// Copyright 2025 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build goexperiment.simd && amd64

package simd_test

import (
	"reflect"
	"simd"
	"slices"
	"testing"
)

var sink any

func TestType(t *testing.T) {
	// Testing:
	// - Defined as another struct's field is ok
	// - Pointer is ok
	// - Type defition is ok
	// - Type alias is ok
	// - Type conversion is ok
	// - Conversion to interface is ok
	type alias = simd.Int32x4
	type maskT simd.Mask32x4
	type myStruct struct {
		x alias
		y *simd.Int32x4
		z maskT
	}
	vals := [4]int32{1, 2, 3, 4}
	v := myStruct{x: simd.LoadInt32x4(&vals)}
	// masking elements 1 and 2.
	want := []int32{2, 4, 0, 0}
	y := simd.LoadInt32x4(&vals)
	v.y = &y
	sink = y

	if !simd.HasAVX512GFNI() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	v.z = maskT(simd.Mask32x4FromBits(0b0011))
	*v.y = v.y.Add(v.x).Masked(simd.Mask32x4(v.z))

	got := [4]int32{}
	v.y.Store(&got)
	for i := range 4 {
		if want[i] != got[i] {
			t.Errorf("Result at %d incorrect: want %d, got %d", i, want[i], got[i])
		}
	}
}

func TestFuncValue(t *testing.T) {
	// Test that simd intrinsic can be used as a function value.
	xv := [4]int32{1, 2, 3, 4}
	yv := [4]int32{5, 6, 7, 8}
	want := []int32{6, 8, 10, 12}
	x := simd.LoadInt32x4(&xv)
	y := simd.LoadInt32x4(&yv)
	fn := simd.Int32x4.Add
	sink = fn
	x = fn(x, y)
	got := [4]int32{}
	x.Store(&got)
	for i := range 4 {
		if want[i] != got[i] {
			t.Errorf("Result at %d incorrect: want %d, got %d", i, want[i], got[i])
		}
	}
}

func TestReflectMethod(t *testing.T) {
	// Test that simd intrinsic can be accessed via reflection.
	// NOTE: we don't yet support reflect method.Call.
	xv := [4]int32{1, 2, 3, 4}
	yv := [4]int32{5, 6, 7, 8}
	want := []int32{6, 8, 10, 12}
	x := simd.LoadInt32x4(&xv)
	y := simd.LoadInt32x4(&yv)
	m, ok := reflect.TypeOf(x).MethodByName("Add")
	if !ok {
		t.Fatal("Add method not found")
	}
	fn := m.Func.Interface().(func(x, y simd.Int32x4) simd.Int32x4)
	x = fn(x, y)
	got := [4]int32{}
	x.Store(&got)
	for i := range 4 {
		if want[i] != got[i] {
			t.Errorf("Result at %d incorrect: want %d, got %d", i, want[i], got[i])
		}
	}
}

func TestVectorConversion(t *testing.T) {
	if !simd.HasAVX512GFNI() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	xv := [4]int32{1, 2, 3, 4}
	x := simd.LoadInt32x4(&xv)
	xPromoted := x.AsInt64x2()
	xPromotedDemoted := xPromoted.AsInt32x4()
	got := [4]int32{}
	xPromotedDemoted.Store(&got)
	for i := range 4 {
		if xv[i] != got[i] {
			t.Errorf("Result at %d incorrect: want %d, got %d", i, xv[i], got[i])
		}
	}
}

func TestMaskConversion(t *testing.T) {
	if !simd.HasAVX512GFNI() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	x := simd.LoadInt32x4Slice([]int32{5, 0, 7, 0})
	mask := simd.Int32x4{}.Sub(x).ToMask()
	y := simd.LoadInt32x4Slice([]int32{1, 2, 3, 4}).Add(x).Masked(mask)
	want := [4]int32{6, 0, 10, 0}
	got := make([]int32, 4)
	y.StoreSlice(got)
	for i := range 4 {
		if want[i] != got[i] {
			t.Errorf("Result at %d incorrect: want %d, got %d", i, want[i], got[i])
		}
	}
}

