/**
 * Copyright (C) 2022 Adrien Hopkins
 *
 * 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 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/>.
 */
package sevenUnitsGUI;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.nio.file.Path;
import java.util.List;
import java.util.Set;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource;

import sevenUnits.unit.BaseDimension;
import sevenUnits.unit.BritishImperial;
import sevenUnits.unit.Metric;
import sevenUnits.unit.Unit;
import sevenUnits.unit.UnitType;
import sevenUnits.unit.UnitValue;
import sevenUnits.utils.NameSymbol;
import sevenUnits.utils.Nameable;
import sevenUnits.utils.ObjectProduct;
import sevenUnits.utils.UncertainDouble;

/**
 * @author Adrien Hopkins
 *
 * @since 2022-02-10
 */
public final class PresenterTest {
	private static final Path TEST_SETTINGS = Path.of("src", "test", "resources",
			"test-settings.txt");
	static final Set<Unit> testUnits = Set.of(Metric.METRE, Metric.KILOMETRE,
			Metric.METRE_PER_SECOND, Metric.KILOMETRE_PER_HOUR);
	
	static final Set<ObjectProduct<BaseDimension>> testDimensions = Set
			.of(Metric.Dimensions.LENGTH, Metric.Dimensions.VELOCITY);
	
	/**
	 * @return rounding rules used by {@link #testRoundingRules}
	 * @since 2022-04-16
	 */
	private static final Stream<Function<UncertainDouble, String>> getRoundingRules() {
		final var SCIENTIFIC_ROUNDING = StandardDisplayRules.uncertaintyBased();
		final var INTEGER_ROUNDING = StandardDisplayRules.fixedDecimals(0);
		final var SIG_FIG_ROUNDING = StandardDisplayRules.fixedPrecision(4);
		
		return Stream.of(SCIENTIFIC_ROUNDING, INTEGER_ROUNDING, SIG_FIG_ROUNDING);
	}
	
	private static final Set<String> names(Set<? extends Nameable> units) {
		return units.stream().map(Nameable::getName).collect(Collectors.toSet());
	}
	
	/**
	 * Test method for {@link Presenter#convertExpressions}
	 * 
	 * @since 2022-02-12
	 */
	@Test
	void testConvertExpressions() {
		// setup
		final ViewBot viewBot = new ViewBot();
		final Presenter presenter = new Presenter(viewBot);
		
		viewBot.setFromExpression("10000.0 m");
		viewBot.setToExpression("km");
		
		// convert expression
		presenter.convertExpressions();
		
		// test result
		final List<UnitConversionRecord> outputs = viewBot
				.expressionConversionList();
		assertEquals("10000.0 m = 10.0 km",
				outputs.get(outputs.size() - 1).toString());
	}
	
	/**
	 * Tests that unit-conversion Views can correctly convert units
	 * 
	 * @since 2022-02-12
	 */
	@Test
	void testConvertUnits() {
		// setup
		final ViewBot viewBot = new ViewBot();
		final Presenter presenter = new Presenter(viewBot);
		
		viewBot.setFromUnitNames(names(testUnits));
		viewBot.setToUnitNames(names(testUnits));
		viewBot.setFromSelection("metre");
		viewBot.setToSelection("kilometre");
		viewBot.setInputValue("10000.0");
		
		// convert units
		presenter.convertUnits();
		
		/*
		 * use result from system as expected - I'm not testing unit conversion
		 * here (that's for the backend tests), I'm just testing that it correctly
		 * calls the unit conversion system
		 */
		final UnitValue expectedInput = UnitValue.of(Metric.METRE, 10000.0);
		final UnitValue expectedOutput = expectedInput
				.convertTo(Metric.KILOMETRE);
		final UnitConversionRecord expectedUC = UnitConversionRecord
				.fromValues(expectedInput, expectedOutput);
		
		assertEquals(List.of(expectedUC), viewBot.unitConversionList());
	}
	
	/**
	 * Tests that duplicate units are successfully removed, if that is asked for
	 * 
	 * @since 2022-04-16
	 */
	@Test
	void testDuplicateUnits() {
		final var metre = Metric.METRE;
		final var meter = Metric.METRE.withName(NameSymbol.of("meter", "m"));
		
