/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

var { AppConstants } = ChromeUtils.importESModule(
  "resource://gre/modules/AppConstants.sys.mjs"
);
var { XPCOMUtils } = ChromeUtils.importESModule(
  "resource://gre/modules/XPCOMUtils.sys.mjs"
);

ChromeUtils.defineESModuleGetters(this, {
  BrowserUtils: "resource://gre/modules/BrowserUtils.sys.mjs",
  DownloadLastDir: "resource://gre/modules/DownloadLastDir.sys.mjs",
  DownloadPaths: "resource://gre/modules/DownloadPaths.sys.mjs",
  Downloads: "resource://gre/modules/Downloads.sys.mjs",
  FileUtils: "resource://gre/modules/FileUtils.sys.mjs",
  NetUtil: "resource://gre/modules/NetUtil.sys.mjs",
  PrivateBrowsingUtils: "resource://gre/modules/PrivateBrowsingUtils.sys.mjs",
});

var ContentAreaUtils = {
  get stringBundle() {
    delete this.stringBundle;
    return (this.stringBundle = Services.strings.createBundle(
      "chrome://global/locale/contentAreaCommands.properties"
    ));
  },
};

function urlSecurityCheck(
  aURL,
  aPrincipal,
  aFlags = Services.scriptSecurityManager
) {
  if (aURL instanceof Ci.nsIURI) {
    Services.scriptSecurityManager.checkLoadURIWithPrincipal(
      aPrincipal,
      aURL,
      aFlags
    );
  } else {
    Services.scriptSecurityManager.checkLoadURIStrWithPrincipal(
      aPrincipal,
      aURL,
      aFlags
    );
  }
}

// Clientele: (Make sure you don't break any of these)
//  - File    ->  Save Page/Frame As...
//  - Context ->  Save Page/Frame As...
//  - Context ->  Save Link As...
//  - Alt-Click links in web pages
//  - Alt-Click links in the UI
//
// Try saving each of these types:
// - A complete webpage using File->Save Page As, and Context->Save Page As
// - A webpage as HTML only using the above methods
// - A webpage as Text only using the above methods
// - An image with an extension (e.g. .jpg) in its file name, using
//   Context->Save Image As...
// - An image without an extension (e.g. a banner ad on cnn.com) using
//   the above method.
// - A linked document using Save Link As...
// - A linked document using Alt-click Save Link As...
//
function saveURL(
  aURL,
  aOriginalURL,
  aFileName,
  aFilePickerTitleKey,
  aShouldBypassCache,
  aSkipPrompt,
  aReferrerInfo,
  aCookieJarSettings,
  aSourceDocument,
  aIsContentWindowPrivate,
  aPrincipal
) {
  internalSave(
    aURL,
    aOriginalURL,
    null,
    aFileName,
    null,
    null,
    aShouldBypassCache,
    aFilePickerTitleKey,
    null,
    aReferrerInfo,
    aCookieJarSettings,
    aSourceDocument,
    aSkipPrompt,
    null,
    aIsContentWindowPrivate,
    aPrincipal
  );
}

// Save the current document inside any browser/frame-like element,
// whether in-process or out-of-process.
function saveBrowser(aBrowser, aSkipPrompt, aBrowsingContext = null) {
  if (!aBrowser) {
    throw new Error("Must have a browser when calling saveBrowser");
  }
  let persistable = aBrowser.frameLoader;
  // PDF.js has its own way to handle saving PDFs since it may need to
  // generate a new PDF to save modified form data.
  if (aBrowser.contentPrincipal.spec == "resource://pdf.js/web/viewer.html") {
    aBrowser.sendMessageToActor("PDFJS:Save", {}, "Pdfjs");
    return;
  }
  let stack = Components.stack.caller;
  persistable.startPersistence(aBrowsingContext, {
    onDocumentReady(document) {
      if (!document || !(document instanceof Ci.nsIWebBrowserPersistDocument)) {
        throw new Error("Must have an nsIWebBrowserPersistDocument!");
      }

      internalSave(
        document.documentURI,
        null, // originalURL
        document,
        null, // file name
        document.contentDisposition,
        document.contentType,
        false, // bypass cache
        null, // file picker title key
        null, // chosen file data
        document.referrerInfo,
        document.cookieJarSettings,
        document,
        aSkipPrompt,
        document.cacheKey
      );
    },
    onError(status) {
      throw new Components.Exception(
        "saveBrowser failed asynchronously in startPersistence",
        status,
        stack
      );
    },
  });
}

function DownloadListener(win, transfer) {
  function makeClosure(name) {
    return function () {
      transfer[name].apply(transfer, arguments);
    };
  }

  this.window = win;

  // Now... we need to forward all calls to our transfer
  for (var i in transfer) {
    if (i != "QueryInterface") {
      this[i] = makeClosure(i);
    }
  }
}