func TestPermute(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	x := []int64{1, 2, 3, 4, 5, 6, 7, 8}
	indices := []uint64{7, 6, 5, 4, 3, 2, 1, 0}
	want := []int64{8, 7, 6, 5, 4, 3, 2, 1}
	got := make([]int64, 8)
	simd.LoadInt64x8Slice(x).Permute(simd.LoadUint64x8Slice(indices)).StoreSlice(got)
	for i := range 8 {
		if want[i] != got[i] {
			t.Errorf("want and got differ at index %d, want=%d, got=%d", i, want[i], got[i])
		}
	}
}

func TestPermute2(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	x := []int64{1, 2, 3, 4, 5, 6, 7, 8}
	y := []int64{-1, -2, -3, -4, -5, -6, -7, -8}
	indices := []uint64{7 + 8, 6, 5 + 8, 4, 3 + 8, 2, 1 + 8, 0}
	want := []int64{-8, 7, -6, 5, -4, 3, -2, 1}
	got := make([]int64, 8)
	simd.LoadInt64x8Slice(x).Permute2(simd.LoadInt64x8Slice(y), simd.LoadUint64x8Slice(indices)).StoreSlice(got)
	for i := range 8 {
		if want[i] != got[i] {
			t.Errorf("want and got differ at index %d, want=%d, got=%d", i, want[i], got[i])
		}
	}
}

func TestCompress(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	v1234 := simd.LoadInt32x4Slice([]int32{1, 2, 3, 4})
	v2400 := v1234.Compress(simd.Mask32x4FromBits(0b1010))
	got := make([]int32, 4)
	v2400.StoreSlice(got)
	want := []int32{2, 4, 0, 0}
	if !slices.Equal(got, want) {
		t.Errorf("want and got differ, want=%v, got=%v", want, got)
	}
}

func TestExpand(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	v3400 := simd.LoadInt32x4Slice([]int32{3, 4, 0, 0})
	v2400 := v3400.Expand(simd.Mask32x4FromBits(0b1010))
	got := make([]int32, 4)
	v2400.StoreSlice(got)
	want := []int32{0, 3, 0, 4}
	if !slices.Equal(got, want) {
		t.Errorf("want and got differ, want=%v, got=%v", want, got)
	}
}

var testShiftAllVal uint64 = 3

func TestShiftAll(t *testing.T) {
	got := make([]int32, 4)
	simd.LoadInt32x4Slice([]int32{0b11, 0b11, 0b11, 0b11}).ShiftAllLeft(2).StoreSlice(got)
	for _, v := range got {
		if v != 0b1100 {
			t.Errorf("expect 0b1100, got %b", v)
		}
	}
	simd.LoadInt32x4Slice([]int32{0b11, 0b11, 0b11, 0b11}).ShiftAllLeft(testShiftAllVal).StoreSlice(got)
	for _, v := range got {
		if v != 0b11000 {
			t.Errorf("expect 0b11000, got %b", v)
		}
	}
}

func TestSlicesInt8(t *testing.T) {
	a := []int8{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
		17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32}
	v := simd.LoadInt8x32Slice(a)
	b := make([]int8, 32, 32)
	v.StoreSlice(b)
	checkSlices(t, a, b)
}

func TestSlicesInt8SetElem(t *testing.T) {
	a := []int8{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
		17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32}
	v := simd.LoadInt8x16Slice(a)

	v = v.SetElem(3, 13)
	a[3] = 13

	b := make([]int8, 16, 16)
	v.StoreSlice(b)
	checkSlices(t, a, b)
}

func TestSlicesInt8GetElem(t *testing.T) {
	a := []int8{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
		17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32}
	v := simd.LoadInt8x16Slice(a)
	e := v.GetElem(2)
	if e != a[2] {
		t.Errorf("GetElem(2) = %d != a[2] = %d", e, a[2])
	}

