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package com.oracle.graal.python.test.parser;

import static org.junit.Assert.assertTrue;

import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.CharBuffer;
import java.util.Arrays;
import java.util.List;

import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Rule;
import org.junit.rules.TestName;

import com.oracle.graal.python.PythonLanguage;
import com.oracle.graal.python.parser.PythonParserImpl;
import com.oracle.graal.python.parser.ScopeInfo;
import com.oracle.graal.python.parser.sst.SSTCheckOffsetVisitor;
import com.oracle.graal.python.parser.sst.SSTNode;
import com.oracle.graal.python.runtime.PythonContext;
import com.oracle.graal.python.runtime.PythonParser;
import com.oracle.graal.python.runtime.exception.PException;
import com.oracle.graal.python.test.PythonTests;
import com.oracle.truffle.api.TruffleFile;
import com.oracle.truffle.api.frame.Frame;
import com.oracle.truffle.api.interop.ExceptionType;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.interop.UnsupportedMessageException;
import com.oracle.truffle.api.nodes.Node;
import com.oracle.truffle.api.source.Source;

public class ParserTestBase {
    protected PythonContext context;
    protected static final String GOLDEN_FILE_EXT = ".tast";
    protected static final String NEW_GOLDEN_FILE_EXT = ".new.tast";
    private static final String SCOPE_FILE_EXT = ".scope";
    private static final String NEW_SCOPE_FILE_EXT = ".new.scope";

    protected boolean printDifferenceDetails = false;
    protected boolean printFormatStringLiteralValues = false;
    protected int printOnlyDiffIfLenIsBigger = 1000;

    private static final boolean REGENERATE_TREE = false;

    @Rule public TestName name = new TestName();

    private ScopeInfo lastGlobalScope;
    private SSTNode lastSST;

    public ParserTestBase() {
    }

    @Before
    public void setUp() {
        PythonTests.enterContext();
        context = PythonContext.get(null);
    }

    @After
    public void tearDown() {
        context = null;
        PythonTests.closeContext();
    }

    protected Source createSource(File testFile) throws Exception {
        TruffleFile src = context.getEnv().getInternalTruffleFile(testFile.getAbsolutePath());
        return PythonLanguage.newSource(context, src, getFileName(testFile));
    }

    public Node parse(String src, String moduleName, PythonParser.ParserMode mode, Frame fd) {
        Source source = Source.newBuilder(PythonLanguage.ID, src, moduleName).build();
        PythonParser parser = context.getParser();
        Node result = ((PythonParserImpl) parser).parseN(mode, 0, context, source, fd, null);
        lastGlobalScope = ((PythonParserImpl) parser).getLastGlobaScope();
        lastSST = ((PythonParserImpl) parser).getLastSST();
        return result;
    }

    public Node parse(String src, String moduleName, PythonParser.ParserMode mode) {
        return parse(src, moduleName, mode, null);
    }

    public Node parse(Source source, PythonParser.ParserMode mode) {
        PythonParser parser = context.getParser();
        Node result = ((PythonParserImpl) parser).parseN(mode, 0, context, source, null, null);
        lastGlobalScope = ((PythonParserImpl) parser).getLastGlobaScope();
        lastSST = ((PythonParserImpl) parser).getLastSST();
        return result;
    }

    protected ScopeInfo getLastGlobalScope() {
        return lastGlobalScope;
    }

    protected SSTNode getLastSST() {
        return lastSST;
    }

    public void checkSyntaxError(String source) throws Exception {
        boolean thrown = false;
        try {
            parse(source, name.getMethodName(), PythonParser.ParserMode.File);
        } catch (PException e) {
            thrown = isSyntaxError(e);
        }

        assertTrue("Expected SyntaxError was not thrown.", thrown);
    }

    public void checkSyntaxErrorMessageContains(String source, String expectedMessage) throws Exception {
        boolean thrown = false;
        try {
            parse(source, name.getMethodName(), PythonParser.ParserMode.File);
        } catch (PException e) {
            thrown = isSyntaxError(e);
            String exceptionMessage = PythonTests.getExceptionMessage(e);
            Assert.assertTrue("The expected message:\n\"" + expectedMessage + "\"\nwas not found in\n\"" + exceptionMessage + "\"", exceptionMessage.contains(expectedMessage));
        }

        assertTrue("Expected SyntaxError was not thrown.", thrown);
    }

    public void checkSyntaxErrorMessage(String source, String expectedMessage) throws Exception {
        boolean thrown = false;
        try {
            parse(source, name.getMethodName(), PythonParser.ParserMode.File);
        } catch (PException e) {
            thrown = isSyntaxError(e);
            Assert.assertEquals(expectedMessage, PythonTests.getExceptionMessage(e));
        }

