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: // The Button module currently supports only Firefox.
michael@0: // See: https://bugzilla.mozilla.org/show_bug.cgi?id=jetpack-panel-apps
michael@0: module.metadata = {
michael@0:   'stability': 'experimental',
michael@0:   'engines': {
michael@0:     'Firefox': '*'
michael@0:   }
michael@0: };
michael@0: 
michael@0: const { Ci } = require('chrome');
michael@0: 
michael@0: const events = require('../event/utils');
michael@0: const { events: browserEvents } = require('../browser/events');
michael@0: const { events: tabEvents } = require('../tab/events');
michael@0: const { events: stateEvents } = require('./state/events');
michael@0: 
michael@0: const { windows, isInteractive, getFocusedBrowser } = require('../window/utils');
michael@0: const { getActiveTab, getOwnerWindow } = require('../tabs/utils');
michael@0: 
michael@0: const { ignoreWindow } = require('../private-browsing/utils');
michael@0: 
michael@0: const { freeze } = Object;
michael@0: const { merge } = require('../util/object');
michael@0: const { on, off, emit } = require('../event/core');
michael@0: 
michael@0: const { add, remove, has, clear, iterator } = require('../lang/weak-set');
michael@0: const { isNil } = require('../lang/type');
michael@0: 
michael@0: const { viewFor } = require('../view/core');
michael@0: 
michael@0: const components = new WeakMap();
michael@0: 
michael@0: const ERR_UNREGISTERED = 'The state cannot be set or get. ' +
michael@0:   'The object may be not be registered, or may already have been unloaded.';
michael@0: 
michael@0: const ERR_INVALID_TARGET = 'The state cannot be set or get for this target.' +
michael@0:   'Only window, tab and registered component are valid targets.';
michael@0: 
michael@0: const isWindow = thing => thing instanceof Ci.nsIDOMWindow;
michael@0: const isTab = thing => thing.tagName && thing.tagName.toLowerCase() === 'tab';
michael@0: const isActiveTab = thing => isTab(thing) && thing === getActiveTab(getOwnerWindow(thing));
michael@0: const isEnumerable = window => !ignoreWindow(window);
michael@0: const browsers = _ =>
michael@0:   windows('navigator:browser', { includePrivate: true }).filter(isInteractive);
michael@0: const getMostRecentTab = _ => getActiveTab(getFocusedBrowser());
michael@0: 
michael@0: function getStateFor(component, target) {
michael@0:   if (!isRegistered(component))
michael@0:     throw new Error(ERR_UNREGISTERED);
michael@0: 
michael@0:   if (!components.has(component))
michael@0:     return null;
michael@0: 
michael@0:   let states = components.get(component);
michael@0: 
michael@0:   if (target) {
michael@0:     if (isTab(target) || isWindow(target) || target === component)
michael@0:       return states.get(target) || null;
michael@0:     else
michael@0:       throw new Error(ERR_INVALID_TARGET);
michael@0:   }
michael@0: 
michael@0:   return null;
michael@0: }
michael@0: exports.getStateFor = getStateFor;
michael@0: 
michael@0: function getDerivedStateFor(component, target) {
michael@0:   if (!isRegistered(component))
michael@0:     throw new Error(ERR_UNREGISTERED);
michael@0: 
michael@0:   if (!components.has(component))
michael@0:     return null;
michael@0: 
michael@0:   let states = components.get(component);
michael@0: 
michael@0:   let componentState = states.get(component);
michael@0:   let windowState = null;
michael@0:   let tabState = null;
michael@0: 
michael@0:   if (target) {
michael@0:     // has a target
michael@0:     if (isTab(target)) {
michael@0:       windowState = states.get(getOwnerWindow(target), null);
michael@0: 
michael@0:       if (states.has(target)) {
michael@0:         // we have a tab state
michael@0:         tabState = states.get(target);
michael@0:       }
michael@0:     }
michael@0:     else if (isWindow(target) && states.has(target)) {
michael@0:       // we have a window state
michael@0:       windowState = states.get(target);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   return freeze(merge({}, componentState, windowState, tabState));
michael@0: }
michael@0: exports.getDerivedStateFor = getDerivedStateFor;
michael@0: 
michael@0: function setStateFor(component, target, state) {
michael@0:   if (!isRegistered(component))
michael@0:     throw new Error(ERR_UNREGISTERED);
michael@0: 
michael@0:   let isComponentState = target === component;
michael@0:   let targetWindows = isWindow(target) ? [target] :
michael@0:                       isActiveTab(target) ? [getOwnerWindow(target)] :
michael@0:                       isComponentState ? browsers() :
michael@0:                       isTab(target) ? [] :
michael@0:                       null;
michael@0: 
michael@0:   if (!targetWindows)
