package protocol

import (
	"bytes"
	"encoding/binary"
	"math"
)

type UxWriter struct {
	buf bytes.Buffer
}

func NewUxWriter() *UxWriter {
	return &UxWriter{}
}

func (w *UxWriter) U8(val byte) *UxWriter {
	w.buf.WriteByte(val)
	return w
}

func (w *UxWriter) Bool(val bool) *UxWriter {
	if val {
		w.buf.WriteByte(1)
	} else {
		w.buf.WriteByte(0)
	}
	return w
}

func (w *UxWriter) I16(val int16) *UxWriter {
	var b [2]byte
	binary.LittleEndian.PutUint16(b[:], uint16(val))
	w.buf.Write(b[:])
	return w
}

func (w *UxWriter) U16(val uint16) *UxWriter {
	var b [2]byte
	binary.LittleEndian.PutUint16(b[:], val)
	w.buf.Write(b[:])
	return w
}

func (w *UxWriter) I32(val int32) *UxWriter {
	var b [4]byte
	binary.LittleEndian.PutUint32(b[:], uint32(val))
	w.buf.Write(b[:])
	return w
}

func (w *UxWriter) U32(val uint32) *UxWriter {
	var b [4]byte
	binary.LittleEndian.PutUint32(b[:], val)
	w.buf.Write(b[:])
	return w
}

func (w *UxWriter) I64(val int64) *UxWriter {
	var b [8]byte
	binary.LittleEndian.PutUint64(b[:], uint64(val))
	w.buf.Write(b[:])
	return w
}

func (w *UxWriter) U64(val uint64) *UxWriter {
	var b [8]byte
	binary.LittleEndian.PutUint64(b[:], val)
	w.buf.Write(b[:])
	return w
}

func (w *UxWriter) F32(val float32) *UxWriter {
	return w.U32(math.Float32bits(val))
}

func (w *UxWriter) F64(val float64) *UxWriter {
	return w.U64(math.Float64bits(val))
}

func (w *UxWriter) WriteVarInt(val int) *UxWriter {
	v := uint32(val)
	for v >= 0x80 {
		w.buf.WriteByte(byte(v | 0x80))
		v >>= 7
	}
	w.buf.WriteByte(byte(v))
	return w
}

func (w *UxWriter) Int7(val int) *UxWriter {
	if val < 0 {
		val = 0
	}
	return w.WriteVarInt(val + 1)
}

func (w *UxWriter) Raw7(val int) *UxWriter {
	if val < 0 {
		val = 0
	}
	return w.WriteVarInt(val)
}

func (w *UxWriter) UxString(str string) *UxWriter {
	utf8 := []byte(str)
	w.WriteVarInt(len(utf8) + 1)
	w.buf.Write(utf8)
	return w
}

func (w *UxWriter) UxStringNullable(str *string) *UxWriter {
	if str == nil {
		w.buf.WriteByte(0x00)
		return w
	}
	return w.UxString(*str)
}

func (w *UxWriter) Raw(b []byte) *UxWriter {
	w.buf.Write(b)
	return w
}

func (w *UxWriter) Bytes() []byte {
	return w.buf.Bytes()
}