}

func TestSlicesInt8TooShortLoad(t *testing.T) {
	defer func() {
		if r := recover(); r != nil {
			t.Logf("Saw EXPECTED panic %v", r)
		} else {
			t.Errorf("Did not see expected panic")
		}
	}()
	a := []int8{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
		17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31} // TOO SHORT, should panic
	v := simd.LoadInt8x32Slice(a)
	b := make([]int8, 32, 32)
	v.StoreSlice(b)
	checkSlices(t, a, b)
}

func TestSlicesInt8TooShortStore(t *testing.T) {
	defer func() {
		if r := recover(); r != nil {
			t.Logf("Saw EXPECTED panic %v", r)
		} else {
			t.Errorf("Did not see expected panic")
		}
	}()
	a := []int8{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
		17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32}
	v := simd.LoadInt8x32Slice(a)
	b := make([]int8, 31) // TOO SHORT, should panic
	v.StoreSlice(b)
	checkSlices(t, a, b)
}

func TestSlicesFloat64(t *testing.T) {
	a := []float64{1, 2, 3, 4, 5, 6, 7, 8} // too long, should be fine
	v := simd.LoadFloat64x4Slice(a)
	b := make([]float64, 4, 4)
	v.StoreSlice(b)
	for i := range b {
		if a[i] != b[i] {
			t.Errorf("a and b differ at index %d, a=%f, b=%f", i, a[i], b[i])
		}
	}
}

// TODO: try to reduce this test to be smaller.
func TestMergeLocals(t *testing.T) {
	testMergeLocalswrapper(t, simd.Int64x4.Add)
}

//go:noinline
func forceSpill() {}

func testMergeLocalswrapper(t *testing.T, op func(simd.Int64x4, simd.Int64x4) simd.Int64x4) {
	t.Helper()
	s0 := []int64{0, 1, 2, 3}
	s1 := []int64{-1, 0, -1, 0}
	want := []int64{-1, 1, 1, 3}
	v := simd.LoadInt64x4Slice(s0)
	m := simd.LoadInt64x4Slice(s1)
	forceSpill()
	got := make([]int64, 4)
	gotv := op(v, m)
	gotv.StoreSlice(got)
	for i := range len(want) {
		if !(got[i] == want[i]) {
			t.Errorf("Result at %d incorrect: want %v, got %v", i, want[i], got[i])
		}
	}
}

func TestBitMaskLoad(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	var bits uint64 = 0b10
	results := [2]int64{}
	want := [2]int64{0, 6}
	m := simd.LoadMask64x2FromBits(&bits)
	simd.LoadInt64x2Slice([]int64{1, 2}).Add(simd.LoadInt64x2Slice([]int64{3, 4})).Masked(m).Store(&results)
	for i := range 2 {
		if results[i] != want[i] {
			t.Errorf("Result at %d incorrect: want %v, got %v", i, want[i], results[i])
		}
	}
}

func TestBitMaskStore(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	var want uint64 = 0b101
	var got uint64
	x := simd.LoadInt32x4Slice([]int32{1, 2, 3, 4})
	y := simd.LoadInt32x4Slice([]int32{5, 0, 5, 0})
	m := y.Greater(x)
	m.StoreToBits(&got)
	if got != want {
		t.Errorf("Result incorrect: want %b, got %b", want, got)
	}
}

func TestBitMaskFromBits(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	results := [2]int64{}
	want := [2]int64{0, 6}
	m := simd.Mask64x2FromBits(0b10)
	simd.LoadInt64x2Slice([]int64{1, 2}).Add(simd.LoadInt64x2Slice([]int64{3, 4})).Masked(m).Store(&results)
	for i := range 2 {
		if results[i] != want[i] {
			t.Errorf("Result at %d incorrect: want %v, got %v", i, want[i], results[i])
		}
	}
}

func TestBitMaskToBits(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	if v := simd.LoadInt16x8Slice([]int16{1, 0, 1, 0, 0, 0, 0, 0}).ToMask().ToBits(); v != 0b101 {
		t.Errorf("Want 0b101, got %b", v)
	}
}

