feat(handler): add a expand handler (#5)

.gitignore

@@ -8,3 +8,6 @@
 *.out
 go.work
 go.work.sum
+
+# environment
+.env

go.mod

@@ -5,12 +5,36 @@ go 1.23.4
 require (
 	github.com/bwmarrin/discordgo v0.28.1
 	github.com/rs/xid v1.6.0
+	github.com/samber/oops v1.15.0
+	github.com/spf13/cobra v1.8.1
+	github.com/spf13/viper v1.19.0
 	go.uber.org/zap v1.27.0
 )
 
 require (
+	github.com/fsnotify/fsnotify v1.7.0 // indirect
 	github.com/gorilla/websocket v1.4.2 // indirect
+	github.com/hashicorp/hcl v1.0.0 // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/magiconair/properties v1.8.7 // indirect
+	github.com/mitchellh/mapstructure v1.5.0 // indirect
+	github.com/oklog/ulid/v2 v2.1.0 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.2 // indirect
+	github.com/sagikazarmark/locafero v0.4.0 // indirect
+	github.com/sagikazarmark/slog-shim v0.1.0 // indirect
+	github.com/samber/lo v1.47.0 // indirect
+	github.com/sourcegraph/conc v0.3.0 // indirect
+	github.com/spf13/afero v1.11.0 // indirect
+	github.com/spf13/cast v1.6.0 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/subosito/gotenv v1.6.0 // indirect
+	go.opentelemetry.io/otel v1.29.0 // indirect
+	go.opentelemetry.io/otel/trace v1.29.0 // indirect
 	go.uber.org/multierr v1.10.0 // indirect
-	golang.org/x/crypto v0.0.0-20210421170649-83a5a9bb288b // indirect
-	golang.org/x/sys v0.0.0-20201119102817-f84b799fce68 // indirect
+	golang.org/x/crypto v0.21.0 // indirect
+	golang.org/x/exp v0.0.0-20230905200255-921286631fa9 // indirect
+	golang.org/x/sys v0.18.0 // indirect
+	golang.org/x/text v0.16.0 // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,28 +1,104 @@
 github.com/bwmarrin/discordgo v0.28.1 h1:gXsuo2GBO7NbR6uqmrrBDplPUx2T3nzu775q/Rd1aG4=
 github.com/bwmarrin/discordgo v0.28.1/go.mod h1:NJZpH+1AfhIcyQsPeuBKsUtYrRnjkyu0kIVMCHkZtRY=
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/cpuguy83/go-md2man/v2 v2.0.4/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
+github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
+github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
+github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
+github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=
 github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
-github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/hashicorp/hcl v1.0.0 h1:0Anlzjpi4vEasTeNFn2mLJgTSwt0+6sfsiTG8qcWGx4=
+github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
+github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
+github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/magiconair/properties v1.8.7 h1:IeQXZAiQcpL9mgcAe1Nu6cX9LLw6ExEHKjN0VQdvPDY=
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+github.com/oklog/ulid/v2 v2.1.0 h1:+9lhoxAP56we25tyYETBBY1YLA2SaoLvUFgrP2miPJU=
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+github.com/pborman/getopt v0.0.0-20170112200414-7148bc3a4c30/go.mod h1:85jBQOZwpVEaDAr341tbn15RS4fCAsIst0qp7i8ex1o=
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 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
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+github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
+github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/rs/xid v1.6.0 h1:fV591PaemRlL6JfRxGDEPl69wICngIQ3shQtzfy2gxU=
 github.com/rs/xid v1.6.0/go.mod h1:7XoLgs4eV+QndskICGsho+ADou8ySMSjJKDIan90Nz0=
-github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
-github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
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 golang.org/x/crypto v0.0.0-20210421170649-83a5a9bb288b/go.mod h1:T9bdIzuCu7OtxOm1hfPfRQxPLYneinmdGuTeoZ9dtd4=
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 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
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 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/app/handler/message_link.go

