/** 微信公众号 H5 网页授权（注册 / 绑定页无 code 时跳转） */

import { getWeChatOAuthConfig } from '@/api/wechat';
import {
  clearStashedInviteRef,
  readStashedInviteRef,
  stashInviteRef,
} from '@/utils/inviteRefStorage';

export type WeChatH5Page = 'register' | 'bind' | 'login';

type WeChatOAuthRuntimeConfig = {
  appId: string;
  /** 规范化后的 origin，如 https://ideship.com；空则用当前页 */
  redirectOrigin: string;
};

let oauthConfigPromise: Promise<WeChatOAuthRuntimeConfig> | null = null;

function normalizeRedirectOrigin(base: string | null | undefined): string {
  const raw = String(base ?? '').trim();
  if (!raw) return '';
  try {
    const url = new URL(raw.includes('://') ? raw : `https://${raw}`);
    return url.origin;
  } catch {
    return '';
  }
}

/** 从其他配置 wechat_mp 取 AppId / OAuth 回调根（进程内缓存） */
export async function resolveWeChatMpOAuthConfig(): Promise<WeChatOAuthRuntimeConfig> {
  if (!oauthConfigPromise) {
    oauthConfigPromise = getWeChatOAuthConfig()
      .then((cfg) => {
        const appId = String(cfg.appId ?? '').trim();
        if (!appId) {
          throw new Error('未配置微信公众号 AppId（其他配置 wechat_mp.AppKey）');
        }
        return {
          appId,
          redirectOrigin: normalizeRedirectOrigin(cfg.oauthRedirectBase),
        };
      })
      .catch((err) => {
        oauthConfigPromise = null;
        throw err;
      });
  }
  return oauthConfigPromise;
}

/** @deprecated 使用 stashInviteRef */
export function stashWeChatInviteRef(inviteCode?: string | null): void {
  stashInviteRef(inviteCode);
}

/** @deprecated 使用 readStashedInviteRef */
export function readStashedWeChatInviteRef(): string {
  return readStashedInviteRef();
}

/** @deprecated 使用 clearStashedInviteRef */
export function clearStashedWeChatInviteRef(): void {
  clearStashedInviteRef();
}

/** 从 OAuth state 解析邀请码（格式 register:CODE） */
export function parseInviteRefFromOAuthState(state: unknown): string {
  const raw = String(state ?? '').trim();
  const match = raw.match(/^(?:register|bind):(.+)$/i);
  if (!match?.[1]) return '';
  try {
    return decodeURIComponent(match[1]).trim();
  } catch {
    return match[1].trim();
  }
}

/**
 * 解析当前页邀请码：query.ref / query.invite → OAuth state → 7 天暂存
 */
export function resolveWeChatInviteRef(query: Record<string, unknown>): string {
  const fromQuery = String(query.ref ?? query.invite ?? '').trim();
  if (fromQuery) {
    stashInviteRef(fromQuery);
    return fromQuery;
  }
  const fromState = parseInviteRefFromOAuthState(query.state);
  if (fromState) {
    stashInviteRef(fromState);
    return fromState;
  }
  return readStashedInviteRef();
}

function resolveOAuthRedirectPath(page: WeChatH5Page, redirectOrigin: string): string {
  const origin = redirectOrigin || window.location.origin;
  if (page === 'login') {
    return `${origin}/h5/login`;
  }
  return `${origin}/wechat/${page}`;
}

/**
 * 跳转微信 OAuth。
 * - AppId / 回调根来自其他配置 wechat_mp（AppKey、BaseUrl）
 * - register/bind：邀请码写入 state + 7 天暂存
 * - login：可选把登录后回跳路径写入 state（login:/h5/orders）
 */
export async function redirectToWeChatOAuth(
  page: WeChatH5Page,
  inviteCode?: string | null,
  options?: { afterLoginPath?: string | null },
): Promise<void> {
  const { appId, redirectOrigin } = await resolveWeChatMpOAuthConfig();
  const redirectUri = encodeURIComponent(resolveOAuthRedirectPath(page, redirectOrigin));

  let state = page;
  if (page === 'login') {
    const after = String(options?.afterLoginPath ?? '').trim();
    if (after.startsWith('/h5')) {
      state = `login:${encodeURIComponent(after)}`;
    }
  } else {
    const code = String(inviteCode ?? '').trim() || readStashedInviteRef();
    if (code) stashInviteRef(code);
    state = code ? `${page}:${encodeURIComponent(code)}` : page;
  }

  window.location.replace(
    `https://open.weixin.qq.com/connect/oauth2/authorize?appid=${appId}` +
      `&redirect_uri=${redirectUri}` +
      `&response_type=code&scope=snsapi_userinfo&state=${state}#wechat_redirect`,
  );
}

/** 从 OAuth state 解析登录后回跳路径 */
export function parseAfterLoginPathFromOAuthState(state: unknown): string {
  const raw = String(state ?? '').trim();
  const match = raw.match(/^login:(.+)$/i);
  if (!match?.[1]) return '';
  try {
    const path = decodeURIComponent(match[1]).trim();
    return path.startsWith('/h5') ? path : '';
  } catch {
    const path = match[1].trim();
    return path.startsWith('/h5') ? path : '';
  }
}