feat(channels): add email channel with SMTP outbound and IMAP polling inbound

Closes #8

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

go.mod

@@ -71,6 +71,9 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/elliotchance/orderedmap/v3 v3.1.0 // indirect
+	github.com/emersion/go-imap/v2 v2.0.0-beta.8 // indirect
+	github.com/emersion/go-message v0.18.2 // indirect
+	github.com/emersion/go-sasl v0.0.0-20241020182733-b788ff22d5a6 // indirect
 	github.com/gdamore/encoding v1.0.1 // indirect
 	github.com/go-logr/logr v1.4.3 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect

go.sum

@@ -87,6 +87,12 @@ github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkp
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/elliotchance/orderedmap/v3 v3.1.0 h1:j4DJ5ObEmMBt/lcwIecKcoRxIQUEnw0L804lXYDt/pg=
 github.com/elliotchance/orderedmap/v3 v3.1.0/go.mod h1:G+Hc2RwaZvJMcS4JpGCOyViCnGeKf0bTYCGTO4uhjSo=
+github.com/emersion/go-imap/v2 v2.0.0-beta.8 h1:5IXZK1E33DyeP526320J3RS7eFlCYGFgtbrfapqDPug=
+github.com/emersion/go-imap/v2 v2.0.0-beta.8/go.mod h1:dhoFe2Q0PwLrMD7oZw8ODuaD0vLYPe5uj2wcOMnvh48=
+github.com/emersion/go-message v0.18.2 h1:rl55SQdjd9oJcIoQNhubD2Acs1E6IzlZISRTK7x/Lpg=
+github.com/emersion/go-message v0.18.2/go.mod h1:XpJyL70LwRvq2a8rVbHXikPgKj8+aI0kGdHlg16ibYA=
+github.com/emersion/go-sasl v0.0.0-20241020182733-b788ff22d5a6 h1:oP4q0fw+fOSWn3DfFi4EXdT+B+gTtzx8GC9xsc26Znk=
+github.com/emersion/go-sasl v0.0.0-20241020182733-b788ff22d5a6/go.mod h1:iL2twTeMvZnrg54ZoPDNfJaJaqy0xIQFuBdrLsmspwQ=
 github.com/ergochat/irc-go v0.6.0 h1:Y0AGV76aeihJfCtLaQh+OyJKFiKGrYC0VTkeMZ6XW28=
 github.com/ergochat/irc-go v0.6.0/go.mod h1:2vi7KNpIPWnReB5hmLpl92eMywQvuIeIIGdt/FQCph0=
 github.com/ergochat/readline v0.1.3 h1:/DytGTmwdUJcLAe3k3VJgowh5vNnsdifYT6uVaf4pSo=

