package store

import (
	"encoding/json"
	"fmt"
	"mime"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"time"

	"github.com/google/uuid"
	"printer.backend/internal/model"
	"printer.backend/internal/paths"
)

// OrderStore persists orders as JSON files with images in per-order subdirectories.
type OrderStore struct {
	dir string
}

// NewOrderStore creates a store under dir (default data/orders).
func NewOrderStore(dir string) *OrderStore {
	if dir == "" {
		dir = paths.OrdersDir
	}
	return &OrderStore{dir: dir}
}

// List returns all orders sorted by creation time (newest first).
func (s *OrderStore) List() ([]model.Order, error) {
	if err := ensureDir(s.dir); err != nil {
		return nil, err
	}
	entries, err := os.ReadDir(s.dir)
	if err != nil {
		return nil, fmt.Errorf("read orders dir: %w", err)
	}

	var out []model.Order
	for _, e := range entries {
		if e.IsDir() || filepath.Ext(e.Name()) != ".json" {
			continue
		}
		o, err := readOrderFile(filepath.Join(s.dir, e.Name()))
		if err != nil {
			return nil, err
		}
		out = append(out, o)
	}

	sort.Slice(out, func(i, j int) bool {
		return out[i].CreatedAt.After(out[j].CreatedAt)
	})
	return out, nil
}

// Get returns an order by ID.
func (s *OrderStore) Get(id string) (model.Order, error) {
	o, err := readOrderFile(s.metaPath(id))
	if err != nil {
		if os.IsNotExist(err) {
			return model.Order{}, fmt.Errorf("order not found: %s", id)
		}
		return model.Order{}, err
	}
	return o, nil
}

func readOrderFile(path string) (model.Order, error) {
	var aux struct {
		model.Order
		RefLink string `json:"ref_link,omitempty"`
	}
	data, err := os.ReadFile(path)
	if err != nil {
		return model.Order{}, err
	}
	if err := json.Unmarshal(data, &aux); err != nil {
		return model.Order{}, err
	}
	o := aux.Order
	if o.Ref == "" && aux.RefLink != "" {
		o.Ref = aux.RefLink
	}
	if o.Images == nil {
		o.Images = []model.OrderImage{}
	}
	return o, nil
}

// Save writes a new order and assigns an ID when empty.
func (s *OrderStore) Save(o model.Order) (model.Order, error) {
	if err := ensureDir(s.dir); err != nil {
		return model.Order{}, err
	}
	if o.ID == "" {
		o.ID = uuid.NewString()
	}
	if o.Images == nil {
		o.Images = []model.OrderImage{}
	}
	now := stampNew(&o.CreatedAt)
	o.CreatedAt = now
	o.UpdatedAt = now

	if err := writeJSON(s.metaPath(o.ID), o); err != nil {
		return model.Order{}, fmt.Errorf("write order: %w", err)
	}
	return o, nil
}

// Update replaces order metadata (preserves id, images, created_at).
func (s *OrderStore) Update(id string, o model.Order) (model.Order, error) {
	existing, err := s.Get(id)
	if err != nil {
		return model.Order{}, err
	}
	o.ID = existing.ID
	o.Images = existing.Images
	o.CreatedAt = existing.CreatedAt
	o.UpdatedAt = time.Now().UTC()

	if err := writeJSON(s.metaPath(id), o); err != nil {
		return model.Order{}, fmt.Errorf("write order: %w", err)
	}
	return o, nil
}

// Delete removes an order and all of its images.
func (s *OrderStore) Delete(id string) error {
	if _, err := s.Get(id); err != nil {
		return err
	}
	if err := os.Remove(s.metaPath(id)); err != nil && !os.IsNotExist(err) {
		return err
	}
	return os.RemoveAll(s.imagesDir(id))
}

// AddImage stores image bytes and appends metadata to the order.
func (s *OrderStore) AddImage(orderID, originalName string, data []byte, contentType string) (model.OrderImage, error) {
	if len(data) == 0 {
		return model.OrderImage{}, fmt.Errorf("empty image data")
	}
	order, err := s.Get(orderID)
	if err != nil {
		return model.OrderImage{}, err
	}

	ext := extensionForImage(originalName, contentType)
	imageID := uuid.NewString()
	filename := imageID + ext

	if err := ensureDir(s.imagesDir(orderID)); err != nil {
		return model.OrderImage{}, err
	}
	path := filepath.Join(s.imagesDir(orderID), filename)
	if err := os.WriteFile(path, data, 0o644); err != nil {
		return model.OrderImage{}, fmt.Errorf("write image: %w", err)
	}

	img := model.OrderImage{
		ID:           imageID,
		OriginalName: filepath.Base(originalName),
		ContentType:  contentType,
		Filename:     filename,
		CreatedAt:    time.Now().UTC(),
	}
	order.Images = append(order.Images, img)
	order.UpdatedAt = time.Now().UTC()
	if err := writeJSON(s.metaPath(orderID), order); err != nil {
		_ = os.Remove(path)
		return model.OrderImage{}, fmt.Errorf("update order: %w", err)
	}
	return img, nil
}

// DeleteImage removes one image from an order.
func (s *OrderStore) DeleteImage(orderID, imageID string) error {
	order, err := s.Get(orderID)
	if err != nil {
		return err
	}

	idx := -1
	var filename string
	for i, img := range order.Images {
		if img.ID == imageID {
			idx = i
			filename = img.Filename
			break
		}
	}
	if idx < 0 {
		return fmt.Errorf("image not found: %s", imageID)
	}

	path := filepath.Join(s.imagesDir(orderID), filename)
	if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
		return err
	}

	order.Images = append(order.Images[:idx], order.Images[idx+1:]...)
	order.UpdatedAt = time.Now().UTC()
	return writeJSON(s.metaPath(orderID), order)
}

// ImagePath returns the filesystem path for an order image.
func (s *OrderStore) ImagePath(orderID, imageID string) (string, model.OrderImage, error) {
	order, err := s.Get(orderID)
	if err != nil {
		return "", model.OrderImage{}, err
	}
	for _, img := range order.Images {
		if img.ID == imageID {
			path := filepath.Join(s.imagesDir(orderID), img.Filename)
			if _, err := os.Stat(path); err != nil {
				return "", model.OrderImage{}, fmt.Errorf("image file missing: %w", err)
			}
			return path, img, nil
		}
	}
	return "", model.OrderImage{}, fmt.Errorf("image not found: %s", imageID)
}

func (s *OrderStore) metaPath(id string) string {
	return filepath.Join(s.dir, id+".json")
}

func (s *OrderStore) imagesDir(orderID string) string {
	return filepath.Join(s.dir, orderID)
}

func extensionForImage(originalName, contentType string) string {
	if ext := filepath.Ext(originalName); ext != "" {
		return strings.ToLower(ext)
	}
	if exts, _ := mime.ExtensionsByType(contentType); len(exts) > 0 {
		return exts[0]
	}
	switch contentType {
	case "image/jpeg":
		return ".jpg"
	case "image/png":
		return ".png"
	case "image/webp":
		return ".webp"
	case "image/gif":
		return ".gif"
	case "image/svg+xml":
		return ".svg"
	default:
		return ".bin"
	}
}