package net.minecraft.util.parsing.packrat.commands;

import com.mojang.brigadier.StringReader;
import com.mojang.brigadier.exceptions.CommandSyntaxException;
import it.unimi.dsi.fastutil.chars.CharList;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import net.minecraft.util.parsing.packrat.Control;
import net.minecraft.util.parsing.packrat.DelayedException;
import net.minecraft.util.parsing.packrat.ParseState;
import net.minecraft.util.parsing.packrat.Scope;
import net.minecraft.util.parsing.packrat.SuggestionSupplier;
import net.minecraft.util.parsing.packrat.Term;

public interface StringReaderTerms {
	static Term<StringReader> word(final String value) {
		return new StringReaderTerms.TerminalWord(value);
	}

	static Term<StringReader> character(final char value) {
		return new StringReaderTerms.TerminalCharacters(CharList.of(value)) {
			@Override
			protected boolean isAccepted(final char v) {
				return value == v;
			}
		};
	}

	static Term<StringReader> characters(final char v1, final char v2) {
		return new StringReaderTerms.TerminalCharacters(CharList.of(v1, v2)) {
			@Override
			protected boolean isAccepted(final char v) {
				return v == v1 || v == v2;
			}
		};
	}

	static StringReader createReader(final String contents, final int cursor) {
		StringReader reader = new StringReader(contents);
		reader.setCursor(cursor);
		return reader;
	}

	public abstract static class TerminalCharacters implements Term<StringReader> {
		private final DelayedException<CommandSyntaxException> error;
		private final SuggestionSupplier<StringReader> suggestions;

		public TerminalCharacters(final CharList values) {
			String joinedValues = (String)values.intStream().mapToObj(Character::toString).collect(Collectors.joining("|"));
			this.error = DelayedException.create(CommandSyntaxException.BUILT_IN_EXCEPTIONS.literalIncorrect(), joinedValues);
			this.suggestions = s -> values.intStream().mapToObj(Character::toString);
		}

		@Override
		public boolean parse(final ParseState<StringReader> state, final Scope scope, final Control control) {
			state.input().skipWhitespace();
			int cursor = state.mark();
			if (state.input().canRead() && this.isAccepted(state.input().read())) {
				return true;
			} else {
				state.errorCollector().store(cursor, this.suggestions, this.error);
				return false;
			}
		}

		protected abstract boolean isAccepted(char value);
	}

	public static final class TerminalWord implements Term<StringReader> {
		private final String value;
		private final DelayedException<CommandSyntaxException> error;
		private final SuggestionSupplier<StringReader> suggestions;

		public TerminalWord(final String value) {
			this.value = value;
			this.error = DelayedException.create(CommandSyntaxException.BUILT_IN_EXCEPTIONS.literalIncorrect(), value);
			this.suggestions = s -> Stream.of(value);
		}

		@Override
		public boolean parse(final ParseState<StringReader> state, final Scope scope, final Control control) {
			state.input().skipWhitespace();
			int cursor = state.mark();
			String value = state.input().readUnquotedString();
			if (!value.equals(this.value)) {
				state.errorCollector().store(cursor, this.suggestions, this.error);
				return false;
			} else {
				return true;
			}
		}

		public String toString() {
			return "terminal[" + this.value + "]";
		}
	}
}