fix: resolve remaining audit findings (SEC, COMP, TECH)

SEC #2: Fix editor command injection by replacing sh -c with direct
exec.Command + strings.Fields. Merge identical editor_unix.go and
editor_default.go into a single editor.go. Fix slice aliasing bug in
args construction.

COMP #5: Extract url_extractor.go, embed_renderer.go, and
attachment_handler.go from the 1600-line messages_list.go to improve
maintainability.

TECH #7: Add image_viewer_args config field for explicit viewer
arguments, making geometry configuration Wayland-friendly.

COMP #11: Fix log level consistency — keyring retrieval and avatar
cache failures now log at Warn instead of Info.

COMP #13-16, TECH #8: Add package doc comments (chat, markdown),
config field validation comments, and DISCORDO_TOKEN security warning.

Additional: Add nil guard for Me() in onTypingStart to prevent
potential panic.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/config/config.go

@@ -95,12 +95,14 @@ type (
 		Status              discord.Status `toml:"status"`
 		HideBlockedUsers    bool           `toml:"hide_blocked_users"`
 		ShowAttachmentLinks bool           `toml:"show_attachment_links"`
-		ImageViewer         string         `toml:"image_viewer"`
-		ImageSaveDir        string         `toml:"image_save_dir"`
+		ImageViewer     string   `toml:"image_viewer"`
+		ImageViewerArgs []string `toml:"image_viewer_args"`
+		ImageSaveDir    string   `toml:"image_save_dir"`
 
-		// Use 0 to disable
+		// Use 0 to disable. Maximum practical value is ~255 (uint8).
 		AutocompleteLimit uint8 `toml:"autocomplete_limit"`
-		MessagesLimit     uint8 `toml:"messages_limit"`
+		// Range: 1-100 (clamped by the Discord API). Use 0 to fall back to the default.
+		MessagesLimit uint8 `toml:"messages_limit"`
 
 		Markdown        MarkdownConfig  `toml:"markdown"`
 		Help            HelpConfig      `toml:"help"`

internal/config/config.toml

@@ -1,3 +1,8 @@
+# WARNING: Avoid passing your Discord token via the DISCORDO_TOKEN environment
+# variable in shared or multi-user environments. Environment variables are
+# visible to other processes (e.g. via /proc). Prefer the keyring-based login
+# flow instead.
+
 # Whether to focus the message input automatically when a channel is selected.
 # Set to false to preview channels without moving focus.
 auto_focus = true
@@ -17,6 +22,12 @@ show_attachment_links = true
 # first argument. Set to "default" to use xdg-open / open.
 image_viewer = "mpv"
 
+# Extra arguments for the image viewer. When set, these are used instead of
+# auto-detected args (e.g. mpv geometry via xdotool). The file path is always
+# appended last. Example: ["--force-window", "--loop-file=inf"]
+# Useful on Wayland where xdotool geometry detection is unavailable.
+image_viewer_args = []
+
 # Directory where images are saved with the save_image keybind.
 # Supports ~ for home directory. Leave empty to use the current directory.
 image_save_dir = ""

internal/config/editor.go

@@ -0,0 +1,17 @@
+package config
+
+import (
+	"os/exec"
+	"strings"
+)
+
+func (cfg *Config) CreateEditorCommand(path string) *exec.Cmd {
+	if cfg.Editor == "" {
+		return nil
+	}
+	parts := strings.Fields(cfg.Editor)
+	args := make([]string, len(parts)-1, len(parts))
+	copy(args, parts[1:])
+	args = append(args, path)
+	return exec.Command(parts[0], args...)
+}

internal/config/editor_default.go

@@ -1,14 +0,0 @@
-//go:build !unix
-
-package config
-
-import (
-	"os/exec"
-)
-
-func (cfg *Config) CreateEditorCommand(path string) *exec.Cmd {
-	if cfg.Editor == "" {
-		return nil
-	}
-	return exec.Command(cfg.Editor, path)
-}

internal/config/editor_unix.go

@@ -1,14 +0,0 @@
-//go:build unix
-
-package config
-
-import (
-	"os/exec"
-)
-
-func (cfg *Config) CreateEditorCommand(path string) *exec.Cmd {
-	if cfg.Editor == "" {
-		return nil
-	}
-	return exec.Command("sh", "-c", cfg.Editor+" \"$@\"", cfg.Editor, path)
-}

internal/markdown/renderer.go

@@ -1,3 +1,8 @@
+// Package markdown converts a goldmark AST (parsed by discordmd) into styled
+// tview.Line slices for terminal rendering. It walks the AST node tree,
+// applying tcell styles for inline formatting (bold, italic, code, spoilers),
+// block elements (code blocks with chroma syntax highlighting, blockquotes,
+// lists), and Discord-specific nodes (mentions, emoji, links with OSC 8 URLs).
 package markdown
 
 import (

internal/notifications/notifications.go

@@ -63,7 +63,7 @@ func Notify(state *ningen.State, message *gateway.MessageCreateEvent, cfg *confi
 
 	imagePath, err := getCachedProfileImage(hash, message.Author.AvatarURLWithType(discord.PNGImage))
 	if err != nil {
-		slog.Info("failed to get profile image from cache for notification", "err", err, "hash", hash)
+		slog.Warn("failed to get profile image from cache for notification", "err", err, "hash", hash)
 	}
 
 	shouldChime := cfg.Notifications.Sound.Enabled && (!cfg.Notifications.Sound.OnlyOnPing || mentions.Has(ningen.MessageMentions|ningen.MessageNotifies))

