[REF][FIX] mail, im_livechat: various improvements (JS)

This commit makes a lot of small improvements of the JS of mail and
related modules.

	A. Mail Manager
	---------------

		im_support:

		- [REF] Slightly more robust way to determine a support
		        message, so that it more reliably falls back on
		        default kind of message (i.e. support channel UUID
		        should be clearly set).

		mail:

		- [REF] Improved method names for readability purposes.
		        Some examples:

		        - `fetchFromServer` becomes `fetchMailStateFromServer`
		        - `_initialize{*}` becomes `_update{*}FromServer`
		        - `_isModerator` becomes `_isMyselfModerator`

		- [REF] Use 'template' pattern design to make Include on
				Mail Manager much more robust. In particular,
				the flow is always as follow:

					1. Initialize internal state.
					2. Listen on buses.
					3. Fetch mail data from server.

		- [REF] Improved workflow for thread window workflow
		        (Shorter & more readable).

	B. Mail Tests
	-------------

		- [REF] Thread Window Tests crashes with clean message when
		        there are some thread windows open before running the
		        tests.

	C. (Model) Message
	------------------

		- [REF] Improved method names for readability purposes
				(e.g. `isAuthor` becomes `isMyselfAuthor`).

	D. (Model) Thread
	-----------------

		- [REF] Improved `init` parameters on each kind of thread.
		- [REF] 'Thread With Cache' has been renamed to 'Searchable
		        Thread': it embraces all kinds of threads that can
		        be used with the search view.
		- [REF] 'DM' has been renamed to 'DM Chat' (for clarity).
		- [IMP] New Livechat model in the backend.
		- [REF] No more direct instances of the Channel class: public
		        and private channels are now 'Multi-User' channels,
		        while DM Chat and Livechat are 'Two-User' channels:

		        This change has been made so that instances of classes
		        always have direct classes as "leaf" in the Class
		        modeling. It eases making changes to a certain model
		        without being too constrained by another model.

		- [REF] As a consequence of above changed, the method `isChat`
		        has been renamed to `isTwoUserThread`.

		        This is to avoid confusion with the terminology
		        'chat', which is more like a shortcut for 'quick real-
		        time conversation'. In other words, the property of
		        'chat' depends of the way to interact on a thread, not
		        of the intrinsic type of the thread.

		        Still, some parts have kept the terminology 'chat',
		        such as in the systray messagin menu.

		- [IMP] Added `message_added` and `message_posted` hooks,
		        which may be useful to easily hook on those events.

	E. Thread Widget
	----------------

		- [REF] Now uses a `mail.model.AbstractThread` for the
		        rendering of a thread, instead of a list of
		        `{mail.model.AbstractMessage}`.
		- [FIX] Stick thread scroll height to bottom on new rendering,
		        if it was previously at the bottom of the thread.
		- [REF] Option ORDER has its meaning changed: it now refers
		        to the chronological order of messages in the thread,
		        in which DESC means 'from top to bottom', while ASC
		        means 'from bottom to top'.
		- [REF] Improved doc on templates, in particular with the
	            option `ORDER`.

	F. Thread Window
	----------------

		- [REF] Moved more logic to thread windows, which were
		        previously in Mail Window Manager.
		- [REF] Now hides the thread widget attribute. So instead of
		        `threadWindow.threadWidget.isAtBottom()`, it uses
		        `threadWindow.isAtBottom()`.
		- [FIX] New received messages when not having focus on Odoo
		        tab should always make the corresponding thread
		        windows "passive" (i.e. windows that keep threads
		        unread until click on them).
		- [FIX] Blank thread window (i.e. 'New message' TW) correctly
		        opens Discuss with 'Inbox' when clicking on 'Expand'
		        Button in the title
		- [FIX] Do not display the composer for channels with property
		        'mass-mailing' set in thread windows.

	G. (Website) Livechat
	---------------------

		- [REF] Some `trigger` have been turned into `trigger_up`.
		- [REF] Some logic has been moved to models (e.g.
		        `{im_livechat.model.WebsiteLivechat}`), from
		        `{im_livechat.im_livechat.LivechatButton}`.
		- [FIX] New messages should be received in real-time. The
		        longpolling was broken with a recent refactoring on
		        bus service (6448420c5dd160470e465dee7729d19d8d5e7bab).

