package net.minecraft.server.packs;

import com.google.common.annotations.VisibleForTesting;
import com.mojang.serialization.Codec;
import com.mojang.serialization.DataResult;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import java.util.List;
import java.util.regex.Pattern;
import net.minecraft.server.packs.metadata.MetadataSectionType;
import net.minecraft.server.packs.metadata.pack.PackFormat;
import net.minecraft.util.InclusiveRange;

public record OverlayMetadataSection(List<OverlayMetadataSection.OverlayEntry> overlays) {
	private static final Pattern DIR_VALIDATOR = Pattern.compile("[-_a-zA-Z0-9.]+");
	public static final MetadataSectionType<OverlayMetadataSection> CLIENT_TYPE = new MetadataSectionType<>(
		"overlays", codecForPackType(PackType.CLIENT_RESOURCES)
	);
	public static final MetadataSectionType<OverlayMetadataSection> SERVER_TYPE = new MetadataSectionType<>("overlays", codecForPackType(PackType.SERVER_DATA));

	private static DataResult<String> validateOverlayDir(final String path) {
		return !DIR_VALIDATOR.matcher(path).matches() ? DataResult.error(() -> path + " is not accepted directory name") : DataResult.success(path);
	}

	@VisibleForTesting
	public static Codec<OverlayMetadataSection> codecForPackType(final PackType packType) {
		return RecordCodecBuilder.create(
			i -> i.group(OverlayMetadataSection.OverlayEntry.listCodecForPackType(packType).fieldOf("entries").forGetter(OverlayMetadataSection::overlays))
				.apply(i, OverlayMetadataSection::new)
		);
	}

	public static MetadataSectionType<OverlayMetadataSection> forPackType(final PackType packType) {
		return switch (packType) {
			case CLIENT_RESOURCES -> CLIENT_TYPE;
			case SERVER_DATA -> SERVER_TYPE;
		};
	}

	public List<String> overlaysForVersion(final PackFormat version) {
		return this.overlays.stream().filter(entry -> entry.isApplicable(version)).map(OverlayMetadataSection.OverlayEntry::overlay).toList();
	}

	public record OverlayEntry(InclusiveRange<PackFormat> format, String overlay) {
		private static Codec<List<OverlayMetadataSection.OverlayEntry>> listCodecForPackType(final PackType packType) {
			int lastPreMinorVersion = PackFormat.lastPreMinorVersion(packType);
			return OverlayMetadataSection.OverlayEntry.IntermediateEntry.CODEC
				.listOf()
				.flatXmap(
					list -> PackFormat.validateHolderList(list, lastPreMinorVersion, (entry, formats) -> new OverlayMetadataSection.OverlayEntry(formats, entry.overlay())),
					list -> DataResult.success(
						list.stream()
							.map(
								entry -> new OverlayMetadataSection.OverlayEntry.IntermediateEntry(
									PackFormat.IntermediaryFormat.fromRange(entry.format(), lastPreMinorVersion), entry.overlay()
								)
							)
							.toList()
					)
				);
		}

		public boolean isApplicable(final PackFormat formatToTest) {
			return this.format.isValueInRange(formatToTest);
		}

		private record IntermediateEntry(PackFormat.IntermediaryFormat format, String overlay) implements PackFormat.IntermediaryFormatHolder {
			private static final Codec<OverlayMetadataSection.OverlayEntry.IntermediateEntry> CODEC = RecordCodecBuilder.create(
				i -> i.group(
						PackFormat.IntermediaryFormat.OVERLAY_CODEC.forGetter(OverlayMetadataSection.OverlayEntry.IntermediateEntry::format),
						Codec.STRING
							.validate(OverlayMetadataSection::validateOverlayDir)
							.fieldOf("directory")
							.forGetter(OverlayMetadataSection.OverlayEntry.IntermediateEntry::overlay)
					)
					.apply(i, OverlayMetadataSection.OverlayEntry.IntermediateEntry::new)
			);

			public String toString() {
				return this.overlay;
			}
		}
	}
}