picker: extract fzf UI logic from store package (task 400)

1 files changed, 152 insertions, 0 deletions

diff --git a/internal/picker/picker.go b/internal/picker/picker.go
new file mode 100644
index 0000000..a8d5e86
--- /dev/null
+++ b/internal/picker/picker.go
@@ -0,0 +1,152 @@
+package picker
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+// Entry represents one selectable row in the interactive picker.
+type Entry struct {
+	RowID       int
+	Description string
+	Kind        string
+	HashSuffix  string
+}
+
+// Selection is the parsed fzf output.
+// Key is the pressed key from --expect (e.g. "ctrl-t", "enter", or "").
+type Selection struct {
+	Description string
+	Key         string
+}
+
+// Run executes fzf and parses its output into a Selection.
+func Run(ctx context.Context, entries []Entry) (Selection, error) {
+	if len(entries) == 0 {
+		return Selection{}, nil
+	}
+	if _, err := exec.LookPath("fzf"); err != nil {
+		return Selection{}, fmt.Errorf("fzf not found in PATH")
+	}
+
+	input, idToDescription := BuildInput(entries)
+	args := BuildArgs(
+		len(entries),
+		os.Getenv("FOOSTORE_TUI_THEME"),
+		os.Getenv("FOOSTORE_FZF_OPTS"),
+	)
+
+	cmd := exec.CommandContext(ctx, "fzf", args...)
+	cmd.Stdin = strings.NewReader(input)
+	var out bytes.Buffer
+	cmd.Stdout = &out
+	cmd.Stderr = os.Stderr
+
+	if err := cmd.Run(); err != nil {
+		// Non-zero exit (for example ESC cancel) is treated as no selection.
+		return Selection{}, nil
+	}
+
+	return ParseSelection(out.String(), idToDescription), nil
+}
+
+// BuildInput formats picker rows as tab-delimited input and builds an id map.
+func BuildInput(entries []Entry) (string, map[string]string) {
+	var b strings.Builder
+	idToDescription := make(map[string]string, len(entries))
+	for _, e := range entries {
+		id := strconv.Itoa(e.RowID)
+		idToDescription[id] = e.Description
+		fmt.Fprintf(
+			&b,
+			"%s\t%s\t%s\t%s\n",
+			id,
+			SanitizeField(e.Description),
+			SanitizeField(e.Kind),
+			SanitizeField(e.HashSuffix),
+		)
+	}
+	return b.String(), idToDescription
+}
+
+// BuildArgs returns fzf arguments for the interactive picker.
+func BuildArgs(entryCount int, theme, extraOpts string) []string {
+	header := "enter select | ctrl-t/alt-t cat | ctrl-y/alt-y paste | ctrl-o/alt-o open | ctrl-e/alt-e edit | esc cancel"
+	status := fmt.Sprintf("foostore interactive picker | %d entries | metadata preview only", entryCount)
+	args := []string{
+		"--height=80%",
+		"--layout=reverse",
+		"--border",
+		"--ansi",
+		"--delimiter=\t",
+		"--with-nth=2,3,4",
+		"--prompt=secret> ",
+		"--expect=enter,ctrl-t,ctrl-y,ctrl-o,ctrl-e,alt-t,alt-y,alt-o,alt-e",
+		"--bind=ctrl-t:ignore,ctrl-y:ignore,ctrl-o:ignore,ctrl-e:ignore,alt-t:ignore,alt-y:ignore,alt-o:ignore,alt-e:ignore",
+		"--header=" + header + "\n" + status,
+		"--preview-window=down,6,wrap,border-top",
+		"--preview=printf 'entry: %s\\nkind: %s\\nhash suffix: %s\\n' {2} {3} {4}",
+		"--color=" + ColorTheme(theme),
+	}
+	if extra := strings.TrimSpace(extraOpts); extra != "" {
+		args = append(args, strings.Fields(extra)...)
+	}
+	return args
+}
+
+// ColorTheme returns the fzf --color value for a named theme.
+func ColorTheme(theme string) string {
+	switch strings.ToLower(strings.TrimSpace(theme)) {
+	case "", "bold":
+		return "fg:#f8fafc,bg:#0b1220,hl:#f59e0b,fg+:#ffffff,bg+:#1d4ed8,hl+:#fde047,info:#22d3ee,prompt:#f43f5e,pointer:#10b981,marker:#a78bfa,spinner:#fb7185,header:#38bdf8,border:#334155,separator:#0ea5e9,query:#e2e8f0,label:#f472b6"
+	case "clean":
+		return "fg:#e5e7eb,bg:#111827,hl:#93c5fd,fg+:#f9fafb,bg+:#1f2937,hl+:#93c5fd,info:#a7f3d0,prompt:#fbbf24,pointer:#34d399,marker:#34d399,spinner:#fbbf24,header:#a7f3d0,border:#374151"
+	case "neon":
+		return "fg:#d1fae5,bg:#020617,hl:#f0abfc,fg+:#ffffff,bg+:#0f172a,hl+:#f9a8d4,info:#67e8f9,prompt:#22d3ee,pointer:#22c55e,marker:#f472b6,spinner:#a78bfa,header:#38bdf8,border:#1d4ed8,separator:#22d3ee,query:#bbf7d0,label:#f0abfc"
+	case "mono":
+		return "fg:#e5e5e5,bg:#111111,hl:#ffffff,fg+:#ffffff,bg+:#222222,hl+:#ffffff,info:#d4d4d4,prompt:#ffffff,pointer:#ffffff,marker:#ffffff,spinner:#ffffff,header:#d4d4d4,border:#444444"
+	default:
+		return ColorTheme("bold")
+	}
+}
+
+// SanitizeField removes tabs/newlines so each row stays tab-delimited.
+func SanitizeField(s string) string {
+	s = strings.ReplaceAll(s, "\t", " ")
+	s = strings.ReplaceAll(s, "\n", " ")
+	return strings.TrimSpace(s)
+}
+
+// ParseSelection decodes fzf --expect output.
+func ParseSelection(output string, idToDescription map[string]string) Selection {
+	lines := strings.Split(strings.TrimRight(output, "\n"), "\n")
+	if len(lines) < 2 {
+		return Selection{}
+	}
+
+	key := strings.TrimSpace(lines[0])
+	row := strings.TrimSpace(lines[1])
+	if row == "" {
+		return Selection{}
+	}
+
+	id := row
+	if parts := strings.SplitN(row, "\t", 2); len(parts) > 0 {
+		id = strings.TrimSpace(parts[0])
+	}
+
+	description, ok := idToDescription[id]
+	if !ok || description == "" {
+		return Selection{}
+	}
+
+	return Selection{
+		Description: description,
+		Key:         key,
+	}
+}