add groups model and db code

src/groupdb.js

@@ -0,0 +1,75 @@
+'use strict';
+
+exports = module.exports = {
+    get: get,
+    add: add,
+    del: del,
+    count: count,
+
+    _clear: clear
+};
+
+var assert = require('assert'),
+    database = require('./database.js'),
+    debug = require('debug')('box:groupdb'),
+    DatabaseError = require('./databaseerror');
+
+var GROUPS_FIELDS = [ 'id', 'name' ].join(',');
+
+function get(groupId, callback) {
+    assert.strictEqual(typeof groupId, 'string');
+    assert.strictEqual(typeof callback, 'function');
+
+    database.query('SELECT ' + GROUPS_FIELDS + ' FROM groups WHERE id = ?', [ groupId ], function (error, result) {
+        if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
+        if (result.length === 0) return callback(new DatabaseError(DatabaseError.NOT_FOUND));
+
+        callback(null, result[0]);
+    });
+}
+
+function add(id, name, callback) {
+    assert.strictEqual(typeof id, 'string');
+    assert.strictEqual(typeof name, 'string');
+    assert.strictEqual(typeof callback, 'function');
+
+    var data = [ id, name ];
+    database.query('INSERT INTO groupd (id, name) VALUES (?, ?)',
+           data, function (error, result) {
+        if (error && error.code === 'ER_DUP_ENTRY') return callback(new DatabaseError(DatabaseError.ALREADY_EXISTS, error));
+        if (error || result.affectedRows !== 1) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
+
+        callback(null);
+    });
+}
+
+function del(id, callback) {
+    assert.strictEqual(typeof id, 'string');
+    assert.strictEqual(typeof callback, 'function');
+
+    database.query('DELETE FROM groups WHERE id = ?', [ id ], function (error, result) {
+        if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
+        if (result.affectedRows !== 1) return callback(new DatabaseError(DatabaseError.NOT_FOUND));
+
+        callback(error);
+    });
+}
+
+function count(callback) {
+    assert.strictEqual(typeof callback, 'function');
+
+    database.query('SELECT COUNT(*) AS total FROM groups', function (error, result) {
+        if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
+
+        return callback(null, result[0].total);
+    });
+}
+
+function clear(callback) {
+    database.query('DELETE FROM groups', function (error) {
+        if (error) return callback(new DatabaseError(DatabaseError.INTERNAL_ERROR, error));
+
+        callback(error);
+    });
+}
+