internal/ui/chat/attachment_handler.go

@@ -0,0 +1,268 @@
+package chat
+
+import (
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"net/url"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/ayn2op/discordo/internal/consts"
+	"github.com/ayn2op/discordo/internal/ui"
+	"github.com/ayn2op/tview/layers"
+	"github.com/diamondburned/arikawa/v3/discord"
+	"github.com/skratchdot/open-golang/open"
+)
+
+const maxAttachmentSize = 100 * 1024 * 1024 // 100 MB
+
+var supportedImageTypes = map[string]bool{
+	"image/jpeg": true,
+	"image/png":  true,
+	"image/webp": true,
+	"image/gif":  true,
+}
+
+func (ml *messagesList) downloadToCache(attachment discord.Attachment) (string, error) {
+	parsed, err := url.Parse(attachment.URL)
+	if err != nil {
+		return "", fmt.Errorf("invalid attachment URL: %w", err)
+	}
+	if parsed.Scheme != "https" {
+		return "", fmt.Errorf("refusing non-HTTPS attachment URL: %s", parsed.Scheme)
+	}
+
+	resp, err := http.Get(attachment.URL)
+	if err != nil {
+		return "", fmt.Errorf("failed to fetch attachment: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("unexpected status %d fetching attachment", resp.StatusCode)
+	}
+
+	dir := filepath.Join(consts.CacheDir(), "attachments")
+	if err := os.MkdirAll(dir, 0700); err != nil {
+		return "", fmt.Errorf("failed to create attachments dir: %w", err)
+	}
+
+	safeName := filepath.Base(attachment.Filename)
+	if safeName == "." || safeName == ".." {
+		safeName = "attachment"
+	}
+	path := filepath.Join(dir, safeName)
+	file, err := os.Create(path)
+	if err != nil {
+		return "", fmt.Errorf("failed to create attachment file: %w", err)
+	}
+	defer file.Close()
+
+	if _, err := io.Copy(file, io.LimitReader(resp.Body, maxAttachmentSize)); err != nil {
+		return "", fmt.Errorf("failed to write attachment file: %w", err)
+	}
+
+	return path, nil
+}
+
+func terminalGeometry() string {
+	out, err := exec.Command("xdotool", "getactivewindow", "getwindowgeometry", "--shell").Output()
+	if err != nil {
+		return ""
+	}
+	var x, y, w, h string
+	for _, line := range strings.Split(string(out), "\n") {
+		switch {
+		case strings.HasPrefix(line, "X="):
+			x = strings.TrimPrefix(line, "X=")
+		case strings.HasPrefix(line, "Y="):
+			y = strings.TrimPrefix(line, "Y=")
+		case strings.HasPrefix(line, "WIDTH="):
+			w = strings.TrimPrefix(line, "WIDTH=")
+		case strings.HasPrefix(line, "HEIGHT="):
+			h = strings.TrimPrefix(line, "HEIGHT=")
+		}
+	}
+	if w != "" && h != "" && x != "" && y != "" {
+		return w + "x" + h + "+" + x + "+" + y
+	}
+	return ""
+}
+
+func viewerArgs(viewer, path string, customArgs []string) []string {
+	if len(customArgs) > 0 {
+		args := make([]string, 0, len(customArgs)+2)
+		args = append(args, viewer)
+		args = append(args, customArgs...)
+		args = append(args, path)
+		return args
+	}
+	if strings.HasSuffix(viewer, "mpv") || strings.Contains(viewer, "mpv ") {
+		args := []string{viewer, "--force-window", "--loop-file=inf"}
+		if geom := terminalGeometry(); geom != "" {
+			args = append(args, "--geometry="+geom)
+		}
+		args = append(args, path)
+		return args
+	}
+	return []string{viewer, path}
+}
+
+func (ml *messagesList) openAttachment(attachment discord.Attachment) {
+	path, err := ml.downloadToCache(attachment)
+	if err != nil {
+		slog.Error("failed to download attachment", "err", err, "url", attachment.URL)
+		return
+	}
+
+	viewer := ml.cfg.ImageViewer
+	if viewer != "" && supportedImageTypes[attachment.ContentType] {
+		if _, err := exec.LookPath(viewer); err != nil {
+			slog.Error("image viewer not found in PATH", "viewer", viewer, "err", err)
+			return
+		}
+		args := viewerArgs(viewer, path, ml.cfg.ImageViewerArgs)
+		cmd := exec.Command(args[0], args[1:]...)
+		cmd.Stdin = os.Stdin
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		ml.chatView.app.Suspend(func() {
+			if err := cmd.Run(); err != nil {
+				slog.Error("failed to run image viewer", "viewer", viewer, "err", err)
+			}
+		})
+		return
+	}
+
+	if err := open.Start(path); err != nil {
+		slog.Error("failed to open attachment file", "err", err, "path", path)
+	}
+}
+
+func (ml *messagesList) saveAttachmentImage(attachment discord.Attachment) {
+	path, err := ml.downloadToCache(attachment)
+	if err != nil {
+		slog.Error("failed to download attachment", "err", err, "url", attachment.URL)
+		return
+	}
+
+	saveDir := ml.cfg.ImageSaveDir
+	if saveDir == "" {
+		saveDir = "."
+	}
+	if err := os.MkdirAll(saveDir, 0700); err != nil {
+		slog.Error("failed to create save directory", "err", err, "path", saveDir)
+		return
+	}
+
+	safeName := filepath.Base(attachment.Filename)
+	if safeName == "." || safeName == ".." {
+		safeName = "attachment"
+	}
+	destPath := filepath.Join(saveDir, safeName)
+	src, err := os.Open(path)
+	if err != nil {
+		slog.Error("failed to open cached file", "err", err, "path", path)
+		return
+	}
+	defer src.Close()
+
+	dst, err := os.Create(destPath)
+	if err != nil {
+		slog.Error("failed to create save file", "err", err, "path", destPath)
+		return
+	}
+	defer dst.Close()
+
+	if _, err := io.Copy(dst, src); err != nil {
+		slog.Error("failed to save image", "err", err)
+		return
+	}
+
+	slog.Info("image saved", "path", destPath)
+}
+
+func (ml *messagesList) saveImage() {
+	msg, err := ml.selectedMessage()
+	if err != nil {
+		slog.Error("failed to get selected message", "err", err)
+		return
+	}
+
+	var images []discord.Attachment
+	for _, a := range msg.Attachments {
+		if supportedImageTypes[a.ContentType] {
+			images = append(images, a)
+		}
+	}
+
+	if len(images) == 0 {
+		return
+	}
+
+	if len(images) == 1 {
+		go ml.saveAttachmentImage(images[0])
+		return
+	}
+
+	var items []attachmentItem
+	for _, a := range images {
+		attachment := a
+		items = append(items, attachmentItem{
+			label: attachment.Filename,
+			open:  func() { go ml.saveAttachmentImage(attachment) },
+		})
+	}
+	ml.attachmentsPicker.SetItems(items)
+	ml.showAttachmentsOverlay()
+}
+
+func (ml *messagesList) openURL(url string) {
+	if err := open.Start(url); err != nil {
+		slog.Error("failed to open URL", "err", err, "url", url)
+	}
+}
+
+func (ml *messagesList) showAttachmentsList(urls []string, attachments []discord.Attachment) {
+	var items []attachmentItem
+	for _, a := range attachments {
+		attachment := a
+		action := func() {
+			if strings.HasPrefix(attachment.ContentType, "image/") {
+				go ml.openAttachment(attachment)
+			} else {
+				go ml.openURL(attachment.URL)
+			}
+		}
+		items = append(items, attachmentItem{
+			label: attachment.Filename,
+			open:  action,
+		})
+	}
+	for _, u := range urls {
+		url := u
+		items = append(items, attachmentItem{
+			label: url,
+			open:  func() { go ml.openURL(url) },
+		})
+	}
+	ml.attachmentsPicker.SetItems(items)
+	ml.showAttachmentsOverlay()
+}
+
+func (ml *messagesList) showAttachmentsOverlay() {
+	ml.chatView.
+		AddLayer(
+			ui.Centered(ml.attachmentsPicker, ml.cfg.Picker.Width, ml.cfg.Picker.Height),
+			layers.WithName(attachmentsListLayerName),
+			layers.WithResize(true),
+			layers.WithVisible(true),
+			layers.WithOverlay(),
+		).
+		SendToFront(attachmentsListLayerName)
+	ml.chatView.app.SetFocus(ml.attachmentsPicker)
+}

