12 files changed, 692 insertions, 0 deletions
diff --git a/forged/internal/ipc/git2c/client.go b/forged/internal/ipc/git2c/client.go
new file mode 100644
index 0000000..d8dc2ea
--- /dev/null
+++ b/forged/internal/ipc/git2c/client.go
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+package git2c
+
+import (
+	"fmt"
+	"net"
+
+	"go.lindenii.runxiyu.org/forge/forged/internal/bare"
+)
+
+// Client represents a connection to the git2d backend daemon.
+type Client struct {
+	socketPath string
+	conn       net.Conn
+	writer     *bare.Writer
+	reader     *bare.Reader
+}
+
+// NewClient establishes a connection to a git2d socket and returns a new Client.
+func NewClient(socketPath string) (*Client, error) {
+	conn, err := net.Dial("unix", socketPath)
+	if err != nil {
+		return nil, fmt.Errorf("git2d connection failed: %w", err)
+	}
+
+	writer := bare.NewWriter(conn)
+	reader := bare.NewReader(conn)
+
+	return &Client{
+		socketPath: socketPath,
+		conn:       conn,
+		writer:     writer,
+		reader:     reader,
+	}, nil
+}
+
+// Close terminates the underlying socket connection.
+func (c *Client) Close() error {
+	if c.conn != nil {
+		return c.conn.Close()
+	}
+	return nil
+}
diff --git a/forged/internal/ipc/git2c/cmd_index.go b/forged/internal/ipc/git2c/cmd_index.go
new file mode 100644
index 0000000..8862b2c
--- /dev/null
+++ b/forged/internal/ipc/git2c/cmd_index.go
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+package git2c
+
+import (
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+)
+
+// CmdIndex requests a repository index from git2d and returns the list of commits
+// and the contents of a README file if available.
+func (c *Client) CmdIndex(repoPath string) ([]Commit, *FilenameContents, error) {
+	if err := c.writer.WriteData([]byte(repoPath)); err != nil {
+		return nil, nil, fmt.Errorf("sending repo path failed: %w", err)
+	}
+	if err := c.writer.WriteUint(1); err != nil {
+		return nil, nil, fmt.Errorf("sending command failed: %w", err)
+	}
+
+	status, err := c.reader.ReadUint()
+	if err != nil {
+		return nil, nil, fmt.Errorf("reading status failed: %w", err)
+	}
+	if status != 0 {
+		return nil, nil, fmt.Errorf("git2d error: %d", status)
+	}
+
+	// README
+	readmeRaw, err := c.reader.ReadData()
+	if err != nil {
+		readmeRaw = nil
+	}
+
+	readmeFilename := "README.md" // TODO
+	readme := &FilenameContents{Filename: readmeFilename, Content: readmeRaw}
+
+	// Commits
+	var commits []Commit
+	for {
+		id, err := c.reader.ReadData()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				break
+			}
+			return nil, nil, fmt.Errorf("reading commit ID failed: %w", err)
+		}
+		title, _ := c.reader.ReadData()
+		authorName, _ := c.reader.ReadData()
+		authorEmail, _ := c.reader.ReadData()
+		authorDate, _ := c.reader.ReadData()
+
+		commits = append(commits, Commit{
+			Hash:    hex.EncodeToString(id),
+			Author:  string(authorName),
+			Email:   string(authorEmail),
+			Date:    string(authorDate),
+			Message: string(title),
+		})
+	}
+
+	return commits, readme, nil
+}
diff --git a/forged/internal/ipc/git2c/cmd_treeraw.go b/forged/internal/ipc/git2c/cmd_treeraw.go
new file mode 100644
index 0000000..492cb84
--- /dev/null
+++ b/forged/internal/ipc/git2c/cmd_treeraw.go
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+package git2c
+
+import (
+	"errors"
+	"fmt"
+	"io"
+)
+
+// CmdTreeRaw queries git2d for a tree or blob object at the given path within the repository.
+// It returns either a directory listing or the contents of a file.
