// Copyright 2014 by Sascha L. Teichmann
// Use of this source code is governed by the MIT license
// that can be found in the LICENSE file.

package main

import (
	"math"

	"bitbucket.org/s_l_teichmann/mtredisalize/common"
)

type Renderer struct {
	width   int
	height  int
	xOfs    int16
	zOfs    int16
	yBuffer []int32
	cBuffer []int32
	filled  []byte
	minYs   []int16
}

func NewRenderer(xOfs, zOfs int16, width, height int) (renderer *Renderer) {
	dim := width * height
	pixSize := dim * 16 * 16
	yBuffer := make([]int32, pixSize)
	cBuffer := make([]int32, pixSize)
	filled := make([]byte, dim)
	minYs := make([]int16, dim)

	for i := 0; i < pixSize; i++ {
		yBuffer[i] = math.MinInt32
		cBuffer[i] = -1
	}

	for i := 0; i < dim; i++ {
		minYs[i] = math.MinInt16
	}

	renderer = &Renderer{
		width:   width,
		height:  height,
		xOfs:    xOfs,
		zOfs:    zOfs,
		yBuffer: yBuffer,
		cBuffer: cBuffer,
		filled:  filled,
		minYs:   minYs}
	return
}

func (r *Renderer) RenderBlock(coord common.Coord, data []byte, nameIndex map[string]int) (err error) {
	x := coord.X + r.xOfs
	z := coord.Z + r.zOfs
	dimIndex := (x << 4) + z
	// We do not need to render the block if the whole 16x16 area
	// is already filled and the block is strictly below.
	if r.filled[dimIndex] == 0xff && r.minYs[dimIndex] > coord.Y {
		return
	}

	var db *DecodedBlock
	if db, err = NewDecodedBlock(data, nameIndex); err != nil {
		return
	}

	_ = db

	ay := int32(coord.Y) << 4

	_ = ay

	for x := 0; x < 16; x++ {
		for z := 0; z < 16; z++ {
			for y := 15; y >= 0; y-- {
				_, _, _ = x, y, z
			}
		}
	}

	return
}