mirror of
https://github.com/arcan1s/ahriman.git
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64 lines
2.2 KiB
TypeScript
64 lines
2.2 KiB
TypeScript
/*
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* Copyright (c) 2021-2026 ahriman team.
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*
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* This file is part of ahriman
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* (see https://github.com/arcan1s/ahriman).
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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import { type RefObject, useCallback, useRef } from "react";
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interface UseAutoScrollResult {
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handleScroll: () => void;
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preRef: RefObject<HTMLElement | null>;
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resetScroll: () => void;
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scrollToBottom: () => void;
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}
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export function useAutoScroll(): UseAutoScrollResult {
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const preRef = useRef<HTMLElement>(null);
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const initialScrollDone = useRef(false);
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const wasAtBottom = useRef(true);
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const handleScroll = useCallback((): void => {
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if (preRef.current) {
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const element = preRef.current;
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wasAtBottom.current = element.scrollTop + element.clientHeight >= element.scrollHeight - 50;
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}
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}, []);
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const resetScroll = useCallback((): void => {
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initialScrollDone.current = false;
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}, []);
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// scroll to bottom on initial load, then only if already near bottom and no active text selection
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const scrollToBottom = useCallback((): void => {
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if (!preRef.current) {
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return;
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}
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const element = preRef.current;
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if (!initialScrollDone.current) {
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element.scrollTop = element.scrollHeight;
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initialScrollDone.current = true;
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} else {
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const hasSelection = !document.getSelection()?.isCollapsed;
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if (wasAtBottom.current && !hasSelection) {
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element.scrollTop = element.scrollHeight;
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}
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}
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}, []);
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return { handleScroll, preRef, resetScroll, scrollToBottom };
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}
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