DownloadListener.prototype = {
  QueryInterface: ChromeUtils.generateQI([
    "nsIInterfaceRequestor",
    "nsIWebProgressListener",
    "nsIWebProgressListener2",
  ]),

  getInterface: function dl_gi(aIID) {
    if (aIID.equals(Ci.nsIAuthPrompt) || aIID.equals(Ci.nsIAuthPrompt2)) {
      var ww = Cc["@mozilla.org/embedcomp/window-watcher;1"].getService(
        Ci.nsIPromptFactory
      );
      return ww.getPrompt(this.window, aIID);
    }

    throw Components.Exception("", Cr.NS_ERROR_NO_INTERFACE);
  },
};

const kSaveAsType_Complete = 0; // Save document with attached objects.
XPCOMUtils.defineConstant(this, "kSaveAsType_Complete", 0);
// const kSaveAsType_URL      = 1; // Save document or URL by itself.
const kSaveAsType_Text = 2; // Save document, converting to plain text.
XPCOMUtils.defineConstant(this, "kSaveAsType_Text", kSaveAsType_Text);

/**
 * internalSave: Used when saving a document or URL.
 *
 * If aChosenData is null, this method:
 *  - Determines a local target filename to use
 *  - Prompts the user to confirm the destination filename and save mode
 *    (aContentType affects this)
 *  - [Note] This process involves the parameters aURL, aReferrerInfo,
 *    aDocument, aDefaultFileName, aFilePickerTitleKey, and aSkipPrompt.
 *
 * If aChosenData is non-null, this method:
 *  - Uses the provided source URI and save file name
 *  - Saves the document as complete DOM if possible (aDocument present and
 *    right aContentType)
 *  - [Note] The parameters aURL, aDefaultFileName, aFilePickerTitleKey, and
 *    aSkipPrompt are ignored.
 *
 * In any case, this method:
 *  - Creates a 'Persist' object (which will perform the saving in the
 *    background) and then starts it.
 *  - [Note] This part of the process only involves the parameters aDocument,
 *    aShouldBypassCache and aReferrerInfo. The source, the save name and the
 *    save mode are the ones determined previously.
 *
 * @param aURL
 *        The String representation of the URL of the document being saved
 * @param aOriginalURL
 *        The String representation of the original URL of the document being
 *        saved. It can useful in case aURL is a blob.
 * @param aDocument
 *        The document to be saved
 * @param aDefaultFileName
 *        The caller-provided suggested filename if we don't
 *        find a better one
 * @param aContentDisposition
 *        The caller-provided content-disposition header to use.
 * @param aContentType
 *        The caller-provided content-type to use
 * @param aShouldBypassCache
 *        If true, the document will always be refetched from the server
 * @param aFilePickerTitleKey
 *        Alternate title for the file picker
 * @param aChosenData
 *        If non-null this contains an instance of object AutoChosen (see below)
 *        which holds pre-determined data so that the user does not need to be
 *        prompted for a target filename.
 * @param aReferrerInfo
 *        the referrerInfo object to use, or null if no referrer should be sent.
 * @param aCookieJarSettings
 *        the cookieJarSettings object to use. This will be used for the channel
 *        used to save.
 * @param aInitiatingDocument [optional]
 *        The document from which the save was initiated.
 *        If this is omitted then aIsContentWindowPrivate has to be provided.
 * @param aSkipPrompt [optional]
 *        If set to true, we will attempt to save the file to the
 *        default downloads folder without prompting.
 * @param aCacheKey [optional]
 *        If set will be passed to saveURI.  See nsIWebBrowserPersist for
 *        allowed values.
 * @param aIsContentWindowPrivate [optional]
 *        This parameter is provided when the aInitiatingDocument is not a
 *        real document object. Stores whether aInitiatingDocument.defaultView
 *        was private or not.
 * @param aPrincipal [optional]
 *        This parameter is provided when neither aDocument nor
 *        aInitiatingDocument is provided. Used to determine what level of
 *        privilege to load the URI with.
 */
function internalSave(
  aURL,
  aOriginalURL,
  aDocument,
  aDefaultFileName,
  aContentDisposition,
  aContentType,
  aShouldBypassCache,
  aFilePickerTitleKey,
  aChosenData,
  aReferrerInfo,
  aCookieJarSettings,
  aInitiatingDocument,
  aSkipPrompt,
  aCacheKey,
  aIsContentWindowPrivate,
  aPrincipal
) {
  if (aSkipPrompt == undefined) {
    aSkipPrompt = false;
  }

  if (aCacheKey == undefined) {
    aCacheKey = 0;
  }

  // Note: aDocument == null when this code is used by save-link-as...
  var saveMode = GetSaveModeForContentType(aContentType, aDocument);

  var file, sourceURI, saveAsType;
  let contentPolicyType = Ci.nsIContentPolicy.TYPE_SAVEAS_DOWNLOAD;
  // Find the URI object for aURL and the FileName/Extension to use when saving.
  // FileName/Extension will be ignored if aChosenData supplied.
  if (aChosenData) {
    file = aChosenData.file;
    sourceURI = aChosenData.uri;
    saveAsType = kSaveAsType_Complete;

    continueSave();
  } else {
    var charset = null;
    if (aDocument) {
      charset = aDocument.characterSet;
    }
    var fileInfo = new FileInfo(aDefaultFileName);
    initFileInfo(
      fileInfo,
      aURL,
      charset,
      aDocument,
      aContentType,
      aContentDisposition
    );
    sourceURI = fileInfo.uri;

    if (aContentType && aContentType.startsWith("image/")) {
      contentPolicyType = Ci.nsIContentPolicy.TYPE_IMAGE;
    }
    var fpParams = {
      fpTitleKey: aFilePickerTitleKey,
      fileInfo,
      contentType: aContentType,
      saveMode,
      saveAsType: kSaveAsType_Complete,
      file,
    };

