package com.mojang.realmsclient.util;

import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.mojang.util.UndashedUuid;
import java.time.Instant;
import java.util.UUID;
import java.util.function.Function;
import org.jetbrains.annotations.Contract;
import org.jspecify.annotations.Nullable;

public class JsonUtils {
	public static <T> T getRequired(final String key, final JsonObject node, final Function<JsonObject, T> parser) {
		JsonElement property = node.get(key);
		if (property == null || property.isJsonNull()) {
			throw new IllegalStateException("Missing required property: " + key);
		} else if (!property.isJsonObject()) {
			throw new IllegalStateException("Required property " + key + " was not a JsonObject as espected");
		} else {
			return (T)parser.apply(property.getAsJsonObject());
		}
	}

	@Nullable
	public static <T> T getOptional(final String key, final JsonObject node, final Function<JsonObject, T> parser) {
		JsonElement property = node.get(key);
		if (property == null || property.isJsonNull()) {
			return null;
		} else if (!property.isJsonObject()) {
			throw new IllegalStateException("Required property " + key + " was not a JsonObject as espected");
		} else {
			return (T)parser.apply(property.getAsJsonObject());
		}
	}

	public static String getRequiredString(final String key, final JsonObject node) {
		String result = getStringOr(key, node, null);
		if (result == null) {
			throw new IllegalStateException("Missing required property: " + key);
		} else {
			return result;
		}
	}

	@Contract("_,_,!null->!null;_,_,null->_")
	@Nullable
	public static String getStringOr(final String key, final JsonObject node, @Nullable final String defaultValue) {
		JsonElement element = node.get(key);
		if (element != null) {
			return element.isJsonNull() ? defaultValue : element.getAsString();
		} else {
			return defaultValue;
		}
	}

	@Contract("_,_,!null->!null;_,_,null->_")
	@Nullable
	public static UUID getUuidOr(final String key, final JsonObject node, @Nullable final UUID defaultValue) {
		String uuidAsString = getStringOr(key, node, null);
		return uuidAsString == null ? defaultValue : UndashedUuid.fromStringLenient(uuidAsString);
	}

	public static int getIntOr(final String key, final JsonObject node, final int defaultValue) {
		JsonElement element = node.get(key);
		if (element != null) {
			return element.isJsonNull() ? defaultValue : element.getAsInt();
		} else {
			return defaultValue;
		}
	}

	public static long getLongOr(final String key, final JsonObject node, final long defaultValue) {
		JsonElement element = node.get(key);
		if (element != null) {
			return element.isJsonNull() ? defaultValue : element.getAsLong();
		} else {
			return defaultValue;
		}
	}

	public static boolean getBooleanOr(final String key, final JsonObject node, final boolean defaultValue) {
		JsonElement element = node.get(key);
		if (element != null) {
			return element.isJsonNull() ? defaultValue : element.getAsBoolean();
		} else {
			return defaultValue;
		}
	}

	public static Instant getDateOr(final String key, final JsonObject node) {
		JsonElement element = node.get(key);
		return element != null ? Instant.ofEpochMilli(Long.parseLong(element.getAsString())) : Instant.EPOCH;
	}
}