class AnalyticsTracker {
  // ========================
  //   Globals & Constants
  // ========================
  static globalState = {
    isSearchListenerAdded: false,
  };

  static API_ENDPOINTS = {
    PRO: "api.deepl.com",
    FREE: "api-free.deepl.com"
  }

  static PAGE_ID_DEVELOPERS_WEBSITE_DOCUMENTATION = 4001;
  static PAGE_ID_DEVELOPERS_WEBSITE_API_REFERENCE = 4002;

  static EVENT_ID_PAGEVIEW = 1;
  static EVENT_ID_NETWORK_REQUEST = 5000;
  static EVENT_ID_SEARCH_INPUT = 5001; // TODO change this after DAP update

  static isProdStage = window.location.hostname === "developers.deepl.com";
  static statisticsUrl = this.isProdStage ? 
    "https://s.deepl.com/web/statistics"
    : "https://s.deepl.dev/web/statistics"

  // ========================
  //   Cookie Helper Inner Class
  // ========================
  static CookieHelper = class {
    static DAP_UID_KEY = 'dapUid';
    static DAP_SID_KEY = 'dapSid';
    
    static YEAR_IN_MINUTES = 60 * 24 * 30 * 12;
    static SID_TTL_MINUTES = 30;

    static getCookieItem(cookieName) {
      if (typeof window === 'undefined') {
        throw new Error('Error occurs when you are going to use a browser-specific code on server-side or other way around. Please check your code logic.');
      }
      const cookies = document.cookie.split('; ') || [];
      const cookie = cookies.find(c => c.startsWith(`${cookieName}=`)) || '';
      const value = cookie.split('=').at(1);
      return value ? decodeURIComponent(value) : value;
    }

    static setCookieItem(cookieName, cookieValue, expiresInMinutes = 0) {
      if (typeof window === 'undefined') {
        throw new Error('Error occurs when you are going to use a browser-specific code on server-side or other way around. Please check your code logic.');
      }
      const cookieValueToStore = (
        typeof cookieValue === 'string' || typeof cookieValue === 'number'
          ? cookieValue
          : JSON.stringify(cookieValue)
      );
      let expireString = '';
      if (expiresInMinutes) {
        const date = new Date();
        const expiresInMilliseconds = expiresInMinutes * 60 * 1000;
        date.setTime(date.getTime() + expiresInMilliseconds);
        expireString = `; expires=${date.toUTCString()}`;
      }
      const domain = AnalyticsTracker.isProdStage ? '.deepl.com' : window.location.hostname;
      const domainString = `; domain=${domain}`;
      const secure = '; secure';
      document.cookie = `${cookieName}=${encodeURIComponent(cookieValueToStore)}${domainString}; path=/${expireString}; samesite=lax${secure}`;
    }

    static mkUUID() {
      if (typeof window === 'undefined') {
        return '';
      }
      if (!Object.prototype.hasOwnProperty.call(window, 'crypto')) {
        return '';
      }
      if (typeof window.crypto.randomUUID === 'function') {
        return window.crypto.randomUUID();
      }
      return [1e7, -1e3, -4e3, -8e3, -1e11].join('').replace(/[018]/g, c =>
        (parseInt(c, 10) ^ (window.crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (parseInt(c, 10) / 4)))).toString(16));
    }

    static getUid() {
      let uid = this.getCookieItem(this.DAP_UID_KEY);
      if (uid === undefined) {
        this.setCookieItem(
          this.DAP_UID_KEY,
          this.mkUUID(),
          this.YEAR_IN_MINUTES
        );
      }
      uid = this.getCookieItem(this.DAP_UID_KEY);
      return uid;
    }

    static getSid() {
      let sidCookie = this.getCookieItem(this.DAP_SID_KEY);
      let sidObj;
      if (sidCookie) {
        try {
          sidObj = JSON.parse(sidCookie);
        } catch {
          sidObj = null;
        }
      }
      const now = Date.now();
      if (sidObj && sidObj.sid && sidObj.lastUpdate) {
        // SID exists already
        if (now - sidObj.lastUpdate > this.SID_TTL_MINUTES * 60 * 1000) {
          sidObj = {
            sid: this.mkUUID(),
            lastUpdate: now
          };
        } else {
          sidObj = {
            ...sidObj,
            lastUpdate: now
          };
        }
      } else {
        // SID does not exist
        sidObj = {
          sid: this.mkUUID(),
          lastUpdate: now
        };
      }
      this.setCookieItem(this.DAP_SID_KEY, JSON.stringify(sidObj), this.SID_TTL_MINUTES);
      return sidObj.sid;
    }
  };