    // Find a URI to use for determining last-downloaded-to directory
    let relatedURI =
      aOriginalURL || aReferrerInfo?.originalReferrer || sourceURI;

    promiseTargetFile(fpParams, aSkipPrompt, relatedURI)
      .then(aDialogAccepted => {
        if (!aDialogAccepted) {
          return;
        }

        saveAsType = fpParams.saveAsType;
        file = fpParams.file;

        continueSave();
      })
      .catch(console.error);
  }

  function continueSave() {
    // XXX We depend on the following holding true in appendFiltersForContentType():
    // If we should save as a complete page, the saveAsType is kSaveAsType_Complete.
    // If we should save as text, the saveAsType is kSaveAsType_Text.
    var useSaveDocument =
      aDocument &&
      ((saveMode & SAVEMODE_COMPLETE_DOM &&
        saveAsType == kSaveAsType_Complete) ||
        (saveMode & SAVEMODE_COMPLETE_TEXT && saveAsType == kSaveAsType_Text));
    // If we're saving a document, and are saving either in complete mode or
    // as converted text, pass the document to the web browser persist component.
    // If we're just saving the HTML (second option in the list), send only the URI.

    let isPrivate = aIsContentWindowPrivate;
    if (isPrivate === undefined) {
      isPrivate =
        aInitiatingDocument.nodeType == 9 /* DOCUMENT_NODE */
          ? PrivateBrowsingUtils.isContentWindowPrivate(
              aInitiatingDocument.defaultView
            )
          : aInitiatingDocument.isPrivate;
    }

    // We have to cover the cases here where we were either passed an explicit
    // principal, or a 'real' document (with a nodePrincipal property), or an
    // nsIWebBrowserPersistDocument which has a principal property.
    let sourcePrincipal =
      aPrincipal ||
      (aDocument && (aDocument.nodePrincipal || aDocument.principal)) ||
      (aInitiatingDocument && aInitiatingDocument.nodePrincipal);

    let sourceOriginalURI = aOriginalURL ? makeURI(aOriginalURL) : null;

    var persistArgs = {
      sourceURI,
      sourceOriginalURI,
      sourcePrincipal,
      sourceReferrerInfo: aReferrerInfo,
      sourceDocument: useSaveDocument ? aDocument : null,
      targetContentType: saveAsType == kSaveAsType_Text ? "text/plain" : null,
      targetFile: file,
      sourceCacheKey: aCacheKey,
      sourcePostData: aDocument ? getPostData(aDocument) : null,
      bypassCache: aShouldBypassCache,
      contentPolicyType,
      cookieJarSettings: aCookieJarSettings,
      isPrivate,
    };

    // Start the actual save process
    internalPersist(persistArgs);
  }
}

/**
 * internalPersist: Creates a 'Persist' object (which will perform the saving
 *  in the background) and then starts it.
 *
 * @param persistArgs.sourceURI
 *        The nsIURI of the document being saved
 * @param persistArgs.sourceCacheKey [optional]
 *        If set will be passed to saveURI
 * @param persistArgs.sourceDocument [optional]
 *        The document to be saved, or null if not saving a complete document
 * @param persistArgs.sourceReferrerInfo
 *        Required and used only when persistArgs.sourceDocument is NOT present,
 *        the nsIReferrerInfo of the referrer info to use, or null if no
 *        referrer should be sent.
 * @param persistArgs.sourcePostData
 *        Required and used only when persistArgs.sourceDocument is NOT present,
 *        represents the POST data to be sent along with the HTTP request, and
 *        must be null if no POST data should be sent.
 * @param persistArgs.targetFile
 *        The nsIFile of the file to create
 * @param persistArgs.contentPolicyType
 *        The type of content we're saving. Will be used to determine what
 *        content is accepted, enforce sniffing restrictions, etc.
 * @param persistArgs.cookieJarSettings [optional]
 *        The nsICookieJarSettings that will be used for the saving channel, or
 *        null that saveURI will create one based on the current
 *        state of the prefs/permissions
 * @param persistArgs.targetContentType
 *        Required and used only when persistArgs.sourceDocument is present,
 *        determines the final content type of the saved file, or null to use
 *        the same content type as the source document. Currently only
 *        "text/plain" is meaningful.
 * @param persistArgs.bypassCache
 *        If true, the document will always be refetched from the server
 * @param persistArgs.isPrivate
 *        Indicates whether this is taking place in a private browsing context.
 */
function internalPersist(persistArgs) {
  var persist = makeWebBrowserPersist();

