/**
 * Generic API service factory
 * Reduces duplication in service layer by providing common CRUD operations
 */

import { z } from 'zod';
import { apiGet, apiPost, apiDelete } from '@/lib/api-client';

/**
 * Options for creating a CRUD API service
 */
export interface CreateCRUDServiceOptions<
  TEntity,
  TCreateRequest,
  TUpdateRequest = TCreateRequest,
> {
  basePath: string;
  entitySchema: z.ZodSchema<TEntity>;
  createRequestSchema?: z.ZodSchema<TCreateRequest>;
  updateRequestSchema?: z.ZodSchema<TUpdateRequest>;
}

/**
 * Result of creating a CRUD service
 */
export interface CRUDService<TEntity, TCreateRequest, TUpdateRequest = TCreateRequest> {
  getById: (id: string) => Promise<TEntity>;
  list: (filters?: Record<string, unknown>) => Promise<TEntity[]>;
  create: (request: TCreateRequest) => Promise<TEntity>;
  update: (id: string, request: TUpdateRequest) => Promise<TEntity>;
  delete: (id: string) => Promise<void>;
}

/**
 * Creates a standard CRUD API service with validation
 * Handles common patterns: GET, POST, PUT, DELETE with Zod validation
 */
export function createCRUDService<TEntity, TCreateRequest, TUpdateRequest = TCreateRequest>(
  options: CreateCRUDServiceOptions<TEntity, TCreateRequest, TUpdateRequest>
): CRUDService<TEntity, TCreateRequest, TUpdateRequest> {
  const { basePath, entitySchema, createRequestSchema, updateRequestSchema } = options;

  const getById = async (id: string): Promise<TEntity> => {
    const data = await apiGet<TEntity>(`${basePath}/${id}`);
    return entitySchema.parse(data);
  };

  const list = async (filters?: Record<string, unknown>): Promise<TEntity[]> => {
    const queryParams = new URLSearchParams();
    if (filters) {
      Object.entries(filters).forEach(([key, value]) => {
        if (value !== undefined && value !== null) {
          if (Array.isArray(value)) {
            value.forEach((v) => queryParams.append(key, String(v)));
          } else {
            queryParams.append(key, String(value));
          }
        }
      });
    }

    const endpoint = `${basePath}${queryParams.toString() ? `?${queryParams.toString()}` : ''}`;
    const data = await apiGet<TEntity[]>(endpoint);
    return z.array(entitySchema).parse(data);
  };

  const create = async (request: TCreateRequest): Promise<TEntity> => {
    const validated = createRequestSchema ? createRequestSchema.parse(request) : request;
    const data = await apiPost<TEntity>(basePath, validated);
    return entitySchema.parse(data);
  };

  const update = async (id: string, request: TUpdateRequest): Promise<TEntity> => {
    const validated = updateRequestSchema ? updateRequestSchema.parse(request) : request;
    const data = await apiPost<TEntity>(`${basePath}/${id}`, validated);
    return entitySchema.parse(data);
  };

  const deleteById = async (id: string): Promise<void> => {
    await apiDelete<void>(`${basePath}/${id}`);
  };

  return {
    getById,
    list,
    create,
    update,
    delete: deleteById,
  };
}

/**
 * Creates a service function with validation
 * Useful for non-CRUD endpoints
 */
export function createValidatedService<TRequest, TResponse>(
  endpoint: string,
  requestSchema: z.ZodSchema<TRequest>,
  responseSchema: z.ZodSchema<TResponse>,
  method: 'GET' | 'POST' = 'POST'
) {
  return async (request: TRequest): Promise<TResponse> => {
    const validated = requestSchema.parse(request);

    let data: TResponse;
    if (method === 'GET') {
      const queryParams = new URLSearchParams();
      Object.entries(validated as Record<string, unknown>).forEach(([key, value]) => {
        if (value !== undefined && value !== null) {
          queryParams.append(key, String(value));
        }
      });
      const url = `${endpoint}${queryParams.toString() ? `?${queryParams.toString()}` : ''}`;
      data = await apiGet<TResponse>(url);
    } else {
      data = await apiPost<TResponse>(endpoint, validated);
    }

    return responseSchema.parse(data);
  };
}