package org.simantics.scl.compiler.tests;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.simantics.scl.compiler.environment.specification.EnvironmentSpecification;
import org.simantics.scl.compiler.errors.CompilationErrorFormatter;
import org.simantics.scl.compiler.module.repository.ImportFailure;
import org.simantics.scl.compiler.module.repository.ImportFailureException;
import org.simantics.scl.compiler.module.repository.ModuleRepository;
import org.simantics.scl.compiler.runtime.RuntimeEnvironment;
import org.simantics.scl.compiler.top.ExpressionEvaluator;
import org.simantics.scl.compiler.top.SCLExpressionCompilationException;
import org.simantics.scl.compiler.types.Type;
import org.simantics.scl.compiler.types.Types;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class MemoryLeakExperiment {
    private static final Logger LOGGER = LoggerFactory.getLogger(MemoryLeakExperiment.class);
    ModuleRepository moduleRepository;

    EnvironmentSpecification environmentSpecification;

    @Before
    public void initialize() throws Exception {
        moduleRepository = InitialRepository.getInitialRepository();

        // Environment for compiling expressions
        environmentSpecification = new EnvironmentSpecification();
        environmentSpecification.importModule("Builtin", "");
        environmentSpecification.importModule("Prelude", "");
    }

    private void testExpression0(String expressionText,
            Object expectedValue,
            Type expectedType) throws Exception {
        
        RuntimeEnvironment runtimeEnvironment;
        try {
            runtimeEnvironment = moduleRepository.createRuntimeEnvironment(environmentSpecification,
                    getClass().getClassLoader());
        } catch(ImportFailureException e) {
            for(ImportFailure failure : e.failures)
                LOGGER.warn("Failed to import " + failure.moduleName);
            throw e;
        }

        // Compiling and running expression
        try {
            Object result = new ExpressionEvaluator(runtimeEnvironment, expressionText)
                    .expectedType(expectedType)
                    .interpretIfPossible(false)
                    .eval();
            if(expectedValue != null)
                Assert.assertEquals(expectedValue, result);
        } catch(SCLExpressionCompilationException e) {
            LOGGER.error(CompilationErrorFormatter.toString(expressionText, e.getErrors()));
            throw e;
        }
    }

    @Test
    public void testIt() throws Exception {
        for(int i=0;i<1000000;++i) {
            testExpression0("fst (\"a\", \"b\")", "a", Types.STRING);
            if(i % 10000 == 0 && i > 0) {
                System.gc();
                System.runFinalization();
                System.gc();
                Thread.sleep(100L);
                double used = (Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory());
                LOGGER.info(i + " " + used*1e-6 + " Mb, " + (used / i) + " b / expression");
            }
        }
    }
}