message_edit: Use move_messages_between_streams_limit_seconds in webapp.

This commit adds code to check time limit as per recently added
move_messages_between_streams_limit_seconds setting when moving
messages between streams in webapp. There is no time limit for
admins and moderators.

We add a new function "is_stream_editable" (similar to already
existing is_topic_editable function) to check whether user is
allowed to move message between streams.

frontend_tests/node_tests/message_edit.js

@@ -134,6 +134,50 @@ run_test("is_topic_editable", ({override}) => {
     assert.equal(message_edit.is_topic_editable(message), true);
 });
 
+run_test("is_stream_editable", ({override}) => {
+    const now = new Date();
+    const current_timestamp = now / 1000;
+
+    const message = {
+        sent_by_me: true,
+        locally_echoed: true,
+        type: "stream",
+    };
+    page_params.realm_allow_message_editing = true;
+    override(settings_data, "user_can_move_messages_between_streams", () => true);
+    page_params.is_admin = true;
+
+    assert.equal(message_edit.is_stream_editable(message), false);
+
+    message.locally_echoed = false;
+    message.failed_request = true;
+    assert.equal(message_edit.is_stream_editable(message), false);
+
+    message.failed_request = false;
+    assert.equal(message_edit.is_stream_editable(message), true);
+
+    page_params.sent_by_me = false;
+    assert.equal(message_edit.is_stream_editable(message), true);
+
+    override(settings_data, "user_can_move_messages_between_streams", () => false);
+    assert.equal(message_edit.is_stream_editable(message), false);
+
+    page_params.is_admin = false;
+    assert.equal(message_edit.is_stream_editable(message), false);
+
+    page_params.realm_move_messages_between_streams_limit_seconds = 259200;
+    message.timestamp = current_timestamp - 60;
+
+    override(settings_data, "user_can_move_messages_between_streams", () => true);
+    assert.equal(message_edit.is_stream_editable(message), true);
+
+    message.timestamp = current_timestamp - 600000;
+    assert.equal(message_edit.is_stream_editable(message), false);
+
+    page_params.is_moderator = true;
+    assert.equal(message_edit.is_stream_editable(message), true);
+});
+
 run_test("get_deletability", ({override}) => {
     page_params.is_admin = true;
     override(settings_data, "user_can_delete_own_message", () => false);

static/js/message_edit.js

@@ -179,16 +179,41 @@ export function get_deletability(message) {
     return false;
 }
 
-export function can_move_message(message) {
-    if (!message.is_stream) {
-        return false;
-    }
-
+export function is_stream_editable(message, edit_limit_seconds_buffer = 0) {
     if (!is_message_editable_ignoring_permissions(message)) {
         return false;
     }
 
-    return is_topic_editable(message) || settings_data.user_can_move_messages_between_streams();
+    if (message.type !== "stream") {
+        return false;
+    }
+
+    if (!settings_data.user_can_move_messages_between_streams()) {
+        return false;
+    }
+
+    // Organization admins and moderators can edit stream indefinitely,
+    // irrespective of the stream editing deadline, if
+    // move_messages_between_streams_policy allows them to do so.
+    if (page_params.is_admin || page_params.is_moderator) {
+        return true;
+    }
+
+    if (page_params.realm_move_messages_between_streams_limit_seconds === null) {
+        // This means no time limit for editing streams.
+        return true;
+    }
+
+    return (
+        page_params.realm_move_messages_between_streams_limit_seconds +
+            edit_limit_seconds_buffer +
+            (message.timestamp - Date.now() / 1000) >
+        0
+    );
+}
+
+export function can_move_message(message) {
+    return is_topic_editable(message) || is_stream_editable(message);
 }
 
 export function stream_and_topic_exist_in_edit_history(message, stream_id, topic) {

static/js/stream_popover.js

@@ -412,6 +412,14 @@ export function build_move_topic_to_stream_popover(current_stream_id, topic_name
         from_message_actions_popover: message !== undefined,
     };
 
+    // When the modal is opened for moving the whole topic from left sidebar,
+    // we do not have any message object and so we disable the stream input
+    // based on the move_messages_between_streams_policy setting. In other
+    // cases message row, message object is available and thus we check
+    // the time-based permissions as well in the below if block to enable or
+    // disable the stream input.
+    let disable_stream_input = !settings_data.user_can_move_messages_between_streams();
+
     let modal_heading = $t_html({defaultMessage: "Move topic"});
     if (message !== undefined) {
         modal_heading = $t_html({defaultMessage: "Move messages"});
@@ -423,6 +431,7 @@ export function build_move_topic_to_stream_popover(current_stream_id, topic_name
         // Though, this will be changed soon as we are going to make topic
         // edit permission independent of message.
         args.disable_topic_input = !message_edit.is_topic_editable(message);
+        disable_stream_input = !message_edit.is_stream_editable(message);
     }
 
     function get_params_from_form() {
@@ -563,10 +572,7 @@ export function build_move_topic_to_stream_popover(current_stream_id, topic_name
 
         stream_widget.setup();
 
-        $("#select_stream_widget .dropdown-toggle").prop(
-            "disabled",
-            !settings_data.user_can_move_messages_between_streams(),
-        );
+        $("#select_stream_widget .dropdown-toggle").prop("disabled", disable_stream_input);
         update_submit_button_disabled_state(stream_widget.value());
         $("#move_topic_modal .inline_topic_edit").on("input", () => {
             update_submit_button_disabled_state(stream_widget.value());