////////////////////////////////////////////////////////////////////////////
//
// Copyright 2016 Realm Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////

'use strict';

const constants = require('./constants');
const lists = require('./lists');
const objects = require('./objects');
const results = require('./results');
const rpc = require('./rpc');
const util = require('./util');

const {keys, propTypes, objectTypes} = constants;
const listenersKey = Symbol();

rpc.registerTypeConverter(objectTypes.LIST, lists.create);
rpc.registerTypeConverter(objectTypes.OBJECT, objects.create);
rpc.registerTypeConverter(objectTypes.RESULTS, results.create);

class Realm {
    constructor(config) {
        let schemas = typeof config == 'object' && config.schema;
        let constructors = {};

        for (let i = 0, len = schemas ? schemas.length : 0; i < len; i++) {
            let item = schemas[i];

            if (typeof item == 'function') {
                let schema = item.schema;
                if (!schema || typeof schema != 'object') {
                    throw new Error("Realm object constructor must have 'schema' property");
                }

                let {name, properties} = schema;
                if (!name || typeof name != 'string') {
                    throw new Error("Realm object schema must have 'name' property");
                } else if (!properties || typeof properties != 'object') {
                    throw new Error("Realm object schema must have 'properties' property"); 
                }

                schemas.splice(i, 1, schema);
                constructors[name] = item;
            }
        }

        let realmId = rpc.createRealm(Array.from(arguments));

        objects.registerConstructors(realmId, constructors);

        this[keys.id] = realmId;
        this[keys.realm] = realmId;
        this[keys.type] = objectTypes.REALM;
        this[listenersKey] = new Set();

        [
            'path',
            'schemaVersion',
        ].forEach((name) => {
            Object.defineProperty(this, name, {get: util.getterForProperty(name)});
        });
    }

    addListener(name, callback) {
        if (typeof callback != 'function') {
            throw new Error('Realm.addListener must be passed a function!');
        }
        if (name != 'change') { 
            throw new Error("Only 'change' notification is supported.");
        }
        this[listenersKey].add(callback);
    }

    removeListener(name, callback) {
        if (typeof callback != 'function') {
            throw new Error('Realm.removeListener must be passed a function!');
        }
        if (name != 'change') { 
            throw new Error("Only 'change' notification is supported.");
        }
        this[listenersKey].delete(callback);
    }

    removeAllListeners(name) {
        if (name != undefined && name != 'change') {
            throw new Error("Only 'change' notification is supported.");
        }
        this[listenersKey].clear();
    }

    write(callback) {
        let realmId = this[keys.realm];

        if (!realmId) {
            throw new TypeError('write method was not called on a Realm object!');
        }
        if (typeof callback != 'function') {
            throw new TypeError('Realm.write() must be passed a function!');
        }

        rpc.beginTransaction(realmId);

        try {
            callback();
        } catch (e) {
            rpc.cancelTransaction(realmId);
            util.fireMutationListeners(realmId);
            throw e;
        }

        rpc.commitTransaction(realmId);

        this[listenersKey].forEach((cb) => cb(this, 'change'));
    }
}

// Non-mutating methods:
util.createMethods(Realm.prototype, objectTypes.REALM, [
    'close',
    'objects',
]);

// Mutating methods:
util.createMethods(Realm.prototype, objectTypes.REALM, [
    'create',
    'delete',
    'deleteAll',
], true);

Object.defineProperties(Realm, {
    Types: {
        value: Object.freeze(propTypes),
    },
    defaultPath: {
        get: util.getterForProperty('defaultPath'),
        set: util.setterForProperty('defaultPath'),
    },
    clearTestState: {
        value: function() {
            util.clearMutationListeners();
            rpc.clearTestState();
        },
    },
});

// The session ID refers to the Realm constructor object in the RPC server.
Realm[keys.id] = rpc.createSession();

module.exports = Realm;