Delete stuff on message delete

still need to do bulk delete

src/discord/gateway.go

@@ -557,11 +557,14 @@ func (bot *botInstance) processEventMsg(ctx context.Context, msg *GatewayMessage
 		if err != nil {
 			return oops.New(err, "error on updated message")
 		}
+	case "MESSAGE_DELETE":
+		bot.messageDelete(ctx, MessageDeleteFromMap(msg.Data))
 	}
 
 	return nil
 }
 
+// TODO: Should this return an error? Or just log errors?
 func (bot *botInstance) messageCreateOrUpdate(ctx context.Context, msg *Message) error {
 	if msg.OriginalHasFields("author") && msg.Author.ID == config.Config.Discord.BotUserID {
 		// Don't process your own messages
@@ -587,6 +590,78 @@ func (bot *botInstance) messageCreateOrUpdate(ctx context.Context, msg *Message)
 	return nil
 }
 
+func (bot *botInstance) messageDelete(ctx context.Context, msgDelete MessageDelete) {
+	log := logging.ExtractLogger(ctx)
+
+	tx, err := bot.dbConn.Begin(ctx)
+	if err != nil {
+		log.Error().Err(err).Msg("failed to start transaction")
+		return
+	}
+	defer tx.Rollback(ctx)
+
+	type deleteMessageQuery struct {
+		Message     models.DiscordMessage `db:"msg"`
+		DiscordUser *models.DiscordUser   `db:"duser"`
+		HMNUser     *models.User          `db:"hmnuser"`
+		SnippetID   *int                  `db:"snippet.id"`
+	}
+	iresult, err := db.QueryOne(ctx, tx, deleteMessageQuery{},
+		`
+		SELECT $columns
+		FROM
+			handmade_discordmessage AS msg
+			LEFT JOIN handmade_discorduser AS duser ON msg.user_id = duser.userid
+			LEFT JOIN auth_user AS hmnuser ON duser.hmn_user_id = hmnuser.id
+			LEFT JOIN handmade_snippet AS snippet ON snippet.discord_message_id = msg.id
+		WHERE msg.id = $1 AND msg.channel_id = $2
+		`,
+		msgDelete.ID, msgDelete.ChannelID,
+	)
+	if errors.Is(err, db.ErrNoMatchingRows) {
+		return
+	} else if err != nil {
+		log.Error().Err(err).Msg("failed to check for message to delete")
+		return
+	}
+	result := iresult.(*deleteMessageQuery)
+
+	log.Debug().Msg("deleting Discord message")
+	_, err = tx.Exec(ctx,
+		`
+		DELETE FROM handmade_discordmessage
+		WHERE id = $1 AND channel_id = $2
+		`,
+		msgDelete.ID,
+		msgDelete.ChannelID,
+	)
+
+	shouldDeleteSnippet := result.HMNUser != nil && result.HMNUser.DiscordDeleteSnippetOnMessageDelete
+	if result.SnippetID != nil && shouldDeleteSnippet {
+		log.Debug().
+			Int("snippet_id", *result.SnippetID).
+			Int("user_id", result.HMNUser.ID).
+			Msg("deleting snippet from Discord message")
+		_, err = tx.Exec(ctx,
+			`
+			DELETE FROM handmade_snippet
+			WHERE id = $1
+			`,
+			result.SnippetID,
+		)
+		if err != nil {
+			log.Error().Err(err).Msg("failed to delete snippet")
+			return
+		}
+	}
+
+	err = tx.Commit(ctx)
+	if err != nil {
+		log.Error().Err(err).Msg("failed to delete Discord message")
+		return
+	}
+}
+
 type MessageToSend struct {
 	ChannelID string
 	Req       CreateMessageRequest

src/discord/payloads.go

@@ -110,6 +110,23 @@ type Resume struct {
 	SequenceNumber int    `json:"seq"`
 }
 
+// https://discord.com/developers/docs/topics/gateway#message-delete
+type MessageDelete struct {
+	ID        string `json:"id"`
+	ChannelID string `json:"channel_id"`
+	GuildID   string `json:"guild_id"`
+}
+
+func MessageDeleteFromMap(m interface{}) MessageDelete {
+	mmap := m.(map[string]interface{})
+
+	return MessageDelete{
+		ID:        mmap["id"].(string),
+		ChannelID: mmap["channel_id"].(string),
+		GuildID:   maybeString(mmap, "guild_id"),
+	}
+}
+
 type ChannelType int
 
 // https://discord.com/developers/docs/resources/channel#channel-object-channel-types

src/discord/todo.txt

@@ -7,9 +7,9 @@ stuff we need to worry about:
 - posts that come in while the bot is down
 - what to do with posts if you unlink your account
 - what to do with posts if you re-link your account
-- what to do if you edit the original discord message
+✔ - what to do if you edit the original discord message
 - what to do if you delete the original discord message
-- the user's preferences re: saving content
+✔ - the user's preferences re: saving content
     - we don't want to save content without the user's consent, especially since it may persist after they disable the integration
 - manually adding content for various reasons
     - maybe a bug prevented something from saving
@@ -17,10 +17,10 @@ stuff we need to worry about:
 
 
 real-time stuff:
-- on new showcase message
+✔ - on new showcase message
     - always save the lightweight record
     - if we have permission, create a snippet
-- on edit
+✔ - on edit
     - re-save the lightweight record and content as if it was new
     - create snippet, unconditionally???? (bug??)
     - update snippet contents if the edit makes sense

src/migration/migrations/2021-08-26T005607Z_FixSnippetConstraints.go

@@ -0,0 +1,49 @@
+package migrations
+
+import (
+	"context"
+	"time"
+
+	"git.handmade.network/hmn/hmn/src/migration/types"
+	"git.handmade.network/hmn/hmn/src/oops"
+	"github.com/jackc/pgx/v4"
+)
+
+func init() {
+	registerMigration(FixSnippetConstraints{})
+}
+
+type FixSnippetConstraints struct{}
+
+func (m FixSnippetConstraints) Version() types.MigrationVersion {
+	return types.MigrationVersion(time.Date(2021, 8, 26, 0, 56, 7, 0, time.UTC))
+}
+
+func (m FixSnippetConstraints) Name() string {
+	return "FixSnippetConstraints"
+}
+
+func (m FixSnippetConstraints) Description() string {
+	return "Fix the ON DELETE behaviors of snippets"
+}
+
+func (m FixSnippetConstraints) Up(ctx context.Context, tx pgx.Tx) error {
+	_, err := tx.Exec(ctx, `
+		ALTER TABLE handmade_snippet
+			DROP CONSTRAINT handmade_snippet_asset_id_c786de4f_fk_handmade_asset_id,
+			DROP CONSTRAINT handmade_snippet_discord_message_id_d16f1f4e_fk_handmade_,
+			DROP CONSTRAINT handmade_snippet_owner_id_fcca1783_fk_auth_user_id,
+			ADD FOREIGN KEY (asset_id) REFERENCES handmade_asset (id) ON DELETE SET NULL,
+			ADD FOREIGN KEY (discord_message_id) REFERENCES handmade_discordmessage (id) ON DELETE SET NULL,
+			ADD FOREIGN KEY (owner_id) REFERENCES auth_user (id) ON DELETE CASCADE;
+	`)
+	if err != nil {
+		return oops.New(err, "failed to fix constraints")
+	}
+
+	return nil
+}
+
+func (m FixSnippetConstraints) Down(ctx context.Context, tx pgx.Tx) error {
+	panic("Implement me")
+}