package locator_test

import (
	"bytes"
	"encoding/hex"
	"testing"

	"g.activething.com/go/DateKeys/extension"
	"g.activething.com/go/DateKeys/internal/testkit"
	"g.activething.com/go/DateKeys/locator"
)

// FuzzUnmarshal reads the plaintext of a locator: it never panics, and what
// it accepts is canonical, so that encoding it again gives the same bytes.
func FuzzUnmarshal(f *testing.F) {
	var v testkit.LocatorVectorFile
	if err := testkit.ReadJSON("../testdata/vectors/locator.json", &v); err != nil {
		f.Fatal(err)
	}
	for _, s := range []string{v.Plaintext, v.Mixed.Plaintext} {
		if b, err := hex.DecodeString(s); err == nil {
			f.Add(b)
		}
	}
	for _, c := range v.PlaintextCases {
		if b, err := hex.DecodeString(c.Plaintext); err == nil {
			f.Add(b)
		}
	}
	f.Add([]byte{0xa0})
	f.Fuzz(func(t *testing.T, b []byte) {
		l, err := locator.Unmarshal(b)
		if err != nil {
			return
		}
		for _, a := range l.Usable() {
			if locator.CheckURI(a.URI) != nil || a.Host() == "" {
				t.Fatalf("a usable address %q that the rules refuse", a.URI)
			}
		}
	})
}

// FuzzParseInfo reads the data of datekeys.capsule: it never panics, and its
// only normative code is ERR_EXTENSION_DATA_INVALID (spec §54, §57).
func FuzzParseInfo(f *testing.F) {
	var v testkit.LocatorVectorFile
	if err := testkit.ReadJSON("../testdata/vectors/locator.json", &v); err != nil {
		f.Fatal(err)
	}
	if b, err := hex.DecodeString(v.Extension); err == nil {
		f.Add(b)
	}
	for _, c := range v.ExtensionCases {
		if b, err := hex.DecodeString(c.Data); err == nil {
			f.Add(b)
		}
	}
	f.Fuzz(func(t *testing.T, b []byte) {
		_, err := locator.ParseInfo(extension.Extension{ID: extension.CapsuleID, Version: 1, Data: b})
		if err != nil && !bytes.Contains([]byte(err.Error()), []byte("ERR_EXTENSION_DATA_INVALID")) {
			t.Fatalf("an error without its code: %v", err)
		}
	})
}

// FuzzCheckURI checks an address: it never panics, and a host that it shows
// is in the address as it is written, with no decoding.
func FuzzCheckURI(f *testing.F) {
	var v testkit.LocatorVectorFile
	if err := testkit.ReadJSON("../testdata/vectors/locator.json", &v); err != nil {
		f.Fatal(err)
	}
	for _, c := range v.URICases {
		f.Add(c.URI)
	}
	f.Fuzz(func(t *testing.T, uri string) {
		if locator.CheckURI(uri) != nil {
			return
		}
		if h := (locator.Address{URI: uri}).Host(); h == "" || !bytes.Contains([]byte(uri), []byte(h)) {
			t.Fatalf("%q: host %q", uri, h)
		}
	})
}