import type { Match3DGeneratedItemAsset } from '../../packages/shared/src/contracts/match3dWorks';
import { readAssetBytes, resolveAssetReadUrl } from './assetReadUrlService';

type CachedMatch3DModelBytes = {
  accessedAt: number;
  promise: Promise<ArrayBuffer>;
};

type Match3DModelBytesOptions = {
  expireSeconds?: number;
  signal?: AbortSignal;
};

const MATCH3D_MODEL_BYTES_CACHE_LIMIT = 36;
const match3dModelBytesCache = new Map<string, CachedMatch3DModelBytes>();

function normalizeMatch3DModelSource(source: string | null | undefined) {
  return source?.trim() ?? '';
}

function isExternalMatch3DModelSource(source: string) {
  return /^(?:https?:)?\/\//iu.test(source.trim());
}

function trimMatch3DModelBytesCache() {
  if (match3dModelBytesCache.size <= MATCH3D_MODEL_BYTES_CACHE_LIMIT) {
    return;
  }

  const staleKeys = [...match3dModelBytesCache.entries()]
    .sort((left, right) => left[1].accessedAt - right[1].accessedAt)
    .slice(0, match3dModelBytesCache.size - MATCH3D_MODEL_BYTES_CACHE_LIMIT)
    .map(([source]) => source);
  staleKeys.forEach((source) => match3dModelBytesCache.delete(source));
}

function waitWithAbort<T>(promise: Promise<T>, signal?: AbortSignal) {
  if (!signal) {
    return promise;
  }
  if (signal.aborted) {
    return Promise.reject(new DOMException('加载已取消', 'AbortError'));
  }

  return new Promise<T>((resolve, reject) => {
    const handleAbort = () => {
      signal.removeEventListener('abort', handleAbort);
      reject(new DOMException('加载已取消', 'AbortError'));
    };
    signal.addEventListener('abort', handleAbort, { once: true });
    promise.then(
      (value) => {
        signal.removeEventListener('abort', handleAbort);
        resolve(value);
      },
      (error) => {
        signal.removeEventListener('abort', handleAbort);
        reject(error);
      },
    );
  });
}

export function resolveMatch3DGeneratedModelAssetSource(
  asset: Match3DGeneratedItemAsset,
) {
  // 中文注释：历史草稿可能同时保留已过期的 Rodin 外部 modelSrc 和后续修复出的平台 objectKey；
  // 试玩、正式游戏和预览都必须优先读取平台私有对象，避免继续请求过期外链。
  const modelSrc = normalizeMatch3DModelSource(asset.modelSrc);
  const objectKey = normalizeMatch3DModelSource(asset.modelObjectKey);
  if (modelSrc && (!isExternalMatch3DModelSource(modelSrc) || !objectKey)) {
    return modelSrc;
  }
  return objectKey || modelSrc;
}

export function resolveMatch3DGeneratedImageViewSource(
  view:
    | NonNullable<Match3DGeneratedItemAsset['imageViews']>[number]
    | null
    | undefined,
) {
  const imageSrc = normalizeMatch3DModelSource(view?.imageSrc);
  const objectKey = normalizeMatch3DModelSource(view?.imageObjectKey);
  return objectKey || imageSrc;
}

export function getMatch3DGeneratedImageViewSources(
  asset: Match3DGeneratedItemAsset,
) {
  const viewSources =
    asset.imageViews
      ?.map(resolveMatch3DGeneratedImageViewSource)
      .filter((source) => source.length > 0) ?? [];
  if (viewSources.length > 0) {
    return [...new Set(viewSources)];
  }
  const primarySource =
    normalizeMatch3DModelSource(asset.imageObjectKey) ||
    normalizeMatch3DModelSource(asset.imageSrc);
  return primarySource ? [primarySource] : [];
}

export function resolveMatch3DGeneratedImageAssetSource(
  asset: Match3DGeneratedItemAsset,
) {
  return getMatch3DGeneratedImageViewSources(asset)[0] ?? '';
}