func TestMergeFloat(t *testing.T) {
	k := make([]int64, 4, 4)
	s := make([]float64, 4, 4)

	a := simd.LoadFloat64x4Slice([]float64{1, 2, 3, 4})
	b := simd.LoadFloat64x4Slice([]float64{4, 2, 3, 1})
	g := a.Greater(b)
	g.AsInt64x4().StoreSlice(k)
	c := a.Merge(b, g)

	c.StoreSlice(s)

	checkSlices[int64](t, k, []int64{0, 0, 0, -1})
	checkSlices[float64](t, s, []float64{4, 2, 3, 4})
}

func TestMergeFloat512(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}

	k := make([]int64, 8, 8)
	s := make([]float64, 8, 8)

	a := simd.LoadFloat64x8Slice([]float64{1, 2, 3, 4, 5, 6, 7, 8})
	b := simd.LoadFloat64x8Slice([]float64{8, 7, 6, 5, 4, 2, 3, 1})
	g := a.Greater(b)
	g.AsInt64x8().StoreSlice(k)
	c := a.Merge(b, g)
	d := a.Masked(g)

	checkSlices[int64](t, k, []int64{0, 0, 0, 0, -1, -1, -1, -1})

	c.StoreSlice(s)
	checkSlices[float64](t, s, []float64{8, 7, 6, 5, 5, 6, 7, 8})

	d.StoreSlice(s)
	checkSlices[float64](t, s, []float64{0, 0, 0, 0, 5, 6, 7, 8})
}

var ro uint8 = 2

func TestRotateAllVariable(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}
	got := make([]int32, 4)
	simd.LoadInt32x4Slice([]int32{0b11, 0b11, 0b11, 0b11}).RotateAllLeft(ro).StoreSlice(got)
	for _, v := range got {
		if v != 0b1100 {
			t.Errorf("Want 0b1100, got %b", v)
		}
	}
}

func TestBroadcastUint32x4(t *testing.T) {
	s := make([]uint32, 4, 4)
	simd.BroadcastUint32x4(123456789).StoreSlice(s)
	checkSlices(t, s, []uint32{123456789, 123456789, 123456789, 123456789})
}

func TestBroadcastFloat32x8(t *testing.T) {
	s := make([]float32, 8, 8)
	simd.BroadcastFloat32x8(123456789).StoreSlice(s)
	checkSlices(t, s, []float32{123456789, 123456789, 123456789, 123456789, 123456789, 123456789, 123456789, 123456789})
}

func TestBroadcastFloat64x2(t *testing.T) {
	s := make([]float64, 2, 2)
	simd.BroadcastFloat64x2(123456789).StoreSlice(s)
	checkSlices(t, s, []float64{123456789, 123456789})
}

func TestBroadcastUint64x2(t *testing.T) {
	s := make([]uint64, 2, 2)
	simd.BroadcastUint64x2(123456789).StoreSlice(s)
	checkSlices(t, s, []uint64{123456789, 123456789})
}

func TestMaskOpt512(t *testing.T) {
	if !simd.HasAVX512() {
		t.Skip("Test requires HasAVX512, not available on this hardware")
		return
	}

	k := make([]int64, 8, 8)
	s := make([]float64, 8, 8)

	a := simd.LoadFloat64x8Slice([]float64{2, 0, 2, 0, 2, 0, 2, 0})
	b := simd.LoadFloat64x8Slice([]float64{1, 1, 1, 1, 1, 1, 1, 1})
	c := simd.LoadFloat64x8Slice([]float64{1, 2, 3, 4, 5, 6, 7, 8})
	d := simd.LoadFloat64x8Slice([]float64{2, 4, 6, 8, 10, 12, 14, 16})
	g := a.Greater(b)
	e := c.Add(d).Masked(g)
	e.StoreSlice(s)
	g.AsInt64x8().StoreSlice(k)
	checkSlices[int64](t, k, []int64{-1, 0, -1, 0, -1, 0, -1, 0})
	checkSlices[float64](t, s, []float64{3, 0, 9, 0, 15, 0, 21, 0})
}