package pfile

import (
	crand "crypto/rand"
	"math/rand"

	"git.crumpington.com/public/jldb/mdb/change"
)

func randomChangeList() (changes []change.Change) {
	count := 1 + rand.Intn(8)
	for i := 0; i < count; i++ {
		change := change.Change{
			CollectionID: 1 + uint64(rand.Int63n(10)),
			ItemID:       1 + uint64(rand.Int63n(10)),
		}

		if rand.Float32() < 0.95 {
			change.Data = randBytes(1 + rand.Intn(pageDataSize*4))
			change.Store = true
		}

		changes = append(changes, change)
	}

	return changes
}

type changeListBuilder []change.Change

func (b *changeListBuilder) Clear() *changeListBuilder {
	*b = (*b)[:0]
	return b
}

func (b *changeListBuilder) Store(cID, iID, dataSize uint64) *changeListBuilder {
	data := make([]byte, dataSize)
	crand.Read(data)
	*b = append(*b, change.Change{
		CollectionID: cID,
		ItemID:       iID,
		Store:        true,
		Data:         data,
	})
	return b
}

func (b *changeListBuilder) Delete(cID, iID uint64) *changeListBuilder {
	*b = append(*b, change.Change{
		CollectionID: cID,
		ItemID:       iID,
		Store:        false,
	})
	return b
}

func (b *changeListBuilder) Build() []change.Change {
	return *b
}