internal/ui/chat/embed_renderer.go

@@ -0,0 +1,248 @@
+package chat
+
+import (
+	"net/url"
+	"strings"
+
+	"github.com/ayn2op/discordo/internal/config"
+	"github.com/ayn2op/discordo/internal/ui"
+	"github.com/ayn2op/tview"
+	"github.com/diamondburned/arikawa/v3/discord"
+	"github.com/gdamore/tcell/v3"
+	"github.com/rivo/uniseg"
+)
+
+type embedLine struct {
+	Text string
+	Kind embedLineKind
+	URL  string
+}
+
+type embedLineKind uint8
+
+const (
+	// Keep this ordering stable: drawEmbeds indexes precomputed style slots by this enum.
+	embedLineProvider embedLineKind = iota
+	embedLineAuthor
+	embedLineTitle
+	embedLineDescription
+	embedLineFieldName
+	embedLineFieldValue
+	embedLineFooter
+	embedLineURL
+	embedLineKindCount
+)
+
+func embedLineStyles(baseStyle tcell.Style, theme config.MessagesListEmbedsTheme) [embedLineKindCount]tcell.Style {
+	styles := [embedLineKindCount]tcell.Style{}
+	styles[embedLineProvider] = ui.MergeStyle(baseStyle, theme.ProviderStyle.Style)
+	styles[embedLineAuthor] = ui.MergeStyle(baseStyle, theme.AuthorStyle.Style)
+	styles[embedLineTitle] = ui.MergeStyle(baseStyle, theme.TitleStyle.Style)
+	styles[embedLineDescription] = ui.MergeStyle(baseStyle, theme.DescriptionStyle.Style)
+	styles[embedLineFieldName] = ui.MergeStyle(baseStyle, theme.FieldNameStyle.Style)
+	styles[embedLineFieldValue] = ui.MergeStyle(baseStyle, theme.FieldValueStyle.Style)
+	styles[embedLineFooter] = ui.MergeStyle(baseStyle, theme.FooterStyle.Style)
+	styles[embedLineURL] = ui.MergeStyle(baseStyle, theme.URLStyle.Style)
+	return styles
+}
+
+type embedLineDedupKey struct {
+	kind embedLineKind
+	text string
+}
+
+func embedLines(embed discord.Embed, contentURLs map[string]struct{}) []embedLine {
+	lines := make([]embedLine, 0, 8)
+	seen := make(map[embedLineDedupKey]struct{}, 8)
+
+	appendUnique := func(s string, kind embedLineKind, rawURL string) {
+		s = strings.TrimSpace(s)
+		if s == "" {
+			return
+		}
+		// Deduplicate by kind+text so the same value can intentionally appear in multiple semantic slots with different styles (e.g. title vs. field).
+		key := embedLineDedupKey{kind: kind, text: s}
+		if _, ok := seen[key]; ok {
+			return
+		}
+		seen[key] = struct{}{}
+		lines = append(lines, embedLine{
+			Text: s,
+			Kind: kind,
+			URL:  rawURL,
+		})
+	}
+
+	appendURL := func(url discord.URL) {
+		u := strings.TrimSpace(string(url))
+		if u == "" {
+			return
+		}
+		// Avoid duplicating links that already appear in message body content.
+		if _, ok := contentURLs[u]; ok {
+			return
+		}
+		appendUnique(linkDisplayText(u), embedLineURL, u)
+	}
+
+	if embed.Provider != nil {
+		appendUnique(embed.Provider.Name, embedLineProvider, "")
+	}
+	if embed.Author != nil {
+		appendUnique(embed.Author.Name, embedLineAuthor, "")
+	}
+	appendUnique(embed.Title, embedLineTitle, string(embed.URL))
+	// Some Discord embeds include markdown-escaped punctuation in raw payload text (e.g. "\."), so normalize for display.
+	appendUnique(unescapeMarkdownEscapes(embed.Description), embedLineDescription, "")
+
+	for _, field := range embed.Fields {
+		switch {
+		case field.Name != "" && field.Value != "":
+			appendUnique(field.Name, embedLineFieldName, "")
+			appendUnique(field.Value, embedLineFieldValue, "")
+		case field.Name != "":
+			appendUnique(field.Name, embedLineFieldName, "")
+		default:
+			appendUnique(field.Value, embedLineFieldValue, "")
+		}
+	}
+
+	if embed.Footer != nil {
+		appendUnique(embed.Footer.Text, embedLineFooter, "")
+	}
+
+	// Prefer media URLs after textual fields so previews read top-to-bottom before jumping to link targets.
+	// When a title exists, embed.URL is represented by title Style.Url metadata instead of a separate URL row.
+	if embed.Title == "" {
+		appendURL(embed.URL)
+	}
+	if embed.Image != nil {
+		appendURL(embed.Image.URL)
+	}
+	if embed.Video != nil {
+		appendURL(embed.Video.URL)
+	}
+
+	return lines
+}
+
+func linkDisplayText(raw string) string {
+	parsed, err := url.Parse(raw)
+	if err != nil || parsed.Host == "" {
+		return raw
+	}
+
+	path := strings.TrimSpace(parsed.EscapedPath())
+	switch {
+	case path == "", path == "/":
+		return parsed.Host
+	case len(path) > 48:
+		return parsed.Host + path[:45] + "..."
+	default:
+		return parsed.Host + path
+	}
+}
+
+func unescapeMarkdownEscapes(s string) string {
+	if !strings.ContainsRune(s, '\\') {
+		return s
+	}
+
+	var b strings.Builder
+	b.Grow(len(s))
+
+	for i := range len(s) {
+		if s[i] == '\\' && i+1 < len(s) && isMarkdownEscapable(s[i+1]) {
+			continue
+		}
+		b.WriteByte(s[i])
+	}
+	return b.String()
+}
+
+func isMarkdownEscapable(c byte) bool {
+	switch c {
+	case '\\', '`', '*', '_', '{', '}', '[', ']', '(', ')', '#', '+', '-', '.', '!', '|', '>', '~':
+		return true
+	default:
+		return false
+	}
+}
+
+func lineWithURL(line tview.Line, rawURL string) tview.Line {
+	out := make(tview.Line, len(line))
+	for i, segment := range line {
+		out[i] = segment
+		out[i].Style = out[i].Style.Url(rawURL)
+	}
+	return out
+}
+
+func wrapStyledLine(line tview.Line, width int) []tview.Line {
+	if width <= 0 {
+		return []tview.Line{line}
+	}
+	if len(line) == 0 {
+		return []tview.Line{line}
+	}
+
+	lines := make([]tview.Line, 0, 2)
+	current := make(tview.Line, 0, len(line))
+	currentWidth := 0
+
+	pushSegment := func(text string, style tcell.Style) {
+		if text == "" {
+			return
+		}
+		if n := len(current); n > 0 && current[n-1].Style == style {
+			current[n-1].Text += text
+			return
+		}
+		current = append(current, tview.Segment{Text: text, Style: style})
+	}
+
+	flush := func() {
+		lineCopy := make(tview.Line, len(current))
+		copy(lineCopy, current)
+		lines = append(lines, lineCopy)
+		current = current[:0]
+		currentWidth = 0
+	}
+
+	for _, segment := range line {
+		state := -1
+		rest := segment.Text
+		for len(rest) > 0 {
+			cluster, nextRest, boundaries, nextState := uniseg.StepString(rest, state)
+			state = nextState
+			rest = nextRest
+			if cluster == "" {
+				continue
+			}
+
+			// Use grapheme width (not rune count) so wrapping stays correct with wide glyphs, emoji, and combining characters.
+			clusterWidth := graphemeClusterWidth(boundaries)
+			if currentWidth > 0 && currentWidth+clusterWidth > width {
+				flush()
+			}
+			pushSegment(cluster, segment.Style)
+			currentWidth += clusterWidth
+
+			if currentWidth >= width {
+				flush()
+			}
+		}
+	}
+
+	if len(current) > 0 {
+		flush()
+	}
+	if len(lines) == 0 {
+		return []tview.Line{{}}
+	}
+	return lines
+}
+
+func graphemeClusterWidth(boundaries int) int {
+	return boundaries >> uniseg.ShiftWidth
+}

internal/ui/chat/events.go

@@ -1,3 +1,7 @@
+// events.go defines the custom event types and command factories that drive
+// the chat UI. Commands (tview.Command) run off the main goroutine and return
+// events (tview.Event) that are dispatched back to HandleEvent on the UI thread.
+
 package chat
 
 import (

internal/ui/chat/messages_list.go

@@ -3,25 +3,15 @@ package chat
 import (
 	"context"
 	"errors"
-	"fmt"
-	"io"
 	"log/slog"
-	"net/http"
-	"net/url"
-	"os"
-	"os/exec"
-	"path/filepath"
 	"slices"
 	"strings"
 	"sync"
 	"time"
 	"unicode/utf8"
 