  // Calculate persist flags.
  const nsIWBP = Ci.nsIWebBrowserPersist;
  const flags = nsIWBP.PERSIST_FLAGS_REPLACE_EXISTING_FILES;
  if (persistArgs.bypassCache) {
    persist.persistFlags = flags | nsIWBP.PERSIST_FLAGS_BYPASS_CACHE;
  } else {
    persist.persistFlags = flags | nsIWBP.PERSIST_FLAGS_FROM_CACHE;
  }

  // Leave it to WebBrowserPersist to discover the encoding type (or lack thereof):
  persist.persistFlags |= nsIWBP.PERSIST_FLAGS_AUTODETECT_APPLY_CONVERSION;

  // Find the URI associated with the target file
  var targetFileURL = makeFileURI(persistArgs.targetFile);

  // Create download and initiate it (below)
  var tr = Cc["@mozilla.org/transfer;1"].createInstance(Ci.nsITransfer);
  tr.init(
    persistArgs.sourceURI,
    persistArgs.sourceOriginalURI,
    targetFileURL,
    "",
    null,
    null,
    null,
    persist,
    persistArgs.isPrivate,
    Ci.nsITransfer.DOWNLOAD_ACCEPTABLE,
    persistArgs.sourceReferrerInfo
  );
  persist.progressListener = new DownloadListener(window, tr);

  if (persistArgs.sourceDocument) {
    // Saving a Document, not a URI:
    var filesFolder = null;
    if (persistArgs.targetContentType != "text/plain") {
      // Create the local directory into which to save associated files.
      filesFolder = persistArgs.targetFile.clone();

      var nameWithoutExtension = getFileBaseName(filesFolder.leafName);
      var filesFolderLeafName =
        ContentAreaUtils.stringBundle.formatStringFromName("filesFolder", [
          nameWithoutExtension,
        ]);

      filesFolder.leafName = filesFolderLeafName;
    }

    var encodingFlags = 0;
    if (persistArgs.targetContentType == "text/plain") {
      encodingFlags |= nsIWBP.ENCODE_FLAGS_FORMATTED;
      encodingFlags |= nsIWBP.ENCODE_FLAGS_ABSOLUTE_LINKS;
      encodingFlags |= nsIWBP.ENCODE_FLAGS_NOFRAMES_CONTENT;
    } else {
      encodingFlags |= nsIWBP.ENCODE_FLAGS_ENCODE_BASIC_ENTITIES;
    }

    const kWrapColumn = 80;
    persist.saveDocument(
      persistArgs.sourceDocument,
      targetFileURL,
      filesFolder,
      persistArgs.targetContentType,
      encodingFlags,
      kWrapColumn
    );
  } else {
    persist.saveURI(
      persistArgs.sourceURI,
      persistArgs.sourcePrincipal,
      persistArgs.sourceCacheKey,
      persistArgs.sourceReferrerInfo,
      persistArgs.cookieJarSettings,
      persistArgs.sourcePostData,
      null,
      targetFileURL,
      persistArgs.contentPolicyType || Ci.nsIContentPolicy.TYPE_SAVEAS_DOWNLOAD,
      persistArgs.isPrivate
    );
  }
}

/**
 * Structure for holding info about automatically supplied parameters for
 * internalSave(...). This allows parameters to be supplied so the user does not
 * need to be prompted for file info.
 * @param aFileAutoChosen This is an nsIFile object that has been
 *        pre-determined as the filename for the target to save to
 * @param aUriAutoChosen  This is the nsIURI object for the target
 */
function AutoChosen(aFileAutoChosen, aUriAutoChosen) {
  this.file = aFileAutoChosen;
  this.uri = aUriAutoChosen;
}

/**
 * Structure for holding info about a URL and the target filename it should be
 * saved to. This structure is populated by initFileInfo(...).
 * @param aSuggestedFileName This is used by initFileInfo(...) when it
 *        cannot 'discover' the filename from the url
 * @param aFileName The target filename
 * @param aFileBaseName The filename without the file extension
 * @param aFileExt The extension of the filename
 * @param aUri An nsIURI object for the url that is being saved
 */
function FileInfo(
  aSuggestedFileName,
  aFileName,
  aFileBaseName,
  aFileExt,
  aUri
) {
  this.suggestedFileName = aSuggestedFileName;
  this.fileName = aFileName;
  this.fileBaseName = aFileBaseName;
  this.fileExt = aFileExt;
  this.uri = aUri;
}

/**
 * Determine what the 'default' filename string is, its file extension and the
 * filename without the extension. This filename is used when prompting the user
 * for confirmation in the file picker dialog.
 * @param aFI A FileInfo structure into which we'll put the results of this method.
 * @param aURL The String representation of the URL of the document being saved
 * @param aURLCharset The charset of aURL.
 * @param aDocument The document to be saved
 * @param aContentType The content type we're saving, if it could be
 *        determined by the caller.
 * @param aContentDisposition The content-disposition header for the object
 *        we're saving, if it could be determined by the caller.
 */
function initFileInfo(
  aFI,
  aURL,
  aURLCharset,
  aDocument,
  aContentType,
  aContentDisposition
) {
  try {
    let uriExt = null;
    // Get an nsIURI object from aURL if possible:
    try {
      aFI.uri = makeURI(aURL, aURLCharset);
      // Assuming nsiUri is valid, calling QueryInterface(...) on it will
      // populate extra object fields (eg filename and file extension).
      uriExt = aFI.uri.QueryInterface(Ci.nsIURL).fileExtension;
    } catch (e) {}

