package ru.bclib.client.models;

import com.google.common.collect.Lists;
import com.mojang.math.Vector3f;
import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;
import net.minecraft.resources.ResourceLocation;

import java.util.List;

@Environment(EnvType.CLIENT)
public class OBJModelBuilder {
	private static final OBJModelBuilder INSTANCE = new OBJModelBuilder();
	private final List<ResourceLocation> textures = Lists.newArrayList();
	private Vector3f offset = new Vector3f();
	private ResourceLocation modelLocation;
	private ResourceLocation particles;
	private boolean useCulling;
	private boolean useShading;
	
	private OBJModelBuilder() {}
	
	/**
	 * Start a new bodel building process, clears data of previous builder.
	 * @return {@link OBJModelBuilder} instance.
	 */
	public static OBJModelBuilder start(ResourceLocation modelLocation) {
		INSTANCE.modelLocation = modelLocation;
		INSTANCE.offset.set(0, 0, 0);
		INSTANCE.useCulling = true;
		INSTANCE.useShading = true;
		INSTANCE.particles = null;
		INSTANCE.textures.clear();
		return INSTANCE;
	}
	
	/**
	 * Add texture to the model. All textures have indexes with same order as in source OBJ model.
	 * @param texture {@link ResourceLocation} texture ID.
	 * @return this {@link OBJModelBuilder}.
	 */
	public OBJModelBuilder addTexture(ResourceLocation texture) {
		textures.add(texture);
		return this;
	}
	
	/**
	 * Culling used to remove block faces if they are on block faces or outside of the block to reduce faces count in rendering.
	 * Opaque blocks shoud have this as true to reduce geometry issues, block like plants should have this as false.
	 * Default value is {@code true}.
	 * @param useCulling {@link Boolean}.
	 * @return this {@link OBJModelBuilder}.
	 */
	public OBJModelBuilder useCulling(boolean useCulling) {
		this.useCulling = useCulling;
		return this;
	}
	
	/**
	 * Shading tints block faces in shades of gray to immitate volume in MC rendering.
	 * Blocks like plants don't have shading, most full opaque blocks - have.
	 * Default value is {@code true}.
	 * @param useShading {@link Boolean}.
	 * @return this {@link OBJModelBuilder}.
	 */
	public OBJModelBuilder useShading(boolean useShading) {
		this.useShading = useShading;
		return this;
	}
	
	/**
	 * Set particle texture for this model.
	 * Not required, if texture is not selected the first texture will be used instead of it.
	 * @param texture {@link ResourceLocation} texture ID.
	 * @return this {@link OBJModelBuilder}.
	 */
	public OBJModelBuilder setParticlesTexture(ResourceLocation texture) {
		this.particles = texture;
		return this;
	}
	
	public OBJModelBuilder setOffset(float x, float y, float z) {
		this.offset.set(x, y, z);
		return this;
	}
	
	/**
	 * Builds model from all required data.
	 * @return {@link OBJBlockModel}.
	 */
	public OBJBlockModel build() {
		byte particleIndex = 0;
		if (particles != null) {
			particleIndex = (byte) textures.indexOf(particles);
			if (particleIndex < 0) {
				particleIndex = (byte) textures.size();
				textures.add(particles);
			}
		}
		ResourceLocation[] sprites = textures.toArray(new ResourceLocation[textures.size()]);
		return new OBJBlockModel(modelLocation, offset, useCulling, useShading, particleIndex, sprites);
	}
}