package ormfield

import (
	"encoding/binary"
	"io"

	"google.golang.org/protobuf/reflect/protoreflect"
)

// Uint64Codec encodes uint64 values as 8-byte big-endian integers.
type Uint64Codec struct{}

func (u Uint64Codec) FixedBufferSize() int {
	return 8
}

func (u Uint64Codec) ComputeBufferSize(protoreflect.Value) (int, error) {
	return u.FixedBufferSize(), nil
}

func (u Uint64Codec) IsOrdered() bool {
	return true
}

func (u Uint64Codec) Compare(v1, v2 protoreflect.Value) int {
	return compareUint(v1, v2)
}

func (u Uint64Codec) Decode(r Reader) (protoreflect.Value, error) {
	var x uint64
	err := binary.Read(r, binary.BigEndian, &x)
	return protoreflect.ValueOfUint64(x), err
}

func (u Uint64Codec) Encode(value protoreflect.Value, w io.Writer) error {
	return binary.Write(w, binary.BigEndian, value.Uint())
}

func compareUint(v1, v2 protoreflect.Value) int {
	x := v1.Uint()
	y := v2.Uint()
	if x == y {
		return 0
	} else if x < y {
		return -1
	} else {
		return 1
	}
}