package main

import (
	"bufio"
	"flag"
	"fmt"
	"io"
	"net/http"
	"os"
	"os/user"
	"path/filepath"
	"regexp"
	"strings"

	"github.com/atotto/clipboard"
)

var commentVar string
var mainContent string

func init() {
	const (
		defaultComment = ""
		usage          = "add a comment to the quicknote"
	)
	flag.StringVar(&commentVar, "c", defaultComment, usage+" (shorthand)")
	flag.StringVar(&commentVar, "comment", defaultComment, usage)
	flag.Parse()
	mainContent = flag.Arg(0)
}

func main() {
	var url, markdownFile string

	urlFromClipboard, err := clipboard.ReadAll()
	if err != nil {
		fmt.Printf("Error getting URL from clipboard: %v\n", err)
		os.Exit(1)
	}
	url = strings.TrimSpace(urlFromClipboard)

	usr, err := user.Current()
	if err != nil {
		fmt.Printf("Error getting user home directory: %v\n", err)
		os.Exit(1)
	}
	markdownFile = filepath.Join(usr.HomeDir, "Documents", "Notes", "quicknote.md")

	resp, err := http.Get(url)
	if err != nil {
		fmt.Printf("Error fetching URL: %v\n", err)
		os.Exit(1)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		fmt.Printf("Error reading response body: %v\n", err)
		os.Exit(1)
	}

	htmlContent := string(body)
	title, err := extractTitle(htmlContent)

	if err != nil {
		fmt.Printf("Error: %v\n", err)
		title = promptForTitle()
	}

	markdownLink := fmt.Sprintf("- [%s](%s)\n", title, url)
	if commentVar != "" {
		markdownLink = fmt.Sprintf("- %s: [%s](%s)\n", strings.TrimSpace(commentVar), title, url)
	}
	err = appendToFile(markdownFile, markdownLink)
	if err != nil {
		fmt.Printf("Error appending to file: %v\n", err)
		os.Exit(1)
	}
}

func extractTitle(html string) (string, error) {
	re := regexp.MustCompile(`(?i)<\s*title\s*>(.*?)<\s*/\s*title\s*>`)
	match := re.FindStringSubmatch(html)
	if len(match) > 0 {
		title := strings.TrimSpace(match[1])
		if title != "" {
			return title, nil
		}
		return "", fmt.Errorf("title tag is empty")
	}
	return "", fmt.Errorf("title tag is not present")
}

func promptForTitle() string {
	reader := bufio.NewReader(os.Stdin)
	fmt.Print("Please enter a title for the URL: ")
	title, _ := reader.ReadString('\n')
	return strings.TrimSpace(title)
}

// appendToFile writes content to the file filename.
func appendToFile(filename, content string) error {
	f, err := os.OpenFile(filename, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return err
	}
	defer f.Close()

	if _, err := f.WriteString(content); err != nil {
		return err
	}
	return nil
}