/**
 * Service Base Class
 * Provides common patterns and utilities for API services
 * Reduces boilerplate and ensures consistency across services
 */

import { z, ZodSchema } from 'zod';
import { httpClient } from '@/lib/http-client';
import { validateData, validateDataStrict, validateArrayWithFallback, ValidationResult } from '@/lib/schema-validation';
import { QueryBuilder } from '@/lib/query-builder';

// Service configuration interface
export interface ServiceConfig {
  basePath: string;
  enableLogging?: boolean;
  defaultTimeout?: number;
  retries?: number;
}

// Generic service response types
export interface ServiceResponse<T> {
  data: T;
  success: boolean;
  error?: string;
}

// Base service class
export abstract class BaseService {
  protected config: Required<ServiceConfig>;

  constructor(config: ServiceConfig) {
    this.config = {
      enableLogging: import.meta.env.DEV,
      defaultTimeout: 30000,
      retries: 3,
      ...config,
    };
  }

  /**
   * Build full endpoint path
   */
  protected buildEndpoint(path: string = ''): string {
    const base = this.config.basePath.replace(/\/$/, ''); // Remove trailing slash
    const cleanPath = path.replace(/^\//, ''); // Remove leading slash
    return cleanPath ? `${base}/${cleanPath}` : base;
  }

  /**
   * Execute HTTP GET request with validation
   */
  protected async get<T>(
    path: string,
    schema: ZodSchema<T>,
    queryParams?: Record<string, unknown>,
    options?: {
      context?: string;
      useArrayFallback?: boolean;
      timeout?: number;
    }
  ): Promise<ValidationResult<T>> {
    const { context, useArrayFallback, timeout } = options || {};
    const endpoint = this.buildEndpoint(path);
    const url = queryParams ? QueryBuilder.create().params(queryParams).toUrl(endpoint) : endpoint;

    if (this.config.enableLogging) {
      console.log(`[Service:${this.constructor.name}] GET ${url}`);
    }

    try {
      const rawData = await httpClient.get(url, {
        timeout: timeout || this.config.defaultTimeout,
        retries: this.config.retries,
      });

      if (useArrayFallback && Array.isArray(rawData)) {
        return validateArrayWithFallback(schema, rawData, { context });
      }

      return validateData(schema, rawData, {
        context: context || `${this.constructor.name}.get`,
        logErrors: this.config.enableLogging,
      });
    } catch (error) {
      const errorMessage = `GET ${endpoint} failed: ${error instanceof Error ? error.message : 'Unknown error'}`;

      if (this.config.enableLogging) {
        console.error(`[Service:${this.constructor.name}] ${errorMessage}`, error);
      }

      return {
        success: false,
        error: {
          message: errorMessage,
          details: [],
        },
      };
    }
  }

  /**
   * Execute HTTP POST request with validation
   */
  protected async post<T>(
    path: string,
    data: unknown,
    schema: ZodSchema<T>,
    options?: {
      context?: string;
      timeout?: number;
      isFormData?: boolean;
    }
  ): Promise<ValidationResult<T>> {
    const { context, timeout, isFormData } = options || {};
    const endpoint = this.buildEndpoint(path);

    if (this.config.enableLogging) {
      console.log(`[Service:${this.constructor.name}] POST ${endpoint}`, isFormData ? 'FormData' : data);
    }

    try {
      const rawData = isFormData
        ? await httpClient.post(endpoint, data as FormData, {
            timeout: timeout || this.config.defaultTimeout,
            retries: this.config.retries,
          })
        : await httpClient.post(endpoint, data, {
            timeout: timeout || this.config.defaultTimeout,
            retries: this.config.retries,
          });

      return validateData(schema, rawData, {
        context: context || `${this.constructor.name}.post`,
        logErrors: this.config.enableLogging,
      });
    } catch (error) {
      const errorMessage = `POST ${endpoint} failed: ${error instanceof Error ? error.message : 'Unknown error'}`;

      if (this.config.enableLogging) {
        console.error(`[Service:${this.constructor.name}] ${errorMessage}`, error);
      }

      return {
        success: false,
        error: {
          message: errorMessage,
          details: [],
        },
      };
    }
  }

