package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strings"
	"time"

	"github.com/fsnotify/fsnotify"
	"github.com/gosimple/slug"
	"gopkg.in/ini.v1"
)

func main() {

	// Read the config file
	home, err := os.UserHomeDir()
	if err != nil {
		log.Fatalln(err)
	}
	config, err := ini.Load(home + "/.config/obs2hugo/obs2hugo.ini")
	if err != nil {
		config, err = ini.Load(home + "/.config/obs2hugo.ini")
		if err != nil {
			log.Fatalln(err)
		}
	}
	// Hugo build action
	buildAction := config.Section("").Key("build_action").String()

	// Watcher directories
	watcherDirs := config.Section("").Key("watcher_dirs").String()

	// Hugo content directory
	destDirs := config.Section("").Key("hugo_dirs").String()

	watcherDirsList := strings.Split(watcherDirs, ":")
	destDirsList := strings.Split(destDirs, ":")

	if len(watcherDirsList) != len(destDirsList) {
		fmt.Println("Error: watcher_dirs and hugo_dirs must have the same number of elements")
		return
	}

	// Creating watcher
	watcher, err := fsnotify.NewWatcher()
	if err != nil {
		fmt.Println("Error creating the watcher:", err)
		return
	}
	defer watcher.Close()

	// Add directories to the watcher
	for _, dir := range watcherDirsList {
		err = filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
			if err != nil {
				fmt.Println("Error accessing to the directory:", err)
				return err
			}
			if info.IsDir() {
				return watcher.Add(path)
			}
			return nil
		})
		if err != nil {
			fmt.Println("Error adding directory to the watcher:", err)
			return
		}
	}

	// Watcher event loop
	for {
		select {
		case event := <-watcher.Events:
			switch {
			case event.Op&fsnotify.Create == fsnotify.Create:
				fmt.Println("New file:", event.Name)
				// TBD
			case event.Op&fsnotify.Write == fsnotify.Write:
				fmt.Println("File modified:", event.Name)
				triggerDir := getTriggerDirectory(event.Name, watcherDirsList)
				if triggerDir == "" {
					fmt.Println("Error: Unable to determine trigger directory for event:", event.Name)
					continue
				}
				newDestDir := getDestinationDirectory(triggerDir, watcherDirsList, destDirsList)
				if newDestDir == "" {
					fmt.Println("Error: Unable to determine destination directory for trigger directory:", triggerDir)
					continue
				}
				processModifiedFile(event.Name, triggerDir, newDestDir)
				// Check if the file contains the "build: true" tag in the frontmatter
				hasBuildTag, err := hasBuildTag(event.Name)
				if err != nil {
					fmt.Println("Error checking build tag in frontmatter:", err)
					continue
				}

				// If the file contains the "build: true" tag, execute the build action specified in the .ini file
				if hasBuildTag && buildAction != "" {
					// Remove the "build: true" tag from the frontmatter
					err = removeBuildTag(event.Name)
					if err != nil {
						fmt.Println("Error removing build tag from frontmatter:", err)
						return
					}
					// Execute build action
					err := executeBuildAction(buildAction)
					if err != nil {
						fmt.Println("Error executing build action:", err)
						continue
					}
				}
			case event.Op&fsnotify.Remove == fsnotify.Remove:
				fmt.Println("File deleted:", event.Name)
				// TBD
			case event.Op&fsnotify.Rename == fsnotify.Rename:
				fmt.Println("File renamed:", event.Name)
				// TBD
			}
		case err := <-watcher.Errors:
			fmt.Println("Watcher error:", err)
		}
	}
}

// Function to determine which watcher directory triggered the event
func getTriggerDirectory(eventPath string, dirs []string) string {
	for _, dir := range dirs {
		if strings.HasPrefix(eventPath, dir) {
			return dir
		}
	}
	return ""
}

