Files
gemini-cli/packages/cli/src/ui/contexts/ScrollProvider.tsx

373 lines
9.9 KiB
TypeScript

/**
* @license
* Copyright 2025 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
import type React from 'react';
import {
createContext,
useCallback,
useContext,
useEffect,
useMemo,
useRef,
useState,
} from 'react';
import { getBoundingBox, type DOMElement } from 'ink';
import { useMouse, type MouseEvent } from '../hooks/useMouse.js';
export interface ScrollState {
scrollTop: number;
scrollHeight: number;
innerHeight: number;
}
export interface ScrollableEntry {
id: string;
ref: React.RefObject<DOMElement>;
getScrollState: () => ScrollState;
scrollBy: (delta: number) => void;
scrollTo?: (scrollTop: number, duration?: number) => void;
hasFocus: () => boolean;
flashScrollbar: () => void;
}
interface ScrollContextType {
register: (entry: ScrollableEntry) => void;
unregister: (id: string) => void;
}
const ScrollContext = createContext<ScrollContextType | null>(null);
const findScrollableCandidates = (
mouseEvent: MouseEvent,
scrollables: Map<string, ScrollableEntry>,
) => {
const candidates: Array<ScrollableEntry & { area: number }> = [];
for (const entry of scrollables.values()) {
if (!entry.ref.current) {
continue;
}
const boundingBox = getBoundingBox(entry.ref.current);
if (!boundingBox) continue;
const { x, y, width, height } = boundingBox;
const isInside =
mouseEvent.col >= x &&
mouseEvent.col < x + width + 1 && // Intentionally add one to width to include scrollbar.
mouseEvent.row >= y &&
mouseEvent.row < y + height;
if (isInside) {
candidates.push({ ...entry, area: width * height });
}
}
// Sort by smallest area first
candidates.sort((a, b) => a.area - b.area);
return candidates;
};
export const ScrollProvider: React.FC<{ children: React.ReactNode }> = ({
children,
}) => {
const [scrollables, setScrollables] = useState(
new Map<string, ScrollableEntry>(),
);
const register = useCallback((entry: ScrollableEntry) => {
setScrollables((prev) => new Map(prev).set(entry.id, entry));
}, []);
const unregister = useCallback((id: string) => {
setScrollables((prev) => {
const next = new Map(prev);
next.delete(id);
return next;
});
}, []);
const scrollablesRef = useRef(scrollables);
useEffect(() => {
scrollablesRef.current = scrollables;
}, [scrollables]);
const pendingScrollsRef = useRef(new Map<string, number>());
const flushScheduledRef = useRef(false);
const dragStateRef = useRef<{
active: boolean;
id: string | null;
offset: number;
}>({
active: false,
id: null,
offset: 0,
});
const scheduleFlush = useCallback(() => {
if (!flushScheduledRef.current) {
flushScheduledRef.current = true;
setTimeout(() => {
flushScheduledRef.current = false;
for (const [id, delta] of pendingScrollsRef.current.entries()) {
const entry = scrollablesRef.current.get(id);
if (entry) {
entry.scrollBy(delta);
}
}
pendingScrollsRef.current.clear();
}, 0);
}
}, []);
const handleScroll = (direction: 'up' | 'down', mouseEvent: MouseEvent) => {
const delta = direction === 'up' ? -1 : 1;
const candidates = findScrollableCandidates(
mouseEvent,
scrollablesRef.current,
);
for (const candidate of candidates) {
const { scrollTop, scrollHeight, innerHeight } =
candidate.getScrollState();
const pendingDelta = pendingScrollsRef.current.get(candidate.id) || 0;
const effectiveScrollTop = scrollTop + pendingDelta;
// Epsilon to handle floating point inaccuracies.
const canScrollUp = effectiveScrollTop > 0.001;
const canScrollDown =
effectiveScrollTop < scrollHeight - innerHeight - 0.001;
if (direction === 'up' && canScrollUp) {
pendingScrollsRef.current.set(candidate.id, pendingDelta + delta);
scheduleFlush();
return true;
}
if (direction === 'down' && canScrollDown) {
pendingScrollsRef.current.set(candidate.id, pendingDelta + delta);
scheduleFlush();
return true;
}
}
return false;
};
const handleLeftPress = (mouseEvent: MouseEvent) => {
// Check for scrollbar interaction first
for (const entry of scrollablesRef.current.values()) {
if (!entry.ref.current || !entry.hasFocus()) {
continue;
}
const boundingBox = getBoundingBox(entry.ref.current);
if (!boundingBox) continue;
const { x, y, width, height } = boundingBox;
// Check if click is on the scrollbar column (x + width)
// The findScrollableCandidates logic implies scrollbar is at x + width.