pkg/channels/email/email.go

@@ -0,0 +1,374 @@
+package email
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net/smtp"
+	"strings"
+	"time"
+
+	gomail "github.com/emersion/go-message/mail"
+
+	imap "github.com/emersion/go-imap/v2"
+	"github.com/emersion/go-imap/v2/imapclient"
+
+	"github.com/sipeed/picoclaw/pkg/bus"
+	"github.com/sipeed/picoclaw/pkg/channels"
+	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/logger"
+)
+
+// EmailChannel implements the Channel interface using SMTP (outbound) and IMAP polling (inbound).
+type EmailChannel struct {
+	*channels.BaseChannel
+	config config.EmailConfig
+	ctx    context.Context
+	cancel context.CancelFunc
+}
+
+// NewEmailChannel creates a new email channel.
+func NewEmailChannel(cfg config.EmailConfig, messageBus *bus.MessageBus) (*EmailChannel, error) {
+	if cfg.SMTPHost == "" {
+		return nil, fmt.Errorf("email smtp_host is required")
+	}
+	if cfg.SMTPFrom == "" {
+		return nil, fmt.Errorf("email smtp_from is required")
+	}
+	if cfg.IMAPHost == "" {
+		return nil, fmt.Errorf("email imap_host is required")
+	}
+	if cfg.IMAPUser == "" {
+		return nil, fmt.Errorf("email imap_user is required")
+	}
+
+	base := channels.NewBaseChannel("email", cfg, messageBus, cfg.AllowFrom,
+		channels.WithReasoningChannelID(cfg.ReasoningChannelID),
+	)
+
+	return &EmailChannel{
+		BaseChannel: base,
+		config:      cfg,
+	}, nil
+}
+
+// Start begins IMAP polling.
+func (c *EmailChannel) Start(ctx context.Context) error {
+	logger.InfoC("email", "Starting email channel")
+	c.ctx, c.cancel = context.WithCancel(ctx)
+
+	interval := c.config.PollIntervalSecs
+	if interval <= 0 {
+		interval = 30
+	}
+
+	go c.pollLoop(time.Duration(interval) * time.Second)
+
+	c.SetRunning(true)
+	logger.InfoCF("email", "Email channel started", map[string]any{
+		"smtp_host": c.config.SMTPHost,
+		"imap_host": c.config.IMAPHost,
+		"interval":  interval,
+	})
+	return nil
+}
+
+// Stop cancels the polling loop.
+func (c *EmailChannel) Stop(ctx context.Context) error {
+	logger.InfoC("email", "Stopping email channel")
+	c.SetRunning(false)
+	if c.cancel != nil {
+		c.cancel()
+	}
+	logger.InfoC("email", "Email channel stopped")
+	return nil
+}
+
+// Send delivers an outbound message via SMTP.
+// msg.ChatID is the recipient email address.
+func (c *EmailChannel) Send(ctx context.Context, msg bus.OutboundMessage) error {
+	if !c.IsRunning() {
+		return channels.ErrNotRunning
+	}
+
+	to := msg.ChatID
+	if to == "" {
+		return fmt.Errorf("chat ID (recipient address) is empty: %w", channels.ErrSendFailed)
+	}
+	if strings.TrimSpace(msg.Content) == "" {
+		return nil
+	}
+
+	subject := c.config.DefaultSubject
+	if subject == "" {
+		subject = "Message"
+	}
+
+	smtpPort := c.config.SMTPPort
+	if smtpPort == 0 {
+		smtpPort = 587
+	}
+
+	addr := fmt.Sprintf("%s:%d", c.config.SMTPHost, smtpPort)
+	smtpUser := c.config.SMTPUser
+	if smtpUser == "" {
+		smtpUser = c.config.SMTPFrom
+	}
+
+	body := fmt.Sprintf("From: %s\r\nTo: %s\r\nSubject: %s\r\n\r\n%s",
+		c.config.SMTPFrom, to, subject, msg.Content)
+
+	var auth smtp.Auth
+	if c.config.SMTPPassword.String() != "" {
