package mem_test

import (
	"testing"
	"unsafe"

	"git.brut.systems/judah/xx/mem"
	"git.brut.systems/judah/xx/testx"
)

func TestBitCast(t *testing.T) {
	a := uint32(0xFFFF_FFFF)
	b := mem.BitCast[float32](&a)
	c := mem.BitCast[uint32](&b)
	if a != c {
		t.Fail()
	}

	v := uint8(0xFF)
	d := mem.BitCast[int8](&v)
	if d != -1 {
		t.Fail()
	}
	e := mem.BitCast[uint8](&d)
	if e != 255 {
		t.Fail()
	}
}

func TestAllocationPrimitives(t *testing.T) {
	t.Run("reserve, unreserve", func(t *testing.T) {
		data, err := mem.Reserve(1 * mem.Gigabyte)
		testx.Expect(t, err == nil, "mem.Reserve returned an error - %s", err)

		testx.Expect(t, len(data) == 1*mem.Gigabyte, "len was %d", len(data))
		testx.Expect(t, cap(data) == 1*mem.Gigabyte, "len was %d", cap(data))

		err = mem.Release(data)
		testx.Expect(t, err == nil, "mem.Unreserve returned an error - %s", err)
	})

	t.Run("commit", func(t *testing.T) {
		data, err := mem.Reserve(1 * mem.Gigabyte)
		testx.Expect(t, err == nil, "mem.Reserve returned an error - %s", err)

		err = mem.Commit(data, mem.AccessRead|mem.AccessWrite)
		testx.Expect(t, err == nil, "mem.Commit returned an error - %s", err)

		for i := range data {
			data[i] = byte(i * i)
		}
	})

	t.Run("decommit", func(t *testing.T) {
		data, err := mem.Reserve(1 * mem.Gigabyte)
		testx.Expect(t, err == nil, "mem.Reserve returned an error - %s", err)

		err = mem.Commit(data, mem.AccessRead|mem.AccessWrite)
		testx.Expect(t, err == nil, "mem.Commit returned an error - %s", err)

		before := uintptr(unsafe.Pointer(&data[0]))

		err = mem.Decommit(data)
		testx.Expect(t, err == nil, "mem.Decommit returned an error - %s", err)

		// accessing data before recommitting it will fail

		err = mem.Commit(data, mem.AccessRead|mem.AccessWrite)
		testx.Expect(t, err == nil, "mem.Commit returned an error - %s", err)

		after := uintptr(unsafe.Pointer(&data[0]))
		testx.Expect(t, before == after, "base pointers did not match between after recommit %d != %d", before, after)

		for i := range data {
			data[i] = byte(i * i)
		}
	})
}