Confessions module

This commit adds a confessions feature that allows users to mark a
"confessional" channel and also to post anonymously to it. The changes
that this comprises of are as follows:

- New discord "slash" commands for both marking a confessional and
  posting to it
- a bunch of stuff in the discord module to register and deregister
  "slash" commands
- New event type to track marked confessionals
- confession module that processes new confession channel links
  and also posts confessions to corresponding confessionals

Not included in this commit:
- a way to cleanup obsolete or reconfigured confession channel links
- access control for the confessional slash commands

Signed-off-by: Ava Affine <ava@sunnypup.io>

internal/confession/confession.go

@@ -0,0 +1,58 @@
+package confession
+
+import (
+	"errors"
+	"sync"
+
+	"github.com/bwmarrin/discordgo"
+	"gitlab.com/whom/bingobot/internal/logging"
+	"gitlab.com/whom/bingobot/internal/state"
+)
+
+/* Activity module
+ * This module posts anonymous confessions according to a linked channel map
+ */
+
+const (
+	ActivityModuleStartFail = "failed to start activity module"
+)
+
+var (
+	// guild ID to channel ID
+	linkLock               sync.RWMutex
+	confessionChannelLinks map[string]state.ConfessionsChannelLinkEvent
+)
+
+func Start() error {
+	ch, err := state.ConfessionsChannelLink.Subscribe()
+	if err != nil {
+		return errors.Join(
+			errors.New(ActivityModuleStartFail),
+			err,
+		)
+	}
+
+	// process incoming events loop
+	go func() {
+		for {
+			ev := <- ch
+			e := ev.(state.ConfessionsChannelLinkEvent)
+			linkLock.Lock()
+			confessionChannelLinks[e.GuildID] = e
+			linkLock.Unlock()
+		}
+	}()
+
+	return nil
+}
+
+func MakeConfession(s *discordgo.Session, guildID string, content string) {
+	linkLock.RLock()
+	link, ok := confessionChannelLinks[guildID]
+	linkLock.RUnlock()
+	if !ok {
+		logging.Error("Failed to send confession in guild %s: no link exists in map", guildID)
+		return
+	}
+	s.ChannelMessageSend(link.ChannelID, content)
+}

internal/discord/commands.go

@@ -0,0 +1,112 @@
+package discord
+
+import (
+	"time"
+
+	"github.com/bwmarrin/discordgo"
+
+	"gitlab.com/whom/bingobot/internal/confession"
+	"gitlab.com/whom/bingobot/internal/logging"
+	"gitlab.com/whom/bingobot/internal/state"
+)
+
+var (
+	// map of guildID to registeredCommands
+	registeredCommands map[string][]*discordgo.ApplicationCommand
+
+	// all commands
+	commandList = []*discordgo.ApplicationCommand{
+		// TODO: Limit usage somehow?
+		// maybe delete this and use the vote module instead
+		&discordgo.ApplicationCommand{
+			Name: "confessional",
+			Description: "mark a channel as a designated confessional for a guild",
+		},
+
+		&discordgo.ApplicationCommand{
+			Name: "confess",
+			Description: "anonymously post a confession in configured channel",
+			Options: []*discordgo.ApplicationCommandOption{
+				&discordgo.ApplicationCommandOption{
+					Name: "confession",
+					Description: "A confession to be posted anonymously",
+					Required: true,
+				},
+			},
+		},
+	}
+
+	commandHandlers = map[string]func(
+		s *discordgo.Session, 
+		i *discordgo.InteractionCreate,
+	) {
+		"confessional": func(s *discordgo.Session, i *discordgo.InteractionCreate) {
+			state.PublishEvent(state.ConfessionsChannelLinkEvent{
+				GuildID: i.GuildID,
+				ChannelID: i.ChannelID,
+				Created: time.Now(),
+			})
+		},
+
+		// handle a confession
+		"confess": func(s *discordgo.Session, i *discordgo.InteractionCreate) {
+			for _, v := range i.ApplicationCommandData().Options {
+				if v.Name == "confession" {
+					confession.MakeConfession(s, i.GuildID, v.StringValue())
+				}
+			}
+		},
+	}
+)
+
+func handleCommand(s *discordgo.Session, e *discordgo.InteractionCreate) {
+	name := e.ApplicationCommandData().Name
+	// TODO: audit log
+	if h, ok := commandHandlers[name]; ok {
+		h(s, e)
+	} else {
+		logging.Debug("no handler for command: %s", name)
+	}
+}
+
+func registerCommands(s *discordgo.Session) {
+	for _, guild := range s.State.Guilds {
+		cmds, err := s.ApplicationCommandBulkOverwrite(
+			s.State.Application.ID,
+			guild.ID,
+			commandList,
+		)
+
+		if err != nil {
+			logging.Error(
+				"Failed to register commands for guild %s: %s",
+				guild.ID, err.Error(),
+			)
+		} else {
+			logging.Info("Registered commands for guild %s", guild.ID)
+			registeredCommands[guild.ID] = cmds
+		}
+	}
+}
+
+func deregisterCommands(s *discordgo.Session) {
+	for guild, commands := range registeredCommands {
+		for _, cmd := range commands {
+			if err := s.ApplicationCommandDelete(
+				s.State.Application.ID,
+				guild,
+				cmd.ID,
+			); err != nil {
+				logging.Error(
+					"Failed to delete %s command (id: %s) from guild %s",
+					cmd.Name, cmd.ID, guild,
+				)
+			} else {
+				logging.Info(
+					"Deregistered command %s (id: %s) from guild %s",
+					cmd.Name, cmd.ID, guild,
+				)
+			}
+		}
+	}
+}

internal/discord/discord.go

@@ -36,10 +36,13 @@ func Connect(token string) error {
 		return fmt.Errorf("failed to open discord session: %s", err)
 	}
 