+		auth = smtp.PlainAuth("", smtpUser, c.config.SMTPPassword.String(), c.config.SMTPHost)
+	}
+
+	// Port 465 uses implicit TLS; port 587 and others use STARTTLS.
+	if smtpPort == 465 {
+		tlsCfg := &tls.Config{ServerName: c.config.SMTPHost}
+		conn, err := tls.Dial("tcp", addr, tlsCfg)
+		if err != nil {
+			return fmt.Errorf("smtp tls dial: %w", channels.ErrTemporary)
+		}
+		client, err := smtp.NewClient(conn, c.config.SMTPHost)
+		if err != nil {
+			return fmt.Errorf("smtp new client: %w", channels.ErrTemporary)
+		}
+		defer client.Close()
+		if err := sendViaSMTPClient(client, auth, c.config.SMTPFrom, to, []byte(body)); err != nil {
+			return err
+		}
+	} else {
+		if err := smtp.SendMail(addr, auth, c.config.SMTPFrom, []string{to}, []byte(body)); err != nil {
+			return fmt.Errorf("smtp send: %w: %w", err, channels.ErrTemporary)
+		}
+	}
+
+	logger.DebugCF("email", "Message sent", map[string]any{"to": to})
+	return nil
+}
+
+func sendViaSMTPClient(client *smtp.Client, auth smtp.Auth, from, to string, body []byte) error {
+	if auth != nil {
+		if err := client.Auth(auth); err != nil {
+			return fmt.Errorf("smtp auth: %w: %w", err, channels.ErrSendFailed)
+		}
+	}
+	if err := client.Mail(from); err != nil {
+		return fmt.Errorf("smtp MAIL FROM: %w: %w", err, channels.ErrSendFailed)
+	}
+	if err := client.Rcpt(to); err != nil {
+		return fmt.Errorf("smtp RCPT TO: %w: %w", err, channels.ErrSendFailed)
+	}
+	w, err := client.Data()
+	if err != nil {
+		return fmt.Errorf("smtp DATA: %w: %w", err, channels.ErrSendFailed)
+	}
+	if _, err := w.Write(body); err != nil {
+		return fmt.Errorf("smtp write body: %w: %w", err, channels.ErrSendFailed)
+	}
+	if err := w.Close(); err != nil {
+		return fmt.Errorf("smtp close data: %w: %w", err, channels.ErrSendFailed)
+	}
+	return client.Quit()
+}
+
+func (c *EmailChannel) pollLoop(interval time.Duration) {
+	// Poll once immediately on start, then on ticker.
+	c.pollIMAP()
+
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-c.ctx.Done():
+			return
+		case <-ticker.C:
+			c.pollIMAP()
+		}
+	}
+}
+
+func (c *EmailChannel) pollIMAP() {
+	imapPort := c.config.IMAPPort
+	if imapPort == 0 {
+		imapPort = 993
+	}
+	addr := fmt.Sprintf("%s:%d", c.config.IMAPHost, imapPort)
+
+	var (
+		client *imapclient.Client
+		err    error
+	)
+
+	// Port 993 = implicit TLS, anything else = plain (STARTTLS not yet supported).
+	if imapPort == 993 {
+		tlsCfg := &tls.Config{ServerName: c.config.IMAPHost}
+		client, err = imapclient.DialTLS(addr, &imapclient.Options{TLSConfig: tlsCfg})
+	} else {
+		client, err = imapclient.DialInsecure(addr, nil)
+	}
+	if err != nil {
+		logger.WarnCF("email", "IMAP dial failed", map[string]any{"err": err})
+		return
+	}
+	defer client.Close()
+
+	if err := client.Login(c.config.IMAPUser, c.config.IMAPPassword.String()).Wait(); err != nil {
+		logger.WarnCF("email", "IMAP login failed", map[string]any{"err": err})
+		return
+	}
+
+	if _, err := client.Select("INBOX", nil).Wait(); err != nil {
+		logger.WarnCF("email", "IMAP SELECT INBOX failed", map[string]any{"err": err})
+		return
+	}
+
+	searchData, err := client.Search(&imap.SearchCriteria{
+		NotFlag: []imap.Flag{imap.FlagSeen},
