package model

import (
	"encoding/json"
	"fmt"
	"io"
	"os"
	"path/filepath"
)

// ModelStore manages custom model files on disk.
type ModelStore struct {
	baseDir string
}

func NewModelStore(baseDir string) *ModelStore {
	_ = os.MkdirAll(baseDir, 0755)
	return &ModelStore{baseDir: baseDir}
}

// SaveModel saves a .nef file for the given model ID.
func (s *ModelStore) SaveModel(id string, file io.Reader) (string, error) {
	dir := filepath.Join(s.baseDir, id)
	if err := os.MkdirAll(dir, 0755); err != nil {
		return "", fmt.Errorf("failed to create model directory: %w", err)
	}

	nefPath := filepath.Join(dir, "model.nef")
	f, err := os.Create(nefPath)
	if err != nil {
		return "", fmt.Errorf("failed to create model file: %w", err)
	}
	defer f.Close()

	written, err := io.Copy(f, file)
	if err != nil {
		return "", fmt.Errorf("failed to write model file: %w", err)
	}

	fmt.Printf("[INFO] Saved model file: %s (%d bytes)\n", nefPath, written)
	return nefPath, nil
}

// SaveMetadata saves model metadata as JSON.
func (s *ModelStore) SaveMetadata(id string, m Model) error {
	dir := filepath.Join(s.baseDir, id)
	if err := os.MkdirAll(dir, 0755); err != nil {
		return fmt.Errorf("failed to create model directory: %w", err)
	}

	metaPath := filepath.Join(dir, "metadata.json")
	data, err := json.MarshalIndent(m, "", "  ")
	if err != nil {
		return fmt.Errorf("failed to marshal metadata: %w", err)
	}

	return os.WriteFile(metaPath, data, 0644)
}

// GetModelPath returns the .nef file path for a model.
func (s *ModelStore) GetModelPath(id string) string {
	return filepath.Join(s.baseDir, id, "model.nef")
}

// DeleteModel removes a model's directory and all files.
func (s *ModelStore) DeleteModel(id string) error {
	dir := filepath.Join(s.baseDir, id)
	return os.RemoveAll(dir)
}

// LoadCustomModels scans the store directory and returns all custom models.
func (s *ModelStore) LoadCustomModels() ([]Model, error) {
	entries, err := os.ReadDir(s.baseDir)
	if err != nil {
		if os.IsNotExist(err) {
			return nil, nil
		}
		return nil, err
	}

	var models []Model
	for _, entry := range entries {
		if !entry.IsDir() {
			continue
		}

		metaPath := filepath.Join(s.baseDir, entry.Name(), "metadata.json")
		data, err := os.ReadFile(metaPath)
		if err != nil {
			continue
		}

		var m Model
		if err := json.Unmarshal(data, &m); err != nil {
			continue
		}
		m.IsCustom = true
		models = append(models, m)
	}

	return models, nil
}