+	registerCommands(session.s)
+
 	return nil
 }
 
 func Close() {
+	deregisterCommands(session.s)
 	err := session.s.Close()
 
 	if err != nil {

internal/discord/handlers.go

@@ -9,6 +9,7 @@ func addHandlers() {
 	session.s.AddHandler(handleConnect)
 	session.s.AddHandler(handleDisconnect)
 	session.s.AddHandler(handleVoiceStateUpdate)
+	session.s.AddHandler(handleCommand) // handles InteractionCreate
 }
 
 func handleConnect(s *discordgo.Session, e *discordgo.Connect) {

internal/state/events.go

@@ -226,3 +226,47 @@ func (te TestEvent) Validate() error {
 func (te TestEvent) Disposable() bool {
 	return te.Dispose
 }
+
+const (
+	ConfessionsLinkEventGuildKey    = "guild_id"
+	ConfessionsLinkEventChannelKey  = "channel_id"
+	ConfessionsLinkEventCreatedKey  = "created"
+	ConfessionsLinkEventObsoleteKey = "obsolete"
+
+	BadConfessionsLinkEventError    = "link event doesnt have required fields"
+)
+
+type ConfessionsChannelLinkEvent struct {
+	GuildID    string
+	ChannelID  string
+	Created    time.Time
+}
+
+func (e ConfessionsChannelLinkEvent) Type() EventType {
+	return ConfessionsChannelLink
+}
+
+func (e ConfessionsChannelLinkEvent) Time() time.Time {
+	return e.Time()
+}
+
+func (e ConfessionsChannelLinkEvent) Data() map[string]string {
+	return map[string]string{
+		ConfessionsLinkEventGuildKey:   e.GuildID,
+		ConfessionsLinkEventChannelKey: e.ChannelID,
+		ConfessionsLinkEventCreatedKey: e.Created.Format(time.RFC3339),
+	}
+}
+
+func (e ConfessionsChannelLinkEvent) Validate() error {
+	if len(e.ChannelID) > 1 || len(e.GuildID) > 1 {
+		return errors.New(BadConfessionsLinkEventError)
+	}
+
+	return nil
+}
+
+func (e ConfessionsChannelLinkEvent) Disposable() bool {
+	// TODO
+	return false
+}

internal/state/state.go

@@ -183,6 +183,7 @@ const (
 	Restoration
 	UserActive
 	Test
+	ConfessionsChannelLink
 	// ...
 
 	// leave this last
@@ -202,6 +203,8 @@ func EventTypeFromString(doc string) EventType {
 		return UserActive
 	case "Test":
 		return Test
+	case "ConfessionsChannelLink":
+		return ConfessionsChannelLink
 	default:
 		// error case
 		return NumEventTypes
@@ -215,6 +218,7 @@ func (et EventType) String() string {
 		"Restoration",
 		"UserActive",
 		"Test",
+		"ConfessionsChannelLink",
 	}
 
 	if et < 0 || et >= NumEventTypes {
@@ -266,24 +270,28 @@ func (et EventType) MakeEvent(data map[string]string) (Event, error) {
 	switch et {
 	case Vote:
 		return VoteEvent(data), nil
+
 	case Challenge:
 		e, err := MakeUserEvent(data)
 		if err != nil {
 			return nil, errors.Join(errors.New(BadChallengeEvent), err)
 		}
 		return ChallengeEvent{*e}, nil
+
 	case Restoration:
 		e, err := MakeUserEvent(data)
 		if err != nil {
 			return nil, errors.Join(errors.New(BadRestorationEvent), err)
 		}
 		return RestorationEvent{*e}, nil
+
 	case UserActive:
 		e, err := MakeUserEvent(data)
 		if err != nil {
 			return nil, errors.Join(errors.New(BadUserActiveEvent), err)
 		}
 		return UserActiveEvent{*e}, nil
+
 	case Test:
 		disp := false
 		if v, ok := data[TestEventDisposeKey]; ok && v == "t" {
@@ -300,6 +308,33 @@ func (et EventType) MakeEvent(data map[string]string) (Event, error) {
 			Dispose: disp,
 			ID:      id,
 		}, nil
+
+	case ConfessionsChannelLink:
+		gid, ok := data[ConfessionsLinkEventGuildKey]
+		if !ok {
+			return nil, errors.New(BadConfessionsLinkEventError)
+		}
+
+		cid, ok := data[ConfessionsLinkEventChannelKey]
+		if !ok {
+			return nil, errors.New(BadConfessionsLinkEventError)
+		}
+
+		ti, ok := data[ConfessionsLinkEventCreatedKey]
+		if !ok {
+			return nil, errors.New(BadConfessionsLinkEventError)
+		}
+		t, err := time.Parse(time.RFC3339, ti)
+		if err != nil {
+			return nil, errors.Join(errors.New(BadConfessionsLinkEventError), err)
+		}
+
+		return ConfessionsChannelLinkEvent{
+			GuildID: gid,
+			ChannelID: cid,
+			Created: t,
+		}, nil
+
 	default:
 		return nil, errors.New(BadEventTypeError)
 	}