+	}, nil).Wait()
+	if err != nil {
+		logger.WarnCF("email", "IMAP SEARCH failed", map[string]any{"err": err})
+		return
+	}
+
+	if len(searchData.AllSeqNums()) == 0 {
+		return
+	}
+
+	seqSet := imap.SeqSetNum(searchData.AllSeqNums()...)
+	bodySection := &imap.FetchItemBodySection{}
+	fetchOptions := &imap.FetchOptions{
+		Envelope:    true,
+		BodySection: []*imap.FetchItemBodySection{bodySection},
+	}
+
+	fetchCmd := client.Fetch(seqSet, fetchOptions)
+
+	for {
+		msg := fetchCmd.Next()
+		if msg == nil {
+			break
+		}
+
+		var (
+			envelope        *imap.Envelope
+			bodySectionData *imapclient.FetchItemDataBodySection
+			seqNum          uint32
+		)
+
+		seqNum = msg.SeqNum
+
+		for {
+			item := msg.Next()
+			if item == nil {
+				break
+			}
+			switch v := item.(type) {
+			case imapclient.FetchItemDataEnvelope:
+				envelope = v.Envelope
+			case imapclient.FetchItemDataBodySection:
+				bodySectionData = &v
+			}
+		}
+
+		if envelope == nil || bodySectionData == nil {
+			continue
+		}
+
+		fromAddr := extractFrom(envelope)
+		if fromAddr == "" {
+			continue
+		}
+
+		messageID := envelope.MessageID
+		plainText := extractPlainText(bodySectionData.Literal)
+
+		sender := bus.SenderInfo{
+			Platform:    "email",
+			PlatformID:  fromAddr,
+			CanonicalID: "email:" + fromAddr,
+			DisplayName: displayName(envelope),
+		}
+
+		c.HandleMessage(c.ctx,
+			bus.Peer{Kind: "direct", ID: fromAddr},
+			messageID, fromAddr, fromAddr, plainText,
+			nil, nil,
+			sender,
+		)
+
+		// Mark message as \Seen
+		storeSeq := imap.SeqSetNum(seqNum)
+		storeFlags := imap.StoreFlags{
+			Op:     imap.StoreFlagsAdd,
+			Flags:  []imap.Flag{imap.FlagSeen},
+			Silent: true,
+		}
+		if err := client.Store(storeSeq, &storeFlags, nil).Close(); err != nil {
+			logger.WarnCF("email", "IMAP STORE \\Seen failed", map[string]any{"err": err, "seq": seqNum})
+		}
+	}
+
+	if err := fetchCmd.Close(); err != nil {
+		logger.WarnCF("email", "IMAP FETCH close error", map[string]any{"err": err})
+	}
+}
+
+func extractFrom(env *imap.Envelope) string {
+	if len(env.From) == 0 {
+		return ""
+	}
+	addr := env.From[0]
+	if addr.Host == "" {
+		return addr.Mailbox
+	}
+	return addr.Mailbox + "@" + addr.Host
+}
+
+func displayName(env *imap.Envelope) string {
+	if len(env.From) == 0 {
+		return ""
+	}
+	if env.From[0].Name != "" {
+		return env.From[0].Name
+	}
+	return extractFrom(env)
+}
+
+// extractPlainText reads the message body and returns the first text/plain part.
+// Falls back to the raw body if parsing fails.
+func extractPlainText(r io.Reader) string {
+	mr, err := gomail.CreateReader(r)
+	if err != nil {
+		// Fallback: read raw bytes
+		b, _ := io.ReadAll(r)
+		return strings.TrimSpace(string(b))
+	}
+
+	for {
+		p, err := mr.NextPart()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			break
+		}
+		inlineHeader, ok := p.Header.(*gomail.InlineHeader)
+		if !ok {
+			continue
+		}
+		ct, _, _ := inlineHeader.ContentType()
+		if ct == "text/plain" || ct == "" {
+			b, _ := io.ReadAll(p.Body)
+			text := strings.TrimSpace(string(b))
+			if text != "" {
+				return text
+			}
+		}
+	}
+	return ""
+}
+

