import {
  CanActivate,
  ExecutionContext,
  ForbiddenException,
  Injectable,
  NotFoundException,
  SetMetadata,
} from '@nestjs/common';
import { Reflector } from '@nestjs/core';
import {
  HQ_PERMISSION_CATALOG,
  HQ_ROLE_DEFAULT_PERMISSIONS,
  computeHqEffectivePermissionKeys,
  expandHqPermissionKeys,
  hasAnySystemSettingsPermission,
  type HqAdminRoleValue,
  type HqPermissionKey,
} from '@dukang/shared-types';
import { Prisma } from '@prisma/client';
import { PrismaService } from '../prisma/prisma.module';
import type { AuthUser } from './jwt-auth.guard';

export const HQ_PERMISSIONS_KEY = 'hq:permissions';
export const RequireHqPermissions = (...keys: string[]) =>
  SetMetadata(HQ_PERMISSIONS_KEY, keys);
/** 任意一项系统设置分组权限即可访问系统设置接口 */
export const RequireAnySystemSettings = () =>
  SetMetadata(HQ_PERMISSIONS_KEY, ['__any_system_settings__']);

/** null = 全国；[] = 无可见城市 */
export type HqCityScope = bigint[] | null;

export function hqStoreCityWhere(scope: HqCityScope): Prisma.StoreWhereInput | undefined {
  if (scope === null) return undefined;
  if (!scope.length) return { id: { equals: BigInt(0) } };
  return { cityId: { in: scope } };
}

export function mergeHqStoreCityWhere(
  where: Prisma.StoreWhereInput,
  scope: HqCityScope,
  requestedCityId?: string,
): Prisma.StoreWhereInput {
  if (requestedCityId) {
    const cityId = BigInt(requestedCityId);
    assertHqCityInScope(scope, cityId);
    return { AND: [where, { cityId }] };
  }
  const scoped = hqStoreCityWhere(scope);
  if (!scoped) return where;
  return { AND: [where, scoped] };
}

export function assertHqCityInScope(scope: HqCityScope, cityId: bigint) {
  if (scope === null) return;
  if (!scope.some((id) => id === cityId)) {
    throw new ForbiddenException('无权访问该城市的门店');
  }
}

@Injectable()
export class HqPermissionsResolver {
  constructor(private readonly prisma: PrismaService) {}

  private async loadActiveAccount(actorId: bigint) {
    const account = await this.prisma.hqAccount.findUnique({
      where: { id: actorId },
      select: { adminRole: true, status: true },
    });
    if (!account || account.status !== 'ACTIVE') {
      throw new ForbiddenException('HQ 账号不可用');
    }
    return account;
  }

  async resolveAccess(actorId: bigint): Promise<{
    keys: HqPermissionKey[];
    isSuperAdmin: boolean;
    adminRole: HqAdminRoleValue;
  }> {
    const account = await this.loadActiveAccount(actorId);
    const adminRole = account.adminRole as HqAdminRoleValue;

    const userRows = await this.prisma.hqAccountPermission.findMany({
      where: { hqAccountId: actorId },
      select: { permissionKey: true, effect: true },
    });
    const grantKeys = userRows
      .filter((r) => r.effect !== 'DENY')
      .map((r) => r.permissionKey);
    const denyKeys = userRows.filter((r) => r.effect === 'DENY').map((r) => r.permissionKey);

    if (adminRole === 'SUPER_ADMIN') {
      return {
        isSuperAdmin: true,
        adminRole,
        keys: expandHqPermissionKeys([
          ...HQ_PERMISSION_CATALOG.map((p) => p.key),
          ...grantKeys,
        ]),
      };
    }

    const roleRows = await this.prisma.hqRolePermission.findMany({
      where: { adminRole },
      select: { permissionKey: true },
    });

    const roleKeys =
      roleRows.length > 0
        ? roleRows.map((r) => r.permissionKey)
        : [...(HQ_ROLE_DEFAULT_PERMISSIONS[adminRole] ?? [])];

    return {
      isSuperAdmin: false,
      adminRole,
      keys: computeHqEffectivePermissionKeys(roleKeys, grantKeys, denyKeys),
    };
  }

  async resolveEffectiveKeys(actorId: bigint): Promise<HqPermissionKey[]> {
    const { keys } = await this.resolveAccess(actorId);
    return keys;
  }

  async resolveCityScope(actorId: bigint): Promise<HqCityScope> {
    const account = await this.loadActiveAccount(actorId);
    if (account.adminRole === 'SUPER_ADMIN') return null;
    const rows = await this.prisma.hqAccountCity.findMany({
      where: { hqAccountId: actorId },
      select: { cityId: true },
    });
    if (!rows.length) {
      return account.adminRole === 'CITY_STORE_SERVICE' ? [] : null;
    }
    return rows.map((r) => r.cityId);
  }

  async assertStoreCityInScope(actorId: bigint, cityId: bigint) {
    const scope = await this.resolveCityScope(actorId);
    assertHqCityInScope(scope, cityId);
  }

  async assertStoreIdInScope(actorId: bigint, storeId: bigint) {
    const store = await this.prisma.store.findUnique({
      where: { id: storeId },
      select: { cityId: true },
    });
    if (!store) {
      throw new NotFoundException('门店不存在');
    }
    await this.assertStoreCityInScope(actorId, store.cityId);
  }
}

@Injectable()
export class HqPermissionGuard implements CanActivate {
  constructor(
    private readonly resolver: HqPermissionsResolver,
    private readonly reflector: Reflector,
  ) {}

  async canActivate(context: ExecutionContext): Promise<boolean> {
    const req = context.switchToHttp().getRequest();
    const user = req.user as AuthUser | undefined;
    if (!user || user.actorType !== 'HQ') {
      throw new ForbiddenException('需要 HQ 权限');
    }
    const { keys, isSuperAdmin } = await this.resolver.resolveAccess(user.actorId);
    req.hqPermissionKeys = keys;

    const required =
      this.reflector.getAllAndOverride<string[]>(HQ_PERMISSIONS_KEY, [
        context.getHandler(),
        context.getClass(),
      ]) ?? [];

    if (!required.length) return true;
    if (isSuperAdmin) return true;
    if (required.includes('__any_system_settings__')) {
      if (!hasAnySystemSettingsPermission(keys)) {
        throw new ForbiddenException('无系统设置权限');
      }
      return true;
    }
    if (!required.some((k) => keys.includes(k as HqPermissionKey))) {
      throw new ForbiddenException('权限不足');
    }
    return true;
  }
}