// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: BSD-3-Clause

package asm

import (
	"strings"
	"testing"

	"sourcedock.dev/petrbalvin/gasm-devkit/parser"
)

// TestGOObjectAARCH64Structure checks the basic structure of the emitted
// AArch64 GOOBJ: the preamble, the magic, the block offsets and the
// non-package symbol definitions.
func TestGOObjectAARCH64Structure(t *testing.T) {
	f, errs := parser.Parse("k_arm64.s", `
#include "textflag.h"

TEXT ·add(SB), NOSPLIT, $0-24
	MOVD a+0(FP), R4
	MOVD b+8(FP), R5
	ADD R5, R4, R4
	MOVD R4, ret+16(FP)
	RET
`)
	if len(errs) > 0 {
		t.Fatalf("parse: %v", errs)
	}
	img, err := AssembleFileARM64(f)
	if err != nil {
		t.Fatalf("AssembleFileARM64: %v", err)
	}
	obj, err := img.GOObjectAARCH64("testpkg", "k_arm64.s")
	if err != nil {
		t.Fatalf("GOObjectAARCH64: %v", err)
	}

	// Check preamble.
	idx := strings.Index(string(obj), "\n!\n")
	if idx < 0 {
		t.Fatal("missing preamble separator")
	}
	preamble := string(obj[:idx])
	if !strings.HasPrefix(preamble, "go object") {
		t.Errorf("preamble = %q, want 'go object ...'", preamble)
	}

	// Check GOOBJ magic.
	magicIdx := idx + 3
	if magicIdx+8 > len(obj) || string(obj[magicIdx:magicIdx+8]) != "\x00go120ld" {
		t.Error("missing GOOBJ magic")
	}

	// The object should contain the function's code.
	if len(img.Code) == 0 {
		t.Error("no code generated")
	}
}