Feat(tui): frontmatter default mode definition

README.md

@@ -717,6 +717,65 @@ files by absolute path, so under `latex` a note can show in the preview the
 contents of any file you can read. Leave latex off for vaults you do not
 trust.
 
+### Open notes in a pane mode from their frontmatter
+
+By default a note opens in the mode `editor.default_view_mode` gives (or the
+mode you last chose, with `keep_view_mode_across_notes`). Two `[terminal]`
+settings, both off by default, let a note's own frontmatter pick the mode when
+it opens in a new tab:
+
+- **`view_mode_field`** names a frontmatter field. It is empty by default;
+  `view-mode` is a good name. A note with `view-mode: preview` (or `edit`, or
+  `split`) opens in that mode. The key and value are not case sensitive. A
+  list, an empty value or any other word is ignored.
+- **`[terminal.view_mode_rules]`** maps a frontmatter `key=value` pair to a mode.
+  A list field matches when any element equals the value.
+
+```toml
+[terminal]
+view_mode_field = "view-mode"
+
+[terminal.view_mode_rules]
+"page-status=done" = "preview"
+"kind=journal" = "edit"
+```
+
+Rules are written `"<key>=<value>" = "<mode>"`, where the mode is `edit`,
+`split` or `preview`. Keys and values are trimmed, unquoted and compared in
+lower case. A rule is invalid, and ignored, when it has no `=`, an empty key,
+an empty value or a mode other than those three. Invalid rules never stop zn
+from starting; `:settings` lists them marked with their reason (`no "="`,
+`empty key`, `empty value` or `bad mode`), and `d` or the mode picker's
+`remove` deletes them.
+
+Precedence:
+
+- A valid `view_mode_field` value beats the rules. Among the rules, the first
+  one in sorted order of the lower-cased `key=value` wins, so
+  `kind=journal` is tried before `page-status=done`.
+- Frontmatter beats the remembered mode and `keep_view_mode_across_notes`.
+  Applying it never changes either of them; a mode you switch to yourself
+  still does.
+- A tab restored from the saved session keeps its saved mode.
+- A note you have just created opens in the editor, whatever its frontmatter
+  says. Reopening it later follows the frontmatter.
+- Reopening a closed tab follows the frontmatter too; the mode the tab was
+  closed in comes back only when the frontmatter asks for none.
+- The pane opened by `:ref`, and a peek from the sidebar, stay in preview.
+- Switching to a tab that is already open never changes its mode, and saving
+  new frontmatter does not either.
+
+Edit them in `:settings` (the `terminal.view_mode_field` row, and the
+`terminal.view_mode_rules` rows with their add row) or with `zn config`:
+
+```bash
+zn config set terminal.view_mode_field view-mode
+zn config set terminal.view_mode_rules.page-status=done preview
+```
+
+Only `zn tui` reads these settings. zn never writes them into the vault, and
+the desktop app ignores them.
+
 ### Vaults and servers inside the app
 
 `:vault` (or `Space v`) lists every saved vault and server, with entries to
@@ -810,7 +869,7 @@ layout choices do not change these terminal layouts.
 | `[view]` | `tasks_view_mode`, `kanban_group_by`, `kanban_statuses`, `note_sort_order` |
 | `[appearance]` | `theme_family`, `theme_mode`, `theme_id` |
 | `[tweaks]` | `accent = "#ff3b30"`: the desktop's Quick tweaks colors |
-| `[terminal]` | `mouse`, `preview_style`, `images`, `theme`, `math`, `render_timeout`, `render_concurrency` (terminal only) |
+| `[terminal]` | `mouse`, `preview_style`, `images`, `theme`, `math`, `render_timeout`, `render_concurrency`, `view_mode_field` and `[terminal.view_mode_rules]` (terminal only) |
 | `[keymaps]` | `"action.id" = "keys"`, or `""` to unbind; `:keymaps` lists the ids |
 | `[kanban_column_titles]` | `review = "In Review"` |
 | `[saved_filters]` | `Important = "!high"` |

internal/cli/commands_config.go

@@ -61,6 +61,10 @@ func cmdConfig(ctx context.Context, args Args) error {
 	return nil
 }
 
