Make the fzf preview command customizable

adapter/fzf/finder.go

@@ -28,6 +28,8 @@ type NoteFinder struct {
 type NoteFinderOpts struct {
 	// Indicates whether fzf is opened for every query, even if empty.
 	AlwaysFilter bool
+	// Preview command to run when selecting a note.
+	PreviewCmd opt.String
 	// When non nil, a "create new note from query" binding will be added to
 	// fzf to create a note in this directory.
 	NewNoteDir *zk.Dir
@@ -84,10 +86,9 @@ func (f *NoteFinder) Find(opts note.FinderOpts) ([]note.Match, error) {
 	}
 
 	fzf, err := New(Opts{
-		// PreviewCmd: opt.NewString("bat -p --theme Nord --color always {1}"),
-		PreviewCmd: opt.NewString(zkBin + " list -f {{raw-content}} {1}"),
+		PreviewCmd: f.opts.PreviewCmd.OrString("cat {1}").NonEmpty(),
 		Padding:    2,
-		Bindings: bindings,
+		Bindings:   bindings,
 	})
 	if err != nil {
 		return selectedMatches, err

cmd/edit.go

@@ -45,6 +45,7 @@ func (cmd *Edit) Run(container *Container) error {
 	err = db.WithTransaction(func(tx sqlite.Transaction) error {
 		finder := container.NoteFinder(tx, fzf.NoteFinderOpts{
 			AlwaysFilter: true,
+			PreviewCmd:   zk.Config.Fzf.Preview,
 			NewNoteDir:   cmd.newNoteDir(zk),
 			BasePath:     zk.Path,
 			CurrentPath:  wd,

cmd/list.go

@@ -61,6 +61,7 @@ func (cmd *List) Run(container *Container) error {
 	err = db.WithTransaction(func(tx sqlite.Transaction) error {
 		finder := container.NoteFinder(tx, fzf.NoteFinderOpts{
 			AlwaysFilter: false,
+			PreviewCmd:   zk.Config.Fzf.Preview,
 			BasePath:     zk.Path,
 			CurrentPath:  wd,
 		})

core/note/create.go

@@ -100,7 +100,7 @@ func create(
 	deps createDeps,
 ) (*createdNote, error) {
 	context := renderContext{
-		Title:   opts.Title.OrDefault(opts.Dir.Config.DefaultTitle),
+		Title:   opts.Title.OrString(opts.Dir.Config.DefaultTitle).Unwrap(),
 		Content: opts.Content.Unwrap(),
 		Dir:     opts.Dir.Name,
 		Extra:   opts.Dir.Config.Extra,

core/note/format.go

@@ -46,7 +46,7 @@ func NewFormatter(basePath string, currentPath string, format opt.String, templa
 }
 
 func resolveFormatTemplate(format opt.String) string {
-	templ, ok := formatTemplates[format.OrDefault("short")]
+	templ, ok := formatTemplates[format.OrString("short").Unwrap()]
 	if !ok {
 		templ = format.String()
 		// Replace raw \n and \t by actual newlines and tabs in user format.

core/zk/config.go

@@ -14,6 +14,7 @@ type Config struct {
 	Dirs    map[string]DirConfig
 	Editor  opt.String
 	Pager   opt.String
+	Fzf     FzfConfig
 	Aliases map[string]string
 }
 
@@ -28,6 +29,11 @@ type DirConfig struct {
 	Extra            map[string]string
 }
 
+// FzfConfig holds the user configuration for running fzf.
+type FzfConfig struct {
+	Preview opt.String
+}
+
 // ConfigOverrides holds user configuration overriden values, for example fed
 // from CLI flags.
 type ConfigOverrides struct {
@@ -128,7 +134,10 @@ func ParseConfig(content []byte, templatesDir string) (*Config, error) {
 		Dirs:      dirs,
 		Editor:    opt.NewNotEmptyString(tomlConf.Editor),
 		Pager:     opt.NewStringWithPtr(tomlConf.Pager),
-		Aliases:   aliases,
+		Fzf: FzfConfig{
+			Preview: opt.NewStringWithPtr(tomlConf.Fzf.Preview),
+		},
+		Aliases: aliases,
 	}, nil
 }
 
@@ -190,6 +199,7 @@ type tomlConfig struct {
 	Dirs         map[string]tomlDirConfig `toml:"dir"`
 	Editor       string
 	Pager        *string
+	Fzf          tomlFzfConfig
 	Aliases      map[string]string `toml:"alias"`
 }
 