-	"github.com/ayn2op/tview/layers"
-
 	"github.com/ayn2op/discordo/internal/clipboard"
 	"github.com/ayn2op/discordo/internal/config"
-	"github.com/ayn2op/discordo/internal/consts"
 	"github.com/ayn2op/discordo/internal/markdown"
 	"github.com/ayn2op/discordo/internal/ui"
 	"github.com/ayn2op/tview"
@@ -36,11 +26,7 @@ import (
 	"github.com/diamondburned/ningen/v3/discordmd"
 	"github.com/gdamore/tcell/v3"
 	"github.com/gdamore/tcell/v3/color"
-	"github.com/rivo/uniseg"
-	"github.com/skratchdot/open-golang/open"
 	"github.com/yuin/goldmark/ast"
-	"github.com/yuin/goldmark/parser"
-	"github.com/yuin/goldmark/text"
 )
 
 type messagesList struct {
@@ -569,241 +555,6 @@ func (ml *messagesList) drawEmbeds(builder *tview.LineBuilder, message discord.M
 	}
 }
 
-func wrapStyledLine(line tview.Line, width int) []tview.Line {
-	if width <= 0 {
-		return []tview.Line{line}
-	}
-	if len(line) == 0 {
-		return []tview.Line{line}
-	}
-
-	lines := make([]tview.Line, 0, 2)
-	current := make(tview.Line, 0, len(line))
-	currentWidth := 0
-
-	pushSegment := func(text string, style tcell.Style) {
-		if text == "" {
-			return
-		}
-		if n := len(current); n > 0 && current[n-1].Style == style {
-			current[n-1].Text += text
-			return
-		}
-		current = append(current, tview.Segment{Text: text, Style: style})
-	}
-
-	flush := func() {
-		lineCopy := make(tview.Line, len(current))
-		copy(lineCopy, current)
-		lines = append(lines, lineCopy)
-		current = current[:0]
-		currentWidth = 0
-	}
-
-	for _, segment := range line {
-		state := -1
-		rest := segment.Text
-		for len(rest) > 0 {
-			cluster, nextRest, boundaries, nextState := uniseg.StepString(rest, state)
-			state = nextState
-			rest = nextRest
-			if cluster == "" {
-				continue
-			}
-
-			// Use grapheme width (not rune count) so wrapping stays correct with wide glyphs, emoji, and combining characters.
-			clusterWidth := graphemeClusterWidth(boundaries)
-			if currentWidth > 0 && currentWidth+clusterWidth > width {
-				flush()
-			}
-			pushSegment(cluster, segment.Style)
-			currentWidth += clusterWidth
-
-			if currentWidth >= width {
-				flush()
-			}
-		}
-	}
-
-	if len(current) > 0 {
-		flush()
-	}
-	if len(lines) == 0 {
-		return []tview.Line{{}}
-	}
-	return lines
-}
-
-func graphemeClusterWidth(boundaries int) int {
-	return boundaries >> uniseg.ShiftWidth
-}
-
-func lineWithURL(line tview.Line, rawURL string) tview.Line {
-	out := make(tview.Line, len(line))
-	for i, segment := range line {
-		out[i] = segment
-		out[i].Style = out[i].Style.Url(rawURL)
-	}
-	return out
-}
-
-type embedLine struct {
-	Text string
-	Kind embedLineKind
-	URL  string
-}
-
-type embedLineKind uint8
-
-const (
-	// Keep this ordering stable: drawEmbeds indexes precomputed style slots by this enum.
-	embedLineProvider embedLineKind = iota
-	embedLineAuthor
-	embedLineTitle
-	embedLineDescription
-	embedLineFieldName
-	embedLineFieldValue
-	embedLineFooter
-	embedLineURL
-	embedLineKindCount
-)
-
-func embedLineStyles(baseStyle tcell.Style, theme config.MessagesListEmbedsTheme) [embedLineKindCount]tcell.Style {
-	styles := [embedLineKindCount]tcell.Style{}
-	styles[embedLineProvider] = ui.MergeStyle(baseStyle, theme.ProviderStyle.Style)
-	styles[embedLineAuthor] = ui.MergeStyle(baseStyle, theme.AuthorStyle.Style)
-	styles[embedLineTitle] = ui.MergeStyle(baseStyle, theme.TitleStyle.Style)
-	styles[embedLineDescription] = ui.MergeStyle(baseStyle, theme.DescriptionStyle.Style)
-	styles[embedLineFieldName] = ui.MergeStyle(baseStyle, theme.FieldNameStyle.Style)
-	styles[embedLineFieldValue] = ui.MergeStyle(baseStyle, theme.FieldValueStyle.Style)
