Add the /code slash command and a full-screen source viewer with syntax highlighting

CHANGELOG.md

@@ -10,6 +10,11 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Added
 
+- `/code <path>[:line]`: full-screen source viewer with syntax highlighting, a
+  CJK-aware caret (`j`/`k`, `g`/`G`, `h`/`l`), and `v` to select lines then `a`
+  to hand them to the chat input. The pane reads files itself, so it answers to
+  the same deny list as the tool gate.
+
 ### Changed
 
 ### Deprecated
@@ -18,6 +23,9 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Fixed
 
+- Horizontal scrolling no longer drops characters from the middle of a
+  wide-glyph (CJK) line in the diff and file views.
+
 ### Security
 
 ## [0.27.4] - 2026-09-20

README.md

@@ -37,6 +37,7 @@ A lean, high-performance terminal coding agent harness in Go — a sibling to Pi
 - [Configuration](#configuration)
 - [Interactive mode](#interactive-mode)
 - [Diff review](#diff-review)
+- [Code viewer](#code-viewer)
 - [Commands](#commands)
 - [Sessions](#sessions)
 - [Headless mode](#headless-mode)
@@ -255,7 +256,7 @@ syntax highlighting. Structural markers (`#`, `` ` ``, `*`) are stripped.
 The editor supports:
 
 - `@` — fuzzy file mention picker (type `@` and start typing a path)
-- `/` — slash command picker (`/sessions`, `/branch`, `/clear`, `/diff`)
+- `/` — slash command picker (`/sessions`, `/branch`, `/clear`, `/diff`, `/code`)
 - `?` — shortcut help picker (lists `/`, `!`, `@`, and key bindings; `Esc` closes)
 - `!command` — run a shell command locally and stream its output into the
   transcript (see [Commands](#commands))
@@ -291,6 +292,18 @@ Slash-picker Enter inserts `/diff` plus a trailing space into the composer; subm
 `s` side-by-side, `i` add/edit a note, `x` delete, `a` send notes to the agent,
 `?` help, `q` / `Esc` close. Notes persist under `.phi/review.json`.
 
+## Code viewer
+
+`/code <path>[:line]` opens a full-screen source viewer: syntax highlighting, a
+CJK-aware caret (`j`/`k`, `h`/`l`, `gg`/`G`), and `v` to select lines then `a`
+to hand them to the chat input as a `path:12-18` reference the model reads.
+The pane reads files itself and answers to the same deny list as the tool
+gate, so sensitive paths (`~/.ssh`, `.env`, …), binaries and files over 8 MiB
+are refused with a toast.
+
+`Esc` closes. The status row shows the path, caret and line count while
+reading, and the selection size while `v` is active.
+
 ## Branch switching
 
 `/branch` opens the branch picker for the working directory. Two columns: the
@@ -324,6 +337,7 @@ unfinished.
 | `/branch`          | Switch the working branch — see [Branch switching](#branch-switching) |
 | `/clear`           | Start a fresh empty session (TUI)             |
 | `/diff`            | Full-screen git review — see [Diff review](#diff-review) |
+| `/code`            | Full-screen source viewer — see [Code viewer](#code-viewer) |
 | `!command`         | Run a shell command locally, stream output into the transcript; `Esc` cancels it |
 
 In the TUI, `!command` runs locally via `bash -c` — outside the agent loop. It

README.zh-CN.md

@@ -40,6 +40,7 @@
 - [配置](#配置)
 - [交互模式](#交互模式)
 - [Diff 审阅](#diff-审阅)
+- [代码查看器](#代码查看器)
 - [命令](#命令)
 - [会话](#会话)
 - [无头模式](#无头模式)
@@ -249,7 +250,7 @@ xychart-beta
 编辑器支持：
 
 - `@` —— 模糊文件选择器（输入 `@` 后开始输入路径）
-- `/` —— 斜杠命令选择器（`/sessions`、`/branch`、`/clear`、`/diff`）
+- `/` —— 斜杠命令选择器（`/sessions`、`/branch`、`/clear`、`/diff`、`/code`）
 - `?` —— 快捷键帮助选择器（列出 `/`、`!`、`@` 和按键绑定；`Esc` 关闭）
 - `!command` —— 在本地运行 shell 命令，并把输出流式写入对话记录
   （见 [命令](#命令)）
@@ -285,6 +286,16 @@ xychart-beta
 审阅层内：`j`/`k` 移动，`s` 左右对照，`i` 添加/编辑批注，`x` 删除，`a` 发给代理，
 `?` 帮助，`q` / `Esc` 关闭。批注保存在 `.phi/review.json`。
 
