/**
 * Gestionnaire des données du carnet d'adresse.
 */
public class ContactsCache {

    private static class Holder {
        static final ContactsCache INSTANCE = new ContactsCache();
    }

    private Context mContext;

    private Map<String, Contact> mContactsMap;
    private List<Contact> mContactsList;

    public ContactsCache() {
    }

    public static ContactsCache getInstance() {
        return Holder.INSTANCE;
    }

    /**
     * Valorise le context.
     * @param context
     */
    public void init(Context context) {
        this.mContext = context;
    }

    /**
     * Retourne un contact particulier à partir de son id.
     * @param contactId L'id du contact.
     * @return
     */
    public Contact getContact(String contactId) {
        if(mContactsMap == null) {
            mContactsMap = loadContacts();
        }
        return mContactsMap.get(contactId);
    }

    /**
     * Retourne la liste des contacts.
     * @return
     */
    public List<Contact> getContactsList() {
        if(mContactsList == null) {
            mContactsList = new ArrayList<>(getContacts().values());
        }
        Collections.sort(mContactsList);

        return mContactsList;
    }

    /**
     * Retourne la table des contacts.
     * @return
     */
    private Map<String, Contact> getContacts() {
        if(mContactsMap == null) {
            mContactsMap = loadContacts();
        }
        return mContactsMap;
    }

    /**
     * Charge les contacts depuis le carnet d'adresse.
     * @return
     */
    protected Map<String, Contact> loadContacts() {
        Map<String, Contact> contactsMap = new HashMap<>();
        Cursor phones = mContext.getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null, ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME);

        if(phones != null) {
            while (phones.moveToNext()) {
                String id = phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone._ID));
                String name = phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
                String phoneNumber = phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                int phoneType = phones.getInt(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.TYPE));
                int phoneTypeStringRes = ContactsContract.CommonDataKinds.Phone.getTypeLabelResource(phoneType);

                Contact tmpContact = new Contact(id, name, phoneNumber, mContext.getString(phoneTypeStringRes));
                contactsMap.put(id, tmpContact);
            }

            phones.close();
        }

        return contactsMap;
    }
}