imap/client/list_messages.go

// Copyright (c) 2025 H0llyW00dzZ All rights reserved.
//
// By accessing or using this software, you agree to be bound by the terms
// of the License Agreement, which you can find at LICENSE files.

package client

import (
	"fmt"

	"github.com/emersion/go-imap"
	"github.com/valyala/bytebufferpool"
)

const (
	// KeyID is the key for the message ID
	KeyID = "id"
	// KeyFrom is the key for the sender's address
	KeyFrom = "from"
	// KeySubject is the key for the message subject
	KeySubject = "subject"
	// KeyBody is the key for the message body
	KeyBody = "body"
)

// ListMessages lists the messages in the specified mailbox based on the MessageConfig
func (c *IMAPClient) ListMessages(mailbox string, numMessages uint32, config MessageConfig) ([]map[string]any, error) {
	if c.client == nil {
		return nil, fmt.Errorf("client is not connected")
	}

	mbox, err := c.client.Select(mailbox, false)
	if err != nil {
		return nil, fmt.Errorf("failed to select %s: %v", mailbox, err)
	}

	from := uint32(1)
	to := mbox.Messages
	if mbox.Messages > numMessages {
		from = mbox.Messages - numMessages + 1
	}
	seqset := new(imap.SeqSet)
	seqset.AddRange(from, to)

	items := []imap.FetchItem{imap.FetchEnvelope}
	if config.GrabBody {
		items = append(items, imap.FetchItem("BODY.PEEK[]"))
	}

	messages := make(chan *imap.Message, numMessages)
	done := make(chan error, 1)
	go func() {
		done <- c.client.Fetch(seqset, items, messages)
	}()

	var results []map[string]any
	for msg := range messages {
		details := make(map[string]any)

		if config.GrabID && msg.Envelope.MessageId != "" {
			details[KeyID] = msg.Envelope.MessageId
		}
		if config.GrabFrom {
			var from []string
			for _, addr := range msg.Envelope.From {
				from = append(from, addr.Address())
			}
			details[KeyFrom] = from
		}
		if config.GrabSubject && msg.Envelope.Subject != "" {
			details[KeySubject] = msg.Envelope.Subject
		}
		if config.GrabBody {
			for _, literal := range msg.Body {
				buf := bytebufferpool.Get()
				if _, err := buf.ReadFrom(literal); err == nil {
					details[KeyBody] = buf.String()
				}
				buf.Reset() // Reset the buffer before returning it to the pool.
				bytebufferpool.Put(buf)
			}
		}
		results = append(results, details)
	}

	if err := <-done; err != nil {
		return nil, fmt.Errorf("failed to fetch messages: %v", err)
	}

	return results, nil
}

// ListUserMessages lists messages for a specific user based on the MessageConfig
func (m *MultiUserIMAP) ListUserMessages(username, mailbox string, numMessages uint32, config MessageConfig) ([]map[string]any, error) {
	m.mu.Lock()
	defer m.mu.Unlock()

	client, exists := m.clients[username]
	if !exists {
		return nil, fmt.Errorf("user not found: %s", username)
	}

	return client.ListMessages(mailbox, numMessages, config)
}