-	styles[embedLineFooter] = ui.MergeStyle(baseStyle, theme.FooterStyle.Style)
-	styles[embedLineURL] = ui.MergeStyle(baseStyle, theme.URLStyle.Style)
-	return styles
-}
-
-type embedLineDedupKey struct {
-	kind embedLineKind
-	text string
-}
-
-func embedLines(embed discord.Embed, contentURLs map[string]struct{}) []embedLine {
-	lines := make([]embedLine, 0, 8)
-	seen := make(map[embedLineDedupKey]struct{}, 8)
-
-	appendUnique := func(s string, kind embedLineKind, rawURL string) {
-		s = strings.TrimSpace(s)
-		if s == "" {
-			return
-		}
-		// Deduplicate by kind+text so the same value can intentionally appear in multiple semantic slots with different styles (e.g. title vs. field).
-		key := embedLineDedupKey{kind: kind, text: s}
-		if _, ok := seen[key]; ok {
-			return
-		}
-		seen[key] = struct{}{}
-		lines = append(lines, embedLine{
-			Text: s,
-			Kind: kind,
-			URL:  rawURL,
-		})
-	}
-
-	appendURL := func(url discord.URL) {
-		u := strings.TrimSpace(string(url))
-		if u == "" {
-			return
-		}
-		// Avoid duplicating links that already appear in message body content.
-		if _, ok := contentURLs[u]; ok {
-			return
-		}
-		appendUnique(linkDisplayText(u), embedLineURL, u)
-	}
-
-	if embed.Provider != nil {
-		appendUnique(embed.Provider.Name, embedLineProvider, "")
-	}
-	if embed.Author != nil {
-		appendUnique(embed.Author.Name, embedLineAuthor, "")
-	}
-	appendUnique(embed.Title, embedLineTitle, string(embed.URL))
-	// Some Discord embeds include markdown-escaped punctuation in raw payload text (e.g. "\."), so normalize for display.
-	appendUnique(unescapeMarkdownEscapes(embed.Description), embedLineDescription, "")
-
-	for _, field := range embed.Fields {
-		switch {
-		case field.Name != "" && field.Value != "":
-			appendUnique(field.Name, embedLineFieldName, "")
-			appendUnique(field.Value, embedLineFieldValue, "")
-		case field.Name != "":
-			appendUnique(field.Name, embedLineFieldName, "")
-		default:
-			appendUnique(field.Value, embedLineFieldValue, "")
-		}
-	}
-
-	if embed.Footer != nil {
-		appendUnique(embed.Footer.Text, embedLineFooter, "")
-	}
-
-	// Prefer media URLs after textual fields so previews read top-to-bottom before jumping to link targets.
-	// When a title exists, embed.URL is represented by title Style.Url metadata instead of a separate URL row.
-	if embed.Title == "" {
-		appendURL(embed.URL)
-	}
-	if embed.Image != nil {
-		appendURL(embed.Image.URL)
-	}
-	if embed.Video != nil {
-		appendURL(embed.Video.URL)
-	}
-
-	return lines
-}
-
-func linkDisplayText(raw string) string {
-	parsed, err := url.Parse(raw)
-	if err != nil || parsed.Host == "" {
-		return raw
-	}
-
-	path := strings.TrimSpace(parsed.EscapedPath())
-	switch {
-	case path == "", path == "/":
-		return parsed.Host
-	case len(path) > 48:
-		return parsed.Host + path[:45] + "..."
-	default:
-		return parsed.Host + path
-	}
-}
-
-func unescapeMarkdownEscapes(s string) string {
-	if !strings.ContainsRune(s, '\\') {
-		return s
-	}
-
-	var b strings.Builder
-	b.Grow(len(s))
-
-	for i := range len(s) {
-		if s[i] == '\\' && i+1 < len(s) && isMarkdownEscapable(s[i+1]) {
-			continue
-		}
-		b.WriteByte(s[i])
-	}
-	return b.String()
-}
-
-func isMarkdownEscapable(c byte) bool {
-	switch c {
-	case '\\', '`', '*', '_', '{', '}', '[', ']', '(', ')', '#', '+', '-', '.', '!', '|', '>', '~':
-		return true
-	default:
-		return false
-	}
-}
-
 func (ml *messagesList) drawForwardedMessage(builder *tview.LineBuilder, message discord.Message, baseStyle tcell.Style) {
 	dimStyle := baseStyle.Dim(true)
 	ml.drawTimestamps(builder, message.Timestamp, baseStyle)
@@ -1092,307 +843,6 @@ func (ml *messagesList) open() {
 	}
 }
 