+// viewModeRulePrefix names a frontmatter view-mode rule under terminal; the
+// rest of the name is the rule's "<key>=<value>" as written in config.toml.
+const viewModeRulePrefix = "view_mode_rules."
+
 func preferenceValues(p config.Prefs) map[string]map[string]any {
 	values := config.ValueTables(p)
 	for section, entries := range map[string]map[string]string{"keymaps": p.KeymapOverrides, "saved_filters": p.SavedTaskFilters, "kanban_column_titles": p.KanbanColumnTitles, "tweaks": p.ThemeTweaks} {
@@ -69,6 +73,9 @@ func preferenceValues(p config.Prefs) map[string]map[string]any {
 			values[section][key] = value
 		}
 	}
+	for _, e := range config.ViewModeRuleEntries(p.ViewModeRules) {
+		values["terminal"][viewModeRulePrefix+e.Key] = e.Mode
+	}
 	return values
 }
 
@@ -109,7 +116,8 @@ func cmdConfigAction(ctx context.Context, args Args, action string) error {
 	}
 	value, exists := values[section][name]
 	if !exists {
-		if action != "set" || (section != "keymaps" && section != "saved_filters" && section != "kanban_column_titles" && section != "tweaks") {
+		isRule := section == "terminal" && strings.HasPrefix(name, viewModeRulePrefix)
+		if action != "set" || (!isRule && section != "keymaps" && section != "saved_filters" && section != "kanban_column_titles" && section != "tweaks") {
 			return fmt.Errorf("unknown preference %q; `zn config list` shows supported keys", key)
 		}
 		value = ""
@@ -119,6 +127,18 @@ func cmdConfigAction(ctx context.Context, args Args, action string) error {
 			return errors.New("usage: zn config set <section.key> <value>")
 		}
 		raw := args.Positional(1)
+		if name, isRule := strings.CutPrefix(name, viewModeRulePrefix); isRule && section == "terminal" {
+			if err := config.SetViewModeRule(name, raw); err != nil {
+				return fmt.Errorf("invalid value for %s: %w", key, err)
+			}
+			mode := strings.ToLower(strings.TrimSpace(raw))
+			if args.Bool("json") {
+				emitJSON(map[string]any{"ok": true, "key": key, "value": mode})
+			} else {
+				emitOK(fmt.Sprintf("%s = %v", key, mode))
+			}
+			return nil
+		}
 		switch value.(type) {
 		case bool:
 			value, err = strconv.ParseBool(raw)

internal/cli/config_viewmode_case_test.go

@@ -0,0 +1,29 @@
+package cli
+
+import (
+	"maps"
+	"os"
+	"testing"
+
+	"github.com/ZenNotes/tui/internal/config"
+)
+
+// `zn config set` on a rule that differs from an existing one only in case
+// changes the existing rule instead of adding a duplicate.
+func TestConfigSetViewModeRuleCaseVariantChangesExisting(t *testing.T) {
+	isolatedCLI(t)
+	path := config.ConfigTomlPath()
+	if err := os.WriteFile(path, []byte("[terminal.view_mode_rules]\n\"page-status=done\" = \"preview\"\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if o, code := runConfig(t, "set", "terminal.view_mode_rules.Page-Status=done", "split"); code != 0 {
+		t.Fatalf("set: exit %d: %s", code, o)
+	}
+	prefs, _, err := config.LoadPrefs()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := map[string]string{"page-status=done": "split"}; !maps.Equal(prefs.ViewModeRules, want) {
+		t.Fatalf("rules %v, want %v", prefs.ViewModeRules, want)
+	}
+}