  // ========================
  //   Request Helper Inner Class
  // ========================
  static RequestHelper = class {
    static async baseRequest(url, getPayload) {
      const payload = getPayload();
      try {
        const response = await fetch(
          url,
          {
            headers: {
              "content-type": "application/json",
            },
            body: JSON.stringify(payload),
            method: "POST",
          }
        );
        const data = await response.json();
        // console.log('Fetched data: ', data);
        return data;
      } catch (error) {
        console.error('Fetch error: ', error);
      }
    }

    static getPageId() {
      const pathname = window.location.pathname;
      const secondSlash = pathname.indexOf("/", 1);
      const firstSubpath = secondSlash !== -1 ? pathname.substring(0, secondSlash) : pathname;
      switch (firstSubpath) {
        case "/docs":
          return AnalyticsTracker.PAGE_ID_DEVELOPERS_WEBSITE_DOCUMENTATION;
        case "/api-reference":
          return AnalyticsTracker.PAGE_ID_DEVELOPERS_WEBSITE_API_REFERENCE;
        default:
          return 0;
      }
    }

    static requestToDAP(eventId, extraFields) {
      // console.log(`[${eventId}]: ${JSON.stringify(extraFields)}`); 
      
      this.baseRequest(
        AnalyticsTracker.statisticsUrl,
        () => ({
          instanceId: AnalyticsTracker.CookieHelper.getUid(),
          sessionId: AnalyticsTracker.CookieHelper.getSid(),
          eventId: eventId,
          pageId: this.getPageId(),
          userAgent: navigator.userAgent,
          interfaceLanguage: navigator.language,
          screenInfo: {
            widthCssPixel: window.screen.width,
            heightCssPixel: window.screen.height,
            viewportWidthCssPixel: window.innerWidth,
            viewportHeightCssPixel: window.innerHeight,
            devicePixelRatio: window.devicePixelRatio
          },
          url: `${window.location.origin}${window.location.pathname}${window.location.search}`,
          ...extraFields
        })
      );
    }
  };

  // ========================
  //   Track Page Navigation Inner Class
  // ========================
  static PageNavigationTracker = class {
    static navigationState = {
      lastTrackedUrl: null
    }

    static sendPageview() {
      AnalyticsTracker.RequestHelper.requestToDAP(
        AnalyticsTracker.EVENT_ID_PAGEVIEW, 
        {
          pageviewData: {
            referrer: document.referrer,
            pageVariant: 0,
          }
        }
      );
    }

    static sendPageviewDeduped() {
      const currentUrl = window.location.href;
      if (currentUrl === this.navigationState.lastTrackedUrl) return; // Skip duplicate
      this.navigationState.lastTrackedUrl = currentUrl;
      this.sendPageview(); 
    }

    static setupNavigationTrackers() {
      const _pushState = history.pushState;
      const _replaceState = history.replaceState;

      history.pushState = function (...args) {
        _pushState.apply(this, args);
        AnalyticsTracker.PageNavigationTracker.sendPageviewDeduped();
      };

      history.replaceState = function (...args) {
        _replaceState.apply(this, args);
        AnalyticsTracker.PageNavigationTracker.sendPageviewDeduped();
      };

      window.addEventListener('popstate', () => {
        AnalyticsTracker.PageNavigationTracker.sendPageviewDeduped();
      });

      window.addEventListener('hashchange', () => {
        AnalyticsTracker.PageNavigationTracker.sendPageviewDeduped();
      });

      this.sendPageviewDeduped();
    }
  };

  // ========================
  //   Network Request Tracking Inner Class
  // ========================
  static NetworkRequestTracker = class {
    static sendOutgoingNetworkResponse(statusCode, apiUrl) {
      AnalyticsTracker.RequestHelper.requestToDAP(
        AnalyticsTracker.EVENT_ID_NETWORK_REQUEST, 
        {
          developersWebsiteNetworkData: {
            statusCode,
            apiUrl 
          }
        }
      );
    }

    static setupNetworkRequestTracking() {
      const originalOpen = XMLHttpRequest.prototype.open;
      const originalSend = XMLHttpRequest.prototype.send;

      XMLHttpRequest.prototype.open = function(method, url) {
        const xhr = this;
        xhr._recordedUrl = url;
        return originalOpen.apply(xhr, arguments);
      };

      XMLHttpRequest.prototype.send = function(body) {
        // Note: we cannot log the url, request body, or response body because of sensitive info
        const xhr = this;
        const originalOnReadyStateChange = xhr.onreadystatechange;
        xhr.onreadystatechange = function() {
          if (xhr.readyState === 4) { // DONE
            
            const urlObj = new URL(xhr._recordedUrl)
            if (
              urlObj.hostname === AnalyticsTracker.API_ENDPOINTS.PRO ||
              urlObj.hostname === AnalyticsTracker.API_ENDPOINTS.FREE
            ) {
              // Prune out any custom query params which could be input data
              const prunedUrl = `${urlObj.origin}${urlObj.pathname}`

              AnalyticsTracker.NetworkRequestTracker.sendOutgoingNetworkResponse(
                xhr.status,
                prunedUrl
              );
            }
            else {
              // do nothing for other requests
            }
          }
          if (originalOnReadyStateChange) {
            originalOnReadyStateChange.apply(xhr, arguments);
          }
        };
        return originalSend.apply(xhr, arguments);
      };
    }
  };