-func extractURLs(content string) []string {
-	src := []byte(content)
-	node := parser.NewParser(
-		parser.WithBlockParsers(discordmd.BlockParsers()...),
-		parser.WithInlineParsers(discordmd.InlineParserWithLink()...),
-	).Parse(text.NewReader(src))
-
-	var urls []string
-	ast.Walk(node, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
-		if entering {
-			switch n := n.(type) {
-			case *ast.AutoLink:
-				urls = append(urls, string(n.URL(src)))
-			case *ast.Link:
-				urls = append(urls, string(n.Destination))
-			}
-		}
-
-		return ast.WalkContinue, nil
-	})
-	return urls
-}
-
-func extractEmbedURLs(embeds []discord.Embed) []string {
-	urls := make([]string, 0, len(embeds)*3)
-	for _, embed := range embeds {
-		if embed.URL != "" {
-			urls = append(urls, string(embed.URL))
-		}
-		if embed.Image != nil && embed.Image.URL != "" {
-			urls = append(urls, string(embed.Image.URL))
-		}
-		if embed.Video != nil && embed.Video.URL != "" {
-			urls = append(urls, string(embed.Video.URL))
-		}
-	}
-	return urls
-}
-
-func messageURLs(msg discord.Message) []string {
-	combined := extractURLs(msg.Content)
-	combined = append(combined, extractEmbedURLs(msg.Embeds)...)
-
-	urls := make([]string, 0, len(combined))
-	seen := make(map[string]struct{}, len(combined))
-	for _, u := range combined {
-		u = strings.TrimSpace(u)
-		if u == "" {
-			continue
-		}
-		if _, ok := seen[u]; ok {
-			continue
-		}
-		seen[u] = struct{}{}
-		urls = append(urls, u)
-	}
-	return urls
-}
-
-func (ml *messagesList) showAttachmentsList(urls []string, attachments []discord.Attachment) {
-	var items []attachmentItem
-	for _, a := range attachments {
-		attachment := a
-		action := func() {
-			if strings.HasPrefix(attachment.ContentType, "image/") {
-				go ml.openAttachment(attachment)
-			} else {
-				go ml.openURL(attachment.URL)
-			}
-		}
-		items = append(items, attachmentItem{
-			label: attachment.Filename,
-			open:  action,
-		})
-	}
-	for _, u := range urls {
-		url := u
-		items = append(items, attachmentItem{
-			label: url,
-			open:  func() { go ml.openURL(url) },
-		})
-	}
-	ml.attachmentsPicker.SetItems(items)
-	ml.showAttachmentsOverlay()
-}
-
-func (ml *messagesList) showAttachmentsOverlay() {
-	ml.chatView.
-		AddLayer(
-			ui.Centered(ml.attachmentsPicker, ml.cfg.Picker.Width, ml.cfg.Picker.Height),
-			layers.WithName(attachmentsListLayerName),
-			layers.WithResize(true),
-			layers.WithVisible(true),
-			layers.WithOverlay(),
-		).
-		SendToFront(attachmentsListLayerName)
-	ml.chatView.app.SetFocus(ml.attachmentsPicker)
-}
-
-const maxAttachmentSize = 100 * 1024 * 1024 // 100 MB
-
-func (ml *messagesList) downloadToCache(attachment discord.Attachment) (string, error) {
-	parsed, err := url.Parse(attachment.URL)
-	if err != nil {
-		return "", fmt.Errorf("invalid attachment URL: %w", err)
-	}
-	if parsed.Scheme != "https" {
-		return "", fmt.Errorf("refusing non-HTTPS attachment URL: %s", parsed.Scheme)
-	}
-
-	resp, err := http.Get(attachment.URL)
-	if err != nil {
-		return "", fmt.Errorf("failed to fetch attachment: %w", err)
-	}
-	defer resp.Body.Close()
-
-	if resp.StatusCode != http.StatusOK {
-		return "", fmt.Errorf("unexpected status %d fetching attachment", resp.StatusCode)
-	}
-
-	dir := filepath.Join(consts.CacheDir(), "attachments")
-	if err := os.MkdirAll(dir, 0700); err != nil {
-		return "", fmt.Errorf("failed to create attachments dir: %w", err)
-	}
-
-	safeName := filepath.Base(attachment.Filename)
-	if safeName == "." || safeName == ".." {
-		safeName = "attachment"
-	}
-	path := filepath.Join(dir, safeName)
-	file, err := os.Create(path)
-	if err != nil {
-		return "", fmt.Errorf("failed to create attachment file: %w", err)
-	}
-	defer file.Close()
-
-	if _, err := io.Copy(file, io.LimitReader(resp.Body, maxAttachmentSize)); err != nil {
-		return "", fmt.Errorf("failed to write attachment file: %w", err)
-	}
-
-	return path, nil
-}
-
-var supportedImageTypes = map[string]bool{
-	"image/jpeg": true,
-	"image/png":  true,
-	"image/webp": true,
-	"image/gif":  true,
-}
-
-func terminalGeometry() string {
