/**
 * Ghost Admin API Client
 * Full CRUD operations for Ghost content using native fetch
 */

import { generateToken } from './ghost.jwt.js';
import type { THttpMethod, IBrowseOptions, IGhostAPIResponse, IGhostErrorResponse } from './ghost.types.js';
import * as fs from 'fs';
import * as path from 'path';

export interface IGhostAdminAPIOptions {
  url: string;
  key: string;
  version?: string;
  ghostPath?: string;
}

export class GhostAdminAPI {
  private url: string;
  private key: string;
  private version: string;
  private ghostPath: string;
  private acceptVersionHeader: string;

  constructor(options: IGhostAdminAPIOptions) {
    this.url = options.url.replace(/\/$/, ''); // Remove trailing slash
    this.key = options.key;
    this.version = options.version || 'v3';
    this.ghostPath = options.ghostPath || 'ghost';

    if (!this.url) {
      throw new Error('GhostAdminAPI: url is required');
    }
    if (!this.key) {
      throw new Error('GhostAdminAPI: key is required');
    }

    // Set accept version header
    if (this.version.match(/^v\d+$/)) {
      this.acceptVersionHeader = `${this.version}.0`;
    } else if (this.version.match(/^v\d+\.\d+$/)) {
      this.acceptVersionHeader = this.version;
    } else {
      this.acceptVersionHeader = 'v6.0';
    }
  }

  /**
   * Build the API prefix based on version
   */
  private getAPIPrefix(): string {
    // v5+ doesn't need version prefix
    if (this.version === 'v5' || this.version === 'v6' || this.version.match(/^v[5-9]\.\d+/)) {
      return `/admin/`;
    }
    // v2-v4 and canary need version prefix
    return `/${this.version}/admin/`;
  }

  /**
   * Build full API URL
   */
  private buildUrl(resource: string, identifier?: string, params?: Record<string, any>): string {
    const apiPrefix = this.getAPIPrefix();
    let endpoint = `${this.url}/${this.ghostPath}/api${apiPrefix}${resource}/`;

    if (identifier) {
      endpoint += `${identifier}/`;
    }

    // Build query string if params exist
    if (params && Object.keys(params).length > 0) {
      const queryString = Object.keys(params)
        .filter(key => params[key] !== undefined && params[key] !== null)
        .map(key => {
          const value = Array.isArray(params[key])
            ? params[key].join(',')
            : params[key];
          return `${key}=${encodeURIComponent(value)}`;
        })
        .join('&');

      if (queryString) {
        endpoint += `?${queryString}`;
      }
    }

    return endpoint;
  }

  /**
   * Get authorization token
   */
  private async getAuthToken(): Promise<string> {
    const audience = this.getAPIPrefix();
    return await generateToken(this.key, audience);
  }

  /**
   * Make API request
   */
  private async makeRequest<T>(
    resource: string,
    method: THttpMethod = 'GET',
    identifier?: string,
    body?: any,
    queryParams?: Record<string, any>
  ): Promise<T | T[] | void> {
    const url = this.buildUrl(resource, identifier, queryParams);
    const token = await this.getAuthToken();

    const headers: Record<string, string> = {
      'Authorization': `Ghost ${token}`,
      'Accept-Version': this.acceptVersionHeader,
      'Accept': 'application/json',
      'User-Agent': 'GhostAdminAPI/2.0'
    };

    const requestOptions: RequestInit = {
      method,
      headers
    };

    // Add body for POST/PUT
    if (body && (method === 'POST' || method === 'PUT')) {
      headers['Content-Type'] = 'application/json';
      requestOptions.body = JSON.stringify(body);
    }

    try {
      const response = await fetch(url, requestOptions);

      if (!response.ok) {
        const errorData: IGhostErrorResponse = await response.json().catch(() => ({
          errors: [{ type: 'UnknownError', message: response.statusText }]
        }));

        const error = errorData.errors?.[0];
        const err = new Error(error?.message || response.statusText);
        Object.assign(err, {
          name: error?.type || 'GhostAdminAPIError',
          statusCode: response.status,
          ...error
        });
        throw err;
      }

      // DELETE returns empty response
      if (method === 'DELETE') {
        return;
      }

      const data: IGhostAPIResponse<T> = await response.json();

      // Extract the resource data
      const resourceData = data[resource];
      if (!resourceData) {
        return data as any; // For some special endpoints that don't follow standard format
      }

      // If it's an array and has meta, attach meta to the array
      if (Array.isArray(resourceData) && data.meta) {
        return Object.assign(resourceData, { meta: data.meta });
      }