        assertTrue("Expected SyntaxError was not thrown.", thrown);
    }

    protected static boolean isSyntaxError(PException e) throws UnsupportedMessageException {
        return InteropLibrary.getUncached().getExceptionType(e) == ExceptionType.PARSE_ERROR;
    }

    public void saveNewTreeResult(File testFile, boolean goldenFileNextToTestFile) throws Exception {
        assertTrue("The test files " + testFile.getAbsolutePath() + " was not found.", testFile.exists());
        TruffleFile src = context.getEnv().getInternalTruffleFile(testFile.getAbsolutePath());
        Source source = PythonLanguage.newSource(context, src, getFileName(testFile));
        Node resultNew = parse(source, PythonParser.ParserMode.File);
        String tree = printTreeToString(resultNew);
        File newGoldenFile = goldenFileNextToTestFile
                        ? new File(testFile.getParentFile(), getFileName(testFile) + NEW_GOLDEN_FILE_EXT)
                        : getGoldenFile(NEW_GOLDEN_FILE_EXT);
        if (REGENERATE_TREE || !newGoldenFile.exists()) {
            try (FileWriter fw = new FileWriter(newGoldenFile)) {
                fw.write(tree);
            }

        }
    }

    public void checkTreeFromFile(File testFile, boolean goldenFileNextToTestFile) throws Exception {
        assertTrue("The test files " + testFile.getAbsolutePath() + " was not found.", testFile.exists());
        TruffleFile src = context.getEnv().getInternalTruffleFile(testFile.getAbsolutePath());
        Source source = PythonLanguage.newSource(context, src, getFileName(testFile));
        Node resultNew = parse(source, PythonParser.ParserMode.File);
        String tree = printTreeToString(resultNew);
        File goldenFile = goldenFileNextToTestFile
                        ? new File(testFile.getParentFile(), getFileName(testFile) + GOLDEN_FILE_EXT)
                        : getGoldenFile(GOLDEN_FILE_EXT);
        if (REGENERATE_TREE || !goldenFile.exists()) {
            try (FileWriter fw = new FileWriter(goldenFile)) {
                fw.write(tree);
            }

        }
        assertDescriptionMatches(tree, goldenFile);
    }

    public void saveNewScope(File testFile, boolean goldenFileNextToTestFile) throws Exception {
        assertTrue("The test files " + testFile.getAbsolutePath() + " was not found.", testFile.exists());
        TruffleFile src = context.getEnv().getInternalTruffleFile(testFile.getAbsolutePath());
        Source source = PythonLanguage.newSource(context, src, getFileName(testFile));
        parse(source, PythonParser.ParserMode.File);
        ScopeInfo scopeNew = getLastGlobalScope();
        StringBuilder scopes = new StringBuilder();
        scopeNew.debugPrint(scopes, 0);
        File newScopeFile = goldenFileNextToTestFile
                        ? new File(testFile.getParentFile(), getFileName(testFile) + NEW_SCOPE_FILE_EXT)
                        : getGoldenFile(NEW_SCOPE_FILE_EXT);
        if (REGENERATE_TREE || !newScopeFile.exists()) {
            try (FileWriter fw = new FileWriter(newScopeFile)) {
                fw.write(scopes.toString());
            }
        }
    }

    public void checkScopeFromFile(File testFile, boolean goldenFileNextToTestFile) throws Exception {
        assertTrue("The test files " + testFile.getAbsolutePath() + " was not found.", testFile.exists());
        TruffleFile src = context.getEnv().getInternalTruffleFile(testFile.getAbsolutePath());
        Source source = PythonLanguage.newSource(context, src, getFileName(testFile));
        parse(source, PythonParser.ParserMode.File);
        ScopeInfo scopeNew = getLastGlobalScope();
        StringBuilder scopes = new StringBuilder();
        scopeNew.debugPrint(scopes, 0);
        File goldenScopeFile = goldenFileNextToTestFile
                        ? new File(testFile.getParentFile(), getFileName(testFile) + SCOPE_FILE_EXT)
                        : getGoldenFile(SCOPE_FILE_EXT);
        if (REGENERATE_TREE || !goldenScopeFile.exists()) {
            try (FileWriter fw = new FileWriter(goldenScopeFile)) {
                fw.write(scopes.toString());
            }