+func (c *Client) CmdTreeRaw(repoPath, pathSpec string) ([]TreeEntry, string, error) {
+	if err := c.writer.WriteData([]byte(repoPath)); err != nil {
+		return nil, "", fmt.Errorf("sending repo path failed: %w", err)
+	}
+	if err := c.writer.WriteUint(2); err != nil {
+		return nil, "", fmt.Errorf("sending command failed: %w", err)
+	}
+	if err := c.writer.WriteData([]byte(pathSpec)); err != nil {
+		return nil, "", fmt.Errorf("sending path failed: %w", err)
+	}
+
+	status, err := c.reader.ReadUint()
+	if err != nil {
+		return nil, "", fmt.Errorf("reading status failed: %w", err)
+	}
+
+	switch status {
+	case 0:
+		kind, err := c.reader.ReadUint()
+		if err != nil {
+			return nil, "", fmt.Errorf("reading object kind failed: %w", err)
+		}
+
+		switch kind {
+		case 1:
+			// Tree
+			count, err := c.reader.ReadUint()
+			if err != nil {
+				return nil, "", fmt.Errorf("reading entry count failed: %w", err)
+			}
+
+			var files []TreeEntry
+			for range count {
+				typeCode, err := c.reader.ReadUint()
+				if err != nil {
+					return nil, "", fmt.Errorf("error reading entry type: %w", err)
+				}
+				mode, err := c.reader.ReadUint()
+				if err != nil {
+					return nil, "", fmt.Errorf("error reading entry mode: %w", err)
+				}
+				size, err := c.reader.ReadUint()
+				if err != nil {
+					return nil, "", fmt.Errorf("error reading entry size: %w", err)
+				}
+				name, err := c.reader.ReadData()
+				if err != nil {
+					return nil, "", fmt.Errorf("error reading entry name: %w", err)
+				}
+
+				files = append(files, TreeEntry{
+					Name:      string(name),
+					Mode:      fmt.Sprintf("%06o", mode),
+					Size:      size,
+					IsFile:    typeCode == 2,
+					IsSubtree: typeCode == 1,
+				})
+			}
+
+			return files, "", nil
+
+		case 2:
+			// Blob
+			content, err := c.reader.ReadData()
+			if err != nil && !errors.Is(err, io.EOF) {
+				return nil, "", fmt.Errorf("error reading file content: %w", err)
+			}
+
+			return nil, string(content), nil
+
+		default:
+			return nil, "", fmt.Errorf("unknown kind: %d", kind)
+		}
+
+	case 3:
+		return nil, "", fmt.Errorf("path not found: %s", pathSpec)
+
+	default:
+		return nil, "", fmt.Errorf("unknown status code: %d", status)
+	}
+}
diff --git a/forged/internal/ipc/git2c/doc.go b/forged/internal/ipc/git2c/doc.go
new file mode 100644
index 0000000..e14dae0
--- /dev/null
+++ b/forged/internal/ipc/git2c/doc.go
@@ -0,0 +1,2 @@
+// Package git2c provides routines to interact with the git2d backend daemon.
+package git2c
diff --git a/forged/internal/ipc/git2c/git_types.go b/forged/internal/ipc/git2c/git_types.go
new file mode 100644
index 0000000..bf13f05
--- /dev/null
+++ b/forged/internal/ipc/git2c/git_types.go
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+package git2c
+
+// Commit represents a single commit object retrieved from the git2d daemon.
+type Commit struct {
+	Hash    string
+	Author  string
+	Email   string
+	Date    string
+	Message string
+}
+
+// FilenameContents holds the filename and byte contents of a file, such as a README.
+type FilenameContents struct {
+	Filename string
+	Content  []byte
+}
+
+// TreeEntry represents a file or directory entry within a Git tree object.
+type TreeEntry struct {
+	Name      string
+	Mode      string
+	Size      uint64
+	IsFile    bool
+	IsSubtree bool
+}
diff --git a/forged/internal/ipc/git2c/perror.go b/forged/internal/ipc/git2c/perror.go
new file mode 100644
index 0000000..96bffd5
--- /dev/null
+++ b/forged/internal/ipc/git2c/perror.go
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+// TODO: Make the C part report detailed error messages too
+
+package git2c
+
+import "errors"
+
+var (
+	Success            error
+	ErrUnknown         = errors.New("git2c: unknown error")
+	ErrPath            = errors.New("git2c: get tree entry by path failed")
+	ErrRevparse        = errors.New("git2c: revparse failed")
+	ErrReadme          = errors.New("git2c: no readme")
+	ErrBlobExpected    = errors.New("git2c: blob expected")
+	ErrEntryToObject   = errors.New("git2c: tree entry to object conversion failed")
+	ErrBlobRawContent  = errors.New("git2c: get blob raw content failed")
+	ErrRevwalk         = errors.New("git2c: revwalk failed")
+	ErrRevwalkPushHead = errors.New("git2c: revwalk push head failed")
+	ErrBareProto       = errors.New("git2c: bare protocol error")
+)
+
+func Perror(errno uint) error {
+	switch errno {
+	case 0:
+		return Success
+	case 3:
+		return ErrPath
+	case 4:
+		return ErrRevparse
+	case 5:
+		return ErrReadme
+	case 6:
+		return ErrBlobExpected
+	case 7:
+		return ErrEntryToObject
+	case 8:
+		return ErrBlobRawContent
+	case 9:
+		return ErrRevwalk
+	case 10:
+		return ErrRevwalkPushHead
+	case 11:
+		return ErrBareProto
+	}
+	return ErrUnknown
+}
diff --git a/forged/internal/ipc/irc/bot.go b/forged/internal/ipc/irc/bot.go
new file mode 100644
index 0000000..6113913
--- /dev/null
+++ b/forged/internal/ipc/irc/bot.go
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+package irc
+
+import (
+	"crypto/tls"
+	"log/slog"
+	"net"
+
+	"go.lindenii.runxiyu.org/forge/forged/internal/common/misc"
+)
+
+// Config contains IRC connection and identity settings for the bot.