internal/cli/config_viewmode_test.go

@@ -0,0 +1,110 @@
+package cli
+
+import (
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/ZenNotes/tui/internal/config"
+)
+
+func runConfig(t *testing.T, args ...string) (string, int) {
+	t.Helper()
+	var code int
+	out := captureOutput(t, func() { code = Main(append([]string{"config"}, args...)) })
+	return out, code
+}
+
+func TestConfigListShowsViewModeRules(t *testing.T) {
+	isolatedCLI(t)
+	if _, code := runConfig(t, "set", "terminal.view_mode_rules.page-status=done", "preview"); code != 0 {
+		t.Fatalf("set exit %d", code)
+	}
+	out, code := runConfig(t, "list")
+	if code != 0 || !strings.Contains(out, "terminal.view_mode_rules.page-status=done = preview\n") {
+		t.Fatalf("list (exit %d): %s", code, out)
+	}
+	out, _ = runConfig(t, "list", "--json")
+	if !strings.Contains(out, `"view_mode_rules.page-status=done": "preview"`) {
+		t.Fatalf("list --json: %s", out)
+	}
+}
+
+func TestConfigGetViewModeRule(t *testing.T) {
+	isolatedCLI(t)
+	runConfig(t, "set", "terminal.view_mode_rules.kind=journal", "split")
+	out, code := runConfig(t, "get", "terminal.view_mode_rules.kind=journal")
+	if code != 0 || strings.TrimSpace(out) != "split" {
+		t.Fatalf("get (exit %d): %q", code, out)
+	}
+	if _, code := runConfig(t, "get", "terminal.view_mode_rules.kind=other"); code == 0 {
+		t.Fatal("get of an unset rule succeeded")
+	}
+}
+
+func TestConfigSetViewModeRuleAddsAndChanges(t *testing.T) {
+	isolatedCLI(t)
+	path := config.ConfigTomlPath()
+	if err := os.WriteFile(path, []byte("[terminal]\nmath = \"latex\"\n\n[editor]\nword_wrap = false\n\n[custom]\nkeep = \"me\"\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	for _, mode := range []string{"preview", "Edit"} {
+		if o, code := runConfig(t, "set", "terminal.view_mode_rules.page-status=done", mode); code != 0 {
+			t.Fatalf("set %s: exit %d: %s", mode, code, o)
+		}
+	}
+	body, _ := os.ReadFile(path)
+	for _, want := range []string{`math = "latex"`, "[editor]", "word_wrap = false", "[custom]", `keep = "me"`, `"page-status=done" = "edit"`} {
+		if !strings.Contains(string(body), want) {
+			t.Fatalf("missing %q in:\n%s", want, body)
+		}
+	}
+	if strings.Contains(string(body), "preview") {
+		t.Fatalf("old mode left behind:\n%s", body)
+	}
+	prefs, _, err := config.LoadPrefs()
+	if err != nil || len(prefs.ViewModeRules) != 1 {
+		t.Fatalf("reload: %+v %v", prefs.ViewModeRules, err)
+	}
+}
+
+func TestConfigSetViewModeRuleRejectsBadMode(t *testing.T) {
+	isolatedCLI(t)
+	path := config.ConfigTomlPath()
+	original := "[terminal]\nmath = \"latex\"\n"
+	if err := os.WriteFile(path, []byte(original), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	for _, args := range [][]string{
+		{"set", "terminal.view_mode_rules.page-status=done", "reading"},
+		{"set", "terminal.view_mode_rules.page-status", "preview"},
+		{"set", "terminal.view_mode_rules.=done", "preview"},
+		{"set", "terminal.view_mode_rules.status=", "preview"},
+	} {
+		if _, code := runConfig(t, args...); code == 0 {
+			t.Fatalf("%v succeeded", args)
+		}
+	}
+	body, _ := os.ReadFile(path)
+	if string(body) != original {
+		t.Fatalf("config changed:\n%s", body)
+	}
+}
+
+func TestConfigSetViewModeField(t *testing.T) {
+	isolatedCLI(t)
+	if _, code := runConfig(t, "set", "terminal.view_mode_field", "view-mode"); code != 0 {
+		t.Fatalf("exit %d", code)
+	}
+	prefs, _, err := config.LoadPrefs()
+	if err != nil || prefs.TerminalViewModeField != "view-mode" {
+		t.Fatalf("field: %q %v", prefs.TerminalViewModeField, err)
+	}
+	if _, code := runConfig(t, "set", "terminal.view_mode_field", ""); code != 0 {
+		t.Fatalf("clear exit %d", code)
+	}
+	prefs, _, err = config.LoadPrefs()
+	if err != nil || prefs.TerminalViewModeField != "" {
+		t.Fatalf("cleared field: %q %v", prefs.TerminalViewModeField, err)
+	}
+}

internal/config/prefs.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"fmt"
 	"os"
 	"strings"
 
