package storage

import (
	"errors"
	"os"
	"path/filepath"
	"strings"
)

// Store manages AsciiDoc files on disk.
type Store struct {
	root string
}

func New(root string) (*Store, error) {
	if err := os.MkdirAll(root, 0755); err != nil {
		return nil, err
	}
	return &Store{root: root}, nil
}

// Read returns the content of a document by its slug path (e.g. "guides/install").
func (s *Store) Read(slug string) (string, error) {
	data, err := os.ReadFile(s.filePath(slug))
	if err != nil {
		if errors.Is(err, os.ErrNotExist) {
			return "", ErrNotFound
		}
		return "", err
	}
	return string(data), nil
}

// Write persists content to disk, creating parent directories as needed.
func (s *Store) Write(slug, content string) error {
	path := s.filePath(slug)
	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
		return err
	}
	return os.WriteFile(path, []byte(content), 0644)
}

// CreateFolder creates a new folder/directory.
func (s *Store) CreateFolder(folderSlug string) error {
	path := s.folderPath(folderSlug)
	return os.MkdirAll(path, 0755)
}

// MoveDocument moves a document from one location to another.
func (s *Store) MoveDocument(fromSlug, toSlug string) error {
	fromPath := s.filePath(fromSlug)
	toPath := s.filePath(toSlug)

	// Ensure target directory exists
	if err := os.MkdirAll(filepath.Dir(toPath), 0755); err != nil {
		return err
	}

	// Move the file
	return os.Rename(fromPath, toPath)
}

// Delete removes a document from disk.
func (s *Store) Delete(slug string) error {
	return os.Remove(s.filePath(slug))
}

// List returns all document slugs under an optional prefix.
func (s *Store) List(prefix string) ([]string, error) {
	base := filepath.Join(s.root, filepath.FromSlash(prefix))
	var slugs []string
	err := filepath.WalkDir(base, func(path string, d os.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if !d.IsDir() && strings.HasSuffix(path, ".adoc") {
			rel, _ := filepath.Rel(s.root, path)
			slug := strings.TrimSuffix(filepath.ToSlash(rel), ".adoc")
			slugs = append(slugs, slug)
		}
		return nil
	})
	return slugs, err
}

// ListImages returns all images in the directory of a given slug.
func (s *Store) ListImages(slug string) ([]map[string]interface{}, error) {
	dir := filepath.Dir(s.filePath(slug))
	var images []map[string]interface{}

	entries, err := os.ReadDir(dir)
	if err != nil {
		if errors.Is(err, os.ErrNotExist) {
			return images, nil
		}
		return nil, err
	}

	for _, entry := range entries {
		if entry.IsDir() {
			continue
		}
		name := entry.Name()
		ext := strings.ToLower(filepath.Ext(name))
		if ext == ".png" || ext == ".jpg" || ext == ".jpeg" || ext == ".gif" || ext == ".svg" || ext == ".webp" {
			info, err := entry.Info()
			if err == nil {
				images = append(images, map[string]interface{}{
					"name": name,
					"size": info.Size(),
					// The URL is relative to the media endpoint mapped in the server.
					"url": "/media/" + strings.TrimPrefix(filepath.ToSlash(filepath.Join(filepath.Dir(slug), name)), "/"),
				})
			}
		}
	}
	return images, nil
}

// SaveImage saves an uploaded image file into the directory of a slug.
func (s *Store) SaveImage(slug, filename string, data []byte) error {
	dir := filepath.Dir(s.filePath(slug))
	if err := os.MkdirAll(dir, 0755); err != nil {
		return err
	}
	return os.WriteFile(filepath.Join(dir, filename), data, 0644)
}

// DeleteImage removes an image file from the directory of a slug.
func (s *Store) DeleteImage(slug, filename string) error {
	dir := filepath.Dir(s.filePath(slug))
	return os.Remove(filepath.Join(dir, filename))
}

// GetImagePath returns the absolute path on disk for a media file.
// It prevents directory traversal out of the root storage path.
func (s *Store) GetImagePath(relPath string) (string, error) {
	if strings.Contains(relPath, "..") {
		return "", errors.New("invalid path")
	}
	return filepath.Join(s.root, filepath.FromSlash(relPath)), nil
}

// ListFolders returns all folder paths relative to root, excluding .git.
func (s *Store) ListFolders() ([]string, error) {
	var folders []string
	err := filepath.WalkDir(s.root, func(path string, d os.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() {
			if d.Name() == ".git" {
				return filepath.SkipDir
			}
			if path != s.root {
				rel, _ := filepath.Rel(s.root, path)
				folders = append(folders, filepath.ToSlash(rel))
			}
		}
		return nil
	})
	return folders, err
}

func (s *Store) filePath(slug string) string {
	return filepath.Join(s.root, filepath.FromSlash(slug)+".adoc")
}

func (s *Store) folderPath(folderSlug string) string {
	return filepath.Join(s.root, filepath.FromSlash(folderSlug))
}

var ErrNotFound = errors.New("document not found")