package storage

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

	"github.com/evanreichard/markdown-editor/internal/logging"
)

var (
	ErrFileNotFound = errors.New("file not found")
	ErrInvalidName  = errors.New("invalid file name")
)

// File represents a markdown file
type File struct {
	Name     string `json:"name"`
	Content  string `json:"content"`
	Modified int64  `json:"modified"`
}

// Storage handles file operations
type Storage struct {
	dataDir string
}

// New creates a new Storage instance
func New(dataDir string) (*Storage, error) {
	if err := os.MkdirAll(dataDir, 0755); err != nil {
		return nil, fmt.Errorf("failed to create data directory: %w", err)
	}
	logging.Logger.WithField("data_dir", dataDir).Info("Storage initialized")
	return &Storage{dataDir: dataDir}, nil
}

// List returns all markdown files
func (s *Storage) List() ([]*File, error) {
	entries, err := os.ReadDir(s.dataDir)
	if err != nil {
		logging.Logger.WithError(err).Error("Failed to list files")
		return nil, fmt.Errorf("failed to read directory: %w", err)
	}

	files := make([]*File, 0)
	for _, entry := range entries {
		if entry.IsDir() || !strings.HasSuffix(entry.Name(), ".md") {
			continue
		}

		info, err := entry.Info()
		if err != nil {
			continue
		}

		files = append(files, &File{
			Name:     entry.Name(),
			Modified: info.ModTime().Unix(),
		})
	}

	logging.Logger.WithField("count", len(files)).Info("Listed files")
	return files, nil
}

// Get reads a markdown file
func (s *Storage) Get(name string) (*File, error) {
	if !s.isValidName(name) {
		logging.Logger.WithField("name", name).Warn("Invalid file name")
		return nil, ErrInvalidName
	}

	path := filepath.Join(s.dataDir, name)
	content, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			logging.Logger.WithField("name", name).Warn("File not found")
			return nil, ErrFileNotFound
		}
		logging.Logger.WithError(err).Error("Failed to read file")
		return nil, fmt.Errorf("failed to read file: %w", err)
	}

	info, err := os.Stat(path)
	if err != nil {
		return nil, fmt.Errorf("failed to get file info: %w", err)
	}

	logging.Logger.WithField("name", name).Info("File retrieved")
	return &File{
		Name:     name,
		Content:  string(content),
		Modified: info.ModTime().Unix(),
	}, nil
}

// Create creates a new markdown file
func (s *Storage) Create(name, content string) (*File, error) {
	if !s.isValidName(name) {
		logging.Logger.WithField("name", name).Warn("Invalid file name for create")
		return nil, ErrInvalidName
	}

	path := filepath.Join(s.dataDir, name)
	if _, err := os.Stat(path); err == nil {
		logging.Logger.WithField("name", name).Warn("File already exists")
		return nil, fmt.Errorf("file already exists")
	}

	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		logging.Logger.WithError(err).Error("Failed to create file")
		return nil, fmt.Errorf("failed to write file: %w", err)
	}

	logging.Logger.WithField("name", name).Info("File created")
	return s.Get(name)
}

// Update updates an existing markdown file
func (s *Storage) Update(name, content string) (*File, error) {
	if !s.isValidName(name) {
		logging.Logger.WithField("name", name).Warn("Invalid file name for update")
		return nil, ErrInvalidName
	}

	path := filepath.Join(s.dataDir, name)
	if _, err := os.Stat(path); os.IsNotExist(err) {
		logging.Logger.WithField("name", name).Warn("File not found for update")
		return nil, ErrFileNotFound
	}

	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		logging.Logger.WithError(err).Error("Failed to update file")
		return nil, fmt.Errorf("failed to write file: %w", err)
	}

	logging.Logger.WithField("name", name).Info("File updated")
	return s.Get(name)
}

// Delete removes a markdown file
func (s *Storage) Delete(name string) error {
	if !s.isValidName(name) {
		logging.Logger.WithField("name", name).Warn("Invalid file name for delete")
		return ErrInvalidName
	}

	path := filepath.Join(s.dataDir, name)
	if err := os.Remove(path); err != nil {
		if os.IsNotExist(err) {
			logging.Logger.WithField("name", name).Warn("File not found for delete")
			return ErrFileNotFound
		}
		logging.Logger.WithError(err).Error("Failed to delete file")
		return fmt.Errorf("failed to delete file: %w", err)
	}

	logging.Logger.WithField("name", name).Info("File deleted")
	return nil
}

// isValidName checks if the file name is valid
func (s *Storage) isValidName(name string) bool {
	if name == "" || strings.Contains(name, "..") || strings.Contains(name, "/") {
		return false
	}
	if !strings.HasSuffix(name, ".md") {
		return false
	}
	return true
}