package net.minecraft.util.datafix.fixes;

import com.google.gson.JsonElement;
import com.mojang.datafixers.DSL;
import com.mojang.datafixers.DataFix;
import com.mojang.datafixers.TypeRewriteRule;
import com.mojang.datafixers.schemas.Schema;
import com.mojang.datafixers.types.Type;
import com.mojang.datafixers.util.Either;
import com.mojang.datafixers.util.Pair;
import com.mojang.datafixers.util.Unit;
import com.mojang.serialization.Dynamic;
import com.mojang.serialization.JavaOps;
import com.mojang.serialization.JsonOps;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import net.minecraft.util.GsonHelper;
import net.minecraft.util.Util;

public class LegacyHoverEventFix extends DataFix {
	public LegacyHoverEventFix(final Schema outputSchema) {
		super(outputSchema, false);
	}

	@Override
	protected TypeRewriteRule makeRule() {
		Type<? extends Pair<String, ?>> hoverEventType = (Type<? extends Pair<String, ?>>)this.getInputSchema()
			.getType(References.TEXT_COMPONENT)
			.findFieldType("hoverEvent");
		return this.createFixer(this.getInputSchema().getTypeRaw(References.TEXT_COMPONENT), hoverEventType);
	}

	private <C, H extends Pair<String, ?>> TypeRewriteRule createFixer(final Type<C> rawTextComponentType, final Type<H> hoverEventType) {
		Type<Pair<String, Either<Either<String, List<C>>, Pair<Either<List<C>, Unit>, Pair<Either<C, Unit>, Pair<Either<H, Unit>, Dynamic<?>>>>>>> textComponentType = DSL.named(
			References.TEXT_COMPONENT.typeName(),
			DSL.or(
				DSL.or(DSL.string(), DSL.list(rawTextComponentType)),
				DSL.and(
					DSL.optional(DSL.field("extra", DSL.list(rawTextComponentType))),
					DSL.optional(DSL.field("separator", rawTextComponentType)),
					DSL.optional(DSL.field("hoverEvent", hoverEventType)),
					DSL.remainderType()
				)
			)
		);
		if (!textComponentType.equals(this.getInputSchema().getType(References.TEXT_COMPONENT))) {
			throw new IllegalStateException(
				"Text component type did not match, expected " + textComponentType + " but got " + this.getInputSchema().getType(References.TEXT_COMPONENT)
			);
		} else {
			return this.fixTypeEverywhere(
				"LegacyHoverEventFix",
				textComponentType,
				ops -> named -> named.mapSecond(
					simpleOrFull -> simpleOrFull.mapRight(full -> full.mapSecond(separatorHoverRemainder -> separatorHoverRemainder.mapSecond(hoverAndRemainder -> {
						Dynamic<?> remainder = (Dynamic<?>)hoverAndRemainder.getSecond();
						Optional<? extends Dynamic<?>> hoverEvent = remainder.get("hoverEvent").result();
						if (hoverEvent.isEmpty()) {
							return hoverAndRemainder;
						} else {
							Optional<? extends Dynamic<?>> legacyHoverValue = ((Dynamic)hoverEvent.get()).get("value").result();
							if (legacyHoverValue.isEmpty()) {
								return hoverAndRemainder;
							} else {
								String hoverAction = (String)((Either)hoverAndRemainder.getFirst()).left().map(Pair::getFirst).orElse("");
								H newHoverEvent = this.fixHoverEvent(hoverEventType, hoverAction, (Dynamic<?>)hoverEvent.get());
								return hoverAndRemainder.mapFirst(ignored -> Either.left(newHoverEvent));
							}
						}
					})))
				)
			);
		}
	}

	private <H> H fixHoverEvent(final Type<H> hoverEventType, final String action, final Dynamic<?> oldHoverEvent) {
		return "show_text".equals(action) ? fixShowTextHover(hoverEventType, oldHoverEvent) : createPlaceholderHover(hoverEventType, oldHoverEvent);
	}

	private static <H> H fixShowTextHover(final Type<H> hoverEventType, final Dynamic<?> oldHoverEvent) {
		Dynamic<?> newHoverEvent = oldHoverEvent.renameField("value", "contents");
		return Util.readTypedOrThrow(hoverEventType, newHoverEvent).getValue();
	}

	private static <H> H createPlaceholderHover(final Type<H> hoverEventType, final Dynamic<?> oldHoverEvent) {
		JsonElement oldJson = oldHoverEvent.convert(JsonOps.INSTANCE).getValue();
		Dynamic<?> placeholderHoverEvent = new Dynamic<>(
			JavaOps.INSTANCE, Map.of("action", "show_text", "contents", Map.of("text", "Legacy hoverEvent: " + GsonHelper.toStableString(oldJson)))
		);
		return Util.readTypedOrThrow(hoverEventType, placeholderHoverEvent).getValue();
	}
}