Add video picker and Discord video attachments.

The picker accepts one MP4 or WebM, the thread lightbox zooms photos, and Discord gets the video as a file on a follow-up message so photo embeds still render.

internal/discord/api.go

@@ -2,6 +2,7 @@ package discord
 
 import (
 	"context"
+	"strings"
 
 	"github.com/bwmarrin/discordgo"
 )
@@ -63,14 +64,27 @@ func (s *sessionAPI) Close() error {
 }
 
 func toMessageSend(msg Message) *discordgo.MessageSend {
+	var files []*discordgo.File
+	for _, f := range msg.Files {
+		files = append(files, &discordgo.File{
+			Name:        f.Name,
+			ContentType: f.ContentType,
+			Reader:      f.Reader,
+		})
+	}
 	return &discordgo.MessageSend{
 		Content:         messageContent(msg),
 		Embeds:          toEmbeds(msg),
+		Files:           files,
 		AllowedMentions: &discordgo.MessageAllowedMentions{},
 	}
 }
 
 func toEmbeds(msg Message) []*discordgo.MessageEmbed {
+	imageURLs := embedImageURLs(msg)
+	if msg.Title == "" && msg.Description == "" && msg.City == "" && msg.Author == "" && len(imageURLs) == 0 {
+		return nil
+	}
 	main := &discordgo.MessageEmbed{
 		Title:       msg.Title,
 		URL:         publicURL(msg.URL),
@@ -92,7 +106,7 @@ func toEmbeds(msg Message) []*discordgo.MessageEmbed {
 		})
 	}
 	embeds := []*discordgo.MessageEmbed{main}
-	for i, url := range msg.ImageURLs {
+	for i, url := range imageURLs {
 		if i == 0 {
 			main.Image = &discordgo.MessageEmbedImage{URL: url}
 			continue
@@ -104,3 +118,16 @@ func toEmbeds(msg Message) []*discordgo.MessageEmbed {
 	}
 	return embeds
 }
+
+func embedImageURLs(msg Message) []string {
+	var attached []string
+	for _, f := range msg.Files {
+		if strings.HasPrefix(f.ContentType, "image/") {
+			attached = append(attached, "attachment://"+f.Name)
+		}
+	}
+	if len(attached) > 0 {
+		return attached
+	}
+	return msg.ImageURLs
+}