michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0: * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0: * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: "use strict";
michael@0: 
michael@0: module.metadata = {
michael@0:   "stability": "experimental",
michael@0:   "engines": {
michael@0:     "Firefox": "> 28"
michael@0:   }
michael@0: };
michael@0: 
michael@0: const { Class } = require("../../core/heritage");
michael@0: const { EventTarget } = require("../../event/target");
michael@0: const { off, setListeners, emit } = require("../../event/core");
michael@0: const { Reactor, foldp, merges, send } = require("../../event/utils");
michael@0: const { Disposable } = require("../../core/disposable");
michael@0: const { InputPort } = require("../../input/system");
michael@0: const { OutputPort } = require("../../output/system");
michael@0: const { identify } = require("../id");
michael@0: const { pairs, object, map, each } = require("../../util/sequence");
michael@0: const { patch, diff } = require("diffpatcher/index");
michael@0: const { contract } = require("../../util/contract");
michael@0: const { id: addonID } = require("../../self");
michael@0: 
michael@0: // Input state is accumulated from the input received form the toolbar
michael@0: // view code & local output. Merging local output reflects local state
michael@0: // changes without complete roundloop.
michael@0: const input = foldp(patch, {}, new InputPort({ id: "toolbar-changed" }));
michael@0: const output = new OutputPort({ id: "toolbar-change" });
michael@0: 
michael@0: // Takes toolbar title and normalizes is to an
michael@0: // identifier, also prefixes with add-on id.
michael@0: const titleToId = title =>
michael@0:   ("toolbar-" + addonID + "-" + title).
michael@0:     toLowerCase().
michael@0:     replace(/\s/g, "-").
michael@0:     replace(/[^A-Za-z0-9_\-]/g, "");
michael@0: 
michael@0: const validate = contract({
michael@0:   title: {
michael@0:     is: ["string"],
michael@0:     ok: x => x.length > 0,
michael@0:     msg: "The `option.title` string must be provided"
michael@0:   },
michael@0:   items: {
michael@0:     is:["undefined", "object", "array"],
michael@0:     msg: "The `options.items` must be iterable sequence of items"
michael@0:   },
michael@0:   hidden: {
michael@0:     is: ["boolean", "undefined"],
michael@0:     msg: "The `options.hidden` must be boolean"
michael@0:   }
michael@0: });
michael@0: 
michael@0: // Toolbars is a mapping between `toolbar.id` & `toolbar` instances,
michael@0: // which is used to find intstance for dispatching events.
michael@0: let toolbars = new Map();
michael@0: 
michael@0: const Toolbar = Class({
michael@0:   extends: EventTarget,
michael@0:   implements: [Disposable],
michael@0:   initialize: function(params={}) {
michael@0:     const options = validate(params);
michael@0:     const id = titleToId(options.title);
michael@0: 
michael@0:     if (toolbars.has(id))
michael@0:       throw Error("Toolbar with this id already exists: " + id);
michael@0: 
michael@0:     // Set of the items in the toolbar isn't mutable, as a matter of fact
michael@0:     // it just defines desired set of items, actual set is under users
michael@0:     // control. Conver test to an array and freeze to make sure users won't
michael@0:     // try mess with it.
michael@0:     const items = Object.freeze(options.items ? [...options.items] : []);
michael@0: 
michael@0:     const initial = {
michael@0:       id: id,
michael@0:       title: options.title,
michael@0:       // By default toolbars are visible when add-on is installed, unless
michael@0:       // add-on authors decides it should be hidden. From that point on
michael@0:       // user is in control.
michael@0:       collapsed: !!options.hidden,
michael@0:       // In terms of state only identifiers of items matter.
michael@0:       items: items.map(identify)
michael@0:     };
michael@0: 
michael@0:     this.id = id;
michael@0:     this.items = items;
michael@0: 
michael@0:     toolbars.set(id, this);
michael@0:     setListeners(this, params);
michael@0: 
michael@0:     // Send initial state to the host so it can reflect it
michael@0:     // into a user interface.
michael@0:     send(output, object([id, initial]));
michael@0:   },
michael@0: 
michael@0:   get title() {
michael@0:     const state = reactor.value[this.id];
michael@0:     return state && state.title;
michael@0:   },
michael@0:   get hidden() {
michael@0:     const state = reactor.value[this.id];
michael@0:     return state && state.collapsed;
michael@0:   },
michael@0: 
michael@0:   destroy: function() {
michael@0:     send(output, object([this.id, null]));
michael@0:   },
michael@0:   // `JSON.stringify` serializes objects based of the return
michael@0:   // value of this method. For convinienc we provide this method
michael@0:   // to serialize actual state data. Note: items will also be
michael@0:   // serialized so they should probably implement `toJSON`.
michael@0:   toJSON: function() {
michael@0:     return {
michael@0:       id: this.id,
michael@0:       title: this.title,
michael@0:       hidden: this.hidden,
michael@0:       items: this.items
michael@0:     };
michael@0:   }
michael@0: });
michael@0: exports.Toolbar = Toolbar;
michael@0: identify.define(Toolbar, toolbar => toolbar.id);
michael@0: 
michael@0: const dispose = toolbar => {
michael@0:   toolbars.delete(toolbar.id);
michael@0:   emit(toolbar, "detach");
michael@0:   off(toolbar);
michael@0: };
michael@0: 
michael@0: const reactor = new Reactor({
michael@0:   onStep: (present, past) => {
michael@0:     const delta = diff(past, present);
michael@0: 
michael@0:     each(([id, update]) => {
michael@0:       const toolbar = toolbars.get(id);
michael@0: 
michael@0:       // Remove
michael@0:       if (!update)
michael@0:         dispose(toolbar);
michael@0:       // Add
michael@0:       else if (!past[id])
michael@0:         emit(toolbar, "attach");
michael@0:       // Update
michael@0:       else
michael@0:         emit(toolbar, update.collapsed ? "hide" : "show", toolbar);
michael@0:     }, pairs(delta));
michael@0:   }
michael@0: });
michael@0: reactor.run(input);