-	out, err := exec.Command("xdotool", "getactivewindow", "getwindowgeometry", "--shell").Output()
-	if err != nil {
-		return ""
-	}
-	var x, y, w, h string
-	for _, line := range strings.Split(string(out), "\n") {
-		switch {
-		case strings.HasPrefix(line, "X="):
-			x = strings.TrimPrefix(line, "X=")
-		case strings.HasPrefix(line, "Y="):
-			y = strings.TrimPrefix(line, "Y=")
-		case strings.HasPrefix(line, "WIDTH="):
-			w = strings.TrimPrefix(line, "WIDTH=")
-		case strings.HasPrefix(line, "HEIGHT="):
-			h = strings.TrimPrefix(line, "HEIGHT=")
-		}
-	}
-	if w != "" && h != "" && x != "" && y != "" {
-		return w + "x" + h + "+" + x + "+" + y
-	}
-	return ""
-}
-
-func viewerArgs(viewer, path string) []string {
-	if strings.HasSuffix(viewer, "mpv") || strings.Contains(viewer, "mpv ") {
-		args := []string{viewer, "--force-window", "--loop-file=inf"}
-		if geom := terminalGeometry(); geom != "" {
-			args = append(args, "--geometry="+geom)
-		}
-		args = append(args, path)
-		return args
-	}
-	return []string{viewer, path}
-}
-
-func (ml *messagesList) openAttachment(attachment discord.Attachment) {
-	path, err := ml.downloadToCache(attachment)
-	if err != nil {
-		slog.Error("failed to download attachment", "err", err, "url", attachment.URL)
-		return
-	}
-
-	viewer := ml.cfg.ImageViewer
-	if viewer != "" && supportedImageTypes[attachment.ContentType] {
-		if _, err := exec.LookPath(viewer); err != nil {
-			slog.Error("image viewer not found in PATH", "viewer", viewer, "err", err)
-			return
-		}
-		args := viewerArgs(viewer, path)
-		cmd := exec.Command(args[0], args[1:]...)
-		cmd.Stdin = os.Stdin
-		cmd.Stdout = os.Stdout
-		cmd.Stderr = os.Stderr
-		ml.chatView.app.Suspend(func() {
-			if err := cmd.Run(); err != nil {
-				slog.Error("failed to run image viewer", "viewer", viewer, "err", err)
-			}
-		})
-		return
-	}
-
-	if err := open.Start(path); err != nil {
-		slog.Error("failed to open attachment file", "err", err, "path", path)
-	}
-}
-
-func (ml *messagesList) saveImage() {
-	msg, err := ml.selectedMessage()
-	if err != nil {
-		slog.Error("failed to get selected message", "err", err)
-		return
-	}
-
-	var images []discord.Attachment
-	for _, a := range msg.Attachments {
-		if supportedImageTypes[a.ContentType] {
-			images = append(images, a)
-		}
-	}
-
-	if len(images) == 0 {
-		return
-	}
-
-	if len(images) == 1 {
-		go ml.saveAttachmentImage(images[0])
-		return
-	}
-
-	var items []attachmentItem
-	for _, a := range images {
-		attachment := a
-		items = append(items, attachmentItem{
-			label: attachment.Filename,
-			open:  func() { go ml.saveAttachmentImage(attachment) },
-		})
-	}
-	ml.attachmentsPicker.SetItems(items)
-	ml.showAttachmentsOverlay()
-}
-
-func (ml *messagesList) saveAttachmentImage(attachment discord.Attachment) {
-	path, err := ml.downloadToCache(attachment)
-	if err != nil {
-		slog.Error("failed to download attachment", "err", err, "url", attachment.URL)
-		return
-	}
-
-	saveDir := ml.cfg.ImageSaveDir
-	if saveDir == "" {
-		saveDir = "."
-	}
-	if err := os.MkdirAll(saveDir, 0700); err != nil {
-		slog.Error("failed to create save directory", "err", err, "path", saveDir)
-		return
-	}
-
-	safeName := filepath.Base(attachment.Filename)
-	if safeName == "." || safeName == ".." {
-		safeName = "attachment"
-	}
-	destPath := filepath.Join(saveDir, safeName)
-	src, err := os.Open(path)
-	if err != nil {
-		slog.Error("failed to open cached file", "err", err, "path", path)
-		return
-	}
-	defer src.Close()
-
-	dst, err := os.Create(destPath)
-	if err != nil {
-		slog.Error("failed to create save file", "err", err, "path", destPath)
-		return
-	}
-	defer dst.Close()
-
-	if _, err := io.Copy(dst, src); err != nil {
-		slog.Error("failed to save image", "err", err)
-		return
-	}
-
-	slog.Info("image saved", "path", destPath)
-}
-
-func (ml *messagesList) openURL(url string) {
-	if err := open.Start(url); err != nil {
-		slog.Error("failed to open URL", "err", err, "url", url)
-	}
-}
-
 func (ml *messagesList) reply(mention bool) {
 	message, err := ml.selectedMessage()
 	if err != nil {