    // Get the default filename:
    let fileName = getDefaultFileName(
      aFI.suggestedFileName || aFI.fileName,
      aFI.uri,
      aDocument,
      aContentDisposition
    );

    let mimeService = this.getMIMEService();
    aFI.fileName = mimeService.validateFileNameForSaving(
      fileName,
      aContentType,
      mimeService.VALIDATE_FORCE_APPEND_EXTENSION
    );

    // If uriExt is blank, consider: aFI.suggestedFileName is supplied if
    // saveURL(...) was the original caller (hence both aContentType and
    // aDocument are blank). If they were saving a link to a website then make
    // the extension .htm .
    if (
      !uriExt &&
      !aDocument &&
      !aContentType &&
      /^http(s?):\/\//i.test(aURL)
    ) {
      aFI.fileExt = "htm";
      aFI.fileBaseName = aFI.fileName;
    } else {
      let idx = aFI.fileName.lastIndexOf(".");
      aFI.fileBaseName =
        idx >= 0 ? aFI.fileName.substring(0, idx) : aFI.fileName;
      aFI.fileExt = idx >= 0 ? aFI.fileName.substring(idx + 1) : null;
    }
  } catch (e) {}
}

/**
 * Given the Filepicker Parameters (aFpP), show the file picker dialog,
 * prompting the user to confirm (or change) the fileName.
 * @param aFpP
 *        A structure (see definition in internalSave(...) method)
 *        containing all the data used within this method.
 * @param aSkipPrompt
 *        If true, attempt to save the file automatically to the user's default
 *        download directory, thus skipping the explicit prompt for a file name,
 *        but only if the associated preference is set.
 *        If false, don't save the file automatically to the user's
 *        default download directory, even if the associated preference
 *        is set, but ask for the target explicitly.
 * @param aRelatedURI
 *        An nsIURI associated with the download. The last used
 *        directory of the picker is retrieved from/stored in the
 *        Content Pref Service using this URI.
 * @return Promise
 * @resolve a boolean. When true, it indicates that the file picker dialog
 *          is accepted.
 */
function promiseTargetFile(
  aFpP,
  /* optional */ aSkipPrompt,
  /* optional */ aRelatedURI
) {
  return (async function () {
    let downloadLastDir = new DownloadLastDir(window);
    let prefBranch = Services.prefs.getBranch("browser.download.");
    let useDownloadDir = prefBranch.getBoolPref("useDownloadDir");

    if (!aSkipPrompt) {
      useDownloadDir = false;
    }

    // Default to the user's default downloads directory configured
    // through download prefs.
    let dirPath = await Downloads.getPreferredDownloadsDirectory();
    let dirExists = await IOUtils.exists(dirPath);
    let dir = new FileUtils.File(dirPath);

    if (useDownloadDir && dirExists) {
      dir.append(aFpP.fileInfo.fileName);
      aFpP.file = uniqueFile(dir);
      return true;
    }

    // We must prompt for the file name explicitly.
    // If we must prompt because we were asked to...
    let file = null;
    if (!useDownloadDir) {
      file = await downloadLastDir.getFileAsync(aRelatedURI);
    }
    if (file && (await IOUtils.exists(file.path))) {
      dir = file;
      dirExists = true;
    }

    if (!dirExists) {
      // Default to desktop.
      dir = Services.dirsvc.get("Desk", Ci.nsIFile);
    }

    let fp = makeFilePicker();
    let titleKey = aFpP.fpTitleKey || "SaveLinkTitle";
    fp.init(
      window.browsingContext,
      ContentAreaUtils.stringBundle.GetStringFromName(titleKey),
      Ci.nsIFilePicker.modeSave
    );

    fp.displayDirectory = dir;
    fp.defaultExtension = aFpP.fileInfo.fileExt;
    fp.defaultString = aFpP.fileInfo.fileName;
    appendFiltersForContentType(
      fp,
      aFpP.contentType,
      aFpP.fileInfo.fileExt,
      aFpP.saveMode
    );

    // The index of the selected filter is only preserved and restored if there's
    // more than one filter in addition to "All Files".
    if (aFpP.saveMode != SAVEMODE_FILEONLY) {
      // eslint-disable-next-line mozilla/use-default-preference-values
      try {
        fp.filterIndex = prefBranch.getIntPref("save_converter_index");
      } catch (e) {}
    }

    let result = await new Promise(resolve => {
      fp.open(function (aResult) {
        resolve(aResult);
      });
    });
    if (result == Ci.nsIFilePicker.returnCancel || !fp.file) {
      return false;
    }

    if (aFpP.saveMode != SAVEMODE_FILEONLY) {
      prefBranch.setIntPref("save_converter_index", fp.filterIndex);
    }