// Function to determine the destination directory for the trigger directory
func getDestinationDirectory(triggerDir string, watcherDirsList, destDirsList []string) string {
	for i, dir := range watcherDirsList {
		if dir == triggerDir {
			return destDirsList[i]
		}
	}
	return ""
}

func processModifiedFile(filePath, directory, destDir string) {
	// Slugified file name without extension
	fileName := strings.TrimSuffix(filepath.Base(filePath), filepath.Ext(filePath))
	slug := slug.Make(fileName)

	// Creating destination directory
	newDir := filepath.Join(destDir, slug)
	err := os.MkdirAll(newDir, os.ModePerm)
	if err != nil {
		fmt.Println("Error creating directory:", err)
		return
	}

	// Copy modified file to the new destination
	newFilePath := filepath.Join(newDir, "index.md")

	// Check if the file already has frontmatter
	hasFrontmatter, err := checkFrontmatter(filePath)
	if err != nil {
		fmt.Println("Error checking frontmatter:", err)
		return
	}

	// If the file doesn't have frontmatter, add it
	if !hasFrontmatter {
		err = addFrontmatter(filePath, fileName)
		if err != nil {
			fmt.Println("Error adding frontmatter:", err)
			return
		}
	}

	err = copyFile(filePath, newFilePath)
	if err != nil {
		fmt.Println("Error copying file:", err)
		return
	}

	// Move images to the gallery directory
	err = moveImagesToGallery(filePath, newDir, directory)
	if err != nil {
		fmt.Println("Error moving images to the gallery:", err)
		return
	}
}

// Function to check if the file already has frontmatter
func checkFrontmatter(filePath string) (bool, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return false, err
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()
		if line == "---" {
			return true, nil
		}
	}

	return false, nil
}

// Function to add frontmatter to the file
func addFrontmatter(filePath, title string) error {
	// Read the content of the original file
	content, err := ioutil.ReadFile(filePath)
	if err != nil {
		return err
	}

	// Create a new temporary file with the frontmatter added
	tempFilePath := filePath + ".tmp"
	frontmatter := fmt.Sprintf("---\ntitle: %s\ndate: %s\ndraft: false\ntags: micropost\n---\n\n", title, time.Now().Format("2006-01-02 15:04:05 -0700"))
	err = ioutil.WriteFile(tempFilePath, []byte(frontmatter+string(content)), os.ModePerm)
	if err != nil {
		return err
	}

	// Replace the original file with the temporary file
	fmt.Println("Rename:", tempFilePath, filePath)
	err = os.Rename(tempFilePath, filePath)
	if err != nil {
		return err
	}

	return nil
}

// Function to check if the file contains the "build: true" tag in the frontmatter
func hasBuildTag(filePath string) (bool, error) {
	// Open the file
	file, err := os.Open(filePath)
	if err != nil {
		return false, err
	}
	defer file.Close()

	// Read the file line by line
	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()

		// Check for the start of the frontmatter
		if line == "---" {
			var frontmatter []string

			// Read the frontmatter
			for scanner.Scan() {
				line := scanner.Text()
				if line == "---" {
					break
				}
				frontmatter = append(frontmatter, line)
			}

			// Check if the frontmatter contains the "build: true" tag
			for _, tag := range frontmatter {
				if strings.Contains(tag, "build: true") {
					return true, nil
				}
			}
			break // We're done checking frontmatter, so break out of the loop
		}
	}

	return false, nil
}

// Function to execute the build action specified in the .ini file
func executeBuildAction(action string) error {
	// Split the action into command and arguments
	parts := strings.Fields(action)
	cmd := parts[0]
	args := parts[1:]

	// Execute the command
	out, err := exec.Command(cmd, args...).Output()
	if err != nil {
		return err
	}

	// Print the command output
	fmt.Println(string(out))

	return nil
}

func copyFile(src, dst string) error {
	sourceFile, err := os.Open(src)
	if err != nil {
		return err
	}
	defer sourceFile.Close()

	newFile, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer newFile.Close()

