package store

import (
	"encoding/json"
	"os"
	"sync"

	"git.pengzhan.dev/noteplace-server/internal/models"
)

// DB represents the structure of the entire JSON database.
type DB struct {
	Users      map[string]models.User      `json:"users"`
	Sessions   map[string]models.Session   `json:"sessions"`
	Places     map[string]models.Place     `json:"places"`
	Addresses  map[string]models.Address   `json:"addresses"`
	Categories map[string]models.Category  `json:"categories"`
	Attributes map[string]models.Attribute `json:"attributes"`
	Ratings    map[string]models.Rating    `json:"ratings"`
}

// Store manages the in-memory data and provides safe access.
type Store struct {
	Mu   sync.RWMutex
	path string
	Data *DB
}

// New creates and initializes a new Store.
func New(path string) (*Store, error) {
	s := &Store{
		path: path,
		Data: &DB{},
	}

	if err := s.load(); err != nil {
		return nil, err
	}

	return s, nil
}

// load reads the database file from disk into the Store.
func (s *Store) load() error {
	s.Mu.Lock()
	defer s.Mu.Unlock()

	file, err := os.ReadFile(s.path)
	if err != nil {
		// If the file doesn't exist, we can assume an empty database.
		if os.IsNotExist(err) {
			s.Data = &DB{
				Users:      map[string]models.User{},
				Sessions:   map[string]models.Session{},
				Places:     map[string]models.Place{},
				Addresses:  map[string]models.Address{},
				Categories: map[string]models.Category{},
				Attributes: map[string]models.Attribute{},
				Ratings:    map[string]models.Rating{},
			}
			return nil
		}
		return err
	}

	return json.Unmarshal(file, s.Data)
}

// Save writes the current in-memory data back to the JSON file.
func (s *Store) Save() error {
	s.Mu.RLock()
	defer s.Mu.RUnlock()

	data, err := json.MarshalIndent(s.Data, "", "  ")
	if err != nil {
		return err
	}

	return os.WriteFile(s.path, data, 0644)
}

// CreateSession adds a new session to the store.