    // Do not store the last save directory as a pref inside the private browsing mode
    downloadLastDir.setFile(aRelatedURI, fp.file.parent);

    aFpP.saveAsType = fp.filterIndex;
    aFpP.file = fp.file;
    aFpP.file.leafName = validateFileName(aFpP.file.leafName);

    return true;
  })();
}

// Since we're automatically downloading, we don't get the file picker's
// logic to check for existing files, so we need to do that here.
//
// Note - this code is identical to that in
//   mozilla/toolkit/mozapps/downloads/src/nsHelperAppDlg.js.in
// If you are updating this code, update that code too! We can't share code
// here since that code is called in a js component.
function uniqueFile(aLocalFile) {
  var collisionCount = 0;
  while (aLocalFile.exists()) {
    collisionCount++;
    if (collisionCount == 1) {
      // Append "(2)" before the last dot in (or at the end of) the filename
      // special case .ext.gz etc files so we don't wind up with .tar(2).gz
      if (aLocalFile.leafName.match(/\.[^\.]{1,3}\.(gz|bz2|Z)$/i)) {
        aLocalFile.leafName = aLocalFile.leafName.replace(
          /\.[^\.]{1,3}\.(gz|bz2|Z)$/i,
          "(2)$&"
        );
      } else {
        aLocalFile.leafName = aLocalFile.leafName.replace(
          /(\.[^\.]*)?$/,
          "(2)$&"
        );
      }
    } else {
      // replace the last (n) in the filename with (n+1)
      aLocalFile.leafName = aLocalFile.leafName.replace(
        /^(.*\()\d+\)/,
        "$1" + (collisionCount + 1) + ")"
      );
    }
  }
  return aLocalFile;
}

/**
 * Download a URL using the Downloads API.
 *
 * @param aURL
 *        the url to download
 * @param [optional] aFileName
 *        the destination file name, if omitted will be obtained from the url.
 * @param aInitiatingDocument
 *        The document from which the download was initiated.
 */
function DownloadURL(aURL, aFileName, aInitiatingDocument) {
  // For private browsing, try to get document out of the most recent browser
  // window, or provide our own if there's no browser window.
  let isPrivate = aInitiatingDocument.defaultView.docShell.QueryInterface(
    Ci.nsILoadContext
  ).usePrivateBrowsing;

  let fileInfo = new FileInfo(aFileName);
  initFileInfo(fileInfo, aURL, null, null, null, null);

  let filepickerParams = {
    fileInfo,
    saveMode: SAVEMODE_FILEONLY,
  };

  (async function () {
    let accepted = await promiseTargetFile(
      filepickerParams,
      true,
      fileInfo.uri
    );
    if (!accepted) {
      return;
    }

    let file = filepickerParams.file;
    let download = await Downloads.createDownload({
      source: { url: aURL, isPrivate },
      target: { path: file.path, partFilePath: file.path + ".part" },
    });
    download.tryToKeepPartialData = true;

    // Ignore errors because failures are reported through the download list.
    download.start().catch(() => {});

    // Add the download to the list, allowing it to be managed.
    let list = await Downloads.getList(Downloads.ALL);
    list.add(download);
  })().catch(console.error);
}

// We have no DOM, and can only save the URL as is.
const SAVEMODE_FILEONLY = 0x00;
XPCOMUtils.defineConstant(this, "SAVEMODE_FILEONLY", SAVEMODE_FILEONLY);
// We have a DOM and can save as complete.
const SAVEMODE_COMPLETE_DOM = 0x01;
XPCOMUtils.defineConstant(this, "SAVEMODE_COMPLETE_DOM", SAVEMODE_COMPLETE_DOM);
// We have a DOM which we can serialize as text.
const SAVEMODE_COMPLETE_TEXT = 0x02;
XPCOMUtils.defineConstant(
  this,
  "SAVEMODE_COMPLETE_TEXT",
  SAVEMODE_COMPLETE_TEXT
);

// If we are able to save a complete DOM, the 'save as complete' filter
// must be the first filter appended.  The 'save page only' counterpart
// must be the second filter appended.  And the 'save as complete text'
// filter must be the third filter appended.
function appendFiltersForContentType(
  aFilePicker,
  aContentType,
  aFileExtension,
  aSaveMode
) {
  // The bundle name for saving only a specific content type.
  var bundleName;
  // The corresponding filter string for a specific content type.
  var filterString;

  // Every case where GetSaveModeForContentType can return non-FILEONLY
  // modes must be handled here.
  if (aSaveMode != SAVEMODE_FILEONLY) {
    switch (aContentType) {
      case "text/html":
        bundleName = "WebPageHTMLOnlyFilter";
        filterString = "*.htm; *.html";
        break;

      case "application/xhtml+xml":
        bundleName = "WebPageXHTMLOnlyFilter";
        filterString = "*.xht; *.xhtml";
        break;

      case "image/svg+xml":
        bundleName = "WebPageSVGOnlyFilter";
        filterString = "*.svg; *.svgz";
        break;

      case "text/xml":
      case "application/xml":
        bundleName = "WebPageXMLOnlyFilter";
        filterString = "*.xml";
        break;
    }
  }

  if (!bundleName) {
    if (aSaveMode != SAVEMODE_FILEONLY) {
      throw new Error(`Invalid save mode for type '${aContentType}'`);
    }