+## 代码查看器
+
+`/code <path>[:line]` 打开全屏源码查看器：语法高亮、支持 CJK 宽度的光标
+（`j`/`k`、`h`/`l`、`gg`/`G`），`v` 选中行后按 `a`，把选中的行作为
+`path:12-18` 引用交给聊天输入框，模型直接可读。查看器自己读文件，并遵守
+与工具门相同的敏感路径清单——`~/.ssh`、`.env` 等敏感路径、二进制文件和
+超过 8 MiB 的文件都会拒绝并以 toast 提示。
+
+`Esc` 关闭。阅读时状态栏显示路径、光标和行数；`v` 激活时显示已选中行数。
+
 ## 切换分支
 
 `/branch` 打开当前目录的分支选择器，只有两列：分支名和它最近的一次提交。
@@ -314,6 +325,7 @@ HEAD 新建一个。敲名字本身就是「新建分支」的全部流程，比
 | `/branch` | 切换工作分支 — 见 [切换分支](#切换分支) |
 | `/clear` | 开启一个全新的空会话（TUI 内） |
 | `/diff` | 全屏 git 审阅 — 见 [Diff 审阅](#diff-审阅) |
+| `/code` | 全屏源码查看器 — 见 [代码查看器](#代码查看器) |
 | `!command` | 在本地运行 shell 命令，把输出流式写入对话记录；`Esc` 取消 |
 
 在 TUI 中，`!command` 通过 `bash -c` 在本地运行——在代理循环之外。它不计入

doc/project-layout.md

@@ -7,7 +7,7 @@
 | `internal/util/update/`  | Self-update check + GitHub Releases install    |
 | `internal/agent/`        | Agent engine, executor, jobs                     |
 | `internal/agent/prompt/` | System prompt templates + Skills/MCP catalogs    |
-| `internal/components/`   | TUI widgets (chat, input, palette, mention, diffview, …) |
+| `internal/components/`   | TUI widgets (chat, input, palette, mention, diffview, codeview, …) |
 | `internal/llm/`          | LLM clients (OpenAI-compatible + Anthropic + Gemini), streaming, skills |
 | `internal/project/`      | Workspace layout and config                    |
 | `internal/project/model/` | Built-in model presets + request interceptors |
@@ -21,6 +21,7 @@
 | `internal/tui/footer/`   | Activity spinner, token labels, update hint |
 | `internal/tui/overlays/` | Permission / continue-ask panels |
 | `internal/tui/diffpane/` | Git diff review overlay (`/diff`) |
+| `internal/tui/codepane/` | Source viewer overlay (`/code`) |
 | `internal/tui/submit/`   | Submit, cancel, slash dispatch, bash runner |
 | `internal/tui/commands/` | Slash/palette registry, session/extension commands |
 | `internal/tui/pathutil/` | Cwd + git branch path labels |

doc/tui.md

@@ -12,6 +12,7 @@ cmd/main.go
        ├─ FooterChrome     status slot (activity↔tokens), bottom row for ext/jobs/hints
        ├─ Overlays         permission ask, continue ask
        ├─ DiffPane         full-screen git diff review (`/diff`)
+       ├─ CodePane         full-screen source viewer (`/code`)
        └─ Submitter        submit / cancel / slash / bash → Controller
 ```
 
@@ -25,6 +26,7 @@ cmd/main.go
 | `FooterChrome` | `ActivityHandler`, `Spinner` | `labelContext()`, `liveJobs()` closures |
 | `Overlays` | `permAskState`, `continueAskState` | `activity` ref, reply callbacks |
 | `DiffPane` | review overlay (rows, notes, search) | `cwd`, submit/copy/toast callbacks |
+| `CodePane` | source overlay (lines, caret, selection) | `cwd`, add-to-chat/toast callbacks |
 | `Submitter` | `BashRunner` | `Controller`, `Bus`, `CommandRegistry`, pane refs |
 
 **Hard rule:** no `*Editor` back-pointers on handlers. Cross-domain work uses injected refs, callbacks, or `Bus.Publish`. Toast feedback uses `ToastMsg` (Editor owns the overlay); do not inject toast callbacks.
@@ -42,6 +44,7 @@ internal/tui/
 ├── footer/                 # FooterChrome, token label helpers
 ├── overlays/               # permission + continue ask
 ├── diffpane/               # git diff review overlay (`/diff`)
+├── codepane/               # source viewer overlay (`/code`)
 ├── submit/                 # Submitter, BashRunner
 ├── commands/               # registry, builtins, SessionCommands, BranchCommands, ExtCommands
 └── pathutil/               # short path + git branch labels
@@ -56,6 +59,7 @@ internal/tui/
 | `footer` | Composer status slot (activity ↔ tokens), bottom footer row (ext status, jobs, update hint) |
 | `overlays` | Modal permission / continue-ask panels; replaces composer when active |
 | `diffpane` | Full-screen git diff review; comments persist under `.phi/review.json` |
+| `codepane` | Full-screen source viewer: syntax highlight, caret, line selection |
 | `submit` | User submit path: agent prompt, slash commands, `!bash`, cancel |
 | `commands` | Slash/palette registry; session load/clear; extension command bridge |
 | `pathutil` | Cwd shortening and git branch labels for composer chrome |
@@ -96,18 +100,24 @@ It does **not** own command side effects — those live in `internal/tui/command
 
