5 files changed, 319 insertions, 0 deletions
diff --git a/internal/chat/chan.go b/internal/chat/chan.go
new file mode 100644
index 0000000..ae78bb6
--- /dev/null
+++ b/internal/chat/chan.go
@@ -0,0 +1,69 @@
+package chat
+
+import (
+	"context"
+	"log/slog"
+	"sync"
+	"time"
+)
+
+type Channel struct {
+	Name   string
+	Users  map[*User]struct{}
+	Events chan any
+	mu     sync.RWMutex
+}
+
+func (c *Channel) Listen(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case ev := <-c.Events:
+			c.processEvent(ev)
+		}
+	}
+}
+
+func (c *Channel) processEvent(ev any) {
+	slog.Info("channel event", slog.String("channel", c.Name), slog.Any("event", ev))
+
+	for u := range c.Users {
+		select {
+		case u.Events <- ev:
+		default:
+		}
+	}
+}
+
+func (c *Channel) Join(u *User) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if _, ok := c.Users[u]; ok {
+		return
+	}
+	c.Events <- UserJoined{
+		User: u,
+		Time: time.Now(),
+		Chan: c,
+	}
+
+	c.Users[u] = struct{}{}
+}
+
+func (c *Channel) Leave(u *User) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if _, ok := c.Users[u]; !ok {
+		return
+	}
+	c.Events <- UserLeft{
+		User: u,
+		Time: time.Now(),
+		Chan: c,
+	}
+
+	delete(c.Users, u)
+}
diff --git a/internal/chat/chat.go b/internal/chat/chat.go
new file mode 100644
index 0000000..4a639ba
--- /dev/null
+++ b/internal/chat/chat.go
@@ -0,0 +1,178 @@
+package chat
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"go.neonxp.ru/qchat/internal/config"
+)
+
+var (
+	helpMessage = "Available commands:\n" +
+		"/join [chan] - change current channel to [chan]\n" +
+		"/chans - list all chans\n" +
+		"/users - list all online users\n" +
+		"ctrl+c - leave chat"
+)
+
+type Chat struct {
+	cfg      *config.Config
+	users    map[*User]struct{}
+	channels map[*Channel]struct{}
+	wg       sync.WaitGroup
+	mu       sync.RWMutex
+}
+
+func New(cfg *config.Config) *Chat {
+	return &Chat{
+		cfg:      cfg,
+		users:    make(map[*User]struct{}, 32),
+		channels: make(map[*Channel]struct{}, 32),
+		wg:       sync.WaitGroup{},
+		mu:       sync.RWMutex{},
+	}
+}
+
+func (c *Chat) Run(ctx context.Context) error {
+	for _, channel := range c.cfg.Channels {
+		c.NewChannel(ctx, channel.Name)
+	}
+
+	c.wg.Wait()
+
+	return nil
+}
+
+func (c *Chat) NewUser(username, identify string) *User {
+	u := &User{
+		Username:    username,
+		Identify:    identify,
+		Chans:       map[string]*Channel{},
+		CurrentChan: nil,
+		Events:      make(chan any, 32),
+		mu:          sync.RWMutex{},
+	}
+
+	ch := c.GetChannel("main")
+	if ch != nil {
+		u.JoinChan(ch)
+	}
+
+	c.users[u] = struct{}{}
+
+	u.Events <- SystemMessage{
+		Message: fmt.Sprintf("Connected to %s chat server...", c.cfg.Server.Name),
+	}
+
+	return u
+}
+
+func (c *Chat) RemoveUser(u *User) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	for ch := range c.channels {
+		ch.Leave(u)
+	}
+
+	close(u.Events)
+
+	delete(c.users, u)
+}
+
+func (c *Chat) NewChannel(ctx context.Context, name string) *Channel {
+	ch := &Channel{
+		Name:   name,
+		Users:  make(map[*User]struct{}, 32),
+		Events: make(chan any),
+		mu:     sync.RWMutex{},
+	}
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.channels[ch] = struct{}{}
+	c.wg.Go(func() {
+		ch.Listen(ctx)
+	})
+
+	return ch
+}
+
+func (c *Chat) GetChannel(name string) *Channel {