    var mimeInfo = getMIMEInfoForType(aContentType, aFileExtension);
    if (mimeInfo) {
      var extString = "";
      for (var extension of mimeInfo.getFileExtensions()) {
        if (extString) {
          extString += "; ";
        } // If adding more than one extension,
        // separate by semi-colon
        extString += "*." + extension;
      }

      if (extString) {
        aFilePicker.appendFilter(mimeInfo.description, extString);
      }
    }
  }

  if (aSaveMode & SAVEMODE_COMPLETE_DOM) {
    aFilePicker.appendFilter(
      ContentAreaUtils.stringBundle.GetStringFromName("WebPageCompleteFilter"),
      filterString
    );
    // We should always offer a choice to save document only if
    // we allow saving as complete.
    aFilePicker.appendFilter(
      ContentAreaUtils.stringBundle.GetStringFromName(bundleName),
      filterString
    );
  }

  if (aSaveMode & SAVEMODE_COMPLETE_TEXT) {
    aFilePicker.appendFilters(Ci.nsIFilePicker.filterText);
  }

  // Always append the all files (*) filter
  aFilePicker.appendFilters(Ci.nsIFilePicker.filterAll);
}

function getPostData(aDocument) {
  if (aDocument instanceof Ci.nsIWebBrowserPersistDocument) {
    return aDocument.postData;
  }
  try {
    // Find the session history entry corresponding to the given document. In
    // the current implementation, nsIWebPageDescriptor.currentDescriptor always
    // returns a session history entry.
    let sessionHistoryEntry = aDocument.defaultView.docShell
      .QueryInterface(Ci.nsIWebPageDescriptor)
      .currentDescriptor.QueryInterface(Ci.nsISHEntry);
    return sessionHistoryEntry.postData;
  } catch (e) {}
  return null;
}

function makeWebBrowserPersist() {
  const persistContractID =
    "@mozilla.org/embedding/browser/nsWebBrowserPersist;1";
  const persistIID = Ci.nsIWebBrowserPersist;
  return Cc[persistContractID].createInstance(persistIID);
}

function makeURI(aURL, aOriginCharset, aBaseURI) {
  return Services.io.newURI(aURL, aOriginCharset, aBaseURI);
}

function makeFileURI(aFile) {
  return Services.io.newFileURI(aFile);
}

function makeFilePicker() {
  const fpContractID = "@mozilla.org/filepicker;1";
  const fpIID = Ci.nsIFilePicker;
  return Cc[fpContractID].createInstance(fpIID);
}

function getMIMEService() {
  const mimeSvcContractID = "@mozilla.org/mime;1";
  const mimeSvcIID = Ci.nsIMIMEService;
  const mimeSvc = Cc[mimeSvcContractID].getService(mimeSvcIID);
  return mimeSvc;
}

// Given aFileName, find the fileName without the extension on the end.
function getFileBaseName(aFileName) {
  // Remove the file extension from aFileName:
  return aFileName.replace(/\.[^.]*$/, "");
}

function getMIMETypeForURI(aURI) {
  try {
    return getMIMEService().getTypeFromURI(aURI);
  } catch (e) {}
  return null;
}

function getMIMEInfoForType(aMIMEType, aExtension) {
  if (aMIMEType || aExtension) {
    try {
      return getMIMEService().getFromTypeAndExtension(aMIMEType, aExtension);
    } catch (e) {}
  }
  return null;
}

function getDefaultFileName(
  aDefaultFileName,
  aURI,
  aDocument,
  aContentDisposition
) {
  // 1) look for a filename in the content-disposition header, if any
  if (aContentDisposition) {
    const mhpContractID = "@mozilla.org/network/mime-hdrparam;1";
    const mhpIID = Ci.nsIMIMEHeaderParam;
    const mhp = Cc[mhpContractID].getService(mhpIID);
    var dummy = { value: null }; // Need an out param...
    var charset = getCharsetforSave(aDocument);

    var fileName = null;
    try {
      fileName = mhp.getParameter(
        aContentDisposition,
        "filename",
        charset,
        true,
        dummy
      );
    } catch (e) {
      try {
        fileName = mhp.getParameter(
          aContentDisposition,
          "name",
          charset,
          true,
          dummy
        );
      } catch (e) {}
    }
    if (fileName) {
      return Services.textToSubURI.unEscapeURIForUI(
        fileName,
        /* dontEscape = */ true
      );
    }
  }

  let docTitle;
  if (aDocument && aDocument.title && aDocument.title.trim()) {
    // If the document looks like HTML or XML, try to use its original title.
    let contentType = aDocument.contentType;
    if (
      contentType == "application/xhtml+xml" ||
      contentType == "application/xml" ||
      contentType == "image/svg+xml" ||
      contentType == "text/html" ||
      contentType == "text/xml"
    ) {
      // 2) Use the document title
      return aDocument.title;
    }
  }

  try {
    var url = aURI.QueryInterface(Ci.nsIURL);
    if (url.fileName != "") {
      // 3) Use the actual file name, if present
      return Services.textToSubURI.unEscapeURIForUI(
        url.fileName,
        /* dontEscape = */ true
      );
    }
  } catch (e) {
    // This is something like a data: and so forth URI... no filename here.
  }

