// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
// SPDX-License-Identifier: GPL-3.0-or-later
package i3ipc

import (
	"bytes"
	"encoding/binary"
	"io"
	"testing"
)

type fragments struct{ io.Reader }

func (r fragments) Read(b []byte) (int, error) { return r.Reader.Read(b[:min(1, len(b))]) }
func TestFraming(t *testing.T) {
	var wire bytes.Buffer
	body := []byte(`{"change":"résumé"}`)
	if err := writeMessage(&wire, modeEvent, body); err != nil {
		t.Fatal(err)
	}
	frame := bytes.Clone(wire.Bytes())
	got, err := readMessage(fragments{&wire})
	if err != nil || got.kind != modeEvent || !bytes.Equal(got.body, body) {
		t.Fatalf("%+v %v", got, err)
	}
	for name, bad := range map[string][]byte{
		"header": frame[:12], "body": frame[:len(frame)-1],
		"magic": append([]byte("no-ipc"), frame[6:]...),
		"json":  append(bytes.Clone(frame[:14]), bytes.Repeat([]byte("x"), len(body))...),
	} {
		t.Run(name, func(t *testing.T) {
			if _, err := readMessage(bytes.NewReader(bad)); err == nil {
				t.Fatal("accepted malformed frame")
			}
		})
	}
	huge := bytes.Clone(frame[:14])
	binary.NativeEndian.PutUint32(huge[6:10], maxPayload+1)
	if _, err := readMessage(bytes.NewReader(huge)); err == nil {
		t.Fatal("accepted oversized frame")
	}
}