File size: 2,593 Bytes
4e23b01 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 | import { compareTurnIds } from '../model/ids';
import type { TranscriptItem } from '../model/item';
export interface TurnPageQuery {
readonly beforeTurn?: string;
readonly afterTurn?: string;
readonly pageSize: number;
}
export interface TurnPage {
readonly items: readonly TranscriptItem[];
readonly hasMore: boolean;
}
export function paginateTurns(items: readonly TranscriptItem[], query: TurnPageQuery): TurnPage {
const pageSize = Math.max(1, query.pageSize);
const segments = splitSegments(items);
if (segments.length === 0) return { items: [], hasMore: false };
if (query.afterTurn !== undefined) {
return page(segments.filter((seg) => seg.turnId && compareTurnIds(seg.turnId, query.afterTurn!) > 0), pageSize, 'newer');
}
if (query.beforeTurn !== undefined) {
const older = segments.filter((seg) => !seg.turnId || compareTurnIds(seg.turnId, query.beforeTurn!) < 0);
return page(older, pageSize, 'older');
}
return page(segments, pageSize, 'older');
}
interface Segment {
readonly items: readonly TranscriptItem[];
readonly turnId?: string;
}
function splitSegments(items: readonly TranscriptItem[]): Segment[] {
const segments: Segment[] = [];
let current: TranscriptItem[] = [];
let currentTurn: string | undefined;
const flush = (): void => {
if (current.length > 0) segments.push({ items: current, turnId: currentTurn });
current = [];
currentTurn = undefined;
};
for (const item of items) {
if (item.kind === 'turn') {
flush();
current = [item];
currentTurn = item.turnId;
} else {
current.push(item);
}
}
flush();
return segments;
}
function page(segments: readonly Segment[], pageSize: number, direction: 'older' | 'newer'): TurnPage {
const head = segments[0]?.turnId === undefined ? segments[0] : undefined;
const turnSegments = head !== undefined ? segments.slice(1) : segments;
if (direction === 'older') {
const selected = turnSegments.slice(-pageSize);
const reachesFirstTurn = selected.length === turnSegments.length;
const hasMore = turnSegments.length > selected.length && selected.length > 0;
return {
items: flatten([...(reachesFirstTurn && head !== undefined ? [head] : []), ...selected]),
hasMore,
};
}
const selected = turnSegments.slice(0, pageSize);
const hasMore = turnSegments.length > selected.length && selected.length > 0;
return { items: flatten(selected), hasMore };
}
function flatten(segments: readonly Segment[]): readonly TranscriptItem[] {
return segments.flatMap((seg) => seg.items);
}
|