 ```text
 xui event
-  └─ Editor.Handle → ComposerPane.Handle (keys, paste, focus)
-       ├─ overlay keys → Overlays (when active)
-       ├─ copy keys    → TranscriptPane
-       └─ submit       → bus.Publish(SubmitMsg)
+  └─ Editor.Handle → full-screen overlay (DiffPane / CodePane, when active)
+       └─ ComposerPane.Handle (keys, paste, focus)
+            ├─ overlay keys → Overlays (when active)
+            ├─ copy keys    → TranscriptPane
+            └─ submit       → bus.Publish(SubmitMsg)
 
 app frame
   └─ Editor.Draw
        ├─ drainBus()          # apply pending Msg batch on UI thread
+       ├─ full-screen overlay (DiffPane / CodePane) + toast
        ├─ layout: list | chat/overlay | footer
        └─ toast overlay (if visible)
 ```
 
+Both full-screen overlays (`DiffPane`, `CodePane`) are UI-goroutine objects: they
+load, handle keys and paint in one place, and their callbacks (add-to-chat, copy,
+toast) run inline — no pane state needs a lock.
+
 `RequestRedraw` → `vx.QueueRefresh()`. The bus coalesces high-frequency stream events; one armed wake can cover many publishes until the next `Drain`.
 
 ---
@@ -135,7 +145,6 @@ app frame
 | `MentionResultsMsg`, `BranchLabelMsg` | `ComposerPane` |
 | `ToastMsg` | `Editor` toast overlay |
 | `ExtCommandResultMsg` | `ExtCommands` |
-| `RedrawMsg` | no-op (redraw already scheduled) |
 
 ---
 

internal/components/chat/chat_input.go

@@ -60,6 +60,10 @@ type ChatInput struct {
 	// "Images: name1 name2".
 	PendingImages []imgutil.Attachment
 
+	// PendingRefs are file slices picked in the code viewer, shown inside the
+	// bordered editor as "Refs: path:12-18".
+	PendingRefs []Ref
+
 	PaddingX int // horizontal inner padding; default 1
 
 	// OnSubmit is called when Enter is pressed (without modifiers).
@@ -70,6 +74,8 @@ type ChatInput struct {
 	OnPendingSkillsChange func(skills []string)
 	// OnPendingImagesChange is called after PendingImages mutates.
 	OnPendingImagesChange func(images []imgutil.Attachment)
+	// OnPendingRefsChange is called after PendingRefs mutates.
+	OnPendingRefsChange func(refs []Ref)
 
 	// OnMentionChange is called after Value or Cursor changes that may
 	// activate/deactivate an @-file mention. active is false when none.
@@ -128,6 +134,9 @@ func (c *ChatInput) PreferredHeight(width int, method xui.WidthMethod) int {
 
 func (c *ChatInput) pendingRowsHeight() int {
 	n := 0
+	if len(c.PendingRefs) > 0 {
+		n++
+	}
 	if len(c.PendingSkills) > 0 {
 		n++
 	}
@@ -162,6 +171,21 @@ func (c *ChatInput) AddPendingImage(att imgutil.Attachment) {
 	c.notifyPendingImages()
 }
 
+// AddPendingRef appends r to the pending references. A ref with no path or no
+// selected text carries nothing, so it is dropped.
+func (c *ChatInput) AddPendingRef(r Ref) {
+	if r.Path == "" || r.Text == "" {
+		return
+	}
+	if slices.ContainsFunc(c.PendingRefs, func(p Ref) bool {
+		return p.Path == r.Path && p.Start == r.Start && p.End == r.End
+	}) {
+		return
+	}
+	c.PendingRefs = append(c.PendingRefs, r)
+	c.notifyPendingRefs()
+}
+
 // PopPendingImage removes the last pending image. Returns false if none.
 func (c *ChatInput) PopPendingImage() bool {
 	if len(c.PendingImages) == 0 {
@@ -172,6 +196,16 @@ func (c *ChatInput) PopPendingImage() bool {
 	return true
 }
 
+// PopPendingRef removes the last pending reference. Returns false if none.
