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 * The Universal Permissive License (UPL), Version 1.0
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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package com.oracle.truffle.sl.test;

import com.oracle.truffle.api.dsl.NodeFactory;
import com.oracle.truffle.api.vm.TruffleVM;
import com.oracle.truffle.sl.SLLanguage;
import com.oracle.truffle.sl.builtins.SLBuiltinNode;
import com.oracle.truffle.sl.test.SLTestRunner.TestCase;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringReader;
import java.net.URL;
import java.nio.charset.Charset;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.ArrayList;
import java.util.List;
import org.junit.Assert;
import org.junit.internal.TextListener;
import org.junit.runner.Description;
import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.manipulation.Filter;
import org.junit.runner.manipulation.NoTestsRemainException;
import org.junit.runner.notification.Failure;
import org.junit.runner.notification.RunNotifier;
import org.junit.runners.ParentRunner;
import org.junit.runners.model.InitializationError;

public final class SLTestRunner extends ParentRunner<TestCase> {

    private static int repeats = 1;

    private static final String SOURCE_SUFFIX = ".sl";
    private static final String INPUT_SUFFIX = ".input";
    private static final String OUTPUT_SUFFIX = ".output";

    private static final String LF = System.getProperty("line.separator");

    static class TestCase {
        protected final Description name;
        protected final Path path;
        protected final String sourceName;
        protected final String testInput;
        protected final String expectedOutput;
        protected String actualOutput;

        protected TestCase(Class<?> testClass, String baseName, String sourceName, Path path, String testInput, String expectedOutput) {
            this.name = Description.createTestDescription(testClass, baseName);
            this.sourceName = sourceName;
            this.path = path;
            this.testInput = testInput;
            this.expectedOutput = expectedOutput;
        }
    }

    private final List<TestCase> testCases;

    public SLTestRunner(Class<?> runningClass) throws InitializationError {
        super(runningClass);
        try {
            testCases = createTests(runningClass);
        } catch (IOException e) {
            throw new InitializationError(e);
        }
    }

    @Override
    protected Description describeChild(TestCase child) {
        return child.name;
    }

    @Override
    protected List<TestCase> getChildren() {
        return testCases;
    }

    protected static List<TestCase> createTests(final Class<?> c) throws IOException, InitializationError {
        SLTestSuite suite = c.getAnnotation(SLTestSuite.class);
        if (suite == null) {
            throw new InitializationError(String.format("@%s annotation required on class '%s' to run with '%s'.", SLTestSuite.class.getSimpleName(), c.getName(), SLTestRunner.class.getSimpleName()));
        }

        String[] paths = suite.value();

        Path root = getRootViaResourceURL(c, paths);

        if (root == null) {
            for (String path : paths) {
                Path candidate = FileSystems.getDefault().getPath(path);
                if (Files.exists(candidate)) {
                    root = candidate;
                    break;
                }
            }
        }
        if (root == null && paths.length > 0) {
            throw new FileNotFoundException(paths[0]);
        }

        final Path rootPath = root;

        final List<TestCase> foundCases = new ArrayList<>();
        Files.walkFileTree(rootPath, new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult visitFile(Path sourceFile, BasicFileAttributes attrs) throws IOException {
                String sourceName = sourceFile.getFileName().toString();
                if (sourceName.endsWith(SOURCE_SUFFIX)) {
                    String baseName = sourceName.substring(0, sourceName.length() - SOURCE_SUFFIX.length());

                    Path inputFile = sourceFile.resolveSibling(baseName + INPUT_SUFFIX);
                    String testInput = "";
                    if (Files.exists(inputFile)) {
                        testInput = readAllLines(inputFile);
                    }

                    Path outputFile = sourceFile.resolveSibling(baseName + OUTPUT_SUFFIX);
                    String expectedOutput = "";
                    if (Files.exists(outputFile)) {
                        expectedOutput = readAllLines(outputFile);
                    }

                    foundCases.add(new TestCase(c, baseName, sourceName, sourceFile, testInput, expectedOutput));
                }
                return FileVisitResult.CONTINUE;
            }
        });
        return foundCases;
    }

    public static Path getRootViaResourceURL(final Class<?> c, String[] paths) {
        URL url = c.getResource(c.getSimpleName() + ".class");
        if (url != null) {
            char sep = File.separatorChar;
            String externalForm = url.toExternalForm();
            String classPart = sep + c.getName().replace('.', sep) + ".class";
            String suffix = null;
            String prefix = null;
            if (externalForm.startsWith("jar:file:")) {
                prefix = "jar:file:";
                suffix = sep + "build/truffle-sl.jar!" + classPart;
            } else if (externalForm.startsWith("file:")) {
                prefix = "file:";
                suffix = sep + "bin" + classPart;
            } else {
                return null;
            }
            if (externalForm.endsWith(suffix)) {
                String base = externalForm.substring(prefix.length(), externalForm.length() - suffix.length());
                for (String path : paths) {
                    String candidate = base + sep + path;
                    if (new File(candidate).exists()) {
                        return FileSystems.getDefault().getPath(candidate);
                    }
                }
            }
        }
        return null;
    }

    private static String readAllLines(Path file) throws IOException {
        // fix line feeds for non unix os
        StringBuilder outFile = new StringBuilder();
        for (String line : Files.readAllLines(file, Charset.defaultCharset())) {
            outFile.append(line).append(LF);
        }
        return outFile.toString();
    }

    public static void setRepeats(int repeats) {
        SLTestRunner.repeats = repeats;
    }

    private static final List<NodeFactory<? extends SLBuiltinNode>> builtins = new ArrayList<>();

    public static void installBuiltin(NodeFactory<? extends SLBuiltinNode> builtin) {
        builtins.add(builtin);
    }

    @Override
    protected void runChild(TestCase testCase, RunNotifier notifier) {
        notifier.fireTestStarted(testCase.name);

        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try {
            TruffleVM vm = TruffleVM.newVM().setIn(new ByteArrayInputStream(repeat(testCase.testInput, repeats).getBytes("UTF-8"))).setOut(out).build();

            String script = readAllLines(testCase.path);

            PrintWriter printer = new PrintWriter(out);
            SLLanguage.run(vm, testCase.path, null, printer, repeats, builtins);
            printer.flush();

            String actualOutput = new String(out.toByteArray());
            Assert.assertEquals(script, repeat(testCase.expectedOutput, repeats), actualOutput);
        } catch (Throwable ex) {
            notifier.fireTestFailure(new Failure(testCase.name, new IllegalStateException("Cannot run " + testCase.sourceName, ex)));
        } finally {
            notifier.fireTestFinished(testCase.name);
        }
    }

    private static String repeat(String s, int count) {
        StringBuilder result = new StringBuilder(s.length() * count);
        for (int i = 0; i < count; i++) {
            result.append(s);
        }
        return result.toString();
    }

    public static void runInMain(Class<?> testClass, String[] args) throws InitializationError, NoTestsRemainException {
        JUnitCore core = new JUnitCore();
        core.addListener(new TextListener(System.out));
        SLTestRunner suite = new SLTestRunner(testClass);
        if (args.length > 0) {
            suite.filter(new NameFilter(args[0]));
        }
        Result r = core.run(suite);
        if (!r.wasSuccessful()) {
            System.exit(1);
        }
    }

    private static final class NameFilter extends Filter {
        private final String pattern;

        private NameFilter(String pattern) {
            this.pattern = pattern.toLowerCase();
        }

        @Override
        public boolean shouldRun(Description description) {
            return description.getMethodName().toLowerCase().contains(pattern);
        }

        @Override
        public String describe() {
            return "Filter contains " + pattern;
        }
    }

}