import { BadRequestException, Injectable, NotFoundException } from '@nestjs/common';
import {
  HQ_ADMIN_ROLE_VALUES,
  HQ_PERMISSION_CATALOG,
  HQ_ROLE_DEFAULT_PERMISSIONS,
  LEGACY_SYSTEM_SETTINGS_KEY,
  computeHqEffectivePermissionKeys,
  expandHqPermissionKeys,
  type HqAdminRoleValue,
  type HqPermissionKey,
} from '@dukang/shared-types';
import { PrismaService } from '../../common/prisma/prisma.module';
import { serializeBigInt } from '../../common/decorators/current-user.decorator';

const VALID_PERMISSION_KEYS = new Set<string>([
  ...HQ_PERMISSION_CATALOG.map((p) => p.key),
  LEGACY_SYSTEM_SETTINGS_KEY,
]);

const EDITABLE_ROLES = new Set<HqAdminRoleValue>(
  HQ_ADMIN_ROLE_VALUES.filter((r) => r !== 'SUPER_ADMIN'),
);

function assertPermissionKeys(keys: string[]) {
  const invalid = keys.filter((key) => !VALID_PERMISSION_KEYS.has(key));
  if (invalid.length) {
    throw new BadRequestException(`无效权限项: ${invalid.join(', ')}`);
  }
}

function asAdminRole(role: string): HqAdminRoleValue {
  if (!(HQ_ADMIN_ROLE_VALUES as readonly string[]).includes(role)) {
    throw new BadRequestException(`无效角色: ${role}`);
  }
  return role as HqAdminRoleValue;
}

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

  catalog() {
    return {
      permissions: HQ_PERMISSION_CATALOG,
      roles: HQ_ADMIN_ROLE_VALUES.map((role) => ({
        role,
        permissionKeys: HQ_ROLE_DEFAULT_PERMISSIONS[role],
      })),
    };
  }

  async getRolePermissions(role: string) {
    const adminRole = asAdminRole(role);
    const rows = await this.prisma.hqRolePermission.findMany({
      where: { adminRole },
      select: { permissionKey: true },
    });
    const permissionKeys =
      rows.length > 0
        ? expandHqPermissionKeys(rows.map((r) => r.permissionKey))
        : [...(HQ_ROLE_DEFAULT_PERMISSIONS[adminRole] ?? [])];
    return { role: adminRole, permissionKeys };
  }

  async saveRolePermissions(role: string, permissionKeys: string[]) {
    const adminRole = asAdminRole(role);
    if (adminRole === 'SUPER_ADMIN') {
      throw new BadRequestException('超级管理员基础权限固定，危险操作请按用户单独授权');
    }
    if (!EDITABLE_ROLES.has(adminRole)) {
      throw new BadRequestException(`无效角色: ${role}`);
    }
    assertPermissionKeys(permissionKeys);
    const normalized = expandHqPermissionKeys(permissionKeys);
    await this.prisma.$transaction([
      this.prisma.hqRolePermission.deleteMany({ where: { adminRole } }),
      ...(normalized.length
        ? [
            this.prisma.hqRolePermission.createMany({
              data: normalized.map((permissionKey) => ({ adminRole, permissionKey })),
            }),
          ]
        : []),
    ]);
    return this.getRolePermissions(role);
  }

  async getAccountPermissions(accountId: bigint) {
    const account = await this.prisma.hqAccount.findUnique({
      where: { id: accountId },
      select: { id: true, name: true, phone: true, loginName: true, adminRole: true, status: true },
    });
    if (!account) throw new NotFoundException('HQ 账号不存在');

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

    if (account.adminRole === 'SUPER_ADMIN') {
      const rolePermissionKeys = HQ_PERMISSION_CATALOG.map((p) => p.key) as HqPermissionKey[];
      const effectivePermissionKeys = computeHqEffectivePermissionKeys(
        rolePermissionKeys,
        grantKeys,
        [],
      );
      return serializeBigInt({
        account,
        permissionKeys: grantKeys,
        rolePermissionKeys,
        grantKeys,
        denyKeys: [] as HqPermissionKey[],
        userPermissionKeys: grantKeys,
        effectivePermissionKeys,
      });
    }

    const rolePerms = await this.getRolePermissions(account.adminRole);
    const effectivePermissionKeys = computeHqEffectivePermissionKeys(
      rolePerms.permissionKeys,
      grantKeys,
      denyKeys,
    );

    return serializeBigInt({
      account,
      permissionKeys: grantKeys,
      rolePermissionKeys: rolePerms.permissionKeys,
      grantKeys,
      denyKeys,
      userPermissionKeys: grantKeys,
      effectivePermissionKeys,
    });
  }

  async saveAccountPermissions(
    accountId: bigint,
    grantKeysInput: string[],
    denyKeysInput: string[] = [],
  ) {
    const account = await this.prisma.hqAccount.findUnique({ where: { id: accountId } });
    if (!account) throw new NotFoundException('HQ 账号不存在');
    assertPermissionKeys(grantKeysInput);
    assertPermissionKeys(denyKeysInput);
    const grantKeys = expandHqPermissionKeys(grantKeysInput);
    const denyKeys =
      account.adminRole === 'SUPER_ADMIN' ? [] : expandHqPermissionKeys(denyKeysInput);
    const overlap = grantKeys.filter((k) => denyKeys.includes(k));
    if (overlap.length) {
      throw new BadRequestException(`同一权限不能同时追加和撤销: ${overlap.join(', ')}`);
    }
    await this.prisma.$transaction([
      this.prisma.hqAccountPermission.deleteMany({ where: { hqAccountId: accountId } }),
      ...(grantKeys.length || denyKeys.length
        ? [
            this.prisma.hqAccountPermission.createMany({
              data: [
                ...grantKeys.map((permissionKey) => ({
                  hqAccountId: accountId,
                  permissionKey,
                  effect: 'GRANT' as const,
                })),
                ...denyKeys.map((permissionKey) => ({
                  hqAccountId: accountId,
                  permissionKey,
                  effect: 'DENY' as const,
                })),
              ],
            }),
          ]
        : []),
    ]);
    return this.getAccountPermissions(accountId);
  }
}