
}

func usage() {
	progName := filepath.Base(os.Args[0])
	fmt.Printf(`%s version %s, (c) 2024 Bob
PS: Don't forget to shuffle the Dict file $ shuf /usr/share/dict/american-english > rnd-english
Usage:
%s [-help] [-db English.db] [-dict rnd-english] [-shuffle] [-compression] [-later]

	-help	Print this help message.
	
	-db		SQLite3 Database to save to

	-dict 		Dictionary file to use
	
	-db-update	Only update the database, skip adding high-freq words and symbols

	-skip-shuffle	Skip shuffling High-Freq. words around
	
	-compression	Compress using high Frequency Words List, less secure
	
	-symbols-last	Use symbols last, gives away size of dict!
`, progName, version, progName)
}