		// load 2 duplicate units
		final var viewBot = new ViewBot();
		final var presenter = new Presenter(viewBot);
		presenter.database.clear();
		presenter.database.addUnit("metre", metre);
		presenter.database.addUnit("meter", meter);
		
		// test that only one of them is included if duplicate units disabled
		presenter.setShowDuplicateUnits(false);
		presenter.updateView();
		assertEquals(1, viewBot.getFromUnitNames().size());
		assertEquals(1, viewBot.getToUnitNames().size());
		
		// test that both of them is included if duplicate units enabled
		presenter.setShowDuplicateUnits(true);
		presenter.updateView();
		assertEquals(2, viewBot.getFromUnitNames().size());
		assertEquals(2, viewBot.getToUnitNames().size());
	}
	
	/**
	 * Tests that one-way conversion correctly filters From and To units
	 * 
	 * @since 2022-04-16
	 */
	@Test
	void testOneWayConversion() {
		// metre is metric, inch is non-metric, tempC is semi-metric
		final var allNames = Set.of("metre", "inch", "tempC");
		final var metricNames = Set.of("metre", "tempC");
		final var nonMetricNames = Set.of("inch", "tempC");
		
		// load view with one metric and one non-metric unit
		final var viewBot = new ViewBot();
		final var presenter = new Presenter(viewBot);
		presenter.database.clear();
		presenter.database.addUnit("metre", Metric.METRE);
		presenter.database.addUnit("inch", BritishImperial.Length.INCH);
		presenter.database.addUnit("tempC", Metric.CELSIUS);
		
		// test that units are removed from each side when one-way conversion is
		// enabled
		presenter.setOneWayConversionEnabled(true);
		presenter.updateView();
		assertEquals(metricNames, viewBot.getFromUnitNames());
		assertEquals(nonMetricNames, viewBot.getToUnitNames());
		
		// test that units are kept when one-way conversion is disabled
		presenter.setOneWayConversionEnabled(false);
		presenter.updateView();
		assertEquals(allNames, viewBot.getFromUnitNames());
		assertEquals(allNames, viewBot.getToUnitNames());
	}
	
	/**
	 * Tests the prefix-viewing functionality.
	 * 
	 * @since 2022-04-16
	 */
	@Test
	void testPrefixViewing() {
		// setup
		final var viewBot = new ViewBot();
		final var presenter = new Presenter(viewBot);
		viewBot.setViewablePrefixNames(Set.of("kilo", "milli"));
		presenter.setNumberDisplayRule(UncertainDouble::toString);
		
		// view prefix
		viewBot.setViewedPrefixName("kilo");
		presenter.prefixSelected(); // just in case
		
		// get correct values
		final var expectedNameSymbol = presenter.database.getPrefix("kilo")
				.getNameSymbol();
		final var expectedMultiplierString = String
				.valueOf(Metric.KILO.getMultiplier());
		
		// test that presenter's values are correct
		final var prefixRecord = viewBot.prefixViewList().get(0);
		assertEquals(expectedNameSymbol, prefixRecord.getNameSymbol());
		assertEquals(expectedMultiplierString, prefixRecord.multiplierString());
	}
	
	/**
	 * Tests that rounding rules are used correctly.
	 * 
	 * @since 2022-04-16
	 */
	@ParameterizedTest
	@MethodSource("getRoundingRules")
	void testRoundingRules(Function<UncertainDouble, String> roundingRule) {
		// setup
		final var viewBot = new ViewBot();
		final var presenter = new Presenter(viewBot);
		presenter.setNumberDisplayRule(roundingRule);
		
		// convert and round
		viewBot.setInputValue("12345.6789");
		viewBot.setFromSelection("metre");
		viewBot.setToSelection("kilometre");
		presenter.convertUnits();
		