3 files changed, 90 insertions, 23 deletions

diff --git a/addons/mail/static/src/xml/abstract_thread_window.xml b/addons/mail/static/src/xml/abstract_thread_window.xml
index e62cdba042b..af72d5dd36c 100644
--- a/addons/mail/static/src/xml/abstract_thread_window.xml
+++ b/addons/mail/static/src/xml/abstract_thread_window.xml
@@ -15,7 +15,7 @@
             </div>
             <div class="o_thread_window_content">
             </div>
-            <div t-if='widget.hasThread()' class="o_thread_composer o_chat_mini_composer">
+            <div t-if="widget.needsComposer()" class="o_thread_composer o_chat_mini_composer">
                 <input class="o_composer_text_field" t-att-placeholder="widget.options.placeholder"/>
             </div>
         </div>
diff --git a/addons/mail/static/src/xml/discuss.xml b/addons/mail/static/src/xml/discuss.xml
index ad9a809ba03..eb03e3c0c55 100644
--- a/addons/mail/static/src/xml/discuss.xml
+++ b/addons/mail/static/src/xml/discuss.xml
@@ -40,7 +40,7 @@
                 <t t-set="counter" t-value="starredCounter"/>
                 <t t-call="mail.discuss.SidebarCounter"/>
             </div>
-            <div t-if="isModerator" t-attf-class="o_mail_discuss_title_main o_mail_discuss_item #{(activeThreadID == 'mailbox_moderation') ? 'o_active': ''}"
+            <div t-if="isMyselfModerator" t-attf-class="o_mail_discuss_title_main o_mail_discuss_item #{(activeThreadID == 'mailbox_moderation') ? 'o_active': ''}"
                  data-thread-id="mailbox_moderation">
                 <span class="o_thread_name"> <i class="fa fa-envelope mr8"/>Moderation Queue</span>
                 <t t-set="counter" t-value="moderationCounter"/>
@@ -58,7 +58,7 @@
                 <t t-set="inputPlaceholder">Add a channel</t>
             </t>
 
-            <t t-set="type" t-value="'dm'"/>
+            <t t-set="type" t-value="'dm_chat'"/>
             <t t-call="mail.discuss.SidebarTitle">
                 <t t-set="title">Direct Messages</t>
                 <t t-set="icon" t-value="fa-user"/>
@@ -133,7 +133,7 @@
             <input type="text" class="o_input" t-attf-placeholder="#{inputPlaceholder}"/>
         </div>
         <t t-foreach="threads" t-as="thread">
-            <t t-set="counter" t-value="thread.getType() === 'mailbox' ? thread.getMailboxCounter() : thread.isChat() ? thread.getUnreadCounter() : thread.getNeedactionCounter()"/>
+            <t t-set="counter" t-value="thread.getType() === 'mailbox' ? thread.getMailboxCounter() : thread.isTwoUserThread() ? thread.getUnreadCounter() : thread.getNeedactionCounter()"/>
             <div t-if="thread.getType() === type" t-att-data-thread-id="thread.getID()" t-att-title="thread.getName()"
                  t-attf-class="o_mail_discuss_item #{thread.hasUnreadMessages() ? ' o_unread_message' : ''} #{(activeThreadID == thread.getID()) ? 'o_active': ''}">
                 <span class="o_thread_name">
@@ -221,7 +221,7 @@
                     <span class="fa fa-inbox"/>
                     <span class="o_tab_title">Inbox</span>
                 </div>
-                <div class="o_mail_mobile_tab" data-type="dm">
+                <div class="o_mail_mobile_tab" data-type="dm_chat">
                     <span class="fa fa-user"/>
                     <span class="o_tab_title">Chat</span>
                 </div>
@@ -246,7 +246,7 @@
             <div t-if="!disableAddThread" class="o_mail_add_thread" t-att-data-type="type">
                 <span t-if="type == 'private' || type == 'public'">#</span>
                 <t t-set="inputPlaceholder" t-if="type == 'private' || type == 'public'">Add a channel</t>
-                <t t-set="inputPlaceholder" t-if="type == 'dm'">Open chat</t>
+                <t t-set="inputPlaceholder" t-if="type == 'dm_chat'">Open chat</t>
                 <input type="text" t-attf-placeholder="#{inputPlaceholder}"/>
             </div>
             <t t-foreach="previews" t-as="preview">
@@ -266,7 +266,7 @@
         @param {string} [preview.documentModel]
         @param {string|integer} preview.id
         @param {string} [preview.imageSRC]
-        @param {boolean} [preview.isAuthor]
+        @param {boolean} [preview.isMyselfAuthor]
         @param {moment} [preview.date]
         @param {string} [preview.author]
         @param {string} [preview.body]
@@ -293,7 +293,7 @@
                     <span class="o_last_message_date"> <t t-esc="preview.date ? preview.date.fromNow() : ''"/> </span>
                 </div>
                 <div t-if="preview.body" class="o_last_message_preview">
-                    <t t-if="preview.isAuthor">
+                    <t t-if="preview.isMyselfAuthor">
                         <span class="fa fa-mail-reply" role="img" aria-label="Reply"/> You:
                     </t>
                     <t t-elif="preview.author">
diff --git a/addons/mail/static/src/xml/thread.xml b/addons/mail/static/src/xml/thread.xml
index b3443418c2b..b33452382ac 100644
--- a/addons/mail/static/src/xml/thread.xml
+++ b/addons/mail/static/src/xml/thread.xml
@@ -3,22 +3,13 @@
 
