package main

import (
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	md "github.com/JohannesKaufmann/html-to-markdown"
	"github.com/JohannesKaufmann/html-to-markdown/plugin"
	"github.com/gomarkdown/markdown"
	"github.com/microcosm-cc/bluemonday"
)

type Template struct {
	TemplateName string `json:"templateName"`
	Filename     string `json:"filename"`
}

func EditFile(w http.ResponseWriter, r *http.Request) {
	userSession, err := validateSession(w, r)
	if err != nil {
		handleError("Error validating session", err)
		return
	}

	// Get template and filename from query parameters
	templateName := r.URL.Query().Get("template")
	filename := r.URL.Query().Get("filename")
	filePath := filepath.Join(fileUploadPath, userSession.username, filename)

	// Read file content
	fileContent, err := readFileContent(filePath)
	if err != nil {
		handleError("Error reading file content", err)
		return
	}

	// Apply template content if specified
	if templateName != "" {
		templatePath := filepath.Join(templateFilePath, templateName)
		templateContent, err := readFileContent(templatePath)
		if err != nil {
			handleError("Error reading template content", err)
			return
		}
		// overwrites file content. Could also change this to append.
		//TODO: Give user setting to choose which method of usage.
		fileContent = markdown.ToHTML([]byte(templateContent), nil, nil)
	}

	// Sanitize file content
	sanitizedContent := sanitizeHTML(fileContent)

	// Convert file content based on file type
	if filepath.Ext(filename) == ".md" {
		// Convert Markdown to HTML
		htmlContent := markdown.ToHTML([]byte(sanitizedContent), nil, nil)
		fileContent = []byte(htmlContent)
	} else if filepath.Ext(filename) == ".html" {
		// Sanitize HTML content to prevent any malicious code
		fileContent = []byte(sanitizedContent)
	}

	templates, err := getTemplateList()
	if err != nil {
		handleError("Error getting template list", err)
		return
	}
	// Update the Templates slice to assign the current filename
	for i := range templates {
		templates[i].Filename = filename
	}
	data := struct {
		Filename    string
		FileContent string
		Templates   []Template // Update type to []Template
	}{
		Filename:    filename,
		FileContent: string(fileContent),
		Templates:   templates, // Assign the template list
	}

	renderTemplate(w, "edit.html", data)
}

func SaveFile(w http.ResponseWriter, r *http.Request) {
	userSession, err := validateSession(w, r)
	if err != nil {
		handleError("Error validating session", err)
		return
	}

	// Get filename from query parameters
	filename := r.URL.Query().Get("filename")
	newFilename := r.FormValue("filename") // Retrieve the new filename from the form
	filePath := filepath.Join(fileUploadPath, userSession.username, filename)
	newFilePath := filepath.Join(fileUploadPath, userSession.username, newFilename) // Create the new file path

	// If the new filename is different from the expected filename
	if newFilename != filename {

		// Check if the file with the new filename already exists
		_, err = os.Stat(newFilePath)
		if err == nil {
			// File with new filename already exists, generate a new unique filename
			count := 1
			extension := filepath.Ext(newFilename)
			filenameWithoutExt := strings.TrimSuffix(newFilename, extension)

			// Keep incrementing the count until a unique filename is found
			for err == nil {
				newFilename = fmt.Sprintf("%s_%d%s", filenameWithoutExt, count, extension)
				newFilePath = filepath.Join(fileUploadPath, userSession.username, newFilename)
				_, err = os.Stat(newFilePath)
				count++
			}
		} else if !os.IsNotExist(err) {
			// Error accessing the file, handle the error or return an error response
			handleError("Error: Unable to access file", err)
			return
		}

		err := updateFilename(userSession.username, filename, newFilename)
		if err != nil {
			handleError("Error updating filename", err)
			return
		}

		err = os.Rename(filePath, newFilePath) // Rename the file to the new filename
		if err != nil {
			handleError("Error renaming file", err)
			return
		}
	}

	// Create or open the file
	file, err := os.Create(newFilePath)
	if err != nil {
		handleError("Error creating file", err)
		return
	}
	defer file.Close()

	// Read the edited content from the request form
	editedContent := r.FormValue("editor")
	// Convert edited content from HTML to Markdown if the file extension is .md
	if strings.HasSuffix(newFilename, ".md") {
		editedContent = convertHTMLtoMarkdown(editedContent)
	}
	// Write the edited content to the file
	_, err = file.WriteString(editedContent)
	if err != nil {
		handleError("Error writing edited content to file", err)
		return
	}

	// Update the edited timestamp for the user and file
	UpdateEditedTimestamp(userSession.username, newFilename)

	http.Redirect(w, r, "/home", http.StatusSeeOther)
}

func handleError(errMsg string, err error) {
	log.Printf("%s: %v", errMsg, err)
}

func readFileContent(filePath string) ([]byte, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	return io.ReadAll(file)
}

func sanitizeHTML(htmlContent []byte) []byte {
	return bluemonday.UGCPolicy().SanitizeBytes(htmlContent)
}

func convertHTMLtoMarkdown(html string) string {
	options := md.Options{
		EscapeMode: "disabled",
	}
	converter := md.NewConverter("", true, &options)
	converter.Use(plugin.Table())
	converter.Use(plugin.Strikethrough("~~"))
	markdown, err := converter.ConvertString(html)
	if err != nil {
		log.Fatal(err)
	}
	return markdown
}

func getTemplateList() ([]Template, error) {
	dir, err := os.Open(templateFilePath)
	if err != nil {
		return nil, err
	}
	defer dir.Close()

	fileInfos, err := dir.Readdir(-1)
	if err != nil {
		return nil, err
	}

	templates := make([]Template, 0)
	for _, fileInfo := range fileInfos {
		if !fileInfo.IsDir() {
			template := Template{
				TemplateName: fileInfo.Name(),
				Filename:     "",
			}
			templates = append(templates, template)
		}
	}

	return templates, nil
}