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/args.go

@@ -3,12 +3,15 @@ package rank
 import (
 	"fmt"
 	"strconv"
-	"strings"
+
+	"github.com/eSlider/2dph/internal/cli"
+	"github.com/integrii/flaggy"
 )
 
 const Usage = `usage: bin/brain/search.go "query" [--root facts|info] [--repo REPO] [-n N] [--hop N] [--json] [--no-web]
        bin/brain/search.go serve [port]
-       bin/brain/search.go --list-model`
+       bin/brain/search.go --list-model
+       source <(./bin/cli/complete.go bash)`
 
 type Options struct {
 	Query     string
@@ -21,62 +24,57 @@ type Options struct {
 	NoWeb     bool
 }
 
+// NewParser is the flaggy schema for search (also used by bin/cli/complete.go).
+func NewParser(opt *Options) *flaggy.Parser {
+	if opt.Limit == 0 {
+		opt.Limit = 20
+	}
+	p := cli.New("brain-search")
+	p.Description = "deduction search: facts → info → web"
+	p.String(&opt.Root, "", "root", "facts or info")
+	p.String(&opt.Repo, "", "repo", "filter by repo")
+	p.Int(&opt.Limit, "n", "n", "max hits")
+	p.Int(&opt.Hop, "", "hop", "walk FROM_FILE depth 1-3")
+	p.Bool(&opt.JSONOut, "", "json", "JSON output")
+	p.Bool(&opt.NoWeb, "", "no-web", "stay local")
+	p.Bool(&opt.ListModel, "", "list-model", "print embedding model")
+	return p
+}
+
 // ParseArgs reads flags. Unknown flags are an error: silently dropping them
 // meant `--hop 1` vanished and its argument `1` was appended to the query.
 func ParseArgs(args []string) (Options, error) {
 	opt := Options{Limit: 20}
-	var queryArgs []string
-
-	for i := 0; i < len(args); i++ {
-		arg := args[i]
-		wantsValue := arg == "--root" || arg == "--repo" || arg == "-n" || arg == "--hop"
-		if wantsValue && i+1 >= len(args) {
-			return opt, fmt.Errorf("%s needs a value", arg)
-		}
-		switch arg {
-		case "--root":
-			i++
-			opt.Root = args[i]
-			if opt.Root != "facts" && opt.Root != "info" {
-				return opt, fmt.Errorf("--root must be facts or info, got %q", opt.Root)
-			}
-		case "--repo":
-			i++
-			opt.Repo = args[i]
-		case "-n":
-			i++
-			n, err := strconv.Atoi(args[i])
-			if err != nil || n < 1 {
-				return opt, fmt.Errorf("-n must be a positive integer, got %q", args[i])
-			}
-			opt.Limit = n
-		case "--hop":
-			i++
-			n, err := strconv.Atoi(args[i])
-			if err != nil || n < 1 {
-				return opt, fmt.Errorf("--hop must be a positive integer, got %q", args[i])
-			}
-			if n > 3 {
-				return opt, fmt.Errorf("--hop max is 3 (File → Commit → Person)")
-			}
-			opt.Hop = n
-		case "--json":
-			opt.JSONOut = true
-		case "--no-web":
-			opt.NoWeb = true
-		case "--list-model":
-			opt.ListModel = true
-		default:
-			if strings.HasPrefix(arg, "-") {
-				return opt, fmt.Errorf("unknown flag %q", arg)
-			}
-			queryArgs = append(queryArgs, arg)
-		}
+	p := NewParser(&opt)
+	var q string
+	p.AddPositionalValue(&q, "query", 1, false, "search query")
+	if err := cli.Parse(p, args); err != nil {
+		return opt, err
+	}
+	opt.Query = cli.Query(q, p.TrailingArguments)
+	if opt.Root != "" && opt.Root != "facts" && opt.Root != "info" {
+		return opt, fmt.Errorf("--root must be facts or info, got %q", opt.Root)
+	}
+	if opt.Limit < 1 {
+		return opt, fmt.Errorf("-n must be a positive integer, got %q", strconv.Itoa(opt.Limit))
+	}
+	if opt.Hop < 0 {
+		return opt, fmt.Errorf("--hop must be a positive integer, got %q", strconv.Itoa(opt.Hop))
+	}
+	if opt.Hop > 3 {
+		return opt, fmt.Errorf("--hop max is 3 (File → Commit → Person)")
 	}
-
-	opt.Query = strings.TrimSpace(strings.Join(queryArgs, " "))
 	if opt.Query == "" && !opt.ListModel {
 		return opt, fmt.Errorf("no query given")
 	}
 	return opt, nil
 }
+
+// Parser is the search schema for bin/cli/complete.go.
+func Parser() *flaggy.Parser {
+	opt := Options{Limit: 20}
+	p := NewParser(&opt)
+	var q string
+	p.AddPositionalValue(&q, "query", 1, false, "search query")
+	return p
+}