import { aiGenerationClient } from "./aiGenerationClient";

interface UploadEntry {
  promise: Promise<string | null>;
  url: string | null;
  status: "pending" | "done" | "failed";
}

const uploadCache = new Map<string, UploadEntry>();

function fileToDataUrl(file: File): Promise<string> {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();
    reader.onload = () => resolve(String(reader.result || ""));
    reader.onerror = () => reject(reader.error || new Error("文件读取失败"));
    reader.readAsDataURL(file);
  });
}

function buildCacheKey(file: File, fingerprint?: string): string {
  if (fingerprint) return fingerprint;
  return `${file.name}__${file.size}__${file.lastModified}`;
}

export function preUploadReference(
  file: File,
  name: string,
  fingerprint?: string,
): Promise<string | null> {
  const key = buildCacheKey(file, fingerprint);
  const cached = uploadCache.get(key);
  if (cached) return cached.promise;

  const scope = file.type.startsWith("video/") ? "reference-video" : "reference-image";

  const promise = (async () => {
    try {
      const dataUrl = await fileToDataUrl(file);
      const uploaded = await aiGenerationClient.uploadAsset({
        dataUrl,
        name,
        mimeType: file.type,
        scope,
      });
      const entry = uploadCache.get(key);
      if (entry) {
        entry.url = uploaded.url;
        entry.status = "done";
      }
      return uploaded.url;
    } catch (error) {
      const entry = uploadCache.get(key);
      if (entry) entry.status = "failed";
      console.warn("[referenceUpload] pre-upload failed:", error);
      return null;
    }
  })();

  uploadCache.set(key, { promise, url: null, status: "pending" });
  return promise;
}

export function getPreUploadedUrl(
  file: File,
  fingerprint?: string,
): string | null {
  const key = buildCacheKey(file, fingerprint);
  return uploadCache.get(key)?.url ?? null;
}

export async function resolvePreUploadedUrl(
  file: File,
  name: string,
  fingerprint?: string,
): Promise<string | null> {
  const key = buildCacheKey(file, fingerprint);
  const cached = uploadCache.get(key);
  if (cached) return cached.promise;
  return preUploadReference(file, name, fingerprint);
}

export function clearUploadCache(): void {
  uploadCache.clear();
}