import type {
  AiArtifactSchema,
  AiChartSchema,
  AiChatMessage,
  AiFormSchema,
  AiReviewSchema,
} from './types';

export function mergeById<T extends { id: string }>(
  current: T[] | undefined,
  incoming: T | T[] | undefined,
): T[] {
  const items = Array.isArray(incoming) ? incoming : incoming ? [incoming] : [];
  if (!items.length) return current ?? [];
  const next = [...(current ?? [])];
  for (const item of items) {
    if (!item || typeof item !== 'object') continue;
    const index = next.findIndex((existing) => existing.id === item.id);
    if (index === -1) {
      next.push(item);
    } else {
      next[index] = item;
    }
  }
  return next;
}

/**
 * 将统一 artifact 归入 uiArtifacts。
 *
 * 注意：不再派发到 legacy 列表（forms/reviews/charts）——渲染层从
 * uiArtifacts 派生，legacy 字段仅保留给历史消息（metadata 中只有
 * a2uiForm/a2uiReview/a2uiChart 的老数据）作兼容读取。
 */
export function mergeArtifactIntoMessage(
  message: AiChatMessage,
  artifact: AiArtifactSchema,
): AiChatMessage {
  message.uiArtifacts = mergeById<AiArtifactSchema>(message.uiArtifacts, artifact);
  return message;
}

/**
 * 从 uiArtifacts 派生 legacy 列表（渲染用）。
 * 仅当 message 上没有显式 legacy 数据（历史消息）时，渲染层回退到 message.forms 等。
 */
export function deriveForms(message: AiChatMessage): AiFormSchema[] {
  return (message.uiArtifacts ?? [])
    .filter((artifact) => artifact.type === 'form')
    .map((artifact) => artifact.payload)
    .filter((payload): payload is AiFormSchema => Boolean(payload) && typeof payload === 'object');
}

export function deriveReviews(message: AiChatMessage): AiReviewSchema[] {
  return (message.uiArtifacts ?? [])
    .filter((artifact) => artifact.type === 'review')
    .map((artifact) => artifact.payload)
    .filter(
      (payload): payload is AiReviewSchema => Boolean(payload) && typeof payload === 'object',
    );
}

export function deriveCharts(message: AiChatMessage): AiChartSchema[] {
  return (message.uiArtifacts ?? [])
    .filter((artifact) => artifact.type === 'chart')
    .map((artifact) => artifact.payload)
    .filter((payload): payload is AiChartSchema => Boolean(payload) && typeof payload === 'object');
}