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.exception.DslDefinitionException;
import org.junit.jupiter.api.Test;

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

/**
 * Unit tests for the GrammarCompiler component.
 * Verifies AST generation, structural constraints, and keyword merging.
 *
 * @author DBA Labs
 */
class GrammarCompilerTest {

    @Test
    void shouldCompileBasicSyntaxIntoAST() {
        GrammarCompiler compiler = new GrammarCompiler();
        String syntax = "CREATE USER username [PASSWORD password] ;";

        GroupNode root = compiler.compile(syntax);

        assertThat(root.type()).isEqualTo(GroupType.REQUIRED);
        AlternativeNode mainBranch = (AlternativeNode) root.children().get(0);

        // CREATE and USER are merged into "CREATE USER" -> 4 nodes total
        assertThat(mainBranch.children()).hasSize(4);

        assertThat(mainBranch.children().get(0)).isInstanceOf(KeywordNode.class)
                .extracting("word").isEqualTo("CREATE USER");
        assertThat(mainBranch.children().get(1)).isInstanceOf(ParameterNode.class)
                .extracting("name").isEqualTo("username");
        assertThat(mainBranch.children().get(2)).isInstanceOf(GroupNode.class);
        assertThat(mainBranch.children().get(3)).isInstanceOf(DelimiterNode.class)
                .extracting("value").isEqualTo(";");
    }

    @Test
    void shouldHandleDynamicMacros() {
        GrammarCompiler compiler = new GrammarCompiler();
        GroupNode root = compiler.compile("ALLOW ${roles} ;");

        AlternativeNode alt = (AlternativeNode) root.children().get(0);
        assertThat(alt.children().get(1)).isInstanceOf(MacroNode.class)
                .extracting("macroName").isEqualTo("roles");
    }

    @Test
    void shouldThrowExceptionOnEmptyBranch() {
        GrammarCompiler compiler = new GrammarCompiler();
        assertThatThrownBy(() -> compiler.compile("{ | A }"))
                .isInstanceOf(DslDefinitionException.class)
                .hasMessageContaining("Empty alternative branch");
    }

    @Test
    void shouldCompileRepeatableParameter() {
        GrammarCompiler compiler = new GrammarCompiler();
        String syntax = "GRANT ACCESS TO target_user ... ;";

        GroupNode root = compiler.compile(syntax);
        AlternativeNode mainBranch = (AlternativeNode) root.children().get(0);

        // GRANT, ACCESS, TO are merged -> "GRANT ACCESS TO", target_user, ;
        assertThat(mainBranch.children()).hasSize(3);

        assertThat(mainBranch.children().get(0)).isInstanceOf(KeywordNode.class)
                .extracting("word").isEqualTo("GRANT ACCESS TO");

        SyntaxNode paramNode = mainBranch.children().get(1);
        assertThat(paramNode).isInstanceOf(ParameterNode.class);
        assertThat(((ParameterNode) paramNode).name()).isEqualTo("target_user");
        assertThat(paramNode.isRepeatable()).isTrue();

        boolean hasParasiticDot = mainBranch.children().stream()
                .anyMatch(node -> node instanceof DelimiterNode d && d.value().equals("."));

        assertThat(hasParasiticDot)
                .as("The AST should not contain parasitic dot delimiters from the ellipsis operator.")
                .isFalse();
    }

    @Test
    void shouldCompileRepeatableRequiredGroup() {
        GrammarCompiler compiler = new GrammarCompiler();
        String syntax = "BLOCK TRAFFIC FROM { IP ip_address | SUBNET subnet_mask } ... ;";

        GroupNode root = compiler.compile(syntax);
        AlternativeNode mainBranch = (AlternativeNode) root.children().get(0);

        // BLOCK, TRAFFIC, FROM are merged -> "BLOCK TRAFFIC FROM", GroupNode, ;
        assertThat(mainBranch.children()).hasSize(3);

        assertThat(mainBranch.children().get(0)).isInstanceOf(KeywordNode.class)
                .extracting("word").isEqualTo("BLOCK TRAFFIC FROM");

        SyntaxNode groupNode = mainBranch.children().get(1);
        assertThat(groupNode).isInstanceOf(GroupNode.class);
        assertThat(((GroupNode) groupNode).type()).isEqualTo(GroupType.REQUIRED);
        assertThat(groupNode.isRepeatable()).isTrue();
    }

    @Test
    void shouldCompileRepeatableOptionalGroup() {
        GrammarCompiler compiler = new GrammarCompiler();
        String syntax = "GENERATE REPORT [ WITH metric_name ] ... ;";

        GroupNode root = compiler.compile(syntax);
        AlternativeNode mainBranch = (AlternativeNode) root.children().get(0);

        // GENERATE, REPORT are merged -> "GENERATE REPORT", GroupNode, ;
        assertThat(mainBranch.children()).hasSize(3);

        assertThat(mainBranch.children().get(0)).isInstanceOf(KeywordNode.class)
                .extracting("word").isEqualTo("GENERATE REPORT");

        SyntaxNode groupNode = mainBranch.children().get(1);
        assertThat(groupNode).isInstanceOf(GroupNode.class);
        assertThat(((GroupNode) groupNode).type()).isEqualTo(GroupType.OPTIONAL);
        assertThat(groupNode.isRepeatable()).isTrue();
    }
}