@@ -0,0 +1,161 @@
+package handler
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"regexp"
+	"time"
+
+	"github.com/aqyuki/felm/internal/app/rule"
+	"github.com/aqyuki/felm/pkg/discord"
+	"github.com/aqyuki/felm/pkg/logging"
+	"github.com/aqyuki/felm/pkg/trace"
+	"github.com/bwmarrin/discordgo"
+	"github.com/samber/oops"
+	"go.uber.org/zap"
+)
+
+var _ discord.MessageCreateHandler = ExpandMessageLink
+
+var ErrMessageLinkNotFound = errors.New("message link not found")
+
+func ExpandMessageLink(ctx context.Context, session *discordgo.Session, message *discordgo.MessageCreate) error {
+	logger := logging.FromContext(ctx)
+
+	logger.Info("handler called",
+		zap.String("trace_id", trace.AcquireTraceID(ctx)),
+		zap.Dict("message",
+			zap.String("guild_id", message.GuildID),
+			zap.String("channel_id", message.ChannelID),
+			zap.String("message_id", message.ID),
+			zap.Dict("author",
+				zap.String("id", message.Author.ID),
+				zap.String("username", message.Author.Username),
+				zap.Bool("is_bot", message.Author.Bot),
+			)))
+
+	if rule.IsBot(message.Author) {
+		logger.Debug("skip processing message because it was sent by bot")
+		return nil
+	}
+
+	ids, err := parseMessageLink(message.Content)
+	if err != nil {
+		if errors.Is(err, ErrMessageLinkNotFound) {
+			logger.Debug("skip processing message because message link not found")
+			return nil
+		}
+		return oops.
+			Trace(trace.AcquireTraceID(ctx)).
+			With("message",
+				oops.With("guild_id", message.GuildID),
+				oops.With("channel_id", message.ChannelID),
+				oops.With("message_id", message.ID)).
+			Wrapf(err, "error occurred while parsing message link (message_id = %s)", message.ID)
+	}
+
+	logger.Info("message link detected",
+		zap.Dict("message_link",
+			zap.String("guild_id", ids.guildID),
+			zap.String("channel_id", ids.channelID),
+			zap.String("message_id", ids.messageID)))
+
+	if !rule.IsSameGuild(ids.guildID, message) {
+		logger.Debug("skip processing message because it was sent from different guild")
+		return nil
+	}
+
+	sourceChannel, err := session.Channel(message.ChannelID)
+	if err != nil {
+		return oops.
+			Trace(trace.AcquireTraceID(ctx)).
+			With("message_detail",
+				oops.With("guild_id", message.GuildID),
+				oops.With("channel_id", message.ChannelID),
+				oops.With("message_id", message.ID)).
+			Wrapf(err, "error occurred while fetching channel information (channel_id = %s)", message.ChannelID)
+	}
+
+	if rule.IsNSFW(sourceChannel) {
+		logger.Debug("skip processing message because it was sent from NSFW channel", zap.String("message_id", message.ID))
+		return nil
+	}
+
+	sourceMessage, err := session.ChannelMessage(ids.channelID, ids.messageID)
+	if err != nil {
+		return oops.
+			Trace(trace.AcquireTraceID(ctx)).
+			With("message_detail",
+				oops.With("guild_id", message.GuildID),
+				oops.With("channel_id", message.ChannelID),
+				oops.With("message_id", message.ID)).
+			Wrapf(err, "error occurred while fetching message information (channel_id = %s, message_id = %s)", ids.channelID, ids.messageID)
+	}
+
+	if !rule.IsExpandable(sourceMessage) {
+		logger.Debug("skip processing message because it was not expandable", zap.String("message_id", message.ID))
+		return nil
+	}
+
+	embed := emptyEmbed(sourceChannel, sourceMessage)
+	if rule.HasContent(sourceMessage) {
+		embed.Description = sourceMessage.Content
+	}
+	if rule.HasImage(sourceMessage) {
+		embed.Image = &discordgo.MessageEmbedImage{
+			URL: sourceMessage.Attachments[0].URL,
+		}
+	}
+
+	replyMsg := &discordgo.MessageSend{
+		Embed:           embed,
+		Reference:       message.Reference(),
+		AllowedMentions: &discordgo.MessageAllowedMentions{RepliedUser: true},
+	}
+	if _, err := session.ChannelMessageSendComplex(message.ChannelID, replyMsg); err != nil {
+		return oops.
+			Trace(trace.AcquireTraceID(ctx)).
+			With("message_detail",
+				oops.With("guild_id", message.GuildID),
+				oops.With("channel_id", message.ChannelID),
+				oops.With("message_id", message.ID)).
+			Wrapf(err, "error occurred while sending message (channel_id = %s)", message.ChannelID)
+	}
+	return nil
+}
+
+var messageRegex = regexp.MustCompile(`https://(?:ptb\.|canary\.)?discord\.com/channels/(?P<guild_id>\d+)/(?P<channel_id>\d+)/(?P<message_id>\d+)`)
+
+type messageLink struct {
+	guildID   string
+	channelID string
+	messageID string
+}
+
+func parseMessageLink(message string) (*messageLink, error) {
+	matches := messageRegex.FindStringSubmatch(message)
+	if len(matches) == 0 {
+		return nil, ErrMessageLinkNotFound
+	}
+
+	return &messageLink{
+		guildID:   matches[messageRegex.SubexpIndex("guild_id")],
+		channelID: matches[messageRegex.SubexpIndex("channel_id")],
+		messageID: matches[messageRegex.SubexpIndex("message_id")],
+	}, nil
+}
+
+func emptyEmbed(channel *discordgo.Channel, message *discordgo.Message) *discordgo.MessageEmbed {
+	return &discordgo.MessageEmbed{
+		Author: &discordgo.MessageEmbedAuthor{
+			Name:    message.Author.Username,
+			IconURL: message.Author.AvatarURL(""),
+		},
+		Color:     0x7fffff,
+		Timestamp: message.Timestamp.Format(time.RFC3339),
+		Footer: &discordgo.MessageEmbedFooter{
+			Text: fmt.Sprintf("from %s", channel.Name),
+		},
+	}
+}

internal/app/profile.go

@@ -0,0 +1,10 @@
+package app
+
+import (
+	"time"
+)
+
+type Profile struct {
+	Token   string
+	Timeout time.Duration
+}

internal/app/rule/common.go

@@ -0,0 +1,27 @@
+package rule
+
+import "github.com/bwmarrin/discordgo"
+
+func IsBot(author *discordgo.User) bool {
+	return author.Bot
+}
+
+func IsSameGuild(guild string, msg *discordgo.MessageCreate) bool {
+	return msg.GuildID == guild
+}
+
+func IsNSFW(channel *discordgo.Channel) bool {
+	return channel.NSFW
+}
+
+func IsExpandable(message *discordgo.Message) bool {
+	return HasContent(message) || HasImage(message)
+}
+
+func HasContent(message *discordgo.Message) bool {
+	return message.Content != ""
+}
+
+func HasImage(message *discordgo.Message) bool {
+	return len(message.Attachments) != 0
+}