import { api } from './api';
import {
  MemberListItem,
  MemberWithProfile,
  MemberFilters,
  MemberStats,
  CreateMemberProfileData,
  UpdateMemberProfileData,
  Befoerderung,
  Untersuchung,
  Fahrgenehmigung,
  Ausbildung,
} from '../types/member.types';

// ----------------------------------------------------------------
// Response envelope shapes
// ----------------------------------------------------------------
interface ApiListResponse<T> {
  success: boolean;
  data: T[];
  meta: { total: number; page: number };
}

interface ApiItemResponse<T> {
  success: boolean;
  data: T;
}

// ----------------------------------------------------------------
// Service
// ----------------------------------------------------------------

/**
 * Builds a URLSearchParams object from the filter object so query
 * strings like ?status[]=aktiv&status[]=jugend are sent correctly.
 */
function buildParams(filters?: MemberFilters): URLSearchParams {
  const params = new URLSearchParams();
  if (!filters) return params;

  if (filters.search) params.append('search', filters.search);
  if (filters.page)     params.append('page', String(filters.page));
  if (filters.pageSize !== undefined) params.append('pageSize', String(filters.pageSize));

  filters.status?.forEach((s) => params.append('status[]', s));
  filters.dienstgrad?.forEach((d) => params.append('dienstgrad[]', d));

  if (filters.sortBy) params.append('sortBy', filters.sortBy);
  if (filters.sortDir) params.append('sortDir', filters.sortDir);

  return params;
}

export const membersService = {
  /**
   * Fetches a paginated, optionally filtered list of members.
   */
  async getMembers(
    filters?: MemberFilters
  ): Promise<{ items: MemberListItem[]; total: number; page: number }> {
    const params = buildParams(filters);
    const response = await api.get<ApiListResponse<MemberListItem>>(
      `/api/members?${params.toString()}`
    );
    if (response.data?.data === undefined || response.data?.data === null) {
      throw new Error('Invalid API response');
    }
    return {
      items: response.data.data,
      total: response.data.meta?.total ?? 0,
      page: response.data.meta?.page ?? 1,
    };
  },

  /**
   * Fetches a single member with their full profile and rank history.
   */
  async getMember(userId: string): Promise<MemberWithProfile> {
    const response = await api.get<ApiItemResponse<MemberWithProfile>>(
      `/api/members/${userId}`
    );
    if (response.data?.data === undefined || response.data?.data === null) {
      throw new Error('Invalid API response');
    }
    return response.data.data;
  },

  /**
   * Creates a new member profile for an existing auth user.
   * Restricted to Kommandant/Admin (enforced server-side).
   */
  async createMemberProfile(
    userId: string,
    data: CreateMemberProfileData
  ): Promise<MemberWithProfile> {
    const response = await api.post<ApiItemResponse<MemberWithProfile>>(
      `/api/members/${userId}/profile`,
      data
    );
    if (response.data?.data === undefined || response.data?.data === null) {
      throw new Error('Invalid API response');
    }
    return response.data.data;
  },

  /**
   * Partially updates a member profile.
   * Kommandant/Admin: full update.
   * Own profile: limited fields only (enforced server-side).
   */
  async updateMember(
    userId: string,
    data: UpdateMemberProfileData
  ): Promise<MemberWithProfile> {
    const response = await api.patch<ApiItemResponse<MemberWithProfile>>(
      `/api/members/${userId}`,
      data
    );
    if (response.data?.data === undefined || response.data?.data === null) {
      throw new Error('Invalid API response');
    }
    return response.data.data;
  },

  /**
   * Fetches aggregate counts for the dashboard KPI widget.
   */
  async getMemberStats(): Promise<MemberStats> {
    const response = await api.get<ApiItemResponse<MemberStats>>('/api/members/stats');
    if (response.data?.data === undefined || response.data?.data === null) {
      throw new Error('Invalid API response');
    }
    return response.data.data;
  },

  async getBefoerderungen(userId: string): Promise<Befoerderung[]> {
    const response = await api.get<ApiItemResponse<Befoerderung[]>>(`/api/members/${userId}/befoerderungen`);
    return response.data?.data ?? [];
  },

  async getUntersuchungen(userId: string): Promise<Untersuchung[]> {
    const response = await api.get<ApiItemResponse<Untersuchung[]>>(`/api/members/${userId}/untersuchungen`);
    return response.data?.data ?? [];
  },

  async getFahrgenehmigungen(userId: string): Promise<Fahrgenehmigung[]> {
    const response = await api.get<ApiItemResponse<Fahrgenehmigung[]>>(`/api/members/${userId}/fahrgenehmigungen`);
    return response.data?.data ?? [];
  },

  async getAusbildungen(userId: string): Promise<Ausbildung[]> {
    const response = await api.get<ApiItemResponse<Ausbildung[]>>(`/api/members/${userId}/ausbildungen`);
    return response.data?.data ?? [];
  },
};