     <!--
         @param {mail.model.AbstractThread} thread
+        @param {Object} options
         @param {boolean} [options.displayEmptyThread]
-        @param {boolean} [options.displayLoadMore]
         @param {boolean} [options.displayNoMatchFound]
-        @param {integer} [options.displayOrder] 1 or -1
-        @param {Object} ORDER
-        @param {integer} ORDER.ASC=1
-        @param {integer} ORDER.DESC=-1
     -->
     <t t-name="mail.widget.Thread">
         <t t-if="thread.hasMessages()">
-            <t t-set="messages" t-value="thread.getMessages()"/>
-            <t t-if="options.displayLoadMore and options.displayOrder == ORDER.ASC"
-               t-call="mail.widget.Thread.LoadMore"/>
             <t t-call="mail.widget.Thread.Content"/>
-            <t t-if="options.displayLoadMore and options.displayOrder == ORDER.DESC"
-               t-call="mail.widget.Thread.LoadMore"/>
         </t>
         <t t-elif="options.displayEmptyThread">
             <t t-call="mail.widget.Thread.Empty" />
@@ -134,14 +125,90 @@
     </div>
 
     <!--
-        @param {mail.model.AbstractMessage[]} messages messages ordered by increasing IDs
+        @param {mail.model.AbstractThread} thread
+        @param {Object} options
+        @param {integer} [options.displayOrder] 1 or -1 chronological order for the thread messages
+        @param {Object} ORDER
+        @param {integer} ORDER.ASC=1 messages are ordered by increasing IDs, from bottom to top
+        @param {integer} ORDER.DESC=-1 messages are ordered by increasing IDs, from top to bottom
+
+        Ordering of messages in the thread, messages are indexed by increasing IDs:
+                    _____________            _____________
+                   |             |          |             |
+                   |  message 1  |          |  message n  |
+                   |  message 2  |          |  ...        |
+                   |  ...        |          |  message 2  |
+                   |  message n  |          |  message 1  |
+                   |_____________|          |_____________|
+
+        ORDER:           DESC                    ASC
+
+    -->
+    <t t-name="mail.widget.Thread.Content">
+        <t t-set="messages" t-value="thread.getMessages()"/>
+        <t t-if="options.displayOrder === ORDER.ASC" t-call="mail.widget.Thread.Content.ASC"/>
+        <t t-else="" t-call="mail.widget.Thread.Content.DESC"/>
+    </t>
+
+    <!--
+        @param {mail.model.AbstractThread} thread
+        @param {Object} options
+        @param {boolean} [options.displayLoadMore=false]
         @param {string|integer} [options.messagesSeparatorPosition] 'top' or
             message ID, the separator is placed just after this message.
+
+                     _____________
+                    |             |
+                    |  message n  |
+                    |  ...        |
+                    |  message 2  |
+                    |  message 1  |
+                    |_____________|
+
+                      ASC Order
+
     -->
-    <t t-name="mail.widget.Thread.Content">
-        <t t-if="options.messagesSeparatorPosition == 'top'" t-call="mail.MessagesSeparator"/>
+    <t t-name="mail.widget.Thread.Content.ASC">
+        <div class="o_mail_thread_content_asc">
+            <t t-if="options.messagesSeparatorPosition == 'top'" t-call="mail.MessagesSeparator"/>
+            <t t-set="messages" t-value="messages.slice().reverse()"/>
+            <t t-call="mail.widget.Thread.Messages"/>
+            <t t-if="options.displayLoadMore" t-call="mail.widget.Thread.LoadMore"/>
+        </div>
+    </t>
+
+    <!--
+        @param {mail.model.AbstractThread} thread
+        @param {Object} options
+        @param {boolean} [options.displayBottomThreadFreeSpace=false]
+        @param {boolean} [options.displayLoadMore=false]
+
+                     _____________
+                    |             |
+                    |  message 1  |
+                    |  message 2  |
+                    |  ...        |
+                    |  message n  |
+                    |_____________|
+
+                      DESC Order
+    -->
+    <t t-name="mail.widget.Thread.Content.DESC">
+        <div class="o_mail_thread_content_desc">
+            <t t-if="options.displayLoadMore" t-call="mail.widget.Thread.LoadMore"/>
+            <t t-call="mail.widget.Thread.Messages"/>
+            <t t-if="options.displayBottomThreadFreeSpace">
+                <div class="o_thread_bottom_free_space"/>
+            </t>
+        </div>
+    </t>
+
+    <!--
+        @param {mail.model.AbstractMessage[]} messages messages are ordered based
+          on desired display order
+    -->
+    <t t-name="mail.widget.Thread.Messages">
         <t t-set="current_day" t-value="0"/>
-        <t t-if="options.displayOrder === ORDER.DESC" t-set="messages" t-value="messages.slice().reverse()"/>
         <t t-foreach="messages" t-as="message">
             <div t-if="current_day !== message.getDateDay()" class="o_thread_date_separator">
                 <span class="o_thread_date">
@@ -261,7 +328,7 @@
                             <t t-if="message.needsModerationByUser()">
                                 <t t-call="mail.MessageModerationDecision"/>
                             </t>
-                            <t t-elif="message.isAuthor()">
+                            <t t-elif="message.isMyselfAuthor()">
                                 <t t-call="mail.MessageModerationFeedback"/>
                             </t>
                         </t>