+func (c *ChatInput) PopPendingRef() bool {
+	if len(c.PendingRefs) == 0 {
+		return false
+	}
+	c.PendingRefs = c.PendingRefs[:len(c.PendingRefs)-1]
+	c.notifyPendingRefs()
+	return true
+}
+
 // PopPendingSkill removes the last pending skill. Returns false if none.
 func (c *ChatInput) PopPendingSkill() bool {
 	if len(c.PendingSkills) == 0 {
@@ -200,6 +234,15 @@ func (c *ChatInput) ClearPendingSkills() {
 	c.notifyPendingSkills()
 }
 
+// ClearPendingRefs removes all pending references.
+func (c *ChatInput) ClearPendingRefs() {
+	if len(c.PendingRefs) == 0 {
+		return
+	}
+	c.PendingRefs = nil
+	c.notifyPendingRefs()
+}
+
 func (c *ChatInput) notifyPendingSkills() {
 	if c.OnPendingSkillsChange != nil {
 		c.OnPendingSkillsChange(c.PendingSkills)
@@ -212,6 +255,12 @@ func (c *ChatInput) notifyPendingImages() {
 	}
 }
 
+func (c *ChatInput) notifyPendingRefs() {
+	if c.OnPendingRefsChange != nil {
+		c.OnPendingRefsChange(c.PendingRefs)
+	}
+}
+
 func (c *ChatInput) padX() int {
 	if c.PaddingX <= 0 {
 		return 1
@@ -269,6 +318,8 @@ func (c *ChatInput) Handle(ctx *components.EventContext, ev xui.Event) {
 				debuglog.Logf("chat backspace popped pending image remaining=%d", len(c.PendingImages))
 			} else if c.PopPendingSkill() {
 				debuglog.Logf("chat backspace popped pending skill remaining=%d", len(c.PendingSkills))
+			} else if c.PopPendingRef() {
+				debuglog.Logf("chat backspace popped pending ref remaining=%d", len(c.PendingRefs))
 			}
 			ctx.ConsumeAndRedraw()
 			return
@@ -440,14 +491,15 @@ func (c *ChatInput) notifyChange() {
 	c.notifyCompleters()
 }
 
-// clear removes all composer text, pending images, and pending skills.
+// clear removes all composer text, pending images, refs, and skills.
 func (c *ChatInput) clear() {
 	if c.Value != "" {
 		c.Value = ""
 		c.Cursor = 0
 		c.notifyChange()
 	}
 	c.ClearPendingImages()
+	c.ClearPendingRefs()
 	c.ClearPendingSkills()
 }
 
@@ -588,6 +640,11 @@ func (c *ChatInput) Draw(ctx components.DrawContext) components.Surface {
 	}
 
 	contentY := 1
+	// Refs paint first so the pending rows stay contiguous above the editor.
+	if len(c.PendingRefs) > 0 {
+		c.paintPendingRefs(&s, 1+pad, contentY, innerW, ctx.Method)
+		contentY++
+	}
 	if len(c.PendingSkills) > 0 {
 		c.paintPendingSkills(&s, 1+pad, contentY, innerW, ctx.Method)
 		contentY++
@@ -689,6 +746,31 @@ func (c *ChatInput) Draw(ctx components.DrawContext) components.Surface {
 	return s
 }
 
+func (c *ChatInput) paintPendingRefs(s *components.Surface, x, y, width int, method xui.WidthMethod) {
+	th := c.Theme
+	if th.Success.Fg.Kind == 0 && th.Foreground.Fg.Kind == 0 {
+		th = components.DefaultTheme()
+	}
+	labelSt := th.Muted
+	labelSt.Dim = true
+	nameSt := th.IdentityOrSuccess()
+	nameSt.Bold = false
+	nameSt.Underline = true
+
+	spans := []components.Span{{Text: "Refs: ", Style: labelSt}}
+	for i, r := range c.PendingRefs {
+		if i > 0 {
+			spans = append(spans, components.Span{Text: " ", Style: labelSt})
+		}
+		spans = append(spans, components.Span{Text: r.Label(), Style: nameSt})
+	}
+	lines := components.WrapSpans(spans, width, method)
+	if len(lines) == 0 {
+		return
+	}
+	components.PaintSpans(s, x, y, lines[0], method)
+}
+
 func (c *ChatInput) paintPendingSkills(s *components.Surface, x, y, width int, method xui.WidthMethod) {
 	th := c.Theme
 	if th.Success.Fg.Kind == 0 && th.Foreground.Fg.Kind == 0 {