        }
        assertDescriptionMatches(scopes.toString(), goldenScopeFile);
    }

    public void checkTreeResult(String source, PythonParser.ParserMode mode, Frame frame) throws Exception {
        Node resultNew = parse(source, name.getMethodName(), mode, frame);
        String tree = printTreeToString(resultNew);
        File goldenFile = getGoldenFile(GOLDEN_FILE_EXT);
        if (REGENERATE_TREE || !goldenFile.exists()) {
            try (FileWriter fw = new FileWriter(goldenFile)) {
                fw.write(tree);
            }

        }
        assertDescriptionMatches(tree, goldenFile);
    }

    public void checkTreeResult(String source, PythonParser.ParserMode mode) throws Exception {
        checkTreeResult(source, mode, null);
    }

    public void checkScopeResult(String source, PythonParser.ParserMode mode) throws Exception {
        parse(source, name.getMethodName(), mode);
        ScopeInfo scopeNew = getLastGlobalScope();
        StringBuilder scopes = new StringBuilder();
        scopeNew.debugPrint(scopes, 0);
        File goldenScopeFile = getGoldenFile(SCOPE_FILE_EXT);
        if (REGENERATE_TREE || !goldenScopeFile.exists()) {
            try (FileWriter fw = new FileWriter(goldenScopeFile)) {
                fw.write(scopes.toString());
            }

        }
        assertDescriptionMatches(scopes.toString(), goldenScopeFile);
    }

    public void checkSSTNodeOffsets(SSTNode node) {
        SSTCheckOffsetVisitor checker = new SSTCheckOffsetVisitor(node);
        boolean result = node.accept(checker);
        assertTrue(checker.getMessage(), result);
    }

    protected String printTreeToString(Node node) {
        return printTreeToString(node, true);
    }

    protected String printTreeToString(Node node, boolean printTmpSlots) {
        ParserTreePrinter visitor = new ParserTreePrinter(printTmpSlots);
        visitor.printFormatStringLiteralDetail = printFormatStringLiteralValues;
        node.accept(visitor);
        return visitor.getTree();
    }

    protected void assertDescriptionMatches(String actual, File goldenFile) throws Exception {
        if (!goldenFile.exists()) {
            if (!goldenFile.createNewFile()) {
                assertTrue("Cannot create file " + goldenFile.getAbsolutePath(), false);
            }
            try (FileWriter fw = new FileWriter(goldenFile)) {
                fw.write(actual);
            }
            assertTrue("Created generated golden file " + goldenFile.getAbsolutePath() + "\nPlease re-run the test.", false);
        }
        String expected = readFile(goldenFile);

        assertDescriptionMatches(actual, expected, goldenFile.getName());
    }

    protected void assertDescriptionMatches(String actual, String expected, String someName) throws Exception {
        final String expectedTrimmed = expected.trim();
        final String actualTrimmed = actual.trim();

        if (expectedTrimmed.equals(actualTrimmed)) {
            // Actual and expected content are equals --> Test passed

        } else {
            // We want to ignore different line separators (like \r\n against \n) because they
            // might be causing failing tests on a different operation systems like Windows :]
            final String expectedUnified = expectedTrimmed.replaceAll("\r", "");
            final String actualUnified = actualTrimmed.replaceAll("\r", "");

            if (expectedUnified.equals(actualUnified)) {
                return; // Only difference is in line separation --> Test passed
            }

            // There are some diffrerences between expected and actual content --> Test failed

            assertTrue("Not matching results: " + (someName == null ? "" : someName) + lineSeparator(2) + getContentDifferences(expectedUnified, actualUnified), false);
        }
    }

    public static String readFile(File f) throws IOException {
        FileReader r = new FileReader(f);
        int fileLen = (int) f.length();
        CharBuffer cb = CharBuffer.allocate(fileLen);
        r.read(cb);
        cb.rewind();
        return cb.toString();
    }

    public File getTestFilesDir() {
        String dataDirPath = System.getProperty("org.graalvm.language.python.home");
        dataDirPath += "/com.oracle.graal.python.test/testData/testFiles";
        File dataDir = new File(dataDirPath);
        assertTrue("The test files folder, was not found.", dataDir.exists());
        return dataDir;
    }

    public File getTestFileFromTestAndTestMethod() {
        File testFilesDir = getTestFilesDir();
        File testDir = new File(testFilesDir + "/" + this.getClass().getSimpleName());
        if (!testDir.exists()) {
            testDir.mkdir();
        }
        File testFile = new File(testDir, name.getMethodName() + ".py");
        return testFile;
    }