michael@0:     throw new Error(ERR_INVALID_TARGET);
michael@0: 
michael@0:   // initialize the state's map
michael@0:   if (!components.has(component))
michael@0:     components.set(component, new WeakMap());
michael@0: 
michael@0:   let states = components.get(component);
michael@0: 
michael@0:   if (state === null && !isComponentState) // component state can't be deleted
michael@0:     states.delete(target);
michael@0:   else {
michael@0:     let base = isComponentState ? states.get(target) : null;
michael@0:     states.set(target, freeze(merge({}, base, state)));
michael@0:   }
michael@0: 
michael@0:   render(component, targetWindows);
michael@0: }
michael@0: exports.setStateFor = setStateFor;
michael@0: 
michael@0: function render(component, targetWindows) {
michael@0:   targetWindows = targetWindows ? [].concat(targetWindows) : browsers();
michael@0: 
michael@0:   for (let window of targetWindows.filter(isEnumerable)) {
michael@0:     let tabState = getDerivedStateFor(component, getActiveTab(window));
michael@0: 
michael@0:     emit(stateEvents, 'data', {
michael@0:       type: 'render',
michael@0:       target: component,
michael@0:       window: window,
michael@0:       state: tabState
michael@0:     });
michael@0: 
michael@0:   }
michael@0: }
michael@0: exports.render = render;
michael@0: 
michael@0: function properties(contract) {
michael@0:   let { rules } = contract;
michael@0:   let descriptor = Object.keys(rules).reduce(function(descriptor, name) {
michael@0:     descriptor[name] = {
michael@0:       get: function() { return getDerivedStateFor(this)[name] },
michael@0:       set: function(value) {
michael@0:         let changed = {};
michael@0:         changed[name] = value;
michael@0: 
michael@0:         setStateFor(this, this, contract(changed));
michael@0:       }
michael@0:     }
michael@0:     return descriptor;
michael@0:   }, {});
michael@0: 
michael@0:   return Object.create(Object.prototype, descriptor);
michael@0: }
michael@0: exports.properties = properties;
michael@0: 
michael@0: function state(contract) {
michael@0:   return {
michael@0:     state: function state(target, state) {
michael@0:       let nativeTarget = target === 'window' ? getFocusedBrowser()
michael@0:                           : target === 'tab' ? getMostRecentTab()
michael@0:                           : target === this ? null
michael@0:                           : viewFor(target);
michael@0: 
michael@0:       if (!nativeTarget && target !== this && !isNil(target))
michael@0:         throw new Error(ERR_INVALID_TARGET);
michael@0: 
michael@0:       target = nativeTarget || target;
michael@0: 
michael@0:       // jquery style
michael@0:       return arguments.length < 2
michael@0:         ? getDerivedStateFor(this, target)
michael@0:         : setStateFor(this, target, contract(state))
michael@0:     }
michael@0:   }
michael@0: }
michael@0: exports.state = state;
michael@0: 
michael@0: const register = (component, state) => {
michael@0:   add(components, component);
michael@0:   setStateFor(component, component, state);
michael@0: }
michael@0: exports.register = register;
michael@0: 
michael@0: const unregister = component => {
michael@0:   remove(components, component);
michael@0: }
michael@0: exports.unregister = unregister;
michael@0: 
michael@0: const isRegistered = component => has(components, component);
michael@0: exports.isRegistered = isRegistered;
michael@0: 
michael@0: let tabSelect = events.filter(tabEvents, e => e.type === 'TabSelect');
michael@0: let tabClose = events.filter(tabEvents, e => e.type === 'TabClose');
michael@0: let windowOpen = events.filter(browserEvents, e => e.type === 'load');
michael@0: let windowClose = events.filter(browserEvents, e => e.type === 'close');
michael@0: 
michael@0: let close = events.merge([tabClose, windowClose]);
michael@0: let activate = events.merge([windowOpen, tabSelect]);
michael@0: 
michael@0: on(activate, 'data', ({target}) => {
michael@0:   let [window, tab] = isWindow(target)
michael@0:                         ? [target, getActiveTab(target)]
michael@0:                         : [getOwnerWindow(target), target];
michael@0: 
michael@0:   if (ignoreWindow(window)) return;
michael@0: 
michael@0:   for (let component of iterator(components)) {
michael@0:     emit(stateEvents, 'data', {
michael@0:       type: 'render',
michael@0:       target: component,
michael@0:       window: window,
michael@0:       state: getDerivedStateFor(component, tab)
michael@0:     });
michael@0:   }
michael@0: });
michael@0: 
michael@0: on(close, 'data', function({target}) {
michael@0:   for (let component of iterator(components)) {
michael@0:     components.get(component).delete(target);
michael@0:   }
michael@0: });