import { getEnvironmentVariable } from "../util/env.js";
import { Tool } from "./base.js";

/**
 * @interface DataForSeoApiConfig
 * @description Represents the configuration object used to set up a DataForSeoAPISearch instance.
 */
export interface DataForSeoApiConfig {
  /**
   * @property apiLogin
   * @type {string}
   * @description The API login credential for DataForSEO. If not provided, it will be fetched from environment variables.
   */
  apiLogin?: string;

  /**
   * @property apiPassword
   * @type {string}
   * @description The API password credential for DataForSEO. If not provided, it will be fetched from environment variables.
   */
  apiPassword?: string;

  /**
   * @property params
   * @type {Record<string, string | number | boolean>}
   * @description Additional parameters to customize the API request.
   */
  params?: Record<string, string | number | boolean>;

  /**
   * @property useJsonOutput
   * @type {boolean}
   * @description Determines if the output should be in JSON format.
   */
  useJsonOutput?: boolean;

  /**
   * @property jsonResultTypes
   * @type {Array<string>}
   * @description Specifies the types of results to include in the output.
   */
  jsonResultTypes?: Array<string>;

  /**
   * @property jsonResultFields
   * @type {Array<string>}
   * @description Specifies the fields to include in each result object.
   */
  jsonResultFields?: Array<string>;

  /**
   * @property topCount
   * @type {number}
   * @description Specifies the maximum number of results to return.
   */
  topCount?: number;
}

type Task = {
  id: string;
  status_code: number;
  status_message: string;
  time: string;
  result: Result[];
};

type Result = {
  keyword: string;
  check_url: string;
  datetime: string;
  spell?: string;
  item_types: string[];
  se_results_count: number;
  items_count: number;
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  items: any[];
};

type ApiResponse = {
  status_code: number;
  status_message: string;
  tasks: Task[];
};

/**
 * @class DataForSeoAPISearch
 * @extends {Tool}
 * @description Represents a wrapper class to work with DataForSEO SERP API.
 */
export class DataForSeoAPISearch extends Tool {
  name = "dataforseo-api-wrapper";

  description =
    "A robust Google Search API provided by DataForSeo. This tool is handy when you need information about trending topics or current events.";

  protected apiLogin: string;

  protected apiPassword: string;

  /**
   * @property defaultParams
   * @type {Record<string, string | number | boolean>}
   * @description These are the default parameters to be used when making an API request.
   */
  protected defaultParams: Record<string, string | number | boolean> = {
    location_name: "United States",
    language_code: "en",
    depth: 10,
    se_name: "google",
    se_type: "organic",
  };

  protected params: Record<string, string | number | boolean> = {};

  protected jsonResultTypes: Array<string> | undefined;

  protected jsonResultFields: Array<string> | undefined;

  protected topCount: number | undefined;

  protected useJsonOutput = false;

  /**
   * @constructor
   * @param {DataForSeoApiConfig} config
   * @description Sets up the class, throws an error if the API login/password isn't provided.
   */
  constructor(config: DataForSeoApiConfig = {}) {
    super();
    const apiLogin =
      config.apiLogin ?? getEnvironmentVariable("DATAFORSEO_LOGIN");
    const apiPassword =
      config.apiPassword ?? getEnvironmentVariable("DATAFORSEO_PASSWORD");
    const params = config.params ?? {};
    if (!apiLogin || !apiPassword) {
      throw new Error(
        "DataForSEO login or password not set. You can set it as DATAFORSEO_LOGIN and DATAFORSEO_PASSWORD in your .env file, or pass it to DataForSeoAPISearch."
      );
    }
    this.params = { ...this.defaultParams, ...params };
    this.apiLogin = apiLogin;
    this.apiPassword = apiPassword;
    this.jsonResultTypes = config.jsonResultTypes;
    this.jsonResultFields = config.jsonResultFields;
    this.useJsonOutput = config.useJsonOutput ?? false;
    this.topCount = config.topCount;
  }

  /**
   * @method _call
   * @param {string} keyword
   * @returns {Promise<string>}
   * @description Initiates a call to the API and processes the response.
   */
  async _call(keyword: string): Promise<string> {
    return this.useJsonOutput
      ? JSON.stringify(await this.results(keyword))
      : this.processResponse(await this.getResponseJson(keyword));
  }

  /**
   * @method results
   * @param {string} keyword
   * @returns {Promise<Array<any>>}
   * @description Fetches the results from the API for the given keyword.
   */
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  async results(keyword: string): Promise<Array<any>> {
    const res = await this.getResponseJson(keyword);
    return this.filterResults(res, this.jsonResultTypes);
  }

