/*
 * Minecraft Forge
 * Copyright (c) 2016-2019.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation version 2.1
 * of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

package net.minecraftforge.client.model.pipeline;

import net.minecraft.client.renderer.color.BlockColors;
import net.minecraft.util.math.MathHelper;


public class VertexLighterSmoothAo extends VertexLighterFlat
{
    public VertexLighterSmoothAo(BlockColors colors)
    {
        super(colors);
    }

    @Override
    protected void updateLightmap(float[] normal, float[] lightmap, float x, float y, float z)
    {
        lightmap[0] = calcLightmap(blockInfo.getBlockLight(), x, y, z);
        lightmap[1] = calcLightmap(blockInfo.getSkyLight(), x, y, z);
    }

    @Override
    protected void updateColor(float[] normal, float[] color, float x, float y, float z, float tint, int multiplier)
    {
        super.updateColor(normal, color, x, y, z, tint, multiplier);
        float a = getAo(x, y, z);
        color[0] *= a;
        color[1] *= a;
        color[2] *= a;
    }

    protected float calcLightmap(float[][][][] light, float x, float y, float z)
    {
        x *= 2;
        y *= 2;
        z *= 2;
        float l2 = x * x + y * y + z * z;
        if(l2 > 6 - 2e-2f)
        {
            float s = (float)Math.sqrt((6 - 2e-2f) / l2);
            x *= s;
            y *= s;
            z *= s;
        }
        float ax = x > 0 ? x : -x;
        float ay = y > 0 ? y : -y;
        float az = z > 0 ? z : -z;
        float e1 = 1 + 1e-4f;
        if(ax > 2 - 1e-4f && ay <= e1 && az <= e1)
        {
            x = x < 0 ? -2 + 1e-4f : 2 - 1e-4f;
        }
        else if(ay > 2 - 1e-4f && az <= e1 && ax <= e1)
        {
            y = y < 0 ? -2 + 1e-4f : 2 - 1e-4f;
        }
        else if(az > 2 - 1e-4f && ax <= e1 && ay <= e1)
        {
            z = z < 0 ? -2 + 1e-4f : 2 - 1e-4f;
        }
        ax = x > 0 ? x : -x;
        ay = y > 0 ? y : -y;
        az = z > 0 ? z : -z;
        if(ax <= e1 && ay + az > 3f - 1e-4f)
        {
            float s = (3f - 1e-4f) / (ay + az);
            y *= s;
            z *= s;
        }
        else if(ay <= e1 && az + ax > 3f - 1e-4f)
        {
            float s = (3f - 1e-4f) / (az + ax);
            z *= s;
            x *= s;
        }
        else if(az <= e1 && ax + ay > 3f - 1e-4f)
        {
            float s = (3f - 1e-4f) / (ax + ay);
            x *= s;
            y *= s;
        }
        else if(ax + ay + az > 4 - 1e-4f)
        {
            float s = (4 - 1e-4f) / (ax + ay + az);
            x *= s;
            y *= s;
            z *= s;
        }

        float l = 0;
        float s = 0;

        for(int ix = 0; ix <= 1; ix++)
        {
            for(int iy = 0; iy <= 1; iy++)
            {
                for(int iz = 0; iz <= 1; iz++)
                {
                    float vx = x * (1 - ix * 2);
                    float vy = y * (1 - iy * 2);
                    float vz = z * (1 - iz * 2);

                    float s3 = vx + vy + vz + 4;
                    float sx = vy + vz + 3;
                    float sy = vz + vx + 3;
                    float sz = vx + vy + 3;

                    float bx = (2 * vx + vy + vz + 6) / (s3 * sy * sz * (vx + 2));
                    s += bx;
                    l += bx * light[0][ix][iy][iz];

                    float by = (2 * vy + vz + vx + 6) / (s3 * sz * sx * (vy + 2));
                    s += by;
                    l += by * light[1][ix][iy][iz];

                    float bz = (2 * vz + vx + vy + 6) / (s3 * sx * sy * (vz + 2));
                    s += bz;
                    l += bz * light[2][ix][iy][iz];
                }
            }
        }

        l /= s;

        if(l > 15f * 0x20 / 0xFFFF) l = 15f * 0x20 / 0xFFFF;
        if(l < 0) l = 0;

        return l;
    }

    protected float getAo(float x, float y, float z)
    {
        int sx = x < 0 ? 1 : 2;
        int sy = y < 0 ? 1 : 2;
        int sz = z < 0 ? 1 : 2;

        if(x < 0) x++;
        if(y < 0) y++;
        if(z < 0) z++;

        float a = 0;
        float[][][] ao = blockInfo.getAo();
        a += ao[sx - 1][sy - 1][sz - 1] * (1 - x) * (1 - y) * (1 - z);
        a += ao[sx - 1][sy - 1][sz - 0] * (1 - x) * (1 - y) * (0 + z);
        a += ao[sx - 1][sy - 0][sz - 1] * (1 - x) * (0 + y) * (1 - z);
        a += ao[sx - 1][sy - 0][sz - 0] * (1 - x) * (0 + y) * (0 + z);
        a += ao[sx - 0][sy - 1][sz - 1] * (0 + x) * (1 - y) * (1 - z);
        a += ao[sx - 0][sy - 1][sz - 0] * (0 + x) * (1 - y) * (0 + z);
        a += ao[sx - 0][sy - 0][sz - 1] * (0 + x) * (0 + y) * (1 - z);
        a += ao[sx - 0][sy - 0][sz - 0] * (0 + x) * (0 + y) * (0 + z);

        a = MathHelper.clamp(a, 0, 1);
        return a;
    }

    @Override
    public void updateBlockInfo()
    {
        blockInfo.updateShift();
        blockInfo.updateLightMatrix();
    }
}
