package pathrule_test

import (
	"errors"
	"testing"
	"unicode/utf8"

	"g.activething.com/go/DateKeys/internal/pathrule"
	"g.activething.com/go/DateKeys/internal/testkit"
)

// FuzzCheckPath: the rules of one entry and the decoder of the head agree on
// every path: a head that holds it alone decodes exactly when the path is
// valid UTF-8 of 1 to 1024 bytes (R1, layer 3) that CheckPath accepts, since
// one path collides with none and makes at most 31 folders (spec §29.5).
func FuzzCheckPath(f *testing.F) {
	var paths testkit.PathVectorFile
	if err := testkit.ReadJSON("../../testdata/vectors/paths.json", &paths); err != nil {
		f.Fatal(err)
	}
	for _, v := range paths.Paths {
		f.Add(v.Path)
	}
	f.Fuzz(func(t *testing.T, p string) {
		err := pathrule.CheckPath(p)
		var e *pathrule.Error
		if err != nil && !errors.As(err, &e) {
			t.Fatalf("an error that is not a pathrule.Error: %v", err)
		}
		valid := err == nil && utf8.ValidString(p) && len(p) >= 1 && len(p) <= pathrule.MaxPathLen
		head, merr := testkit.TreeHead([]string{p})
		if merr != nil {
			return
		}
		if got, _ := testkit.HeadResult(head); (got == testkit.ResultOK) != valid {
			t.Fatalf("path %+q: CheckPath %v, the head decodes to %s", p, err, got)
		}
	})
}