pkg/channels/email/init.go

@@ -0,0 +1,16 @@
+package email
+
+import (
+	"github.com/sipeed/picoclaw/pkg/bus"
+	"github.com/sipeed/picoclaw/pkg/channels"
+	"github.com/sipeed/picoclaw/pkg/config"
+)
+
+func init() {
+	channels.RegisterFactory("email", func(cfg *config.Config, b *bus.MessageBus) (channels.Channel, error) {
+		if !cfg.Channels.Email.Enabled {
+			return nil, nil
+		}
+		return NewEmailChannel(cfg.Channels.Email, b)
+	})
+}

pkg/config/config.go

@@ -314,6 +314,7 @@ type ChannelsConfig struct {
 	IRC          IRCConfig          `json:"irc"           yaml:"irc,omitempty"`
 	VK           VKConfig           `json:"vk"            yaml:"vk,omitempty"`
 	TeamsWebhook TeamsWebhookConfig `json:"teams_webhook" yaml:"teams_webhook,omitempty"`
+	Email        EmailConfig        `json:"email"         yaml:"email,omitempty"`
 }
 
 // GroupTriggerConfig controls when the bot responds in group chats.
@@ -596,6 +597,26 @@ type TeamsWebhookTarget struct {
 	Title      string       `json:"title,omitempty"      yaml:"-"`
 }
 
+type EmailConfig struct {
+	Enabled bool `json:"enabled" env:"PICOCLAW_CHANNELS_EMAIL_ENABLED"`
+	// SMTP (outbound)
+	SMTPHost       string       `json:"smtp_host"       env:"PICOCLAW_CHANNELS_EMAIL_SMTP_HOST"`
+	SMTPPort       int          `json:"smtp_port"       env:"PICOCLAW_CHANNELS_EMAIL_SMTP_PORT"`
+	SMTPFrom       string       `json:"smtp_from"       env:"PICOCLAW_CHANNELS_EMAIL_SMTP_FROM"`
+	SMTPUser       string       `json:"smtp_user"       env:"PICOCLAW_CHANNELS_EMAIL_SMTP_USER"`
+	SMTPPassword   SecureString `json:"smtp_password,omitzero" yaml:"smtp_password,omitempty" env:"PICOCLAW_CHANNELS_EMAIL_SMTP_PASSWORD"`
+	DefaultSubject string       `json:"default_subject" env:"PICOCLAW_CHANNELS_EMAIL_DEFAULT_SUBJECT"`
+	// IMAP (inbound)
+	IMAPHost         string              `json:"imap_host"          env:"PICOCLAW_CHANNELS_EMAIL_IMAP_HOST"`
+	IMAPPort         int                 `json:"imap_port"          env:"PICOCLAW_CHANNELS_EMAIL_IMAP_PORT"`
+	IMAPUser         string              `json:"imap_user"          env:"PICOCLAW_CHANNELS_EMAIL_IMAP_USER"`
+	IMAPPassword     SecureString        `json:"imap_password,omitzero" yaml:"imap_password,omitempty" env:"PICOCLAW_CHANNELS_EMAIL_IMAP_PASSWORD"`
+	PollIntervalSecs int                 `json:"poll_interval_secs" env:"PICOCLAW_CHANNELS_EMAIL_POLL_INTERVAL_SECS"`
+	// Common
+	AllowFrom          FlexibleStringSlice `json:"allow_from"            env:"PICOCLAW_CHANNELS_EMAIL_ALLOW_FROM"`
+	ReasoningChannelID string              `json:"reasoning_channel_id"  env:"PICOCLAW_CHANNELS_EMAIL_REASONING_CHANNEL_ID"`
+}
+
 type HeartbeatConfig struct {
 	Enabled  bool `json:"enabled"  env:"PICOCLAW_HEARTBEAT_ENABLED"`
 	Interval int  `json:"interval" env:"PICOCLAW_HEARTBEAT_INTERVAL"` // minutes, min 5

pkg/gateway/gateway.go

@@ -19,6 +19,7 @@ import (
 	"github.com/sipeed/picoclaw/pkg/bus"
 	"github.com/sipeed/picoclaw/pkg/channels"
 	_ "github.com/sipeed/picoclaw/pkg/channels/dingtalk"
+	_ "github.com/sipeed/picoclaw/pkg/channels/email"
 	_ "github.com/sipeed/picoclaw/pkg/channels/discord"
 	_ "github.com/sipeed/picoclaw/pkg/channels/feishu"
 	_ "github.com/sipeed/picoclaw/pkg/channels/irc"