package main

import (
	"path/filepath"
	"os"
	"database/sql"
	"flag"
	"fmt"
	"log"
	"strings"
	"strconv"

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

var version = "0.0.1"

func main() {
	// Define a command-line flags
	help := flag.Bool("help", false, "print a short usage message")	
	dbPtr := flag.String("db", "./english_words.db", "SQLite3 DB file to use")
	filenamePtr := flag.String("file", "results.txt", "Name of the file to write results to")
	pwdPtr := flag.String("pwd", "", "Enter a password")
	flag.Parse()
	
	if *help {
		usage()
		return
	}
	
	// Open the SQLite3 database file
	db, err := sql.Open("sqlite3", *dbPtr)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()
	
	for {
	
		// Get user input for the test query
		fmt.Print("Enter keyword: ")
		var searchTerm string
		fmt.Scanln(&searchTerm)
		
		// Exit the loop if Enter key is pressed without entering a search term
		if searchTerm == "" {
			break
		}

		// Execute the first query with case-sensitive like
		query := "SELECT id FROM words WHERE word COLLATE BINARY = ?"
		rows, err := db.Query(query, searchTerm)
		if err != nil {
			log.Fatal(err)
		}
		defer rows.Close()
		
		// If no results, try case-insensitive like
		if !rows.Next() {
			rows.Close() // Close the previous result set before executing a new query

			// Execute the second query with case-insensitive like
			query = "SELECT id FROM words WHERE LOWER(word) LIKE ?"
			rows, err = db.Query(query, strings.ToLower(searchTerm))
			if err != nil {
				log.Fatal(err)
			}
			defer rows.Close()
			if rows.Next() {			
				// Process the results
				//fmt.Println("Results for case-insensitive LIKE:")
				writeResultsToFile(*filenamePtr, rows)
			} else {				
				if strings.Contains(searchTerm, "*") {
					result := strings.Replace(searchTerm, "*", "", -1)
					if (*pwdPtr != "") {
						writeDataToFile(*filenamePtr, xorStringWithPassword(compressRLE(result), *pwdPtr))
					} else {
						writeDataToFile(*filenamePtr, xorBy13(compressRLE(result)))
					}
				} else {
					fmt.Println("Not found! Please retype and add an * at the end to save")
				}
					
			}
		} else {
			// Process the results
			//fmt.Println("Results for case-sensitive LIKE:")
			writeResultsToFile(*filenamePtr, rows)
		}
	}
}

func writeDataToFile(filename string, data string) {
	file, err := os.OpenFile(filename, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()

	result := fmt.Sprintf("_%s ", data)
	_, err = file.WriteString(result)
	if err != nil {
		log.Fatal(err)
	}

	//fmt.Printf("Added to %s\n", filename)
}

func writeResultsToFile(filename string, rows *sql.Rows) {
	file, err := os.OpenFile(filename, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()

	var id int
	err = rows.Scan(&id)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("Added ID %d\n", id)
	
	result := fmt.Sprintf("%d ", id)
	_, err = file.WriteString(result)
	if err != nil {
		log.Fatal(err)
	}

	if err := rows.Err(); err != nil {
		log.Fatal(err)
	}
	//fmt.Printf("Results written to %s\n", filename)
}

func xorBy13(input string) string {
	var result strings.Builder

	for _, char := range input {
		xored := char ^ 13
		result.WriteRune(xored)
	}

	return result.String()
}

func xorStringWithPassword(input string, password string) string {
	inputBytes := []byte(input)
	passwordBytes := []byte(password)

	for i := 0; i < len(inputBytes); i++ {
		inputBytes[i] ^= passwordBytes[i%len(passwordBytes)]
	}

	return string(inputBytes)
}

// compressRLE compresses a string using Run-Length Encoding
func compressRLE(input string) string {
	result := ""
	count := 1

	for i := 1; i < len(input); i++ {
		if input[i-1] == input[i] {
			count++
		} else {
			result += string(input[i-1]) + strconv.Itoa(count)
			count = 1
		}
	}

	// Add the last character and its count
	result += string(input[len(input)-1]) + strconv.Itoa(count)

	return result
}

func usage() {
	progName := filepath.Base(os.Args[0])
	fmt.Printf(`%s version %s, (c) 2024 Bob

Usage:
%s [-help] [-db english_words.db] [-file results.txt] [-pwd MyPassword]

	-db 	SQLite3 DB file to use
	-file	Name of the file to write results to
	-pwd	Enter a password

`, progName, version, progName)
}