src/game/java/net/minecraft/commands/arguments/item/FunctionArgument.java

package net.minecraft.commands.arguments.item;

import com.mojang.brigadier.StringReader;
import com.mojang.brigadier.arguments.ArgumentType;
import com.mojang.brigadier.context.CommandContext;
import com.mojang.brigadier.exceptions.CommandSyntaxException;
import com.mojang.brigadier.exceptions.DynamicCommandExceptionType;
import com.mojang.datafixers.util.Either;
import com.mojang.datafixers.util.Pair;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import net.minecraft.commands.CommandSourceStack;
import net.minecraft.commands.functions.CommandFunction;
import net.minecraft.network.chat.Component;
import net.minecraft.resources.ResourceLocation;

public class FunctionArgument implements ArgumentType<FunctionArgument.Result> {
    private static final Collection<String> EXAMPLES = Arrays.asList("foo", "foo:bar", "#foo");
    private static final DynamicCommandExceptionType ERROR_UNKNOWN_TAG = new DynamicCommandExceptionType(
        p_308403_ -> Component.translatableEscape("arguments.function.tag.unknown", p_308403_)
    );
    private static final DynamicCommandExceptionType ERROR_UNKNOWN_FUNCTION = new DynamicCommandExceptionType(
        p_308402_ -> Component.translatableEscape("arguments.function.unknown", p_308402_)
    );

    public static FunctionArgument functions() {
        return new FunctionArgument();
    }

    public FunctionArgument.Result parse(StringReader p_120909_) throws CommandSyntaxException {
        if (p_120909_.canRead() && p_120909_.peek() == '#') {
            p_120909_.skip();
            final ResourceLocation resourcelocation1 = ResourceLocation.read(p_120909_);
            return new FunctionArgument.Result() {
                @Override
                public Collection<CommandFunction<CommandSourceStack>> create(CommandContext<CommandSourceStack> p_120943_) throws CommandSyntaxException {
                    return FunctionArgument.getFunctionTag(p_120943_, resourcelocation1);
                }

                @Override
                public Pair<ResourceLocation, Either<CommandFunction<CommandSourceStack>, Collection<CommandFunction<CommandSourceStack>>>> unwrap(
                    CommandContext<CommandSourceStack> p_120945_
                ) throws CommandSyntaxException {
                    return Pair.of(resourcelocation1, Either.right(FunctionArgument.getFunctionTag(p_120945_, resourcelocation1)));
                }

                @Override
                public Pair<ResourceLocation, Collection<CommandFunction<CommandSourceStack>>> unwrapToCollection(CommandContext<CommandSourceStack> p_310998_) throws CommandSyntaxException {
                    return Pair.of(resourcelocation1, FunctionArgument.getFunctionTag(p_310998_, resourcelocation1));
                }
            };
        } else {
            final ResourceLocation resourcelocation = ResourceLocation.read(p_120909_);
            return new FunctionArgument.Result() {
                @Override
                public Collection<CommandFunction<CommandSourceStack>> create(CommandContext<CommandSourceStack> p_120952_) throws CommandSyntaxException {
                    return Collections.singleton(FunctionArgument.getFunction(p_120952_, resourcelocation));
                }

                @Override
                public Pair<ResourceLocation, Either<CommandFunction<CommandSourceStack>, Collection<CommandFunction<CommandSourceStack>>>> unwrap(
                    CommandContext<CommandSourceStack> p_120954_
                ) throws CommandSyntaxException {
                    return Pair.of(resourcelocation, Either.left(FunctionArgument.getFunction(p_120954_, resourcelocation)));
                }

                @Override
                public Pair<ResourceLocation, Collection<CommandFunction<CommandSourceStack>>> unwrapToCollection(CommandContext<CommandSourceStack> p_310823_) throws CommandSyntaxException {
                    return Pair.of(resourcelocation, Collections.singleton(FunctionArgument.getFunction(p_310823_, resourcelocation)));
                }
            };
        }
    }

    static CommandFunction<CommandSourceStack> getFunction(CommandContext<CommandSourceStack> p_120929_, ResourceLocation p_120930_) throws CommandSyntaxException {
        return p_120929_.getSource().getServer().getFunctions().get(p_120930_).orElseThrow(() -> ERROR_UNKNOWN_FUNCTION.create(p_120930_.toString()));
    }

    static Collection<CommandFunction<CommandSourceStack>> getFunctionTag(CommandContext<CommandSourceStack> p_235274_, ResourceLocation p_235275_) throws CommandSyntaxException {
        Collection<CommandFunction<CommandSourceStack>> collection = p_235274_.getSource().getServer().getFunctions().getTag(p_235275_);
        if (collection == null) {
            throw ERROR_UNKNOWN_TAG.create(p_235275_.toString());
        } else {
            return collection;
        }
    }

    public static Collection<CommandFunction<CommandSourceStack>> getFunctions(CommandContext<CommandSourceStack> p_120911_, String p_120912_) throws CommandSyntaxException {
        return p_120911_.getArgument(p_120912_, FunctionArgument.Result.class).create(p_120911_);
    }

    public static Pair<ResourceLocation, Either<CommandFunction<CommandSourceStack>, Collection<CommandFunction<CommandSourceStack>>>> getFunctionOrTag(
        CommandContext<CommandSourceStack> p_120921_, String p_120922_
    ) throws CommandSyntaxException {
        return p_120921_.getArgument(p_120922_, FunctionArgument.Result.class).unwrap(p_120921_);
    }

    public static Pair<ResourceLocation, Collection<CommandFunction<CommandSourceStack>>> getFunctionCollection(
        CommandContext<CommandSourceStack> p_312555_, String p_311726_
    ) throws CommandSyntaxException {
        return p_312555_.getArgument(p_311726_, FunctionArgument.Result.class).unwrapToCollection(p_312555_);
    }

    @Override
    public Collection<String> getExamples() {
        return EXAMPLES;
    }

    public interface Result {
        Collection<CommandFunction<CommandSourceStack>> create(CommandContext<CommandSourceStack> p_120955_) throws CommandSyntaxException;

        Pair<ResourceLocation, Either<CommandFunction<CommandSourceStack>, Collection<CommandFunction<CommandSourceStack>>>> unwrap(
            CommandContext<CommandSourceStack> p_120956_
        ) throws CommandSyntaxException;

        Pair<ResourceLocation, Collection<CommandFunction<CommandSourceStack>>> unwrapToCollection(CommandContext<CommandSourceStack> p_313207_) throws CommandSyntaxException;
    }
}