package cuckoo_test

import (
	"bytes"
	"encoding/binary"
	"maps"
	"testing"

	"github.com/stretchr/testify/assert"

	"git.maximhutz.com/tools/go-cuckoo"
)

func offsetHash(seed uint32) cuckoo.Hash[uint32] {
	return func(x uint32) uint64 {
		v := uint64(x) ^ uint64(seed)
		v = (v ^ (v >> 30)) * 0xbf58476d1ce4e5b9
		v = (v ^ (v >> 27)) * 0x94d049bb133111eb
		return v ^ (v >> 31)
	}
}

func FuzzInsertLookup(f *testing.F) {
	f.Fuzz(func(t *testing.T, data []byte, seedA, seedB uint32) {
		assert := assert.New(t)

		actual := cuckoo.NewCustomTable[uint32, uint32](
			offsetHash(seedA),
			offsetHash(seedB),
			func(a, b uint32) bool { return a == b },
		)

		expected := map[uint32]uint32{}

		if seedA == seedB {
			return
		}

		r := bytes.NewReader(data)
		var key, value uint32
		var drop bool
		for binary.Read(r, binary.LittleEndian, &key) == nil &&
			binary.Read(r, binary.LittleEndian, &value) == nil {

			if drop {
				err := actual.Drop(key)
				assert.NoError(err)

				delete(expected, key)

				_, err = actual.Get(key)
				assert.Error(err)
			} else {
				err := actual.Put(key, value)
				assert.NoError(err)

				expected[key] = value

				found, err := actual.Get(key)
				assert.NoError(err)
				assert.Equal(value, found)
			}
			assert.Equal(expected, maps.Collect(actual.Entries()))

			drop = !drop
		}
	})
}