		// test the result of the rounding
		final String expectedOutputString = roundingRule
				.apply(UncertainDouble.of(12.3456789, 0));
		final String actualOutputString = viewBot.unitConversionList().get(0)
				.outputValueString();
		assertEquals(expectedOutputString, actualOutputString);
	}
	
	/**
	 * Tests that settings can be saved to and loaded from a file.
	 * 
	 * @since 2022-04-16
	 */
	@Test
	void testSettingsSaving() {
		// setup
		final var viewBot = new ViewBot();
		final var presenter = new Presenter(viewBot);
		
		// set and save custom settings
		presenter.setOneWayConversionEnabled(true);
		presenter.setShowDuplicateUnits(true);
		presenter.setNumberDisplayRule(StandardDisplayRules.fixedPrecision(11));
		presenter.saveSettings(TEST_SETTINGS);
		
		// overwrite custom settings
		presenter.setOneWayConversionEnabled(false);
		presenter.setShowDuplicateUnits(false);
		presenter.setNumberDisplayRule(StandardDisplayRules.uncertaintyBased());
		
		// load settings & test that they're the same
		presenter.loadSettings(TEST_SETTINGS);
		assertTrue(presenter.oneWayConversionEnabled());
		assertTrue(presenter.duplicateUnitsShown());
		assertEquals(StandardDisplayRules.fixedPrecision(11),
				presenter.getNumberDisplayRule());
	}
	
	/**
	 * Ensures the Presenter generates the correct data upon a unit-viewing.
	 * 
	 * @since 2022-04-16
	 */
	@Test
	void testUnitViewing() {
		// setup
		final var viewBot = new ViewBot();
		final var presenter = new Presenter(viewBot);
		viewBot.setViewableUnitNames(names(testUnits));
		
		// view unit
		viewBot.setViewedUnitName("metre");
		presenter.unitNameSelected(); // just in case this isn't triggered
												// automatically
		
		// get correct values
		final var expectedNameSymbol = presenter.database.getUnit("metre")
				.getNameSymbol();
		final var expectedDefinition = "(Base unit)";
		final var expectedDimensionName = presenter
				.getDimensionName(Metric.METRE.getDimension());
		final var expectedUnitType = UnitType.METRIC;
		
		// test for correctness
		final var viewRecord = viewBot.unitViewList().get(0);
		assertEquals(expectedNameSymbol, viewRecord.getNameSymbol());
		assertEquals(expectedDefinition, viewRecord.definition());
		assertEquals(expectedDimensionName, viewRecord.dimensionName());
		assertEquals(expectedUnitType, viewRecord.unitType());
	}
	
	/**
	 * Test for {@link Presenter#updateView()}
	 * 
	 * @since 2022-02-12
	 */
	@Test
	void testUpdateView() {
		// setup
		final ViewBot viewBot = new ViewBot();
		final Presenter presenter = new Presenter(viewBot);
		
		// override default database units
		presenter.database.clear();
		for (final Unit unit : testUnits) {
			presenter.database.addUnit(unit.getPrimaryName().orElseThrow(), unit);
		}
		for (final var dimension : testDimensions) {
			presenter.database.addDimension(
					dimension.getPrimaryName().orElseThrow(), dimension);
		}
		
		// set from and to units
		viewBot.setFromUnitNames(names(testUnits));
		viewBot.setToUnitNames(names(testUnits));
		viewBot.setDimensionNames(names(testDimensions));
		viewBot.setSelectedDimensionName(Metric.Dimensions.LENGTH.getName());
		
		// filter to length units only, then get the filtered sets of units
		presenter.updateView();
		final Set<String> fromUnits = viewBot.getFromUnitNames();
		final Set<String> toUnits = viewBot.getToUnitNames();
		
		// test that fromUnits/toUnits is [METRE, KILOMETRE]
		assertEquals(Set.of("metre", "kilometre"), fromUnits);
		assertEquals(Set.of("metre", "kilometre"), toUnits);
	}
}