mautrix-whatsapp/urlpreview.go

// mautrix-whatsapp - A Matrix-WhatsApp puppeting bridge.
// Copyright (C) 2022 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package main

import (
	"bytes"
	"context"
	"encoding/json"
	"image"
	"net/http"

	"github.com/tidwall/gjson"
	"google.golang.org/protobuf/proto"
	"maunium.net/go/mautrix/appservice"
	"maunium.net/go/mautrix/event"
	"maunium.net/go/mautrix/id"

	"go.mau.fi/whatsmeow"
	waProto "go.mau.fi/whatsmeow/binary/proto"
)

type BeeperLinkPreview struct {
	MatchedURL   string              `json:"matched_url"`
	CanonicalURL string              `json:"og:url,omitempty"`
	Title        string              `json:"og:title,omitempty"`
	Type         string              `json:"og:type,omitempty"`
	Description  string              `json:"og:description,omitempty"`
	Image        id.ContentURIString `json:"og:image,omitempty"`
	ImageWidth   int                 `json:"og:image:width,omitempty"`
	ImageHeight  int                 `json:"og:image:height,omitempty"`

	MatchedURLFallback string `json:"matchedUrl"`
}

func (portal *Portal) convertURLPreviewToBeeper(intent *appservice.IntentAPI, source *User, msg *waProto.ExtendedTextMessage) (output *BeeperLinkPreview) {
	if msg.GetMatchedText() == "" {
		return
	}

	output = &BeeperLinkPreview{
		MatchedURL:   msg.GetMatchedText(),
		CanonicalURL: msg.GetCanonicalUrl(),
		Title:        msg.GetTitle(),
		Description:  msg.GetDescription(),
	}
	output.MatchedURLFallback = output.MatchedURL
	if len(output.CanonicalURL) == 0 {
		output.CanonicalURL = output.MatchedURL
	}

	var thumbnailData []byte
	if msg.ThumbnailDirectPath != nil {
		var err error
		thumbnailData, err = source.Client.DownloadThumbnail(msg)
		if err != nil {
			portal.log.Warnfln("Failed to download thumbnail for link preview: %v", err)
		}
	} else if msg.JpegThumbnail != nil {
		thumbnailData = msg.JpegThumbnail
	}
	if thumbnailData != nil {
		mxc, err := intent.UploadBytes(thumbnailData, http.DetectContentType(thumbnailData))
		if err != nil {
			portal.log.Warnfln("Failed to reupload thumbnail for link preview: %v", err)
		} else {
			output.Image = mxc.ContentURI.CUString()
			output.ImageHeight = int(msg.GetThumbnailHeight())
			output.ImageWidth = int(msg.GetThumbnailWidth())
			if output.ImageHeight == 0 || output.ImageWidth == 0 {
				src, _, err := image.Decode(bytes.NewReader(thumbnailData))
				if err == nil {
					imageBounds := src.Bounds()
					output.ImageWidth, output.ImageHeight = imageBounds.Max.X, imageBounds.Max.Y
				}
			}
		}
	}
	if msg.GetPreviewType() == waProto.ExtendedTextMessage_VIDEO {
		output.Type = "video.other"
	}

	return
}

func (portal *Portal) convertURLPreviewToWhatsApp(sender *User, evt *event.Event, dest *waProto.ExtendedTextMessage) {
	rawPreview := gjson.GetBytes(evt.Content.VeryRaw, `com\.beeper\.linkpreview`)
	if !rawPreview.Exists() || !rawPreview.IsObject() {
		return
	}
	var preview BeeperLinkPreview
	if err := json.Unmarshal([]byte(rawPreview.Raw), &preview); err != nil {
		return
	}
	if len(preview.MatchedURL) == 0 {
		if len(preview.MatchedURLFallback) == 0 {
			return
		} else {
			preview.MatchedURL = preview.MatchedURLFallback
		}
	}

	dest.MatchedText = &preview.MatchedURL
	if len(preview.CanonicalURL) > 0 {
		dest.CanonicalUrl = &preview.CanonicalURL
	}
	if len(preview.Description) > 0 {
		dest.Description = &preview.Description
	}
	if len(preview.Title) > 0 {
		dest.Title = &preview.Title
	}
	imageMXC := preview.Image.ParseOrIgnore()
	if !imageMXC.IsEmpty() {
		data, err := portal.MainIntent().DownloadBytes(imageMXC)
		if err != nil {
			portal.log.Errorfln("Failed to download URL preview image %s: %v", preview.Image, err)
			return
		}
		uploadResp, err := sender.Client.Upload(context.Background(), data, whatsmeow.MediaLinkThumbnail)
		if err != nil {
			portal.log.Errorfln("Failed to upload URL preview thumbnail in %s: %v", evt.ID, err)
			return
		}
		dest.ThumbnailSha256 = uploadResp.FileSHA256
		dest.ThumbnailEncSha256 = uploadResp.FileEncSHA256
		dest.ThumbnailDirectPath = &uploadResp.DirectPath
		dest.MediaKey = uploadResp.MediaKey
		var width, height int
		dest.JpegThumbnail, width, height, err = createJPEGThumbnailAndGetSize(data)
		if err != nil {
			portal.log.Warnfln("Failed to create JPEG thumbnail for URL preview in %s: %v", evt.ID, err)
		}
		if preview.ImageHeight > 0 && preview.ImageWidth > 0 {
			dest.ThumbnailWidth = proto.Uint32(uint32(preview.ImageWidth))
			dest.ThumbnailHeight = proto.Uint32(uint32(preview.ImageHeight))
		} else if width > 0 && height > 0 {
			dest.ThumbnailWidth = proto.Uint32(uint32(width))
			dest.ThumbnailHeight = proto.Uint32(uint32(height))
		}
	}
}