  // ========================
  //   Search Input Tracking Inner Class
  // ========================
  static SearchInputTracker = class {
    static InputClassification = {
      Partial: 'Partial',
      Submitted: 'Submitted', // Not implemented yet
      AiAssistant: 'AiAssistant'
    };

    static filteredHostnames = ['leaves.mintlify.com'];

    static sendSearchInput(searchInputText, classification) {
      AnalyticsTracker.RequestHelper.requestToDAP(
        AnalyticsTracker.EVENT_ID_SEARCH_INPUT, 
        {
          searchInputText,
          classification
        }
      );
    }

    static addSearchInputListener() {
      const searchInput = document.getElementById('search-input');
      if (!AnalyticsTracker.globalState.isSearchListenerAdded && searchInput) {
        searchInput.addEventListener('input', (event) => {
          const inputText = event.target.value;
          this.sendSearchInput(inputText, this.InputClassification.Partial);
        });
        AnalyticsTracker.globalState.isSearchListenerAdded = true;
      }
    }

    static removeSearchInputListener() {
      const searchInput = document.getElementById('search-input');
      if (AnalyticsTracker.globalState.isSearchListenerAdded && !searchInput) {
        AnalyticsTracker.globalState.isSearchListenerAdded = false;
      }
    }

    static setupSearchInputTracking() {
      // As the user is typing
      const observer = new MutationObserver((mutations) => {
        mutations.forEach((mutation) => {
          if (mutation.addedNodes.length) {
            this.addSearchInputListener();
          }
          if (mutation.removedNodes.length) {
            this.removeSearchInputListener();
          }
        });
      });
      observer.observe(document.body, { childList: true, subtree: true });
      this.addSearchInputListener();

      // When a user submits to the AI Assistant
      const originalFetch = window.fetch;
      window.fetch = async (...args) => {
        try {
          const url = typeof args[0] === 'string' ? args[0] : args[0].url;
          const requestHostname = new URL(url).hostname;
          if (this.filteredHostnames.includes(requestHostname)) {
            this.sendSearchInput(args[1].body, this.InputClassification.AiAssistant);
          }
          return originalFetch(...args);;
        } catch (error) {
          return originalFetch(...args);
        }
      };
    }
  };

  // ========================
  //   Initialization
  // ========================
  static init() {
    this.PageNavigationTracker.setupNavigationTrackers();
    this.NetworkRequestTracker.setupNetworkRequestTracking();
    // this.SearchInputTracker.setupSearchInputTracking(); // Disable this for now
  }
}

// Initialize on page load
AnalyticsTracker.init();


Upload and translate a document

Sets whether the translated text should lean towards formal or informal language.
This feature is only available for certain target languages. Setting this parameter 
with a target language that does not support formality will fail, unless one of the 
`prefer_...` options are used.
Possible options are:
  * `default` (default)
  * `more` - for a more formal language
  * `less` - for a more informal language
  * `prefer_more` - for a more formal language if available, otherwise fallback to default formality
  * `prefer_less` - for a more informal language if available, otherwise fallback to default formality

Language of the text to be translated. If this parameter is omitted, the API will attempt to 
detect the language of the text and translate it.

The language into which the text should be translated.

auth header

The document function returns a JSON object containing the ID and encryption key assigned to the uploaded document. Once received by the server, uploaded documents are immediately encrypted using a uniquely generated encryption key. This key is not persistently stored on the server. Therefore, it must be stored by the client and sent back to the server with every subsequent request that refers to this particular document.

Bad request. Please check error message and your parameters.

Authorization failed. Please supply a valid `DeepL-Auth-Key` via the `Authorization` header.

The requested resource could not be found.

Too many requests. Please wait and resend your request.

Quota exceeded. The character limit has been reached.

Resource currently unavailable. Try again later.

Upload and Translate a Document

DeepL Documentation

Welcome to the developer home of DeepL API.

Introduction

About

Learn where to find your authentication key and how to access the DeepL API.

Access and authentication

A guide to creating API keys, getting API key-level usage, and setting API key-level limits.

Managing API keys

Make your first API requests to translate and improve text with the DeepL API.

Your first API request

Use our official Postman collection to get familiar with and test the DeepL API.

Test your API requests with Postman

The DeepL API supports the following languages. We will update this list as we introduce new languages.

Languages supported

Here's what we recommend reviewing to get your DeepL API application ready for production.

Pre-production checklist

Learn more about alpha and beta features in the DeepL API and how to best make use of them.

Alpha and beta features

Error handling

CORS requests

Translation context

Language detection

Subscription-level cost control

Learn how to translate XML content with the DeepL API.

XML handling

Learn how to work with structured XML content with the DeepL API.

Structured XML content

Learn how to customize XML outline detection with the DeepL API.

Customized XML outline detection

Learn how to translate HTML content with the DeepL API.

HTML handling

Brief summaries of recent DeepL API releases, such as support for new languages and document formats, new API parameters, and more.

Release notes

Here's what API users can expect when DeepL adds translation support for a new language or language variant.

API Reference

Upload and translate a document

Authorizations

Body

Response