import type { ChatMessage } from '@/lib/api';

export interface ChatMediaMetadata {
  fileName?: string;
  fileSize?: number;
  durationMs?: number;
  albumId?: string;
  albumIndex?: number;
  albumCount?: number;
  width?: number;
  height?: number;
  sendAsFile?: boolean;
  e2e?: boolean;
}

export function parseChatMediaMetadata(metadataJson?: string): ChatMediaMetadata {
  if (!metadataJson) return {};
  try {
    return JSON.parse(metadataJson) as ChatMediaMetadata;
  } catch {
    return {};
  }
}

export type ChatDisplayItem =
  | { kind: 'message'; message: ChatMessage }
  | { kind: 'album'; albumId: string; messages: ChatMessage[] };

export function groupChatMessagesForDisplay(messages: ChatMessage[]): ChatDisplayItem[] {
  const items: ChatDisplayItem[] = [];
  let index = 0;

  while (index < messages.length) {
    const message = messages[index]!;
    const meta = parseChatMediaMetadata(message.metadataJson);

    if (meta.albumId && message.storageKey) {
      const albumMessages: ChatMessage[] = [message];
      let cursor = index + 1;
      while (cursor < messages.length) {
        const next = messages[cursor]!;
        const nextMeta = parseChatMediaMetadata(next.metadataJson);
        if (
          nextMeta.albumId === meta.albumId &&
          next.senderId === message.senderId &&
          next.storageKey
        ) {
          albumMessages.push(next);
          cursor += 1;
          continue;
        }
        break;
      }

      albumMessages.sort((left, right) => {
        const leftIndex = parseChatMediaMetadata(left.metadataJson).albumIndex ?? 0;
        const rightIndex = parseChatMediaMetadata(right.metadataJson).albumIndex ?? 0;
        return leftIndex - rightIndex;
      });

      items.push({ kind: 'album', albumId: meta.albumId, messages: albumMessages });
      index = cursor;
      continue;
    }

    items.push({ kind: 'message', message });
    index += 1;
  }

  return items;
}

export function collectChatImageMessages(messages: ChatMessage[]) {
  return messages.filter((message) => message.type === 'IMAGE' && message.storageKey);
}