package main

import (
	"archive/zip"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"
)

// bundleFilesToZip bundles the files in the specified folder to a zip file
func bundleFilesToZip(folderPath string, destination string) error {
	// Create the zip file
	zipFile, err := os.Create(destination)
	if err != nil {
		log.Printf("Error creating zip file: %v", err)
		return err
	}
	defer zipFile.Close() // Close the zip file at the end of the function execution using defer

	// Create a new zip archive
	archive := zip.NewWriter(zipFile)
	defer archive.Close()

	// Traverse the files and directories in the specified folder path
	err = filepath.WalkDir(folderPath, func(path string, d os.DirEntry, err error) error {
		if err != nil {
			return err
		}

		// Get file/directory info
		info, err := d.Info()
		if err != nil {
			return err
		}

		// Get the file info header for the entry in the zip file
		header, err := zip.FileInfoHeader(info)
		if err != nil {
			return err
		}

		// Set the header name to be relative to the folder path
		relativePath, err := filepath.Rel(folderPath, path)
		if err != nil {
			return err
		}
		header.Name = relativePath

		if info.IsDir() {
			// Create the folder entry in the zip file
			header.Name += "/"
			header.Method = zip.Store
			_, err = archive.CreateHeader(header)
			if err != nil {
				return err
			}
		} else {
			// Create a file entry in the zip file
			writer, err := archive.CreateHeader(header)
			if err != nil {
				return err
			}

			// Open the source file for reading
			srcFile, err := os.Open(path)
			if err != nil {
				return err
			}
			defer srcFile.Close()

			// Copy the file contents to the zip file
			_, err = io.Copy(writer, srcFile)
			if err != nil {
				return err
			}
		}

		return nil
	})

	if err != nil {
		log.Printf("Error bundling files to zip: %v", err)
		return err
	}

	return nil
}

// deleteFolder deletes the folder at the specified path
func deleteFolder(folderPath string) error {
	err := os.RemoveAll(folderPath)
	if err != nil {
		log.Printf("Error deleting folder: %v", err)
		return err
	}

	return nil
}

// exportFiles exports the files in a folder to a zip file and serves it as a download
func exportFiles(w http.ResponseWriter, r *http.Request) {
	// Get the user's session for the folder path
	userSession, err := validateSession(w, r)
	if err != nil {
		// Handle the error as needed
		return
	}
	username := userSession.username
	dateTime := time.Now().Format("2006-01-02_15-04-05") // Format the current date and time as "YYYY-MM-DD_HH-MM-SS"

	// Get the folder path from the URL parameter
	folderPath := r.URL.Query().Get("folder")

	// If no folder path is given, export the user's folder
	if folderPath == "" {
		folderPath = filepath.Join(fileUploadPath, userSession.username)
	}

	// Create a temporary folder to store the exported files
	tempFolder := filepath.Join(".", "temp")
	err2 := makeFolder(tempFolder)
	if err != nil {
		http.Error(w, "Error creating temporary folder", http.StatusInternalServerError)
		log.Println(err2)
		return
	}

	// Copy the user's folder to the temporary folder
	err = copyFolder(folderPath, tempFolder)
	if err != nil {
		http.Error(w, "Error copying folder", http.StatusInternalServerError)
		log.Println(err)
		return
	}

	// Convert HTML files to Markdown in the temporary folder
	err = filepath.WalkDir(tempFolder, func(path string, d os.DirEntry, err error) error {
		if err != nil {
			return err
		}

		if strings.HasSuffix(path, ".md") {
			content, err := os.ReadFile(path)
			if err != nil {
				log.Printf("Error reading file: %v", err)
				return err
			}

			// Convert HTML to Markdown
			markdown := convertHTMLtoMarkdown(string(content))

			// Write the Markdown content back to the file
			err = os.WriteFile(path, []byte(markdown), os.ModePerm)
			if err != nil {
				log.Printf("Error writing Markdown file: %v", err)
				return err
			}
		}

		return nil
	})

	if err != nil {
		http.Error(w, "Error converting HTML files to Markdown", http.StatusInternalServerError)
		log.Println(err)
		return
	}

	// Generate a unique name for the zip file
	zipFileName := username + "_" + dateTime + ".zip"
	zipFilePath := filepath.Join(".", zipFileName)

	// Bundle the files in the temporary folder into a zip file
	err = bundleFilesToZip(tempFolder, zipFilePath)
	if err != nil {
		http.Error(w, "Error bundling files to zip", http.StatusInternalServerError)
		log.Println(err)
		return
	}

	// Delete the temporary folder
	err = deleteFolder(tempFolder)
	if err != nil {
		log.Println(err)
	}

	// Open the zip file for reading
	zipFile, err := os.Open(zipFilePath)
	if err != nil {
		http.Error(w, "Error opening zip file", http.StatusInternalServerError)
		log.Println(err)
		return
	}
	defer zipFile.Close()

	// Set the response headers
	w.Header().Set("Content-Type", "application/octet-stream")
	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s", zipFileName))

	// Write the zip file contents to the response writer
	_, err = io.Copy(w, zipFile)
	if err != nil {
		log.Println(err)
	}

	// Delete the generated zip file
	err = os.Remove(zipFilePath)
	if err != nil {
		// Log the error, but don't interrupt the response handling
		log.Printf("Error deleting zip file: %v", err)
	}
}

// copyFolder copies the files and directories from the source path to the destination path
func copyFolder(source string, destination string) error {
	// Traverse the files and directories in the specified folder path
	err := filepath.WalkDir(source, func(path string, d os.DirEntry, err error) error {
		if err != nil {
			return err
		}

		// Skip the source folder itself
		if path == source {
			return nil
		}

		// Get the relative path within the source folder
		relativePath, err := filepath.Rel(source, path)
		if err != nil {
			log.Printf("Error getting relative path: %v", err)
			return err
		}

		// Create the corresponding destination path
		destPath := filepath.Join(destination, relativePath)

		if d.IsDir() {
			// Create the directory in the destination
			err := os.MkdirAll(destPath, os.ModePerm)
			if err != nil {
				log.Printf("Error creating destination folder: %v", err)
				return err
			}
		} else {
			// Copy the file from source to destination
			err := copyFile(path, destPath)
			if err != nil {
				log.Printf("Error copying file: %v", err)
				return err
			}
		}

		return nil
	})

	if err != nil {
		log.Printf("Error copying folder: %v", err)
		return err
	}

	return nil
}

// copyFile copies a file from the source path to the destination path
func copyFile(source string, destination string) error {
	srcFile, err := os.Open(source)
	if err != nil {
		log.Printf("Error opening source file: %v", err)
		return err
	}
	defer srcFile.Close()

	destFile, err := os.Create(destination)
	if err != nil {
		log.Printf("Error creating destination file: %v", err)
		return err
	}
	defer destFile.Close()

	_, err = io.Copy(destFile, srcFile)
	if err != nil {
		log.Printf("Error copying file: %v", err)
		return err
	}

	return nil
}