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

package verify

import (
	"runtime"
	"testing"
)

// requireHost skips the test unless the test binary runs on the named
// architecture: the JIT executes native code, so a kernel assembled for
// arm64 only runs on an arm64 host.
func requireHost(t *testing.T, goarch string) {
	t.Helper()
	if runtime.GOARCH != goarch {
		t.Skipf("runs only on %s hosts (this host is %s)", goarch, runtime.GOARCH)
	}
}

func TestABIArm64(t *testing.T) {
	requireHost(t, "arm64")

	k, err := Load("../testdata/verify/abi_arm64.s")
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	t.Cleanup(k.Close)

	// cleanAdd preserves everything and computes correctly.
	args := make([]byte, 24)
	PutUint64(args, 0, 3)
	PutUint64(args, 8, 4)
	out, report, err := k.CallFuncChecked("cleanAdd", args)
	if err != nil {
		t.Fatalf("CallFuncChecked: %v", err)
	}
	if got := int64(GetUint64(out, 16)); got != 7 {
		t.Errorf("cleanAdd(3, 4) = %d, want 7", got)
	}
	if !report.OK() {
		t.Errorf("cleanAdd: %s", report)
	}

	// dirtyFP clobbers the frame pointer (R29).  The kernel passes its
	// argument through, so the argument must carry the expected value the
	// way the amd64 twin test seeds it.
	args = make([]byte, 16)
	PutUint64(args, 0, 0x1234)
	out, report, err = k.CallFuncChecked("dirtyFP", args)
	if err != nil {
		t.Fatalf("CallFuncChecked: %v", err)
	}
	if got := int64(GetUint64(out, 8)); got != 0x1234 {
		t.Errorf("dirtyFP returned %d, want %d", got, int64(0x1234))
	}
	if !report.FPClobbered {
		t.Error("dirtyFP: expected frame pointer clobbered, but report says clean")
	}
	if report.GClobbered {
		t.Errorf("dirtyFP: only R29 should be clobbered: %s", report)
	}

	// dirtyG clobbers the goroutine pointer (R28) and still returns its
	// argument.
	args = make([]byte, 16)
	PutUint64(args, 0, 0x5678)
	out, report, err = k.CallFuncChecked("dirtyG", args)
	if err != nil {
		t.Fatalf("CallFuncChecked: %v", err)
	}
	if got := int64(GetUint64(out, 8)); got != 0x5678 {
		t.Errorf("dirtyG returned %d, want %d", got, int64(0x5678))
	}
	if !report.GClobbered {
		t.Error("dirtyG: expected g clobbered, but report says clean")
	}
	if report.FPClobbered {
		t.Errorf("dirtyG: only R28 should be clobbered: %s", report)
	}
}

func TestABIRiscv64(t *testing.T) {
	requireHost(t, "riscv64")

	k, err := Load("../testdata/verify/abi_riscv64.s")
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	t.Cleanup(k.Close)

	// cleanAdd preserves g and computes correctly.
	args := make([]byte, 24)
	PutUint64(args, 0, 3)
	PutUint64(args, 8, 4)
	out, report, err := k.CallFuncChecked("cleanAdd", args)
	if err != nil {
		t.Fatalf("CallFuncChecked: %v", err)
	}
	if got := int64(GetUint64(out, 16)); got != 7 {
		t.Errorf("cleanAdd(3, 4) = %d, want 7", got)
	}
	if !report.OK() {
		t.Errorf("cleanAdd: %s", report)
	}

	// dirtyG clobbers the goroutine pointer (X27).
	_, report, err = k.CallFuncChecked("dirtyG", make([]byte, 16))
	if err != nil {
		t.Fatalf("CallFuncChecked: %v", err)
	}
	if !report.GClobbered {
		t.Error("dirtyG: expected g clobbered, but report says clean")
	}
	if report.FPClobbered || report.RedZoneHit {
		t.Errorf("dirtyG: unexpected additional violations: %s", report)
	}
}

func TestABILoong64(t *testing.T) {
	requireHost(t, "loong64")

	k, err := Load("../testdata/verify/abi_loong64.s")
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	t.Cleanup(k.Close)

	// cleanAdd preserves g and computes correctly.
	args := make([]byte, 24)
	PutUint64(args, 0, 3)
	PutUint64(args, 8, 4)
	out, report, err := k.CallFuncChecked("cleanAdd", args)
	if err != nil {
		t.Fatalf("CallFuncChecked: %v", err)
	}
	if got := int64(GetUint64(out, 16)); got != 7 {
		t.Errorf("cleanAdd(3, 4) = %d, want 7", got)
	}
	if !report.OK() {
		t.Errorf("cleanAdd: %s", report)
	}

	// dirtyG clobbers the goroutine pointer (R22).
	_, report, err = k.CallFuncChecked("dirtyG", make([]byte, 16))
	if err != nil {
		t.Fatalf("CallFuncChecked: %v", err)
	}
	if !report.GClobbered {
		t.Error("dirtyG: expected g clobbered, but report says clean")
	}
	if report.FPClobbered || report.RedZoneHit {
		t.Errorf("dirtyG: unexpected additional violations: %s", report)
	}
}