////////////////////////////////////////////////////////////////////////////
//
// 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';

import { NativeModules } from 'react-native';
import { keys, propTypes, objectTypes } from './constants';
import * as lists from './lists';
import * as objects from './objects';
import * as results from './results';
import * as rpc from './rpc';
import * as util from './util';

const {debugHosts, debugPort} = NativeModules.Realm;
const listenersKey = Symbol();

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

export default 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)});
        });
    }

    create(type, ...args) {
        if (typeof type == 'function') {
            type = objects.typeForConstructor(this[keys.realm], type);
        }

        let method = util.createMethod(objectTypes.REALM, 'create', true);
        return method.apply(this, [type, ...args]);
    }

    objects(type, ...args) {
        if (typeof type == 'function') {
            type = objects.typeForConstructor(this[keys.realm], type);
        }

        let method = util.createMethod(objectTypes.REALM, 'objects');
        return method.apply(this, [type, ...args]);
    }

    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',
]);

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

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

for (let i = 0, len = debugHosts.length; i < len; i++) {
    try {
        // The session ID refers to the Realm constructor object in the RPC server.
        Realm[keys.id] = rpc.createSession(debugHosts[i] + ':' + debugPort);
        break;
    } catch (e) {
        // Only throw exception after all hosts have been tried.
        if (i < len - 1) {
            continue;
        }

        // Log the original exception for debugging purposes.
        console.error(e);

        throw new Error(
            'Realm failed to connect to the embedded debug server inside the app. ' +
            'If attempting to use Chrome debugging from a device, ensure the device is ' +
            'reachable on the same network as this machine.'
        );
    }
}