/**
 * 鉴权中间件(ADR-012)—— app 层唯一一处;身份判定读 org 出口(ADR-010 的分工不变)。
 *
 * ① 查路由注册表拿 access;public 直接放行。
 * ② 取凭据:Authorization: Bearer;GET 且没带头时认 ?ticket=(EventSource / <a href> 的路)。
 *    方法先归一(HEAD 按 GET),再查表、再判票据 —— 两处都按分发时的方法算。
 * ③ Bearer → org.authenticate(验签 + 名册即时更新 + 角色→端);票据 → org.principalOf(从库现算)。
 * ④ 401 = 没凭据 / 凭据坏了(该重新登录);403 = 人对了但进不了这个端 / 账号停用(重新登录没用)。
 *    401 与 403 不混用 —— 前端靠它分辨「该重新登录」和「没权限」(手册 4.5)。
 */
import type { MiddlewareHandler } from 'hono';
import type { ApiError, Principal, RouteAccess, StaffId, Surface } from '@contracts';
import { SURFACE_LABEL, staffIdSchema } from '@contracts';
import { AccountDisabledError, TokenRejectedError } from '@modules/org';
import type { AppEnv } from './http-env.ts';
import type { RouteRegistry } from './route-registry.ts';
import type { TicketIssuer } from './ticket.ts';

/** org 出口里中间件用到的那两口 —— 窄接口,测试好伪造 */
export type Authenticator = {
  authenticate(token: string): Promise<Principal>;
  principalOf(staffId: StaffId): Promise<Principal | undefined>;
};

export type AuthMiddlewareDeps = {
  readonly registry: RouteRegistry;
  readonly org: Authenticator;
  readonly tickets: TicketIssuer;
  readonly clock: { now(): Date };
};

export function bearerOf(header: string | undefined): string | undefined {
  if (header === undefined) return undefined;
  const match = /^bearer\s+(\S+)\s*$/i.exec(header.trim());
  return match?.[1];
}

/** access 要求的端;public / any 不要求 */
export function requiredEnds(access: RouteAccess): readonly Surface[] | undefined {
  if (access === 'public' || access === 'any') return undefined;
  return typeof access === 'string' ? [access] : access;
}

export function forbiddenBody(need: readonly Surface[], principal: Principal): ApiError {
  const needText = need.map((s) => `「${SURFACE_LABEL[s]}」`).join(' / ');
  const roles = principal.roles.length === 0 ? '无' : principal.roles.join(', ');
  const can = principal.ends.length === 0 ? '无端可进' : principal.ends.map((s) => SURFACE_LABEL[s]).join('、');
  return {
    code: 'forbidden',
    message: `进入${needText}需要授权;你的角色(${roles})可进:${can}`,
    detail: { need: [...need], ends: [...principal.ends] },
  };
}

const unauthenticated = (message: string): ApiError => ({ code: 'unauthenticated', message });

export function createAuthMiddleware(deps: AuthMiddlewareDeps): MiddlewareHandler<AppEnv> {
  return async (c, next) => {
    c.set('principal', undefined);
    /*
     * HEAD 按 GET 判。Hono 在 #dispatch 里把 HEAD 改写成 GET 再分发,而 `c.req.method`
     * 读的是请求行上的原始方法 —— 不归一的话 lookup 必然 miss,落进 `?? 'any'` 兜底,
     * 于是「只要登录就能跑任何 GET 处理器」。**凭据与归属一律按分发时的方法判,
     * 不按请求行上的字面方法。**
     */
    const method = c.req.method === 'HEAD' ? 'GET' : c.req.method;
    // 未知路由按 any 处置:先鉴权再 404,与从前一致(不给没登录的人探路由表)
    const access = deps.registry.lookup(method, c.req.path) ?? 'any';
    if (access === 'public') {
      await next();
      return undefined;
    }

    const bearer = bearerOf(c.req.header('authorization'));
    const ticket = method === 'GET' ? c.req.query('ticket') : undefined;
    if (bearer === undefined && (ticket === undefined || ticket === '')) {
      return c.json(unauthenticated('缺少 Bearer token'), 401);
    }

    let principal: Principal;
    try {
      if (bearer !== undefined) {
        principal = await deps.org.authenticate(bearer);
      } else {
        const opened = deps.tickets.verify(ticket ?? '', deps.clock.now());
        if (opened === undefined) {
          return c.json(unauthenticated('票据无效或已过期 —— 重新取一张 GET /api/auth/ticket'), 401);
        }
        const found = await deps.org.principalOf(staffIdSchema.parse(opened.staffId));
        if (found === undefined) return c.json(unauthenticated('票据对应的员工不存在'), 401);
        principal = found;
      }
    } catch (error) {
      if (error instanceof TokenRejectedError) return c.json(unauthenticated(error.message), 401);
      if (error instanceof AccountDisabledError) {
        const body: ApiError = { code: 'forbidden', message: error.message };
        return c.json(body, 403);
      }
      throw error;
    }

    const need = requiredEnds(access);
    if (need !== undefined && !need.some((s) => principal.ends.includes(s))) {
      return c.json(forbiddenBody(need, principal), 403);
    }

    c.set('principal', principal);
    await next();
    return undefined;
  };
}