//
//  WKWebViewJavascriptBridgeJS.swift
//  WKWebViewJavascriptBridge
//
//  Created by Lision on 2018/1/21.
//  Copyright © 2018年 Lision. All rights reserved.
//

import Foundation

let WKWebViewJavascriptBridgeJS = """
;(function() {
    if (window.WKWebViewJavascriptBridge) {
        return;
    }

    if (!window.onerror) {
        window.onerror = function(msg, url, line) {
            console.log("WKWebViewJavascriptBridge: ERROR:" + msg + "@" + url + ":" + line);
        }
    }
    window.WKWebViewJavascriptBridge = {
        registerHandler: registerHandler,
        callHandler: callHandler,
        _fetchQueue: _fetchQueue,
        _handleMessageFromiOS: _handleMessageFromiOS
    };

    var sendMessageQueue = [];
    var messageHandlers = {};

    var responseCallbacks = {};
    var uniqueId = 1;

    function registerHandler(handlerName, handler) {
        messageHandlers[handlerName] = handler;
    }

    function callHandler(handlerName, data, responseCallback) {
        if (arguments.length == 2 && typeof data == 'function') {
            responseCallback = data;
            data = null;
        }
        _doSend({ handlerName:handlerName, data:data }, responseCallback);
    }

    function _doSend(message, responseCallback) {
        if (responseCallback) {
            var callbackID = 'cb_'+(uniqueId++)+'_'+new Date().getTime();
            responseCallbacks[callbackID] = responseCallback;
            message['callbackID'] = callbackID;
        }
        sendMessageQueue.push(message);
        window.webkit.messageHandlers.iOS_Native_FlushMessageQueue.postMessage(null)
    }

    function _fetchQueue() {
        var messageQueueString = JSON.stringify(sendMessageQueue);
        sendMessageQueue = [];
        return messageQueueString;
    }

    function _dispatchMessageFromiOS(messageJSON) {
        var message = JSON.parse(messageJSON);
        var messageHandler;
        var responseCallback;

        if (message.responseID) {
            responseCallback = responseCallbacks[message.responseID];
            if (!responseCallback) {
                return;
            }
            responseCallback(message.responseData);
            delete responseCallbacks[message.responseID];
        } else {
            if (message.callbackID) {
                var callbackResponseId = message.callbackID;
                responseCallback = function(responseData) {
                    _doSend({ handlerName:message.handlerName, responseID:callbackResponseId, responseData:responseData });
                };
            }

            var handler = messageHandlers[message.handlerName];
            if (!handler) {
                console.log("WKWebViewJavascriptBridge: WARNING: no handler for message from iOS:", message);
            } else {
                handler(message.data, responseCallback);
            }
        }
    }

    function _handleMessageFromiOS(messageJSON) {
        _dispatchMessageFromiOS(messageJSON);
    }

    setTimeout(_callWVJBCallbacks, 0);
    function _callWVJBCallbacks() {
        var callbacks = window.WKWVJBCallbacks;
        delete window.WKWVJBCallbacks;
        for (var i = 0; i < callbacks.length; i++) {
            callbacks[i](WKWebViewJavascriptBridge);
        }
    }
})();
"""