import type { ContextualChatEntry } from '../game-chat.js';

export type ChatMessageEntry = Extract<ContextualChatEntry, { type: 'message' }>;
export type ChatBoundaryEntry = Extract<ContextualChatEntry, { type: 'boundary' }>;
export type ChatTimelineItem =
    | { type: 'message'; entry: ChatMessageEntry }
    | { type: 'boundaries'; entries: ChatBoundaryEntry[] };

/** Group adjacent lifecycle events for display without discarding log history. */
export function groupChatTimeline(entries: readonly ContextualChatEntry[]): ChatTimelineItem[] {
    const timeline: ChatTimelineItem[] = [];
    for (const entry of entries) {
        if (entry.type === 'message') {
            timeline.push({ type: 'message', entry });
        } else {
            const previous = timeline.at(-1);
            if (previous?.type === 'boundaries') previous.entries.push(entry);
            else timeline.push({ type: 'boundaries', entries: [entry] });
        }
    }
    return timeline;
}