package main

import (
	"encoding/csv"
	"errors"
	"fmt"
    "log"
	"os"
	"time"
	"internal/replace"
)

func main() {
	run, err := getArgs()
	if err != nil {
		log.Fatal(err)
		return
	}

	corpusBytes, err := os.ReadFile("./csv/corpus.csv")
    if err != nil {
        log.Fatal(err)
        return
    }

	// Read the CSV file containing replacement key-value pairs
	pairsHandle, err := os.Open("./csv/pairs.csv")
	if err != nil {
		fmt.Println("Error opening pairs:", err)
		return
	}
	defer pairsHandle.Close()

	replacements, err := csv.NewReader(pairsHandle).ReadAll()
	if err != nil {
		fmt.Println("Error reading pairs:", err)
		return
	}

	corpus := string(corpusBytes)

	var pairs []string
	var replaced string
	var startTime time.Time
	var elapsedTime time.Duration
	for _, algo := range run {
		switch algo {
		case "cw":
			// Prepare
			cw := replace.NewCommentzWalter()
			for _, record := range replacements {
				cw.AddPattern(record[0], record[1])
			}
			cw.BuildMatchingMachine()

			// Replace
			startTime = time.Now()
			replaced = cw.CommentzWalterReplace(corpus)
			elapsedTime = time.Since(startTime)
		case "bm":
			// Prepare...
			for _, record := range replacements {
				pairs = append(pairs, record[0], record[1])
			}

			// Replace
			startTime = time.Now()
			replaced = replace.BoyerMooreReplace(corpus, pairs)
			elapsedTime = time.Since(startTime)
		}
		fmt.Printf("\n%s: %s\n", algo, elapsedTime)
	}

	// Write replaced text to a file
	outputHandle, err := os.OpenFile("./csv/replaced.csv", os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0755)
	if err != nil {
		fmt.Println("Error creating output file:", err)
		return
	}
	defer outputHandle.Close()

	// Write replaced text to the file
	_, err = outputHandle.WriteString(replaced)
	if err != nil {
		fmt.Println("Error writing to file:", err)
		return
	}
}

func getArgs() ([]string, error) {
	var run = []string{"bm", "cw"}

	if len(os.Args) > 1 {
		switch os.Args[1] {
		case "all":
			run = []string{"bm", "cw"}
		case "cw":
			run = []string{"cw"}
		case "bm":
			run = []string{"bm"}
		default:
			return []string{}, errors.New("Invalid argument.")
		}
	}

	return run, nil
}