    public File getGoldenDataDir() {
        String dataDirPath = System.getProperty("org.graalvm.language.python.home");
        dataDirPath += "/com.oracle.graal.python.test/testData/goldenFiles";
        File dataDir = new File(dataDirPath);
        assertTrue("The golden files folder, was not found.", dataDir.exists());
        return dataDir;
    }

    public File getGoldenFile(String ext) {
        File goldenDir = getGoldenDataDir();
        File testDir = new File(goldenDir + "/" + this.getClass().getSimpleName());
        if (!testDir.exists()) {
            testDir.mkdir();
        }
        File goldenFile = new File(testDir, name.getMethodName() + ext);
        return goldenFile;
    }

    protected String getFileName(File file) {
        return file.getName().substring(0, file.getName().lastIndexOf('.'));
    }

    private String getContentDifferences(String expected, String actual) {
        StringBuilder sb = new StringBuilder();
        if (printDifferenceDetails || (expected.length() < printOnlyDiffIfLenIsBigger && actual.length() < printOnlyDiffIfLenIsBigger)) {
            sb.append("Expected content is:").append(lineSeparator(2)).append(expected).append(lineSeparator(2)).append("but actual is:").append(lineSeparator(2)).append(actual).append(
                            lineSeparator(2)).append("It differs in the following things:").append(lineSeparator(2));
        } else {
            sb.append("Expected and actual differ in the following things:").append(lineSeparator(2));
        }

        List<String> expectedLines = Arrays.asList(expected.split("\n"));
        List<String> actualLines = Arrays.asList(actual.split("\n"));

        if (expectedLines.size() != actualLines.size()) {
            sb.append("Number of lines: \n\tExpected: ").append(expectedLines.size()).append("\n\tActual: ").append(actualLines.size()).append("\n\n");
        }

        // Appending lines which are missing in expected content and are present in actual content
        boolean noErrorInActual = true;
        for (String actualLine : actualLines) {
            if (expectedLines.contains(actualLine) == false) {
                if (noErrorInActual) {
                    sb.append("Actual content contains following lines which are missing in expected content: ").append(lineSeparator(1));
                    noErrorInActual = false;
                }
                sb.append("\t").append(actualLine).append(lineSeparator(1));
            }
        }

        // Appending lines which are missing in actual content and are present in expected content
        boolean noErrorInExpected = true;
        for (String expectedLine : expectedLines) {
            if (actualLines.contains(expectedLine) == false) {
                // If at least one line missing in actual content we want to append header line
                if (noErrorInExpected) {
                    sb.append("Expected content contains following lines which are missing in actual content: ").append(lineSeparator(1));
                    noErrorInExpected = false;
                }
                sb.append("\t").append(expectedLine).append(lineSeparator(1));
            }
        }

        // If both values are true it means the content is the same, but some lines are
        // placed on a different line number in actual and expected content
        if (noErrorInActual && noErrorInExpected && expectedLines.size() == actualLines.size()) {
            for (int lineNumber = 0; lineNumber < expectedLines.size(); lineNumber++) {
                String expectedLine = expectedLines.get(lineNumber);
                String actualLine = actualLines.get(lineNumber);

                if (!expectedLine.equals(actualLine)) {
                    sb.append("Line ").append(lineNumber).append(" contains different content than expected: ").append(lineSeparator(1)).append("Expected: \t").append(expectedLine).append(
                                    lineSeparator(1)).append("Actual:  \t").append(actualLine).append(lineSeparator(2));

                }
            }
        }

        return sb.toString();
    }

    private static String lineSeparator(int number) {
        final String lineSeparator = System.getProperty("line.separator");
        if (number > 1) {
            final StringBuilder sb = new StringBuilder();

            for (int i = 0; i < number; i++) {
                sb.append(lineSeparator);
            }
            return sb.toString();
        }
        return lineSeparator;
    }

    public void checkScopeAndTree(String source, PythonParser.ParserMode mode) throws Exception {
        checkScopeResult(source, mode);
        checkSSTNodeOffsets(lastSST);
        checkTreeResult(source, mode);
    }

    public void checkScopeAndTree(String source) throws Exception {
        checkScopeAndTree(source, PythonParser.ParserMode.File);
    }

    public void checkTreeResult(String source) throws Exception {
        checkTreeResult(source, PythonParser.ParserMode.File);
        checkSSTNodeOffsets(lastSST);
    }

    public void checkScopeAndTreeFromFile(File testFile) throws Exception {
        checkScopeFromFile(testFile, true);
        checkSSTNodeOffsets(lastSST);
        checkTreeFromFile(testFile, true);
    }
}