      // If it's an array with single item and no meta, return the item
      if (Array.isArray(resourceData) && resourceData.length === 1 && !data.meta) {
        return resourceData[0];
      }

      return resourceData as T | T[];
    } catch (error) {
      throw error;
    }
  }

  /**
   * Create resource API methods factory
   */
  private createResourceAPI(resourceType: string) {
    return {
      browse: (options?: IBrowseOptions) => {
        return this.makeRequest(resourceType, 'GET', undefined, undefined, options);
      },

      read: (data: { id?: string; slug?: string; email?: string }, queryParams?: Record<string, any>) => {
        if (data.slug) {
          return this.makeRequest(resourceType, 'GET', `slug/${data.slug}`, undefined, queryParams);
        }
        if (data.email) {
          return this.makeRequest(resourceType, 'GET', `email/${data.email}`, undefined, queryParams);
        }
        if (data.id) {
          return this.makeRequest(resourceType, 'GET', data.id, undefined, queryParams);
        }
        throw new Error('Must provide id, slug, or email');
      },

      add: (data: any, queryParams?: Record<string, any>) => {
        if (!data || !Object.keys(data).length) {
          return Promise.reject(new Error('Missing data'));
        }
        const body: any = {};
        body[resourceType] = [data];
        return this.makeRequest(resourceType, 'POST', undefined, body, queryParams);
      },

      edit: (data: any, queryParams?: Record<string, any>) => {
        if (!data) {
          return Promise.reject(new Error('Missing data'));
        }
        if (!data.id) {
          return Promise.reject(new Error('Must include data.id'));
        }

        const id = data.id;
        const updateData = { ...data };
        delete updateData.id;

        const body: any = {};
        body[resourceType] = [updateData];

        return this.makeRequest(resourceType, 'PUT', id, body, queryParams);
      },

      delete: (data: { id?: string; email?: string }, queryParams?: Record<string, any>) => {
        if (!data) {
          return Promise.reject(new Error('Missing data'));
        }
        if (!data.id && !data.email) {
          return Promise.reject(new Error('Must include either data.id or data.email'));
        }

        const identifier = data.email ? `email/${data.email}` : data.id;
        return this.makeRequest(resourceType, 'DELETE', identifier, undefined, queryParams);
      }
    };
  }

  // Resource APIs
  public posts = this.createResourceAPI('posts');
  public pages = this.createResourceAPI('pages');
  public tags = this.createResourceAPI('tags');
  public members = this.createResourceAPI('members');
  public users = this.createResourceAPI('users');

  // Webhooks (limited operations)
  public webhooks = {
    add: (data: any, queryParams?: Record<string, any>) => {
      const body: any = { webhooks: [data] };
      return this.makeRequest('webhooks', 'POST', undefined, body, queryParams);
    },

    edit: (data: any, queryParams?: Record<string, any>) => {
      if (!data.id) {
        return Promise.reject(new Error('Must include data.id'));
      }
      const id = data.id;
      const updateData = { ...data };
      delete updateData.id;
      const body: any = { webhooks: [updateData] };
      return this.makeRequest('webhooks', 'PUT', id, body, queryParams);
    },

    delete: (data: { id: string }, queryParams?: Record<string, any>) => {
      if (!data.id) {
        return Promise.reject(new Error('Must include data.id'));
      }
      return this.makeRequest('webhooks', 'DELETE', data.id, undefined, queryParams);
    }
  };

  // Image upload
  public images = {
    upload: async (data: { file: string }) => {
      if (!data || !data.file) {
        throw new Error('Must provide file path');
      }

      const url = this.buildUrl('images', 'upload');
      const token = await this.getAuthToken();

      // Read file
      const fileBuffer = fs.readFileSync(data.file);
      const fileName = path.basename(data.file);

      // Create FormData
      const formData = new FormData();
      // Convert Buffer to ArrayBuffer for Blob
      const arrayBuffer = fileBuffer.buffer.slice(fileBuffer.byteOffset, fileBuffer.byteOffset + fileBuffer.byteLength) as ArrayBuffer;
      const blob = new Blob([arrayBuffer], { type: 'image/*' });
      formData.append('file', blob, fileName);

      const response = await fetch(url, {
        method: 'POST',
        headers: {
          'Authorization': `Ghost ${token}`,
          'Accept-Version': this.acceptVersionHeader,
          'User-Agent': 'GhostAdminAPI/2.0'
        },
        body: formData
      });

      if (!response.ok) {
        const errorData: IGhostErrorResponse = await response.json().catch(() => ({
          errors: [{ type: 'UnknownError', message: response.statusText }]
        }));

        const error = errorData.errors?.[0];
        const err = new Error(error?.message || response.statusText);
        throw err;
      }

      const result = await response.json();
      return result.images?.[0] || result;
    }
  };
}