From 512e977d0d2a58ae6f9b405f4e81ed133bc0a556 Mon Sep 17 00:00:00 2001
From: Sam <sam@nilptr.dev>
Date: Fri, 17 Jun 2022 15:49:16 +0200
Subject: [PATCH] feat: discord commands

---
 backend/routes.go         |   2 +
 backend/routes/bot/bot.go | 167 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 169 insertions(+)
 create mode 100644 backend/routes/bot/bot.go

diff --git a/backend/routes.go b/backend/routes.go
index a9159e8..d23f5f9 100644
--- a/backend/routes.go
+++ b/backend/routes.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"codeberg.org/u1f320/pronouns.cc/backend/routes/auth"
+	"codeberg.org/u1f320/pronouns.cc/backend/routes/bot"
 	"codeberg.org/u1f320/pronouns.cc/backend/routes/user"
 	"codeberg.org/u1f320/pronouns.cc/backend/server"
 	"github.com/go-chi/chi/v5"
@@ -14,5 +15,6 @@ func mountRoutes(s *server.Server) {
 	s.Router.Route("/v1", func(r chi.Router) {
 		auth.Mount(s, r)
 		user.Mount(s, r)
+		bot.Mount(s, r)
 	})
 }
diff --git a/backend/routes/bot/bot.go b/backend/routes/bot/bot.go
new file mode 100644
index 0000000..5d3b6aa
--- /dev/null
+++ b/backend/routes/bot/bot.go
@@ -0,0 +1,167 @@
+package bot
+
+import (
+	"crypto/ed25519"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"os"
+
+	"codeberg.org/u1f320/pronouns.cc/backend/db"
+	"codeberg.org/u1f320/pronouns.cc/backend/log"
+	"codeberg.org/u1f320/pronouns.cc/backend/server"
+	"github.com/bwmarrin/discordgo"
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/render"
+)
+
+type Bot struct {
+	*server.Server
+
+	publicKey ed25519.PublicKey
+	baseURL   string
+}
+
+func Mount(srv *server.Server, r chi.Router) {
+	publicKey, err := hex.DecodeString(os.Getenv("DISCORD_PUBLIC_KEY"))
+	if err != nil {
+		return
+	}
+
+	b := &Bot{
+		Server:    srv,
+		publicKey: publicKey,
+		baseURL:   os.Getenv("BASE_URL"),
+	}
+
+	r.HandleFunc("/interactions", b.handle)
+}
+
+func (bot *Bot) handle(w http.ResponseWriter, r *http.Request) {
+	if !discordgo.VerifyInteraction(r, bot.publicKey) {
+		http.Error(w, "Forbidden", http.StatusForbidden)
+		return
+	}
+
+	var ev *discordgo.InteractionCreate
+
+	if err := json.NewDecoder(r.Body).Decode(&ev); err != nil {
+		http.Error(w, "Bad Request", http.StatusBadRequest)
+	}
+
+	// we can always respond to ping with pong
+	if ev.Type == discordgo.InteractionPing {
+		log.Debug("received ping interaction")
+		render.JSON(w, r, discordgo.InteractionResponse{
+			Type: discordgo.InteractionResponsePong,
+		})
+		return
+	}
+
+	if ev.Type != discordgo.InteractionApplicationCommand {
+		return
+	}
+	data := ev.ApplicationCommandData()
+
+	switch data.Name {
+	case "Show user's pronouns":
+		bot.userPronouns(w, r, ev)
+	case "Show author's pronouns":
+	}
+}
+
+func (bot *Bot) userPronouns(w http.ResponseWriter, r *http.Request, ev *discordgo.InteractionCreate) {
+	ctx := r.Context()
+
+	var du *discordgo.User
+	for _, user := range ev.ApplicationCommandData().Resolved.Users {
+		du = user
+		break
+	}
+	if du == nil {
+		return
+	}
+
+	u, err := bot.DB.DiscordUser(ctx, du.ID)
+	if err != nil {
+		if err == db.ErrUserNotFound {
+			respond(w, r, &discordgo.MessageEmbed{
+				Description: du.String() + " does not have any pronouns set.",
+			})
+			return
+		}
+
+		log.Errorf("getting discord user: %v", err)
+		return
+	}
+
+	avatarURL := du.AvatarURL("")
+	if u.AvatarURL != nil {
+		avatarURL = *u.AvatarURL
+	}
+	name := u.Username
+	if u.DisplayName != nil {
+		name = fmt.Sprintf("%s (%s)", *u.DisplayName, u.Username)
+	}
+	url := bot.baseURL
+	if url != "" {
+		url += "/@" + u.Username
+	}
+
+	e := &discordgo.MessageEmbed{
+		Author: &discordgo.MessageEmbedAuthor{
+			Name:    name,
+			IconURL: avatarURL,
+			URL:     url,
+		},
+	}
+
+	if u.Bio != nil {
+		e.Fields = append(e.Fields, &discordgo.MessageEmbedField{
+			Name:  "Bio",
+			Value: *u.Bio,
+		})
+	}
+
+	fields, err := bot.DB.UserFields(ctx, u.ID)
+	if err != nil {
+		respond(w, r, e)
+
+		log.Errorf("getting user fields: %v", err)
+		return
+	}
+
+	for _, field := range fields {
+		if len(field.Favourite) == 0 {
+			continue
+		}
+
+		var value string
+		for _, fav := range field.Favourite {
+			if len(value) > 500 {
+				break
+			}
+
+			value += fav + "\n"
+		}
+
+		e.Fields = append(e.Fields, &discordgo.MessageEmbedField{
+			Name:   field.Name,
+			Value:  value,
+			Inline: true,
+		})
+	}
+
+	respond(w, r, e)
+}
+
+func respond(w http.ResponseWriter, r *http.Request, embeds ...*discordgo.MessageEmbed) {
+	render.JSON(w, r, discordgo.InteractionResponse{
+		Type: discordgo.InteractionResponseChannelMessageWithSource,
+		Data: &discordgo.InteractionResponseData{
+			Embeds: embeds,
+			Flags:  uint64(discordgo.MessageFlagsEphemeral),
+		},
+	})
+}