internal/ui/chat/model.go

@@ -1,3 +1,7 @@
+// Package chat implements the core chat UI: guild/channel navigation, message
+// display, message input, and attachment handling. It uses a command/event
+// architecture where user actions produce tview.Command functions that run
+// asynchronously and return tview.Event values to drive state transitions.
 package chat
 
 import (

internal/ui/chat/state.go

@@ -193,7 +193,7 @@ func (m *Model) onTypingStart(event *gateway.TypingStartEvent) {
 	}
 
 	me, _ := m.state.Cabinet.Me()
-	if event.UserID == me.ID {
+	if me != nil && event.UserID == me.ID {
 		return
 	}
 

internal/ui/chat/url_extractor.go

@@ -0,0 +1,70 @@
+package chat
+
+import (
+	"strings"
+
+	"github.com/diamondburned/arikawa/v3/discord"
+	"github.com/diamondburned/ningen/v3/discordmd"
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/text"
+)
+
+func extractURLs(content string) []string {
+	src := []byte(content)
+	node := parser.NewParser(
+		parser.WithBlockParsers(discordmd.BlockParsers()...),
+		parser.WithInlineParsers(discordmd.InlineParserWithLink()...),
+	).Parse(text.NewReader(src))
+
+	var urls []string
+	ast.Walk(node, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
+		if entering {
+			switch n := n.(type) {
+			case *ast.AutoLink:
+				urls = append(urls, string(n.URL(src)))
+			case *ast.Link:
+				urls = append(urls, string(n.Destination))
+			}
+		}
+
+		return ast.WalkContinue, nil
+	})
+	return urls
+}
+
+func extractEmbedURLs(embeds []discord.Embed) []string {
+	urls := make([]string, 0, len(embeds)*3)
+	for _, embed := range embeds {
+		if embed.URL != "" {
+			urls = append(urls, string(embed.URL))
+		}
+		if embed.Image != nil && embed.Image.URL != "" {
+			urls = append(urls, string(embed.Image.URL))
+		}
+		if embed.Video != nil && embed.Video.URL != "" {
+			urls = append(urls, string(embed.Video.URL))
+		}
+	}
+	return urls
+}
+
+func messageURLs(msg discord.Message) []string {
+	combined := extractURLs(msg.Content)
+	combined = append(combined, extractEmbedURLs(msg.Embeds)...)
+
+	urls := make([]string, 0, len(combined))
+	seen := make(map[string]struct{}, len(combined))
+	for _, u := range combined {
+		u = strings.TrimSpace(u)
+		if u == "" {
+			continue
+		}
+		if _, ok := seen[u]; ok {
+			continue
+		}
+		seen[u] = struct{}{}
+		urls = append(urls, u)
+	}
+	return urls
+}

internal/ui/root/events.go

@@ -26,7 +26,7 @@ func getToken() tview.Command {
 	return func() tview.Event {
 		token, err := keyring.GetToken()
 		if err != nil {
-			slog.Info("failed to retrieve token from keyring", "err", err)
+			slog.Warn("failed to retrieve token from keyring", "err", err)
 			return &loginEvent{}
 		}
 		return &tokenEvent{token: token}