+// This should usually be a part of the primary config struct.
+type Config struct {
+	Net   string `scfg:"net"`
+	Addr  string `scfg:"addr"`
+	TLS   bool   `scfg:"tls"`
+	SendQ uint   `scfg:"sendq"`
+	Nick  string `scfg:"nick"`
+	User  string `scfg:"user"`
+	Gecos string `scfg:"gecos"`
+}
+
+// Bot represents an IRC bot client that handles events and allows for sending messages.
+type Bot struct {
+	config            *Config
+	ircSendBuffered   chan string
+	ircSendDirectChan chan misc.ErrorBack[string]
+}
+
+// NewBot creates a new Bot instance using the provided configuration.
+func NewBot(c *Config) (b *Bot) {
+	b = &Bot{
+		config: c,
+	}
+	return
+}
+
+// Connect establishes a new IRC session and starts handling incoming and outgoing messages.
+// This method blocks until an error occurs or the connection is closed.
+func (b *Bot) Connect() error {
+	var err error
+	var underlyingConn net.Conn
+	if b.config.TLS {
+		underlyingConn, err = tls.Dial(b.config.Net, b.config.Addr, nil)
+	} else {
+		underlyingConn, err = net.Dial(b.config.Net, b.config.Addr)
+	}
+	if err != nil {
+		return err
+	}
+	defer underlyingConn.Close()
+
+	conn := NewConn(underlyingConn)
+
+	logAndWriteLn := func(s string) (n int, err error) {
+		slog.Debug("irc tx", "line", s)
+		return conn.WriteString(s + "\r\n")
+	}
+
+	_, err = logAndWriteLn("NICK " + b.config.Nick)
+	if err != nil {
+		return err
+	}
+	_, err = logAndWriteLn("USER " + b.config.User + " 0 * :" + b.config.Gecos)
+	if err != nil {
+		return err
+	}
+
+	readLoopError := make(chan error)
+	writeLoopAbort := make(chan struct{})
+	go func() {
+		for {
+			select {
+			case <-writeLoopAbort:
+				return
+			default:
+			}
+
+			msg, line, err := conn.ReadMessage()
+			if err != nil {
+				readLoopError <- err
+				return
+			}
+
+			slog.Debug("irc rx", "line", line)
+
+			switch msg.Command {
+			case "001":
+				_, err = logAndWriteLn("JOIN #chat")
+				if err != nil {
+					readLoopError <- err
+					return
+				}
+			case "PING":
+				_, err = logAndWriteLn("PONG :" + msg.Args[0])
+				if err != nil {
+					readLoopError <- err
+					return
+				}
+			case "JOIN":
+				c, ok := msg.Source.(Client)
+				if !ok {
+					slog.Error("unable to convert source of JOIN to client")
+				}
+				if c.Nick != b.config.Nick {
+					continue
+				}
+			default:
+			}
+		}
+	}()
+
+	for {
+		select {
+		case err = <-readLoopError:
+			return err
+		case line := <-b.ircSendBuffered:
+			_, err = logAndWriteLn(line)
+			if err != nil {
+				select {
+				case b.ircSendBuffered <- line:
+				default:
+					slog.Error("unable to requeue message", "line", line)
+				}
+				writeLoopAbort <- struct{}{}
+				return err
+			}
+		case lineErrorBack := <-b.ircSendDirectChan:
+			_, err = logAndWriteLn(lineErrorBack.Content)
+			lineErrorBack.ErrorChan <- err
+			if err != nil {
+				writeLoopAbort <- struct{}{}
+				return err
+			}
+		}
+	}
+}
+
+// SendDirect sends an IRC message directly to the connection and bypasses
+// the buffering system.
