feat: parse all Go CLIs with flaggy; dump bash complete. (#36)

stdlib flag dropped --hop after the query. One wrapper in internal/cli,
source <(./bin/cli/complete.go bash). Gitea #34.

internal/brain/rank/readargs.go

@@ -0,0 +1,59 @@
+package rank
+
+import (
+	"fmt"
+
+	"github.com/eSlider/2dph/internal/cli"
+	"github.com/integrii/flaggy"
+)
+
+type GetOptions struct {
+	ID      string
+	Body    bool
+	JSONOut bool
+}
+
+func GetParser(opt *GetOptions) *flaggy.Parser {
+	p := cli.New("brain-get")
+	p.Description = "read one leaf"
+	p.Bool(&opt.Body, "", "body", "full text instead of snippet")
+	p.Bool(&opt.JSONOut, "", "json", "JSON output")
+	p.AddPositionalValue(&opt.ID, "id", 1, false, "leaf id")
+	return p
+}
+
+func ParseGet(args []string) (GetOptions, error) {
+	var opt GetOptions
+	if err := cli.Parse(GetParser(&opt), args); err != nil {
+		return opt, err
+	}
+	if opt.ID == "" {
+		return opt, fmt.Errorf("id required")
+	}
+	return opt, nil
+}
+
+type JSONFlag struct {
+	JSONOut bool
+}
+
+func bindJSON(name string, opt *JSONFlag) *flaggy.Parser {
+	p := cli.New(name)
+	p.Bool(&opt.JSONOut, "", "json", "JSON output")
+	return p
+}
+
+func StatsParser() *flaggy.Parser {
+	opt := JSONFlag{}
+	return bindJSON("brain-stats", &opt)
+}
+
+func EvalParser() *flaggy.Parser {
+	opt := JSONFlag{}
+	return bindJSON("brain-eval", &opt)
+}
+
+func ParseJSONFlag(name string, args []string) (JSONFlag, error) {
+	var opt JSONFlag
+	return opt, cli.Parse(bindJSON(name, &opt), args)
+}