	_, err = io.Copy(newFile, sourceFile)
	if err != nil {
		return err
	}
	return nil
}

func removeBuildTag(filePath string) error {
	// Read file content
	content, err := ioutil.ReadFile(filePath)
	if err != nil {
		return err
	}

	contentStr := string(content)

	// Find frontmatter
	start := strings.Index(contentStr, "---")
	end := strings.Index(contentStr[start+3:], "---")

	// Verify if frontmatter exists
	if start != -1 && end != -1 {
		frontmatter := contentStr[start : start+3+end+3]

		// Look for "build: true" in the frontmatter
		buildTagIndex := strings.Index(frontmatter, "build: true")
		if buildTagIndex != -1 {
			// Delete "build: true" from frontmatter
			frontmatter = strings.ReplaceAll(frontmatter, "build: true\n", "")

			contentStr = strings.Replace(contentStr, string(content[start:start+3+end+3]), frontmatter, 1)

			err := ioutil.WriteFile(filePath, []byte(contentStr), 0644)
			if err != nil {
				return err
			}
		}
	}

	return nil
}

func moveImagesToGallery(filePath, destDir, directory string) error {
	// Routes
	destFilePath := filepath.Join(destDir, "index.md")
	slugDir := slug.Make(strings.TrimSuffix(filepath.Base(filePath), filepath.Ext(filePath)))
	galleryDir := filepath.Join(destDir, "gallery")

	// Read file content
	content, err := os.ReadFile(filePath)
	if err != nil {
		return err
	}

	// Regexp to find the markdown images
	re := regexp.MustCompile(`!\[\[([^]]+)\]\]`)
	matches := re.FindAllStringSubmatch(string(content), -1)

	// Create gallery dir if it doesn't exist
	if _, err := os.Stat(galleryDir); os.IsNotExist(err) {
		err := os.Mkdir(galleryDir, os.ModePerm)
		if err != nil {
			return err
		}
	}

	// Move every image found
	for _, match := range matches {
		imagePath := match[1]
		imageName := filepath.Base(imagePath)
		ext := filepath.Ext(imageName)
		slugName := slug.Make(strings.TrimSuffix(imageName, ext))
		imageSrc := filepath.Join(directory, imagePath)
		imageDest := filepath.Join(galleryDir, slugName+ext)
		// Open source file
		srcFile, err := os.Open(imageSrc)
		if err != nil {
			fmt.Printf("Error opening source file %s: %s\n", imageSrc, err)
			continue
		}
		defer srcFile.Close()

		// Create destination file
		destFile, err := os.Create(imageDest)
		if err != nil {
			fmt.Printf("Error creating destination file %s: %s\n", imageDest, err)
			continue
		}
		defer destFile.Close()

		// Copy source to destination
		_, err = io.Copy(destFile, srcFile)
		if err != nil {
			fmt.Printf("Error copying file %s to %s: %s\n", imageSrc, imageDest, err)
			continue
		}

		// Modify link text
		newImageMarkdown := fmt.Sprintf("![%s](%s/gallery/%s)", strings.TrimSuffix(slugName, ext), slugDir, slugName+ext)
		content = bytes.Replace(content, []byte(match[0]), []byte(newImageMarkdown), -1)

		fmt.Printf("Image %s was copied to %s\n", imageSrc, imageDest)
	}

	// Replace [gallery] pattern
	content = bytes.Replace(content, []byte("[gallery]"), []byte("{{< gallery match=\"gallery/*\" sortOrder=\"asc\" rowHeight=\"150\" margins=\"5\" thumbnailResizeOptions=\"600x600 q90 Lanczos\" previewType=\"blur\" embedPreview=\"true\" >}}"), -1)

	// Write markdown file new content
	err = os.WriteFile(destFilePath, content, os.ModePerm)
	if err != nil {
		fmt.Printf("Error writing file content to the file: %s: %s\n", filePath, err)
	}

	return nil
}