+func (b *Bot) SendDirect(line string) error {
+	ech := make(chan error, 1)
+
+	b.ircSendDirectChan <- misc.ErrorBack[string]{
+		Content:   line,
+		ErrorChan: ech,
+	}
+
+	return <-ech
+}
+
+// Send queues a message to be sent asynchronously via the buffered send queue.
+// If the queue is full, the message is dropped and an error is logged.
+func (b *Bot) Send(line string) {
+	select {
+	case b.ircSendBuffered <- line:
+	default:
+		slog.Error("irc sendq full", "line", line)
+	}
+}
+
+// ConnectLoop continuously attempts to maintain an IRC session.
+// If the connection drops, it automatically retries with no delay.
+func (b *Bot) ConnectLoop() {
+	b.ircSendBuffered = make(chan string, b.config.SendQ)
+	b.ircSendDirectChan = make(chan misc.ErrorBack[string])
+
+	for {
+		err := b.Connect()
+		slog.Error("irc session error", "error", err)
+	}
+}
diff --git a/forged/internal/ipc/irc/conn.go b/forged/internal/ipc/irc/conn.go
new file mode 100644
index 0000000..15294ee
--- /dev/null
+++ b/forged/internal/ipc/irc/conn.go
@@ -0,0 +1,49 @@
+package irc
+
+import (
+	"bufio"
+	"net"
+	"slices"
+
+	"go.lindenii.runxiyu.org/forge/forged/internal/common/misc"
+)
+
+type Conn struct {
+	netConn   net.Conn
+	bufReader *bufio.Reader
+}
+
+func NewConn(netConn net.Conn) Conn {
+	return Conn{
+		netConn:   netConn,
+		bufReader: bufio.NewReader(netConn),
+	}
+}
+
+func (c *Conn) ReadMessage() (msg Message, line string, err error) {
+	raw, err := c.bufReader.ReadSlice('\n')
+	if err != nil {
+		return
+	}
+
+	if raw[len(raw)-1] == '\n' {
+		raw = raw[:len(raw)-1]
+	}
+	if raw[len(raw)-1] == '\r' {
+		raw = raw[:len(raw)-1]
+	}
+
+	lineBytes := slices.Clone(raw)
+	line = misc.BytesToString(lineBytes)
+	msg, err = Parse(lineBytes)
+
+	return
+}
+
+func (c *Conn) Write(p []byte) (n int, err error) {
+	return c.netConn.Write(p)
+}
+
+func (c *Conn) WriteString(s string) (n int, err error) {
+	return c.netConn.Write(misc.StringToBytes(s))
+}
diff --git a/forged/internal/ipc/irc/doc.go b/forged/internal/ipc/irc/doc.go
new file mode 100644
index 0000000..dcfca82
--- /dev/null
+++ b/forged/internal/ipc/irc/doc.go
@@ -0,0 +1,2 @@
+// Package irc provides basic IRC bot functionality.
+package irc
diff --git a/forged/internal/ipc/irc/errors.go b/forged/internal/ipc/irc/errors.go
new file mode 100644
index 0000000..3506c70
--- /dev/null
+++ b/forged/internal/ipc/irc/errors.go
@@ -0,0 +1,8 @@
+package irc
+
+import "errors"
+
+var (
+	ErrInvalidIRCv3Tag = errors.New("invalid ircv3 tag")
+	ErrMalformedMsg    = errors.New("malformed irc message")
+)
diff --git a/forged/internal/ipc/irc/message.go b/forged/internal/ipc/irc/message.go
new file mode 100644
index 0000000..5843226
--- /dev/null
+++ b/forged/internal/ipc/irc/message.go
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: Copyright (c) 2018-2024 luk3yx <https://luk3yx.github.io>
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+package irc
+
+import (
+	"bytes"
+
+	"go.lindenii.runxiyu.org/forge/forged/internal/common/misc"
+)
+
+type Message struct {
+	Command string
+	Source  Source
+	Tags    map[string]string
+	Args    []string
+}
+
+// All strings returned are borrowed from the input byte slice.
