From efa0d81ff6e07efab8f13465628edd7e1ab31bab Mon Sep 17 00:00:00 2001
From: Robert Sesek <rsesek@bluestatic.org>
Date: Tue, 13 Dec 2016 00:59:58 -0500
Subject: [PATCH] Implement POP3 LIST, RETR, and DELE.

---
 pop3.go        | 45 +++++++++++++++++++++++++++------
 pop3/conn.go   | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++
 pop3/server.go |  5 ++--
 3 files changed, 108 insertions(+), 9 deletions(-)

diff --git a/pop3.go b/pop3.go
index 84e075b..ad4d1a4 100644
--- a/pop3.go
+++ b/pop3.go
@@ -4,8 +4,10 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"net"
 	"os"
+	"path"
 
 	"src.bluestatic.org/mailpopbox/pop3"
 )
@@ -62,9 +64,31 @@ func (server *pop3Server) OpenMailbox(user, pass string) (pop3.Mailbox, error) {
 }
 
 func (server *pop3Server) openMailbox(maildrop string) (*mailbox, error) {
+	files, err := ioutil.ReadDir(maildrop)
+	if err != nil {
+		// TODO: hide error, log instead
+		return nil, err
+	}
+
 	mb := &mailbox{
-		messages: make([]message, 0),
+		messages: make([]message, 0, len(files)),
+	}
+
+	i := 0
+	for _, file := range files {
+		if file.IsDir() {
+			continue
+		}
+
+		msg := message{
+			filename: path.Join(maildrop, file.Name()),
+			index:    i,
+			size:     file.Size(),
+		}
+		mb.messages = append(mb.messages, msg)
+		i++
 	}
+
 	return mb, nil
 }
 
@@ -75,7 +99,7 @@ type mailbox struct {
 type message struct {
 	filename string
 	index    int
-	size     int
+	size     int64
 	deleted  bool
 }
 
@@ -84,7 +108,11 @@ func (m message) ID() int {
 }
 
 func (m message) Size() int {
-	return m.size
+	return int(m.size)
+}
+
+func (m message) Deleted() bool {
+	return m.deleted
 }
 
 func (mb *mailbox) ListMessages() ([]pop3.Message, error) {
@@ -95,13 +123,16 @@ func (mb *mailbox) ListMessages() ([]pop3.Message, error) {
 	return msgs, nil
 }
 
-func (mb *mailbox) Retrieve(msg pop3.Message) (io.ReadCloser, error) {
-	filename := msg.(*message).filename
+func (mb *mailbox) Retrieve(idx int) (io.ReadCloser, error) {
+	if idx > len(mb.messages) {
+		return nil, errors.New("no such message")
+	}
+	filename := mb.messages[idx-1].filename
 	return os.Open(filename)
 }
 
-func (mb *mailbox) Delete(msg pop3.Message) error {
-	message := msg.(*message)
+func (mb *mailbox) Delete(idx int) error {
+	message := &mb.messages[idx-1]
 	if message.deleted {
 		return errors.New("already deleted")
 	}
diff --git a/pop3/conn.go b/pop3/conn.go
index c909bae..5341bcb 100644
--- a/pop3/conn.go
+++ b/pop3/conn.go
@@ -2,6 +2,7 @@ package pop3
 
 import (
 	"fmt"
+	"io"
 	"net"
 	"net/textproto"
 	"strings"
@@ -150,6 +151,24 @@ func (conn *connection) doSTAT() {
 		conn.err(errStateTxn)
 		return
 	}
+
+	msgs, err := conn.mb.ListMessages()
+	if err != nil {
+		conn.err(err.Error())
+		return
+	}
+
+	size := 0
+	num := 0
+	for _, msg := range msgs {
+		if msg.Deleted() {
+			continue
+		}
+		size += msg.Size()
+		num++
+	}
+
+	conn.ok(fmt.Sprintf("%d %d", num, size))
 }
 
 func (conn *connection) doLIST() {
@@ -157,6 +176,18 @@ func (conn *connection) doLIST() {
 		conn.err(errStateTxn)
 		return
 	}
+
+	msgs, err := conn.mb.ListMessages()
+	if err != nil {
+		conn.err(err.Error())
+		return
+	}
+
+	conn.ok("scan listing")
+	for _, msg := range msgs {
+		conn.tp.PrintfLine("%d %d", msg.ID(), msg.Size())
+	}
+	conn.tp.PrintfLine(".")
 }
 
 func (conn *connection) doRETR() {
@@ -164,6 +195,21 @@ func (conn *connection) doRETR() {
 		conn.err(errStateTxn)
 		return
 	}
+
+	idx, ok := conn.intParam()
+	if !ok {
+		return
+	}
+
+	rc, err := conn.mb.Retrieve(idx)
+	if err != nil {
+		conn.err(err.Error())
+		return
+	}
+
+	w := conn.tp.DotWriter()
+	io.Copy(w, rc)
+	w.Close()
 }
 
 func (conn *connection) doDELE() {
@@ -171,6 +217,17 @@ func (conn *connection) doDELE() {
 		conn.err(errStateTxn)
 		return
 	}
+
+	idx, ok := conn.intParam()
+	if !ok {
+		return
+	}
+
+	if err := conn.mb.Delete(idx); err != nil {
+		conn.err(err.Error())
+	} else {
+		conn.ok("")
+	}
 }
 
 func (conn *connection) doRSET() {
@@ -181,3 +238,13 @@ func (conn *connection) doRSET() {
 	conn.mb.Reset()
 	conn.ok("")
 }
+
+func (conn *connection) intParam() (int, bool) {
+	var cmd string
+	var param int
+	if _, err := fmt.Sscanf(conn.line, "%s %d", &cmd, &param); err != nil {
+		conn.err(errSyntax)
+		return 0, false
+	}
+	return param, true
+}
diff --git a/pop3/server.go b/pop3/server.go
index 1bce28f..f0377b5 100644
--- a/pop3/server.go
+++ b/pop3/server.go
@@ -7,12 +7,13 @@ import (
 type Message interface {
 	ID() int
 	Size() int
+	Deleted() bool
 }
 
 type Mailbox interface {
 	ListMessages() ([]Message, error)
-	Retrieve(Message) (io.ReadCloser, error)
-	Delete(Message) error
+	Retrieve(int) (io.ReadCloser, error)
+	Delete(int) error
 	Close() error
 	Reset()
 }
-- 
2.43.5