  /**
   * @method prepareRequest
   * @param {string} keyword
   * @returns {{url: string; headers: HeadersInit; data: BodyInit}}
   * @description Prepares the request details for the API call.
   */
  protected prepareRequest(keyword: string): {
    url: string;
    headers: HeadersInit;
    data: BodyInit;
  } {
    if (this.apiLogin === undefined || this.apiPassword === undefined) {
      throw new Error("api_login or api_password is not provided");
    }

    const credentials = Buffer.from(
      `${this.apiLogin}:${this.apiPassword}`,
      "utf-8"
    ).toString("base64");
    const headers = {
      Authorization: `Basic ${credentials}`,
      "Content-Type": "application/json",
    };

    const params = { ...this.params };
    params.keyword ??= keyword;
    const data = [params];

    return {
      url: `https://api.dataforseo.com/v3/serp/${params.se_name}/${params.se_type}/live/advanced`,
      headers,
      data: JSON.stringify(data),
    };
  }

  /**
   * @method getResponseJson
   * @param {string} keyword
   * @returns {Promise<ApiResponse>}
   * @description Executes a POST request to the provided URL and returns a parsed JSON response.
   */
  protected async getResponseJson(keyword: string): Promise<ApiResponse> {
    const requestDetails = this.prepareRequest(keyword);
    const response = await fetch(requestDetails.url, {
      method: "POST",
      headers: requestDetails.headers,
      body: requestDetails.data,
    });

    if (!response.ok) {
      throw new Error(
        `Got ${response.status} error from DataForSEO: ${response.statusText}`
      );
    }

    const result: ApiResponse = await response.json();
    return this.checkResponse(result);
  }

  /**
   * @method checkResponse
   * @param {ApiResponse} response
   * @returns {ApiResponse}
   * @description Checks the response status code.
   */
  private checkResponse(response: ApiResponse): ApiResponse {
    if (response.status_code !== 20000) {
      throw new Error(
        `Got error from DataForSEO SERP API: ${response.status_message}`
      );
    }
    for (const task of response.tasks) {
      if (task.status_code !== 20000) {
        throw new Error(
          `Got error from DataForSEO SERP API: ${task.status_message}`
        );
      }
    }
    return response;
  }

  /* eslint-disable @typescript-eslint/no-explicit-any */
  /**
   * @method filterResults
   * @param {ApiResponse} res
   * @param {Array<string> | undefined} types
   * @returns {Array<any>}
   * @description Filters the results based on the specified result types.
   */
  private filterResults(
    res: ApiResponse,
    types: Array<string> | undefined
  ): Array<any> {
    const output: Array<any> = [];
    for (const task of res.tasks || []) {
      for (const result of task.result || []) {
        for (const item of result.items || []) {
          if (
            types === undefined ||
            types.length === 0 ||
            types.includes(item.type)
          ) {
            const newItem = this.cleanupUnnecessaryItems(item);
            if (Object.keys(newItem).length !== 0) {
              output.push(newItem);
            }
          }
          if (this.topCount !== undefined && output.length >= this.topCount) {
            break;
          }
        }
      }
    }
    return output;
  }

  /* eslint-disable @typescript-eslint/no-explicit-any */
  /* eslint-disable no-param-reassign */
  /**
   * @method cleanupUnnecessaryItems
   * @param {any} d
   * @description Removes unnecessary items from the response.
   */
  private cleanupUnnecessaryItems(d: any): any {
    if (Array.isArray(d)) {
      return d.map((item) => this.cleanupUnnecessaryItems(item));
    }

    const toRemove = ["xpath", "position", "rectangle"];
    if (typeof d === "object" && d !== null) {
      return Object.keys(d).reduce((newObj: any, key: string) => {
        if (
          (this.jsonResultFields === undefined ||
            this.jsonResultFields.includes(key)) &&
          !toRemove.includes(key)
        ) {
          if (typeof d[key] === "object" && d[key] !== null) {
            newObj[key] = this.cleanupUnnecessaryItems(d[key]);
          } else {
            newObj[key] = d[key];
          }
        }
        return newObj;
      }, {});
    }

    return d;
  }

  /**
   * @method processResponse
   * @param {ApiResponse} res
   * @returns {string}
   * @description Processes the response to extract meaningful data.
   */
  protected processResponse(res: ApiResponse): string {
    let returnValue = "No good search result found";
    for (const task of res.tasks || []) {
      for (const result of task.result || []) {
        const { item_types } = result;
        const items = result.items || [];
        if (item_types.includes("answer_box")) {
          returnValue = items.find(
            (item: { type: string; text: string }) => item.type === "answer_box"
          ).text;
        } else if (item_types.includes("knowledge_graph")) {
          returnValue = items.find(
            (item: { type: string; description: string }) =>
              item.type === "knowledge_graph"
          ).description;
        } else if (item_types.includes("featured_snippet")) {
          returnValue = items.find(
            (item: { type: string; description: string }) =>
              item.type === "featured_snippet"
          ).description;
        } else if (item_types.includes("shopping")) {
          returnValue = items.find(
            (item: { type: string; price: string }) => item.type === "shopping"
          ).price;
        } else if (item_types.includes("organic")) {
          returnValue = items.find(
            (item: { type: string; description: string }) =>
              item.type === "organic"
          ).description;
        }
        if (returnValue) {
          break;
        }
      }
    }
    return returnValue;
  }
}