+	for ch := range c.channels {
+		if ch.Name == name {
+			return ch
+		}
+	}
+
+	return nil
+}
+
+func (c *Chat) Message(user *User, message string) {
+	if user.CurrentChan == nil {
+		return
+	}
+
+	user.CurrentChan.Events <- Message{
+		User:    user,
+		Message: message,
+		Time:    time.Now(),
+	}
+}
+
+func (c *Chat) SelfMessage(user *User, message string) {
+	if user.CurrentChan == nil {
+		return
+	}
+
+	user.CurrentChan.Events <- SelfMessage{
+		User:    user,
+		Message: message,
+	}
+}
+func (c *Chat) SystemMessage(user *User, message string) {
+	user.Events <- SystemMessage{
+		Message: message,
+	}
+}
+
+func (c *Chat) Input(ctx context.Context, user *User, input string) {
+	cmd := strings.ToLower(input)
+	switch {
+	case strings.HasPrefix(cmd, "/me "):
+		c.SelfMessage(user, strings.TrimPrefix(input, "/me "))
+	case cmd == "/help":
+		c.SystemMessage(user, helpMessage)
+	case cmd == "/list":
+		list := make([]string, 0, len(c.channels))
+		for ch := range c.channels {
+			list = append(list, ch.Name)
+		}
+		c.SystemMessage(user, "Chans:\n"+strings.Join(list, "\n"))
+	case cmd == "/users":
+		list := make([]string, 0, len(c.users))
+		for u := range c.users {
+			list = append(list, u.NUsername())
+		}
+		c.SystemMessage(user, "Users:\n"+strings.Join(list, "\n"))
+	case strings.HasPrefix(cmd, "/join "):
+		newChanName := strings.TrimPrefix(input, "/join ")
+		var newChan *Channel
+		for ch := range c.channels {
+			if ch.Name == newChanName {
+				newChan = ch
+				break
+			}
+		}
+		if newChan == nil {
+			newChan = c.NewChannel(ctx, newChanName)
+		}
+		user.CurrentChan.Leave(user)
+		user.CurrentChan = newChan
+		newChan.Join(user)
+	default:
+		c.Message(user, input)
+	}
+}
diff --git a/internal/chat/message.go b/internal/chat/message.go
new file mode 100644
index 0000000..081d640
--- /dev/null
+++ b/internal/chat/message.go
@@ -0,0 +1,20 @@
+package chat
+
+import (
+	"time"
+)
+
+type SystemMessage struct {
+	Message string
+}
+
+type Message struct {
+	User    *User
+	Time    time.Time
+	Message string
+}
+
+type SelfMessage struct {
+	User    *User
+	Message string
+}
diff --git a/internal/chat/presence.go b/internal/chat/presence.go
new file mode 100644
index 0000000..995f214
--- /dev/null
+++ b/internal/chat/presence.go
@@ -0,0 +1,17 @@
+package chat
+
+import (
+	"time"
+)
+
+type UserJoined struct {
+	User *User
+	Chan *Channel
+	Time time.Time
+}
+
+type UserLeft struct {
+	User *User
+	Chan *Channel
+	Time time.Time
+}
diff --git a/internal/chat/user.go b/internal/chat/user.go
new file mode 100644
index 0000000..e897f32
--- /dev/null
+++ b/internal/chat/user.go
@@ -0,0 +1,35 @@
+package chat
+
+import (
+	"sync"
+)
+
+type User struct {
+	Username    string
+	Identify    string
+	Chans       map[string]*Channel
+	CurrentChan *Channel
+	Events      chan any
+	mu          sync.RWMutex
+}
+
+func (u *User) JoinChan(channel *Channel) {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+
+	if _, ok := u.Chans[channel.Name]; ok {
+		return
+	}
+
+	u.Chans[channel.Name] = channel
+	u.CurrentChan = channel
+	channel.Join(u)
+}
+
+func (u *User) NUsername() string {
+	username := u.Username
+	identify := u.Identify
+	shortIdentify := identify[max(0, len(identify)-5):]
+
+	return username[:min(len(username), 10)] + " (" + shortIdentify + ")"
+}