export function getMatch3DGeneratedImageAssetSources(
  assets: readonly Match3DGeneratedItemAsset[] = [],
) {
  return [
    ...new Set(
      assets.flatMap((asset) => getMatch3DGeneratedImageViewSources(asset)),
    ),
  ];
}

export function hasMatch3DGeneratedImageAsset(
  assets: readonly Match3DGeneratedItemAsset[] | null | undefined,
) {
  return Boolean(
    assets?.some((asset) => getMatch3DGeneratedImageViewSources(asset).length > 0),
  );
}

export function getMatch3DGeneratedModelAssetSources(
  assets: readonly Match3DGeneratedItemAsset[] = [],
) {
  return [
    ...new Set(
      assets
        .map(resolveMatch3DGeneratedModelAssetSource)
        .filter((source) => source.length > 0),
    ),
  ];
}

export function readMatch3DGeneratedModelBytes(
  source: string | null | undefined,
  options: Match3DModelBytesOptions = {},
) {
  const normalizedSource = normalizeMatch3DModelSource(source);
  if (!normalizedSource) {
    return Promise.reject(new Error('抓大鹅 3D 模型路径不能为空'));
  }

  const cached = match3dModelBytesCache.get(normalizedSource);
  if (cached) {
    cached.accessedAt = Date.now();
    return waitWithAbort(cached.promise, options.signal);
  }

  const entry: CachedMatch3DModelBytes = {
    accessedAt: Date.now(),
    promise: readAssetBytes(normalizedSource, {
      expireSeconds: options.expireSeconds,
    }).then(async (response) => {
      const bytes = await response.arrayBuffer();
      if (bytes.byteLength <= 0) {
        throw new Error('抓大鹅 3D 模型内容为空');
      }
      return bytes;
    }),
  };
  match3dModelBytesCache.set(normalizedSource, entry);
  trimMatch3DModelBytesCache();

  entry.promise.catch(() => {
    if (match3dModelBytesCache.get(normalizedSource) === entry) {
      match3dModelBytesCache.delete(normalizedSource);
    }
  });

  return waitWithAbort(entry.promise, options.signal);
}

export async function preloadMatch3DGeneratedModelSources(
  sources: readonly string[],
  options: Omit<Match3DModelBytesOptions, 'signal'> = {},
) {
  const normalizedSources = [
    ...new Set(
      sources
        .map(normalizeMatch3DModelSource)
        .filter((source) => source.length > 0),
    ),
  ];
  await Promise.allSettled(
    normalizedSources.map((source) =>
      readMatch3DGeneratedModelBytes(source, {
        expireSeconds: options.expireSeconds,
      }),
    ),
  );
}

export function preloadMatch3DGeneratedModelAssets(
  assets: readonly Match3DGeneratedItemAsset[] = [],
  options: Omit<Match3DModelBytesOptions, 'signal'> = {},
) {
  return preloadMatch3DGeneratedModelSources(
    getMatch3DGeneratedModelAssetSources(assets),
    options,
  );
}

export async function preloadMatch3DGeneratedImageAssets(
  assets: readonly Match3DGeneratedItemAsset[] = [],
  options: Omit<Match3DModelBytesOptions, 'signal'> = {},
) {
  const sources = getMatch3DGeneratedImageAssetSources(assets);
  await Promise.allSettled(
    sources.map((source) =>
      resolveAssetReadUrl(source, {
        expireSeconds: options.expireSeconds,
      }),
    ),
  );
}

export async function preloadMatch3DGeneratedRuntimeAssets(
  assets: readonly Match3DGeneratedItemAsset[] = [],
  options: Omit<Match3DModelBytesOptions, 'signal'> = {},
) {
  // 中文注释：新抓大鹅运行态以 2D 图片为主；3D 模型只作为历史草稿预览兼容。
  await preloadMatch3DGeneratedImageAssets(assets, options);
}

export function clearMatch3DGeneratedModelBytesCache() {
  match3dModelBytesCache.clear();
}