/*
 * RiskScape™ Copyright New Zealand Institute for Earth Science Limited
 * (Earth Sciences New Zealand) is distributed for research purposes only
 * under the terms of AGPLv3.
 *
 * RiskScape™ Copyright 2026 New Zealand Institute for Earth Science
 * Limited (Earth Sciences New Zealand). All rights reserved. Source code
 * available under the AGPLv3.
 * 
 * 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, either version 3 of the License, or (at your option) any
 *  later version.
 * 
 * This program is distributed for RESEARCH PURPOSES ONLY, in the hope that it will
 * be useful for research and education initiatives.
 * 
 * If you are not a researcher, or you are a researcher who wishes to use this
 * program on terms other than AGPLv3 (including those who wish to restrict the
 * distribution of any source code created using this program), please contact:
 * https://riskscape.org.nz
 * 
 * This program is distributed 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
 * <http://www.gnu.org/licenses/>.
 * 
 * By way of summary only, under the AGPLv3:
 *     • Permissions of this strongest copyleft license are conditioned
 *       on making available complete source code of licensed works and
 *       modifications, which include larger works using a licensed work,
 *       under the same license.
 *     • Copyright and license notices must be preserved.
 *     • Contributors provide an express grant of patent rights.
 *     • When a modified version is used to provide a service over a
 *       network, the complete source code of the modified version must be made
 *       available.
 */
package nz.org.riskscape.engine.function;

import static org.hamcrest.Matchers.*;
import static org.junit.Assert.*;

import org.junit.Test;

import nz.org.riskscape.engine.Matchers;
import nz.org.riskscape.engine.Tuple;
import nz.org.riskscape.engine.problem.ProblemMatchers;
import nz.org.riskscape.engine.rl.BaseExpressionRealizerTest;
import nz.org.riskscape.engine.types.Nullable;
import nz.org.riskscape.engine.types.Struct;
import nz.org.riskscape.engine.types.TypeProblems;
import nz.org.riskscape.engine.types.Types;

public class FlattenFunctionTest extends BaseExpressionRealizerTest {

  // This doesn't cover everything that the flattenprojection does, just the basics

  public FlattenFunctionTest() {
    project.getFunctionSet().add(new FlattenFunction().identified("flatten_struct"));
  }

  @Test
  public void canFlattenNonNestedStruct() throws Exception {
    // A struct with no nested structs should remain unchanged
    assertThat(evaluateConstant("flatten_struct({foo: 'bar'})"), is(tuple("{foo: 'bar'}")));
  }

  @Test
  public void canFlattenStructOneLevelDeep() throws Exception {
    evaluateConstant("flatten_struct({foo: {bar: 'baz'}})");
    assertThat(evaluated, is(tuple("{foo_bar: 'baz'}")));
  }

  @Test
  public void canFlattenStructTwoLevelsDeep() throws Exception {
    evaluateConstant("flatten_struct({foo: {bar: {baz: 'qux'}}})");
    assertThat(evaluated, is(tuple("{foo_bar_baz: 'qux'}")));
  }

  @Test
  public void canFlattenStructWithDuplicateKeys() throws Exception {
    evaluateConstant("flatten_struct({foo: {bar: 'qux'}, foo_bar: 33})");
    // not ideal that the rename is applied to the second item in this case, but oh well
    assertThat(evaluated, is(tuple("{foo_bar: 'qux', foo_bar_1: 33}")));
  }

  @Test
  public void canUseCustomJoinCharacter() throws Exception {
    evaluateConstant("flatten_struct({foo: {bar: 'baz'}}, '_join_')");
    assertThat(evaluated, is(tuple("{foo_join_bar: 'baz'}")));
  }

  @Test
  public void canFlattenNullableStruct() throws Exception {
    Tuple value = tuple("{foo: {bar: 'baz'}}");
    Struct inputType = Struct.of("tuple", Nullable.of(value.getStruct()));

    evaluate("flatten_struct(tuple)", Tuple.ofValues(inputType, value));

    assertThat(evaluated, is(tuple("{foo_bar: 'baz'}")));

    // input is nullable, so is result
    assertTrue(realized.getResultType().isNullable());

    evaluate("flatten_struct(null_of('struct(foo: struct(bar: text))'))", Tuple.EMPTY_TUPLE);
    assertThat(evaluated, nullValue());
  }

  @Test
  public void failsIfJoinCharNotString() throws Exception {
    evaluate("flatten_struct({}, 1)", Tuple.EMPTY_TUPLE);
    assertThat(
        realizationProblems,
        contains(Matchers.hasAncestorProblem(ProblemMatchers.isProblem(TypeProblems.class, (r, t) ->
          t.mismatch(r.any(), r.eq(Nullable.TEXT), r.eq(Types.INTEGER)))))
    );
  }

  @Test
  public void failsIfStructArgNotAStruct() throws Exception {
    evaluate("flatten_struct('foo')", Tuple.EMPTY_TUPLE);
    assertThat(
        realizationProblems,
        contains(Matchers.hasAncestorProblem(TypeProblems.get().mismatch(parser.parse("'foo'"),
            Struct.EMPTY_STRUCT, Types.TEXT)))
    );
  }
}
