Intuitive DSL for Java

/*
 * This file is part of the Intuitive DSL project.
 * Copyright (c) 2026 DBA Labs - Switzerland. All rights reserved.
 *
 * This program is dual-licensed under a commercial license and the AGPLv3.
 * For commercial licensing, contact us at [email protected] or visit https://www.dbalabs.ch.
 *
 * AGPLv3 licensing:
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, version 3 (19 November 2007).
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/agpl-3.0.html>.
 */

package ch.dbalabs.intuitivedsl.grammar;

import ch.dbalabs.intuitivedsl.annotation.Bind;
import ch.dbalabs.intuitivedsl.annotation.DslCommand;
import ch.dbalabs.intuitivedsl.core.ExecutionContext;
import ch.dbalabs.intuitivedsl.core.IntuitiveDslEngine;
import ch.dbalabs.intuitivedsl.exception.DslDefinitionException;
import ch.dbalabs.intuitivedsl.exception.DslSyntaxException;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;

/**
 * Sentinel tests that freeze the product contract around the repeat operator.
 *
 * Product decision:
 * - "..." is the only repetition operator.
 * - "." remains a valid standalone delimiter and must not be treated as repetition.
 */
class RepeatOperatorContractSentinelTest {

    private final GrammarCompiler compiler = new GrammarCompiler();
    private IntuitiveDslEngine engine;

    @BeforeEach
    void setUp() {
        engine = new IntuitiveDslEngine();
    }

    @Test
    void shouldCompileCanonicalEllipsisRepeatOperator() {
        GroupNode root = compiler.compile("GRANT ACCESS TO target_user ... ;");
        AlternativeNode main = (AlternativeNode) root.children().get(0);

        assertThat(main.children()).hasSize(3);
        assertThat(main.children().get(0)).isInstanceOf(KeywordNode.class)
                .extracting("word")
                .isEqualTo("GRANT ACCESS TO");
        assertThat(main.children().get(1)).isInstanceOf(ParameterNode.class);
        assertThat(main.children().get(1).isRepeatable()).isTrue();
        assertThat(main.children()).noneMatch(node -> node instanceof DelimiterNode d && ".".equals(d.value()));
    }

    @Test
    void shouldTreatSingleDotAsLiteralDelimiterInsteadOfRepeatOperator() {
        GroupNode root = compiler.compile("SET VERSION major . minor ;");
        AlternativeNode main = (AlternativeNode) root.children().get(0);

        assertThat(main.children()).hasSize(5);
        assertThat(main.children().get(0)).isInstanceOf(KeywordNode.class)
                .extracting("word")
                .isEqualTo("SET VERSION");
        assertThat(main.children().get(1)).isInstanceOf(ParameterNode.class)
                .extracting("name")
                .isEqualTo("major");
        assertThat(main.children().get(1).isRepeatable()).isFalse();
        assertThat(main.children().get(2)).isInstanceOf(DelimiterNode.class)
                .extracting("value")
                .isEqualTo(".");
        assertThat(main.children().get(3)).isInstanceOf(ParameterNode.class)
                .extracting("name")
                .isEqualTo("minor");
    }

    @Test
    void shouldNeverPromoteLiteralDotsToRepeatableNodes() {
        GroupNode root = compiler.compile("PAIR left . middle . right ;");
        AlternativeNode main = (AlternativeNode) root.children().get(0);

        assertThat(main.children()).hasSize(7);
        assertThat(main.children().get(0)).isInstanceOf(KeywordNode.class)
                .extracting("word")
                .isEqualTo("PAIR");
        assertThat(main.children().get(1)).isInstanceOf(ParameterNode.class)
                .extracting("name")
                .isEqualTo("left");
        assertThat(main.children().get(2)).isInstanceOf(DelimiterNode.class)
                .extracting("value")
                .isEqualTo(".");
        assertThat(main.children().get(3)).isInstanceOf(ParameterNode.class)
                .extracting("name")
                .isEqualTo("middle");
        assertThat(main.children().get(4)).isInstanceOf(DelimiterNode.class)
                .extracting("value")
                .isEqualTo(".");
        assertThat(main.children().get(5)).isInstanceOf(ParameterNode.class)
                .extracting("name")
                .isEqualTo("right");
        assertThat(main.children())
                .filteredOn(SyntaxNode::isRepeatable)
                .as("Literal dot delimiters must never turn adjacent nodes into repeatable nodes.")
                .isEmpty();
    }

    @Test
    void shouldRejectLeadingEllipsisWithoutTargetNode() {
        assertThatThrownBy(() -> compiler.compile("... user ;"))
                .isInstanceOf(DslDefinitionException.class)
                .hasMessageContaining("Operator '...' needs a preceding node");
    }

    @Test
    void shouldRejectLiteralDotInUserInputForRepeatableSyntax() {
        engine.register(GrantAccessCommand.class);

        assertThatThrownBy(() -> engine.execute("GRANT ACCESS TO alice . ;", ExecutionContext.createDefault()))
                .isInstanceOf(DslSyntaxException.class)
                .satisfies(error -> {
                    DslSyntaxException ex = (DslSyntaxException) error;
                    assertThat(ex.getUnexpectedToken()).isNotNull();
                    assertThat(ex.getUnexpectedToken().value()).isEqualTo(".");
                });
    }

    @Test
    void shouldAcceptLiteralDotWhenGrammarExplicitlyRequiresIt() {
        engine.register(VersionCommand.class);

        VersionCommand command = engine.execute("SET VERSION 1 . 2 ;", ExecutionContext.createDefault());

        assertThat(command.major).isEqualTo("1");
        assertThat(command.minor).isEqualTo("2");
    }

    @DslCommand(name = "Grant Access", syntax = "GRANT ACCESS TO target_user ... ;")
    public static class GrantAccessCommand implements Runnable {
        @Bind("target_user")
        private String targetUser;

        @Override
        public void run() {
        }
    }

    @DslCommand(name = "Version", syntax = "SET VERSION major . minor ;")
    public static class VersionCommand implements Runnable {
        @Bind("major")
        private String major;

        @Bind("minor")
        private String minor;

        @Override
        public void run() {
        }
    }
}