  // Don't use the title if it's from a data URI
  if (docTitle && aURI?.scheme != "data") {
    // 4) Use the document title
    return docTitle;
  }

  if (aDefaultFileName) {
    // 5) Use the caller-provided name, if any
    return aDefaultFileName;
  }

  try {
    if (aURI.host) {
      // 6) Use the host.
      return aURI.host;
    }
  } catch (e) {
    // Some files have no information at all, like Javascript generated pages
  }

  return "";
}

// This is only used after the user has entered a filename.
function validateFileName(aFileName) {
  let processed =
    DownloadPaths.sanitize(aFileName, {
      compressWhitespaces: false,
      allowInvalidFilenames: true,
    }) || "_";
  if (AppConstants.platform == "android") {
    // If a large part of the filename has been sanitized, then we
    // will use a default filename instead
    if (processed.replace(/_/g, "").length <= processed.length / 2) {
      // We purposefully do not use a localized default filename,
      // which we could have done using
      // ContentAreaUtils.stringBundle.GetStringFromName("UntitledSaveFileName")
      // since it may contain invalid characters.
      var original = processed;
      processed = "download";

      // Preserve a suffix, if there is one
      if (original.includes(".")) {
        var suffix = original.split(".").slice(-1)[0];
        if (suffix && !suffix.includes("_")) {
          processed += "." + suffix;
        }
      }
    }
  }
  return processed;
}

function GetSaveModeForContentType(aContentType, aDocument) {
  // We can only save a complete page if we have a loaded document,
  if (!aDocument) {
    return SAVEMODE_FILEONLY;
  }

  // Find the possible save modes using the provided content type
  var saveMode = SAVEMODE_FILEONLY;
  switch (aContentType) {
    case "text/html":
    case "application/xhtml+xml":
    case "image/svg+xml":
      saveMode |= SAVEMODE_COMPLETE_TEXT;
    // Fall through
    case "text/xml":
    case "application/xml":
      saveMode |= SAVEMODE_COMPLETE_DOM;
      break;
  }

  return saveMode;
}

function getCharsetforSave(aDocument) {
  if (aDocument) {
    return aDocument.characterSet;
  }

  if (document.commandDispatcher.focusedWindow) {
    return document.commandDispatcher.focusedWindow.document.characterSet;
  }

  return window.content.document.characterSet;
}

/**
 * Open a URL from chrome, determining if we can handle it internally or need to
 *  launch an external application to handle it.
 * @param aURL The URL to be opened
 *
 * WARNING: Please note that openURL() does not perform any content security checks!!!
 */
function openURL(aURL) {
  var uri = aURL instanceof Ci.nsIURI ? aURL : makeURI(aURL);

  var protocolSvc = Cc[
    "@mozilla.org/uriloader/external-protocol-service;1"
  ].getService(Ci.nsIExternalProtocolService);

  let recentWindow = Services.wm.getMostRecentWindow("navigator:browser");

  if (!protocolSvc.isExposedProtocol(uri.scheme)) {
    // If we're not a browser, use the external protocol service to load the URI.
    protocolSvc.loadURI(uri, recentWindow?.document.contentPrincipal);
  } else {
    if (recentWindow) {
      recentWindow.openWebLinkIn(uri.spec, "tab", {
        triggeringPrincipal: recentWindow.document.contentPrincipal,
      });
      return;
    }

    var loadgroup = Cc["@mozilla.org/network/load-group;1"].createInstance(
      Ci.nsILoadGroup
    );
    var appstartup = Services.startup;

    var loadListener = {
      onStartRequest: function ll_start(aRequest) {
        appstartup.enterLastWindowClosingSurvivalArea();
      },
      onStopRequest: function ll_stop(aRequest, aStatusCode) {
        appstartup.exitLastWindowClosingSurvivalArea();
      },
      QueryInterface: ChromeUtils.generateQI([
        "nsIRequestObserver",
        "nsISupportsWeakReference",
      ]),
    };
    loadgroup.groupObserver = loadListener;

    var uriListener = {
      doContent(ctype, preferred, request, handler) {
        return false;
      },
      isPreferred(ctype, desired) {
        return false;
      },
      canHandleContent(ctype, preferred, desired) {
        return false;
      },
      loadCookie: null,
      parentContentListener: null,
      getInterface(iid) {
        if (iid.equals(Ci.nsIURIContentListener)) {
          return this;
        }
        if (iid.equals(Ci.nsILoadGroup)) {
          return loadgroup;
        }
        throw Components.Exception("", Cr.NS_ERROR_NO_INTERFACE);
      },
    };

    var channel = NetUtil.newChannel({
      uri,
      loadUsingSystemPrincipal: true,
    });

    if (channel) {
      channel.channelIsForDownload = true;
    }

    var uriLoader = Cc["@mozilla.org/uriloader;1"].getService(Ci.nsIURILoader);
    uriLoader.openURI(
      channel,
      Ci.nsIURILoader.IS_CONTENT_PREFERRED,
      uriListener
    );
  }
}