package net.minecraft.client.renderer;

import com.mojang.datafixers.util.Either;
import com.mojang.serialization.Codec;
import com.mojang.serialization.DataResult;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import it.unimi.dsi.fastutil.objects.ObjectArraySet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.function.Function;
import java.util.stream.Stream;
import net.minecraft.resources.Identifier;
import net.minecraft.util.ExtraCodecs;

public record PostChainConfig(Map<Identifier, PostChainConfig.InternalTarget> internalTargets, List<PostChainConfig.Pass> passes) {
	public static final Codec<PostChainConfig> CODEC = RecordCodecBuilder.create(
		i -> i.group(
				Codec.unboundedMap(Identifier.CODEC, PostChainConfig.InternalTarget.CODEC).optionalFieldOf("targets", Map.of()).forGetter(PostChainConfig::internalTargets),
				PostChainConfig.Pass.CODEC.listOf().optionalFieldOf("passes", List.of()).forGetter(PostChainConfig::passes)
			)
			.apply(i, PostChainConfig::new)
	);

	public sealed interface Input permits PostChainConfig.TargetInput, PostChainConfig.TextureInput {
		Codec<PostChainConfig.Input> CODEC = Codec.xor(PostChainConfig.TextureInput.CODEC, PostChainConfig.TargetInput.CODEC)
			.xmap(either -> either.map(Function.identity(), Function.identity()), input -> {
				return switch (input) {
					case PostChainConfig.TextureInput texture -> Either.left(texture);
					case PostChainConfig.TargetInput target -> Either.right(target);
					default -> throw new MatchException(null, null);
				};
			});

		String samplerName();

		Set<Identifier> referencedTargets();
	}

	public record InternalTarget(Optional<Integer> width, Optional<Integer> height, boolean persistent, int clearColor) {
		public static final Codec<PostChainConfig.InternalTarget> CODEC = RecordCodecBuilder.create(
			i -> i.group(
					ExtraCodecs.POSITIVE_INT.optionalFieldOf("width").forGetter(PostChainConfig.InternalTarget::width),
					ExtraCodecs.POSITIVE_INT.optionalFieldOf("height").forGetter(PostChainConfig.InternalTarget::height),
					Codec.BOOL.optionalFieldOf("persistent", false).forGetter(PostChainConfig.InternalTarget::persistent),
					ExtraCodecs.ARGB_COLOR_CODEC.optionalFieldOf("clear_color", 0).forGetter(PostChainConfig.InternalTarget::clearColor)
				)
				.apply(i, PostChainConfig.InternalTarget::new)
		);
	}

	public record Pass(
		Identifier vertexShaderId, Identifier fragmentShaderId, List<PostChainConfig.Input> inputs, Identifier outputTarget, Map<String, List<UniformValue>> uniforms
	) {
		private static final Codec<List<PostChainConfig.Input>> INPUTS_CODEC = PostChainConfig.Input.CODEC.listOf().validate(inputs -> {
			Set<String> samplerName = new ObjectArraySet<>(inputs.size());

			for (PostChainConfig.Input input : inputs) {
				if (!samplerName.add(input.samplerName())) {
					return DataResult.error(() -> "Encountered repeated sampler name: " + input.samplerName());
				}
			}

			return DataResult.success(inputs);
		});
		private static final Codec<Map<String, List<UniformValue>>> UNIFORM_BLOCKS_CODEC = Codec.unboundedMap(Codec.STRING, UniformValue.CODEC.listOf());
		public static final Codec<PostChainConfig.Pass> CODEC = RecordCodecBuilder.create(
			i -> i.group(
					Identifier.CODEC.fieldOf("vertex_shader").forGetter(PostChainConfig.Pass::vertexShaderId),
					Identifier.CODEC.fieldOf("fragment_shader").forGetter(PostChainConfig.Pass::fragmentShaderId),
					INPUTS_CODEC.optionalFieldOf("inputs", List.of()).forGetter(PostChainConfig.Pass::inputs),
					Identifier.CODEC.fieldOf("output").forGetter(PostChainConfig.Pass::outputTarget),
					UNIFORM_BLOCKS_CODEC.optionalFieldOf("uniforms", Map.of()).forGetter(PostChainConfig.Pass::uniforms)
				)
				.apply(i, PostChainConfig.Pass::new)
		);

		public Stream<Identifier> referencedTargets() {
			Stream<Identifier> inputTargets = this.inputs.stream().flatMap(input -> input.referencedTargets().stream());
			return Stream.concat(inputTargets, Stream.of(this.outputTarget));
		}
	}

	public record TargetInput(String samplerName, Identifier targetId, boolean useDepthBuffer, boolean bilinear) implements PostChainConfig.Input {
		public static final Codec<PostChainConfig.TargetInput> CODEC = RecordCodecBuilder.create(
			i -> i.group(
					Codec.STRING.fieldOf("sampler_name").forGetter(PostChainConfig.TargetInput::samplerName),
					Identifier.CODEC.fieldOf("target").forGetter(PostChainConfig.TargetInput::targetId),
					Codec.BOOL.optionalFieldOf("use_depth_buffer", false).forGetter(PostChainConfig.TargetInput::useDepthBuffer),
					Codec.BOOL.optionalFieldOf("bilinear", false).forGetter(PostChainConfig.TargetInput::bilinear)
				)
				.apply(i, PostChainConfig.TargetInput::new)
		);

		@Override
		public Set<Identifier> referencedTargets() {
			return Set.of(this.targetId);
		}
	}

	public record TextureInput(String samplerName, Identifier location, int width, int height, boolean bilinear) implements PostChainConfig.Input {
		public static final Codec<PostChainConfig.TextureInput> CODEC = RecordCodecBuilder.create(
			i -> i.group(
					Codec.STRING.fieldOf("sampler_name").forGetter(PostChainConfig.TextureInput::samplerName),
					Identifier.CODEC.fieldOf("location").forGetter(PostChainConfig.TextureInput::location),
					ExtraCodecs.POSITIVE_INT.fieldOf("width").forGetter(PostChainConfig.TextureInput::width),
					ExtraCodecs.POSITIVE_INT.fieldOf("height").forGetter(PostChainConfig.TextureInput::height),
					Codec.BOOL.optionalFieldOf("bilinear", false).forGetter(PostChainConfig.TextureInput::bilinear)
				)
				.apply(i, PostChainConfig.TextureInput::new)
		);

		@Override
		public Set<Identifier> referencedTargets() {
			return Set.of();
		}
	}
}