package change

import (
	"bytes"
	crand "crypto/rand"
	"math/rand"
	"testing"
)

func randChange() Change {
	c := Change{
		CollectionID: rand.Uint64(),
		ItemID:       rand.Uint64(),
		Store:        rand.Float32() < 0.5,
	}

	if c.Store {
		data := make([]byte, 1+rand.Intn(100))
		crand.Read(data)
		c.Data = data
	}

	c.WritePageIDs = make([]uint64, rand.Intn(10))
	for i := range c.WritePageIDs {
		c.WritePageIDs[i] = rand.Uint64()
	}

	c.ClearPageIDs = make([]uint64, rand.Intn(10))
	for i := range c.ClearPageIDs {
		c.ClearPageIDs[i] = rand.Uint64()
	}

	return c
}

func randChangeSlice() []Change {
	changes := make([]Change, 1+rand.Intn(10))
	for i := range changes {
		changes[i] = randChange()
	}
	return changes
}

func TestWriteRead(t *testing.T) {
	in := randChangeSlice()
	var out []Change

	buf := &bytes.Buffer{}
	if err := Write(in, buf); err != nil {
		t.Fatal(err)
	}

	out, err := Read(out, buf)
	if err != nil {
		t.Fatal(err)
	}

	if len(in) != len(out) {
		t.Fatal(len(in), len(out))
	}
	for i := range in {
		in[i].AssertEqual(t, out[i])
	}
}