if (
mouseEvent.col === x + width &&
mouseEvent.row >= y &&
mouseEvent.row < y + height
) {
const { scrollTop, scrollHeight, innerHeight } = entry.getScrollState();
if (scrollHeight <= innerHeight) continue;
const thumbHeight = Math.max(
1,
Math.floor((innerHeight / scrollHeight) * innerHeight),
);
const maxScrollTop = scrollHeight - innerHeight;
const maxThumbY = innerHeight - thumbHeight;
if (maxThumbY <= 0) continue;
const currentThumbY = Math.round(
(scrollTop / maxScrollTop) * maxThumbY,
);
const absoluteThumbTop = y + currentThumbY;
const absoluteThumbBottom = absoluteThumbTop + thumbHeight;
const isTop = mouseEvent.row === y;
const isBottom = mouseEvent.row === y + height - 1;
const hitTop = isTop ? absoluteThumbTop : absoluteThumbTop - 1;
const hitBottom = isBottom
? absoluteThumbBottom
: absoluteThumbBottom + 1;
const isThumbClick =
mouseEvent.row >= hitTop && mouseEvent.row < hitBottom;
let offset = 0;
const relativeMouseY = mouseEvent.row - y;
if (isThumbClick) {
offset = relativeMouseY - currentThumbY;
} else {
// Track click - Jump to position
// Center the thumb on the mouse click
const targetThumbY = Math.max(
0,
Math.min(maxThumbY, relativeMouseY - Math.floor(thumbHeight / 2)),
);
const newScrollTop = Math.round(
(targetThumbY / maxThumbY) * maxScrollTop,
);
if (entry.scrollTo) {
entry.scrollTo(newScrollTop);
} else {
entry.scrollBy(newScrollTop - scrollTop);
}
offset = relativeMouseY - targetThumbY;
}
// Start drag (for both thumb and track clicks)
dragStateRef.current = {
active: true,
id: entry.id,
offset,
};
return true;
}
}
const candidates = findScrollableCandidates(
mouseEvent,
scrollablesRef.current,
);
if (candidates.length > 0) {
// The first candidate is the innermost one.
candidates[0].flashScrollbar();
// We don't consider just flashing the scrollbar as handling the event
// in a way that should prevent other handlers (like drag warning)
// from checking it, although for left-press it doesn't matter much.
// But returning false is safer.
return false;
}
return false;
};
const handleMove = (mouseEvent: MouseEvent) => {
const state = dragStateRef.current;
if (!state.active || !state.id) return false;
const entry = scrollablesRef.current.get(state.id);
if (!entry || !entry.ref.current) {
state.active = false;
return false;
}
const boundingBox = getBoundingBox(entry.ref.current);
if (!boundingBox) return false;
const { y } = boundingBox;
const { scrollTop, scrollHeight, innerHeight } = entry.getScrollState();
const thumbHeight = Math.max(
1,
Math.floor((innerHeight / scrollHeight) * innerHeight),
);
const maxScrollTop = scrollHeight - innerHeight;
const maxThumbY = innerHeight - thumbHeight;
if (maxThumbY <= 0) return false;
const relativeMouseY = mouseEvent.row - y;
// Calculate the target thumb position based on the mouse position and the offset.
// We clamp it to the valid range [0, maxThumbY].
const targetThumbY = Math.max(
0,
Math.min(maxThumbY, relativeMouseY - state.offset),
);
const targetScrollTop = Math.round(
(targetThumbY / maxThumbY) * maxScrollTop,
);
if (entry.scrollTo) {
entry.scrollTo(targetScrollTop, 0);
} else {
entry.scrollBy(targetScrollTop - scrollTop);
}
return true;
};
const handleLeftRelease = () => {
if (dragStateRef.current.active) {
dragStateRef.current = {
active: false,
id: null,
offset: 0,
};
return true;
}
return false;
};
useMouse(
(event: MouseEvent) => {
if (event.name === 'scroll-up') {
return handleScroll('up', event);
} else if (event.name === 'scroll-down') {
return handleScroll('down', event);
} else if (event.name === 'left-press') {
return handleLeftPress(event);
} else if (event.name === 'move') {
return handleMove(event);
} else if (event.name === 'left-release') {
return handleLeftRelease();
}
return false;
},
{ isActive: true },
);
const contextValue = useMemo(
() => ({ register, unregister }),
[register, unregister],
);
return (
<ScrollContext.Provider value={contextValue}>
{children}
</ScrollContext.Provider>
);
};
let nextId = 0;
export const useScrollable = (
entry: Omit<ScrollableEntry, 'id'>,
isActive: boolean,
) => {
const context = useContext(ScrollContext);
if (!context) {
throw new Error('useScrollable must be used within a ScrollProvider');
}
const [id] = useState(() => `scrollable-${nextId++}`);
useEffect(() => {
if (isActive) {
context.register({ ...entry, id });
return () => {
context.unregister(id);
};
}
return;
}, [context, entry, id, isActive]);
};