import type { ApiRetryOptions } from '../apiClient';

const EDITOR_RETRYABLE_STATUS_CODES = [408, 425, 429, 502, 503, 504];
const EDITOR_RETRY_MAX_RETRIES = 2;
const EDITOR_RETRY_BASE_DELAY_MS = 800;
const EDITOR_RETRY_MAX_DELAY_MS = 3000;

export const EDITOR_REQUEST_RETRY_OPTIONS = {
  maxRetries: EDITOR_RETRY_MAX_RETRIES,
  baseDelayMs: EDITOR_RETRY_BASE_DELAY_MS,
  maxDelayMs: EDITOR_RETRY_MAX_DELAY_MS,
  retryUnsafeMethods: true,
  retryableStatusCodes: EDITOR_RETRYABLE_STATUS_CODES,
} satisfies ApiRetryOptions;

// 生成接口在 inline 模式下会直接调用 provider；服务端尚无结果级幂等前，
// 浏览器不能自动重试 POST，否则响应丢失会重复生成与持久化。
export const EDITOR_GENERATION_REQUEST_RETRY_OPTIONS = {
  maxRetries: 0,
  retryUnsafeMethods: false,
} satisfies ApiRetryOptions;

type EditorDirectUploadTarget = {
  host: string;
  formFields: Record<string, string | null | undefined>;
};

function buildRetryDelayMs(attempt: number) {
  return Math.min(
    EDITOR_RETRY_MAX_DELAY_MS,
    EDITOR_RETRY_BASE_DELAY_MS * Math.max(1, attempt),
  );
}

function waitForRetryDelay(attempt: number) {
  return new Promise((resolve) => {
    setTimeout(resolve, buildRetryDelayMs(attempt));
  });
}

function isRetryableEditorUploadStatus(status: number) {
  return EDITOR_RETRYABLE_STATUS_CODES.includes(status);
}

function buildDirectUploadFormData(
  upload: EditorDirectUploadTarget,
  file: File,
) {
  const formData = new FormData();
  Object.entries(upload.formFields).forEach(([key, value]) => {
    if (value !== null && value !== undefined) {
      formData.append(key, value);
    }
  });
  formData.append('file', file, file.name);
  return formData;
}

export async function postEditorDirectUploadFile(
  upload: EditorDirectUploadTarget,
  file: File,
  errorMessage: string,
  // 中文注释：调用方超时后仅停止 await 是不够的——这一步是唯一往 OSS 写实体的动作，
  // 不取消的话被放弃的上传会继续跑完并注册对象，用户重试再产生一份，留下不可见的孤儿。
  signal?: AbortSignal,
) {
  for (let attempt = 0; ; attempt += 1) {
    const response = await fetch(upload.host, {
      method: 'POST',
      body: buildDirectUploadFormData(upload, file),
      signal,
    });

    if (response.ok) {
      return;
    }

    if (
      attempt >= EDITOR_RETRY_MAX_RETRIES ||
      !isRetryableEditorUploadStatus(response.status)
    ) {
      throw new Error(errorMessage);
    }

    await waitForRetryDelay(attempt + 1);
  }
}