  /**
   * Execute HTTP PUT request with validation
   */
  protected async put<T>(
    path: string,
    data: unknown,
    schema: ZodSchema<T>,
    options?: {
      context?: string;
      timeout?: number;
    }
  ): Promise<ValidationResult<T>> {
    const { context, timeout } = options || {};
    const endpoint = this.buildEndpoint(path);

    if (this.config.enableLogging) {
      console.log(`[Service:${this.constructor.name}] PUT ${endpoint}`, data);
    }

    try {
      const rawData = await httpClient.put(endpoint, data, {
        timeout: timeout || this.config.defaultTimeout,
        retries: this.config.retries,
      });

      return validateData(schema, rawData, {
        context: context || `${this.constructor.name}.put`,
        logErrors: this.config.enableLogging,
      });
    } catch (error) {
      const errorMessage = `PUT ${endpoint} failed: ${error instanceof Error ? error.message : 'Unknown error'}`;

      if (this.config.enableLogging) {
        console.error(`[Service:${this.constructor.name}] ${errorMessage}`, error);
      }

      return {
        success: false,
        error: {
          message: errorMessage,
          details: [],
        },
      };
    }
  }

  /**
   * Execute HTTP DELETE request
   */
  protected async delete(
    path: string,
    options?: {
      context?: string;
      timeout?: number;
    }
  ): Promise<ValidationResult<void>> {
    const { context, timeout } = options || {};
    const endpoint = this.buildEndpoint(path);

    if (this.config.enableLogging) {
      console.log(`[Service:${this.constructor.name}] DELETE ${endpoint}`);
    }

    try {
      await httpClient.delete(endpoint, {
        timeout: timeout || this.config.defaultTimeout,
        retries: this.config.retries,
      });

      return { success: true, data: undefined };
    } catch (error) {
      const errorMessage = `DELETE ${endpoint} failed: ${error instanceof Error ? error.message : 'Unknown error'}`;

      if (this.config.enableLogging) {
        console.error(`[Service:${this.constructor.name}] ${errorMessage}`, error);
      }

      return {
        success: false,
        error: {
          message: errorMessage,
          details: [],
        },
      };
    }
  }

  /**
   * Strict validation wrapper (throws on failure)
   */
  protected validateStrict<T>(schema: ZodSchema<T>, data: unknown, context?: string): T {
    return validateDataStrict(schema, data, context || this.constructor.name);
  }

  /**
   * Create a query builder for this service
   */
  protected createQuery(): QueryBuilder {
    return QueryBuilder.create();
  }

  /**
   * Log service events (only in development)
   */
  protected log(message: string, ...args: unknown[]): void {
    if (this.config.enableLogging) {
      console.log(`[Service:${this.constructor.name}] ${message}`, ...args);
    }
  }

  /**
   * Log errors (only in development)
   */
  protected logError(message: string, error?: unknown): void {
    if (this.config.enableLogging) {
      console.error(`[Service:${this.constructor.name}] ${message}`, error);
    }
  }
}

/**
 * CRUD Service mixin for common patterns
 */
export abstract class CrudService<T, TCreate, TUpdate = Partial<TCreate>> extends BaseService {
  protected abstract entitySchema: ZodSchema<T>;
  protected abstract createSchema: ZodSchema<TCreate>;
  protected abstract updateSchema: ZodSchema<TUpdate>;

  /**
   * Get all entities
   */
  async getAll(options?: {
    query?: Record<string, unknown>;
    context?: string;
    useArrayFallback?: boolean;
  }): Promise<ValidationResult<T[]>> {
    return this.get('', this.entitySchema.array(), options?.query, {
      context: options?.context || 'getAll',
      useArrayFallback: options?.useArrayFallback ?? true,
    });
  }

  /**
   * Get entity by ID
   */
  async getById(id: string, options?: { context?: string }): Promise<ValidationResult<T>> {
    return this.get(id, this.entitySchema, undefined, {
      context: options?.context || `getById(${id})`,
    });
  }

  /**
   * Create new entity
   */
  async create(data: TCreate, options?: { context?: string }): Promise<ValidationResult<T>> {
    const validatedData = this.validateStrict(this.createSchema, data, 'create validation');
    return this.post('', validatedData, this.entitySchema, {
      context: options?.context || 'create',
    });
  }

  /**
   * Update entity
   */
  async update(id: string, data: TUpdate, options?: { context?: string }): Promise<ValidationResult<T>> {
    const validatedData = this.validateStrict(this.updateSchema, data, 'update validation');
    return this.put(id, validatedData, this.entitySchema, {
      context: options?.context || `update(${id})`,
    });
  }

  /**
   * Delete entity
   */
  async remove(id: string, options?: { context?: string }): Promise<ValidationResult<void>> {
    return this.delete(id, {
      context: options?.context || `delete(${id})`,
    });
  }
}

/**
 * Factory function to create service instances
 */
export function createService<T extends BaseService>(
  ServiceClass: new (config: ServiceConfig) => T,
  basePath: string,
  options?: Partial<ServiceConfig>
): T {
  return new ServiceClass({
    basePath,
    enableLogging: import.meta.env.DEV,
    ...options,
  });
}