@@ -80,6 +81,12 @@ type Prefs struct {
 	// TerminalMath is typst or latex: the engine for display math. Anything
 	// else loads as typst; zn doctor reports it.
 	TerminalMath string
+	// TerminalViewModeField names the frontmatter field that picks a note's
+	// pane mode when it opens in a new tab. Empty turns the feature off.
+	TerminalViewModeField string
+	// ViewModeRules maps "<key>=<value>" to a pane mode, from
+	// [terminal.view_mode_rules]. Entries are raw; see ViewModeRuleEntries.
+	ViewModeRules map[string]string
 	// RenderTimeout (seconds) bounds one external render; RenderConcurrency
 	// caps how many run at once. Non-positive values load as the defaults.
 	RenderTimeout     int
@@ -115,6 +122,7 @@ func DefaultPrefs() Prefs {
 		PreviewStyle:             "auto",
 		TerminalMouse:            true,
 		TerminalMath:             "typst",
+		ViewModeRules:            map[string]string{},
 		RenderTimeout:            10,
 		RenderConcurrency:        2,
 		UnifiedSidebar:           true,
@@ -236,6 +244,19 @@ func applyPrefs(p *Prefs, doc map[string]any) {
 	setString(terminal, "images", &p.TerminalImages)
 	setString(terminal, "theme", &p.TerminalTheme)
 	setString(terminal, "math", &p.TerminalMath)
+	setString(terminal, "view_mode_field", &p.TerminalViewModeField)
+	if rules, ok := terminal["view_mode_rules"].(map[string]any); ok {
+		p.ViewModeRules = map[string]string{}
+		for k, v := range rules {
+			// A mode that is not a string is kept as text, so the rule is
+			// listed as invalid and can be removed instead of vanishing.
+			s, isString := v.(string)
+			if !isString {
+				s = fmt.Sprint(v)
+			}
+			p.ViewModeRules[k] = s
+		}
+	}
 	setInt(terminal, "render_timeout", &p.RenderTimeout)
 	setInt(terminal, "render_concurrency", &p.RenderConcurrency)
 	if strings.TrimSpace(p.PreviewStyle) == "" {

internal/config/prefs_validate.go

@@ -27,7 +27,7 @@ func ValidateConfig() error {
 // lenientKeys are checked only when strict (zn doctor): LoadPrefs falls back
 // to their defaults, so a bad value never stops zn from starting.
 var lenientKeys = map[string]map[string]bool{
-	"terminal": {"math": true, "render_timeout": true, "render_concurrency": true},
+	"terminal": {"math": true, "view_mode_field": true, "render_timeout": true, "render_concurrency": true},
 }
 
 func validateKnownValues(doc map[string]any, strict bool) error {

internal/config/prefs_values.go

@@ -13,7 +13,7 @@ func ValueTables(p Prefs) map[string]map[string]any {
 		"editor":     {"tab_size": p.EditorTabSize, "scroll_off": p.EditorScrollOff, "word_wrap": p.WordWrap, "default_view_mode": p.DefaultPaneMode, "line_number_mode": p.LineNumberMode, "completed_task_style": p.CompletedTaskStyle, "time_format": p.TimeFormat, "auto_pairs": p.AutoPairs, "auto_pair_quotes_in_prose": p.AutoPairQuotesInProse, "tabs_enabled": p.TabsEnabled, "wrap_tabs": p.WrapTabs, "keep_view_mode_across_notes": p.RetainViewMode, "markdown_snippets": p.MarkdownSnippets, "hide_builtin_templates": p.HideBuiltinTemplates, "text_replacements_enabled": p.TextReplacementsEnabled, "sync_title_heading_on_rename": p.SyncTitleHeadingOnRename},
 		"appearance": {"theme_family": p.ThemeFamily, "theme_mode": p.ThemeMode, "theme_id": p.ThemeID, "unified_sidebar": p.UnifiedSidebar},
 		"view":       {"note_sort_order": p.NoteSortOrder, "group_by_kind": p.GroupByKind, "nested_tags": p.NestedTags, "quick_note_date_title": p.QuickNoteDateTitle, "quick_note_title_prefix": p.QuickNoteTitlePrefix, "calendar_week_start": p.CalendarWeekStart, "calendar_show_week_numbers": p.CalendarShowWeekNumbers, "tasks_view_mode": p.TasksViewMode, "show_archived_tasks": p.ShowArchivedTasks, "kanban_group_by": p.KanbanGroupBy, "kanban_folder_root": p.KanbanFolderRoot},
-		"terminal":   {"mouse": p.TerminalMouse, "preview_style": p.PreviewStyle, "images": p.TerminalImages, "theme": p.TerminalTheme, "math": p.TerminalMath, "render_timeout": p.RenderTimeout, "render_concurrency": p.RenderConcurrency},
+		"terminal":   {"mouse": p.TerminalMouse, "preview_style": p.PreviewStyle, "images": p.TerminalImages, "theme": p.TerminalTheme, "math": p.TerminalMath, "view_mode_field": p.TerminalViewModeField, "render_timeout": p.RenderTimeout, "render_concurrency": p.RenderConcurrency},
 	}
 }