From 8926fcb3a62fc36914e89cf46ffeff27dc1eecda Mon Sep 17 00:00:00 2001
From: Bruno Windels <brunow@matrix.org>
Date: Fri, 24 May 2019 14:41:24 +0200
Subject: [PATCH] helper functions to find next & previous editable events in
 timeline

---
 src/utils/EventUtils.js | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/utils/EventUtils.js b/src/utils/EventUtils.js
index 68f6d4b14e..d7c2285e7b 100644
--- a/src/utils/EventUtils.js
+++ b/src/utils/EventUtils.js
@@ -16,7 +16,8 @@ limitations under the License.
 
 import { EventStatus } from 'matrix-js-sdk';
 import MatrixClientPeg from '../MatrixClientPeg';
-
+import { findLastIndex, findIndex } from "lodash";
+import shouldHideEvent from "../shouldHideEvent";
 /**
  * Returns whether an event should allow actions like reply, reactions, edit, etc.
  * which effectively checks whether it's a regular message that has been sent and that we
@@ -50,3 +51,35 @@ export function canEditContent(mxEvent) {
         mxEvent.getOriginalContent().msgtype === "m.text" &&
         mxEvent.getSender() === MatrixClientPeg.get().getUserId();
 }
+
+export function findPreviousEditableEvent(room, fromEventId = undefined) {
+    const liveTimeline = room.getLiveTimeline();
+    const events = liveTimeline.getEvents();
+    let startFromIdx = events.length - 1;
+    if (fromEventId) {
+        const fromEventIdx = findLastIndex(events, e => e.getId() === fromEventId);
+        if (fromEventIdx !== -1) {
+            startFromIdx = fromEventIdx - 1;
+        }
+    }
+    const nextEventIdx = findLastIndex(events, e => !shouldHideEvent(e) && canEditContent(e), startFromIdx);
+    if (nextEventIdx !== -1) {
+        return events[nextEventIdx];
+    }
+}
+
+export function findNextEditableEvent(room, fromEventId = undefined) {
+    const liveTimeline = room.getLiveTimeline();
+    const events = liveTimeline.getEvents();
+    let startFromIdx = 0;
+    if (fromEventId) {
+        const fromEventIdx = findIndex(events, e => e.getId() === fromEventId);
+        if (fromEventIdx !== -1) {
+            startFromIdx = fromEventIdx + 1;
+        }
+    }
+    const nextEventIdx = findIndex(events, e => !shouldHideEvent(e) && canEditContent(e), startFromIdx);
+    if (nextEventIdx !== -1) {
+        return events[nextEventIdx];
+    }
+}