+func Parse(raw []byte) (msg Message, err error) {
+	sp := bytes.Split(raw, []byte{' '}) // TODO: Use bytes.Cut instead here
+
+	if bytes.HasPrefix(sp[0], []byte{'@'}) { // TODO: Check size manually
+		if len(sp[0]) < 2 {
+			err = ErrMalformedMsg
+			return
+		}
+		sp[0] = sp[0][1:]
+
+		msg.Tags, err = tagsToMap(sp[0])
+		if err != nil {
+			return
+		}
+
+		if len(sp) < 2 {
+			err = ErrMalformedMsg
+			return
+		}
+		sp = sp[1:]
+	} else {
+		msg.Tags = nil // TODO: Is a nil map the correct thing to use here?
+	}
+
+	if bytes.HasPrefix(sp[0], []byte{':'}) { // TODO: Check size manually
+		if len(sp[0]) < 2 {
+			err = ErrMalformedMsg
+			return
+		}
+		sp[0] = sp[0][1:]
+
+		msg.Source = parseSource(sp[0])
+
+		if len(sp) < 2 {
+			err = ErrMalformedMsg
+			return
+		}
+		sp = sp[1:]
+	}
+
+	msg.Command = misc.BytesToString(sp[0])
+	if len(sp) < 2 {
+		return
+	}
+	sp = sp[1:]
+
+	for i := 0; i < len(sp); i++ {
+		if len(sp[i]) == 0 {
+			continue
+		}
+		if sp[i][0] == ':' {
+			if len(sp[i]) < 2 {
+				sp[i] = []byte{}
+			} else {
+				sp[i] = sp[i][1:]
+			}
+			msg.Args = append(msg.Args, misc.BytesToString(bytes.Join(sp[i:], []byte{' '})))
+			// TODO: Avoid Join by not using sp in the first place
+			break
+		}
+		msg.Args = append(msg.Args, misc.BytesToString(sp[i]))
+	}
+
+	return
+}
+
+var ircv3TagEscapes = map[byte]byte{ //nolint:gochecknoglobals
+	':': ';',
+	's': ' ',
+	'r': '\r',
+	'n': '\n',
+}
+
+func tagsToMap(raw []byte) (tags map[string]string, err error) {
+	tags = make(map[string]string)
+	for rawTag := range bytes.SplitSeq(raw, []byte{';'}) {
+		key, value, found := bytes.Cut(rawTag, []byte{'='})
+		if !found {
+			err = ErrInvalidIRCv3Tag
+			return
+		}
+		if len(value) == 0 {
+			tags[misc.BytesToString(key)] = ""
+		} else {
+			if !bytes.Contains(value, []byte{'\\'}) {
+				tags[misc.BytesToString(key)] = misc.BytesToString(value)
+			} else {
+				valueUnescaped := bytes.NewBuffer(make([]byte, 0, len(value)))
+				for i := 0; i < len(value); i++ {
+					if value[i] == '\\' {
+						i++
+						byteUnescaped, ok := ircv3TagEscapes[value[i]]
+						if !ok {
+							byteUnescaped = value[i]
+						}
+						valueUnescaped.WriteByte(byteUnescaped)
+					} else {
+						valueUnescaped.WriteByte(value[i])
+					}
+				}
+				tags[misc.BytesToString(key)] = misc.BytesToString(valueUnescaped.Bytes())
+			}
+		}
+	}
+	return
+}
diff --git a/forged/internal/ipc/irc/source.go b/forged/internal/ipc/irc/source.go
new file mode 100644
index 0000000..c6baf75
--- /dev/null
+++ b/forged/internal/ipc/irc/source.go
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+package irc
+
+import (
+	"bytes"
+
+	"go.lindenii.runxiyu.org/forge/forged/internal/common/misc"
+)
+
+type Source interface {
+	AsSourceString() string
+}
+
+func parseSource(s []byte) Source {
+	nick, userhost, found := bytes.Cut(s, []byte{'!'})
+	if !found {
+		return Server{name: misc.BytesToString(s)}
+	}
+
+	user, host, found := bytes.Cut(userhost, []byte{'@'})
+	if !found {
+		return Server{name: misc.BytesToString(s)}
+	}
+
+	return Client{
+		Nick: misc.BytesToString(nick),
+		User: misc.BytesToString(user),
+		Host: misc.BytesToString(host),
+	}
+}
+
+type Server struct {
+	name string
+}
+
+func (s Server) AsSourceString() string {
+	return s.name
+}
+
+type Client struct {
+	Nick string
+	User string
+	Host string
+}
+
+func (c Client) AsSourceString() string {
+	return c.Nick + "!" + c.User + "@" + c.Host
+}