package messages

import (
	"github.com/pektezol/bitreader"
)

type SvcBspDecal struct {
	Pos               []vectorCoord
	DecalTextureIndex int16
	EntityIndex       int16
	ModelIndex        int16
	LowPriority       int8
}

type vectorCoord struct {
	Value float32
	Valid bool
}

func ParseSvcBspDecal(reader *bitreader.ReaderType) SvcBspDecal {
	svcBspDecal := SvcBspDecal{
		Pos:               readVectorCoords(reader),
		DecalTextureIndex: int16(reader.TryReadBits(9)),
	}
	if reader.TryReadBool() {
		svcBspDecal.EntityIndex = int16(reader.TryReadBits(11))
		svcBspDecal.ModelIndex = int16(reader.TryReadBits(11))
	}
	svcBspDecal.LowPriority = int8(reader.TryReadBits(1))
	return svcBspDecal
}

func readVectorCoords(reader *bitreader.ReaderType) []vectorCoord {
	const COORD_INTEGER_BITS uint8 = 14
	const COORD_FRACTIONAL_BITS uint8 = 5
	const COORD_DENOMINATOR uint8 = 1 << COORD_FRACTIONAL_BITS
	const COORD_RESOLUTION float32 = 1.0 / float32(COORD_DENOMINATOR)
	readVectorCoord := func() float32 {
		value := float32(0)
		integer := reader.TryReadBits(1)
		fraction := reader.TryReadBits(1)
		if integer != 0 || fraction != 0 {
			sign := reader.TryReadBits(1)
			if integer != 0 {
				integer = reader.TryReadBits(int(COORD_INTEGER_BITS)) + 1
			}
			if fraction != 0 {
				fraction = reader.TryReadBits(int(COORD_FRACTIONAL_BITS))
			}
			value = float32(integer) + float32(fraction)*COORD_RESOLUTION
			if sign != 0 {
				value = -value
			}
		}
		return value
	}
	x := reader.TryReadBits(1)
	y := reader.TryReadBits(1)
	z := reader.TryReadBits(1)
	return []vectorCoord{{Value: readVectorCoord(), Valid: x != 0}, {Value: readVectorCoord(), Valid: y != 0}, {Value: readVectorCoord(), Valid: z != 0}}
}