src/papod.go: Add message parsing code with some tests

1 files changed, 154 insertions, 13 deletions

diff --git a/src/papod.go b/src/papod.go
index 413b902..38f6d4c 100644
--- a/src/papod.go
+++ b/src/papod.go
@@ -1,7 +1,8 @@
 package papo
 
 import (
-	// "bufio"
+	"bufio"
+	"bytes"
 	"crypto/rand"
 	"database/sql"
 	"encoding/hex"
@@ -14,7 +15,9 @@ import (
 	"math/big"
 	"net"
 	"os"
+	"regexp"
 	"runtime/debug"
+	"strings"
 	"sync"
 	"syscall"
 	"time"
@@ -247,14 +250,18 @@ func MakeCounter(label string) func(...any) {
 
 var EmitActiveConnection = MakeGauge("active-connections")
 var EmitNicksInChannel   = MakeGauge("nicks-in-channel")
-var EmitReceivedCommand  = MakeCounter("received-command")
+var EmitReceivedMessage  = MakeCounter("received-message")
 
 const pingFrequency  = time.Duration(30) * time.Second
 const pongMaxLatency = time.Duration(5)  * time.Second
 
 
 func Fatal(err error) {
-	slog.Error("fatal-error", "error", err, "stack", string(debug.Stack()))
+	Error(
+		"Fatal error", "fatal-error",
+		"error", err,
+		"stack", string(debug.Stack()),
+	)
 	syscall.Kill(os.Getpid(), syscall.SIGABRT)
 	os.Exit(3)
 }
@@ -274,28 +281,160 @@ type Context struct {
 	tx chan int
 }
 
+type Connection struct {
+	conn            net.Conn
+	// id              *UUID
+	id              string
+	isAuthenticated bool
+}
+
+type MessageParams struct {
+	Middle   []string
+	Trailing string
+}
+
 type Message struct {
-	Prefix   string
+	Prefix  string
+	Command string
+	Params  MessageParams
+	Raw     string
+}
+
+var (
+	CmdUser = Message { Command: "USER" }
+)
+
+func SplitOnCRLF(data []byte, _atEOF bool) (int, []byte, error) {
+	idx := bytes.Index(data, []byte { '\r', '\n' })
+	if idx == -1 {
+		return 0, nil, nil
+	}
+
+	return idx + 2, data[0:idx], nil
+}
+
+func SplitOnRawMessage(data []byte, atEOF bool) (int, []byte, error) {
+	advance, token, error := SplitOnCRLF(data, atEOF)
+
+	if len(token) == 0 {
+		return advance, nil, error
+	}
+
+	return advance, token, error
 }
 
-func ReadLoop(ctx *Context, conn net.Conn) {
-	fmt.Println("ReadLoop")
+func SplitSpaces(r rune) bool {
+	return r == ' '
+}
+
+func ParseMessageParams(params string) MessageParams {
+	const sep = " :"
+
+	var middle string
+	var trailing string
+
+	idx := strings.Index(params, sep)
+	if idx == -1 {
+		middle = params
+		trailing = ""
+	} else {
+		middle = params[:idx]
+		trailing = params[idx + len(sep):]
+	}
+
+	return MessageParams {
+		Middle: strings.FieldsFunc(middle, SplitSpaces),
+		Trailing: trailing,
+	}
 }
 
-func WriteLoop(ctx *Context, conn net.Conn) {
+var MessageRegex = regexp.MustCompilePOSIX(
+	//  <prefix>   <command>             <params>
+	//1 2          3                     4
+	`^(:([^ ]+) +)?([a-zA-Z]+|[0-9]{3}) *( .*)$`,
+	//                                 ^^^^ FIXME: test these spaces
+)
+func ParseMessage(rawMessage string) (Message, error) {
+	var msg Message
+
+	components := MessageRegex.FindStringSubmatch(rawMessage)
+	if components == nil {
+		return msg, nil
+	}
+
+	msg = Message {
+		Prefix:  components[2],
+		Command: components[3],
+		Params:  ParseMessageParams(components[4]),
+		Raw:     rawMessage,
+	}
+	return msg, nil
+}
+
+func HandleMessage(msg Message) {
+	fmt.Printf("msg: %#v\n", msg)
+}
+
+func ReplyAnonymous() {
+}
+
+func PersistMessage(msg Message) {
+}
+
+func ActionsFor(msg Message) []int {
+	return []int { }
+}
+
+func RunAction(action int) {
+}
+
+func ProcessMessage(ctx *Context, connection *Connection, rawMessage string) {
+	msg, err := ParseMessage(rawMessage)
+	if err != nil {
+		return
+	}
+
+	if msg.Command == CmdUser.Command {
+		connection.id = msg.Params.Middle[0]
+		connection.isAuthenticated = true
+	}
+
+	if !connection.isAuthenticated {
+		go ReplyAnonymous()
+		return
+	}
+
+	for _, action := range ActionsFor(msg) {
+		RunAction(action)
+	}
+}
+
+func ReadLoop(ctx *Context, connection *Connection) {
+	scanner := bufio.NewScanner(connection.conn)
+	scanner.Split(SplitOnRawMessage)
+	for scanner.Scan() {
+		ProcessMessage(ctx, connection, scanner.Text())
+	}
+}
+
+func WriteLoop(ctx *Context, connection *Connection) {
 	fmt.Println("WriteLoop")
 }
 
-func PingLoop(ctx *Context, conn net.Conn) {
+func PingLoop(ctx *Context, connection *Connection) {
 	fmt.Println("PingLoop")
 }
 
 func HandleConnection(ctx *Context, conn net.Conn) {
 	EmitActiveConnection.Inc()
 	// FIXME: WaitGroup here?
-	go ReadLoop(ctx, conn)
-	go WriteLoop(ctx, conn)
-	go PingLoop(ctx, conn)
+	connection := Connection {
+		conn: conn,
+		isAuthenticated: false,
+	}
+	go  ReadLoop(ctx, &connection)
+	go WriteLoop(ctx, &connection)
+	go  PingLoop(ctx, &connection)
 }
 
 func IRCdLoop(ctx *Context, publicSocketPath string) {
@@ -306,8 +445,9 @@ func IRCdLoop(ctx *Context, publicSocketPath string) {
 	for {
 		conn, err := listener.Accept()
 		if err != nil {
-			slog.Warn(
+			Warning(
 				"Error accepting a public IRCd connection",
+				"accept-connection",
 				"err", err,
 			)
 			// conn.Close() // FIXME: is conn nil?
@@ -325,8 +465,9 @@ func CommandListenerLoop(ctx *Context, commandSocketPath string) {
 	for {
 		conn, err := listener.Accept()
 		if err != nil {
-			slog.Warn(
+			Warning(
 				"Error accepting a command connection",
+				"accept-command",
 				"err", err,
 			)
 			continue