@@ -209,6 +219,10 @@ type tomlIDConfig struct {
 	Case    string
 }
 
+type tomlFzfConfig struct {
+	Preview *string
+}
+
 func charsetFromString(charset string) Charset {
 	switch charset {
 	case "alphanum":

core/zk/config_test.go

@@ -14,8 +14,6 @@ func TestParseDefaultConfig(t *testing.T) {
 
 	assert.Nil(t, err)
 	assert.Equal(t, conf, &Config{
-		Editor: opt.NullString,
-		Pager:  opt.NullString,
 		DirConfig: DirConfig{
 			FilenameTemplate: "{{id}}",
 			Extension:        "md",
@@ -29,7 +27,12 @@ func TestParseDefaultConfig(t *testing.T) {
 			Lang:         "en",
 			Extra:        make(map[string]string),
 		},
-		Dirs:    make(map[string]DirConfig),
+		Dirs:   make(map[string]DirConfig),
+		Editor: opt.NullString,
+		Pager:  opt.NullString,
+		Fzf: FzfConfig{
+			Preview: opt.NullString,
+		},
 		Aliases: make(map[string]string),
 	})
 }
@@ -57,6 +60,9 @@ func TestParseComplete(t *testing.T) {
 		length = 4
 		case = "lower"
 
+		[fzf]
+		preview = "bat {1}"
+
 		[extra]
 		hello = "world"
 		salut = "le monde"
@@ -139,6 +145,9 @@ func TestParseComplete(t *testing.T) {
 		},
 		Editor: opt.NewString("vim"),
 		Pager:  opt.NewString("less"),
+		Fzf: FzfConfig{
+			Preview: opt.NewString("bat {1}"),
+		},
 		Aliases: map[string]string{
 			"ls": "zk list $@",
 			"ed": "zk edit $@",
@@ -236,12 +245,20 @@ func TestParseMergesDirConfig(t *testing.T) {
 	})
 }
 
-func TestParsePreserveEmptyPager(t *testing.T) {
-	conf, err := ParseConfig([]byte(`pager = ""`), "")
+// Some properties like `pager` and `fzf.preview` differentiate between not
+// being set and an empty string.
+func TestParsePreservePropertiesAllowingEmptyValues(t *testing.T) {
+	conf, err := ParseConfig([]byte(`
+		pager = ""
+		[fzf]
+		preview = ""
+	`), "")
 
 	assert.Nil(t, err)
 	assert.Equal(t, conf.Pager.IsNull(), false)
 	assert.Equal(t, conf.Pager, opt.NewString(""))
+	assert.Equal(t, conf.Fzf.Preview.IsNull(), false)
+	assert.Equal(t, conf.Fzf.Preview, opt.NewString(""))
 }
 
 func TestParseIDCharset(t *testing.T) {

util/opt/opt.go

@@ -41,6 +41,15 @@ func (s String) IsEmpty() bool {
 	return !s.IsNull() && *s.value == ""
 }
 
+// NonEmpty returns a null String if the String is empty.
+func (s String) NonEmpty() String {
+	if s.IsEmpty() {
+		return NullString
+	} else {
+		return s
+	}
+}
+
 // Or returns the receiver if it is not null, otherwise the given optional
 // String.
 func (s String) Or(other String) String {
@@ -51,19 +60,23 @@ func (s String) Or(other String) String {
 	}
 }
 
-// OrDefault returns the optional String value or the given default string if
+// OrString returns the optional String value or the given default string if
 // it is null.
-func (s String) OrDefault(def string) string {
+func (s String) OrString(alt string) String {
 	if s.IsNull() {
-		return def
+		return NewString(alt)
 	} else {
-		return *s.value
+		return s
 	}
 }
 
 // Unwrap returns the optional String value or an empty String if none is set.
 func (s String) Unwrap() string {
-	return s.OrDefault("")
+	if s.IsNull() {
+		return ""
+	} else {
+		return *s.value
+	}
 }
 
 func (s String) Equal(other String) bool {
@@ -72,7 +85,7 @@ func (s String) Equal(other String) bool {
 }
 
 func (s String) String() string {
-	return s.OrDefault("")
+	return s.Unwrap()
 }
 
 func (s String) MarshalJSON() ([]byte, error) {