/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.plugins.surefire.report;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.maven.plugin.surefire.log.api.ConsoleLogger;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import static java.nio.charset.StandardCharsets.UTF_8;
import static org.apache.maven.shared.utils.StringUtils.isBlank;

/**
 *
 */
public final class TestSuiteXmlParser extends DefaultHandler {
    private final ConsoleLogger consoleLogger;

    private ReportTestSuite defaultSuite;

    private ReportTestSuite currentSuite;

    private Map<String, Integer> classesToSuitesIndex;

    private List<ReportTestSuite> suites;

    private StringBuilder currentElement;

    private ReportTestCase testCase;

    private boolean valid;

    public TestSuiteXmlParser(ConsoleLogger consoleLogger) {
        this.consoleLogger = consoleLogger;
    }

    public List<ReportTestSuite> parse(String xmlPath) throws ParserConfigurationException, SAXException, IOException {
        File f = new File(xmlPath);
        try (InputStreamReader stream = new InputStreamReader(new FileInputStream(f), UTF_8)) {
            return parse(stream);
        }
    }

    public List<ReportTestSuite> parse(InputStreamReader stream)
            throws ParserConfigurationException, SAXException, IOException {
        SAXParserFactory factory = SAXParserFactory.newInstance();

        SAXParser saxParser = factory.newSAXParser();

        valid = true;

        classesToSuitesIndex = new HashMap<>();
        suites = new ArrayList<>();

        saxParser.parse(new InputSource(stream), this);

        if (currentSuite != defaultSuite) { // omit the defaultSuite if it's empty and there are alternatives
            if (defaultSuite.getNumberOfTests() == 0) {
                suites.remove(classesToSuitesIndex
                        .get(defaultSuite.getFullClassName())
                        .intValue());
            }
        }

        return suites;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        if (valid) {
            try {
                switch (qName) {
                    case "testsuite":
                        defaultSuite = new ReportTestSuite();
                        currentSuite = defaultSuite;
                        String timeStr = attributes.getValue("time");
                        if (timeStr != null) {
                            defaultSuite.setTimeElapsed(Float.parseFloat(timeStr));
                        } else {
                            consoleLogger.warning("No time attribute found on testsuite element");
                        }

                        final String name = attributes.getValue("name");
                        final String group = attributes.getValue("group");
                        defaultSuite.setFullClassName(
                                isBlank(group)
                                        ? /*name is full class name*/ name
                                        : /*group is package name*/ group + "." + name);

                        suites.add(defaultSuite);
                        classesToSuitesIndex.put(defaultSuite.getFullClassName(), suites.size() - 1);
                        break;
                    case "testcase":
                        // Although this element does not contain any text, this line must be retained because the
                        // nested elements do have text content.
                        currentElement = new StringBuilder();

                        testCase = new ReportTestCase().setName(attributes.getValue("name"));

                        String fullClassName = attributes.getValue("classname");

                        // if the testcase declares its own classname, it may need to belong to its own suite
                        if (fullClassName != null) {
                            Integer currentSuiteIndex = classesToSuitesIndex.get(fullClassName);
                            if (currentSuiteIndex == null) {
                                currentSuite = new ReportTestSuite().setFullClassName(fullClassName);
                                suites.add(currentSuite);
                                classesToSuitesIndex.put(fullClassName, suites.size() - 1);
                            } else {
                                currentSuite = suites.get(currentSuiteIndex);
                            }
                        }

                        timeStr = attributes.getValue("time");

                        testCase.setFullClassName(currentSuite.getFullClassName())
                                .setClassName(currentSuite.getName())
                                .setFullName(currentSuite.getFullClassName() + "." + testCase.getName())
                                .setTime(timeStr != null ? Float.parseFloat(timeStr) : 0.0f);

                        if (currentSuite != defaultSuite) {
                            currentSuite.setTimeElapsed(testCase.getTime() + currentSuite.getTimeElapsed());
                        }
                        break;
                    case "failure":
                        currentElement = new StringBuilder();

                        testCase.setFailure(attributes.getValue("message"), attributes.getValue("type"));
                        currentSuite.incrementNumberOfFailures();
                        break;
                    case "error":
                        currentElement = new StringBuilder();

                        testCase.setError(attributes.getValue("message"), attributes.getValue("type"));
                        currentSuite.incrementNumberOfErrors();
                        break;
                    case "skipped":
                        String message = attributes.getValue("message");
                        testCase.setSkipped(message != null ? message : "skipped");
                        currentSuite.incrementNumberOfSkipped();
                        break;
                    case "flakyFailure":
                    case "flakyError":
                        currentSuite.incrementNumberOfFlakes();
                        break;
                    case "failsafe-summary":
                        valid = false;
                        break;
                    case "time":
                        currentElement = new StringBuilder();
                        break;
                    default:
                        break;
                }
            } catch (NumberFormatException e) {
                throw new SAXException("Failed to parse time value", e);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        switch (qName) {
            case "testcase":
                currentSuite.getTestCases().add(testCase);
                break;
            case "failure":
            case "error":
                testCase.setFailureDetail(currentElement.toString())
                        .setFailureErrorLine(parseErrorLine(currentElement, testCase.getFullClassName()));
                break;
            case "time":
                try {
                    defaultSuite.setTimeElapsed(Float.parseFloat(currentElement.toString()));
                } catch (NumberFormatException e) {
                    throw new SAXException("Failed to parse time value", e);
                }
                break;
            default:
                break;
        }
        // TODO extract real skipped reasons
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void characters(char[] ch, int start, int length) {
        assert start >= 0;
        assert length >= 0;
        if (valid && isNotBlank(start, length, ch)) {
            currentElement.append(ch, start, length);
        }
    }

    public boolean isValid() {
        return valid;
    }

    static boolean isNotBlank(int from, int len, char... s) {
        assert from >= 0;
        assert len >= 0;
        if (s != null) {
            for (int i = 0; i < len; i++) {
                char c = s[from++];
                if (c != ' ' && c != '\t' && c != '\n' && c != '\r' && c != '\f') {
                    return true;
                }
            }
        }
        return false;
    }

    static boolean isNumeric(StringBuilder s, final int from, final int to) {
        assert from >= 0;
        assert from <= to;
        for (int i = from; i != to; ) {
            if (!Character.isDigit(s.charAt(i++))) {
                return false;
            }
        }
        return from != to;
    }

    static String parseErrorLine(StringBuilder currentElement, String fullClassName) {
        final String[] linePatterns = {"at " + fullClassName + '.', "at " + fullClassName + '$'};
        int[] indexes = lastIndexOf(currentElement, linePatterns);
        int patternStartsAt = indexes[0];
        if (patternStartsAt != -1) {
            int searchFrom = patternStartsAt + (linePatterns[indexes[1]]).length();
            searchFrom = 1 + currentElement.indexOf(":", searchFrom);
            int searchTo = currentElement.indexOf(")", searchFrom);
            return isNumeric(currentElement, searchFrom, searchTo)
                    ? currentElement.substring(searchFrom, searchTo)
                    : "";
        }
        return "";
    }

    static int[] lastIndexOf(StringBuilder source, String... linePatterns) {
        int end = source.indexOf("Caused by:");
        if (end == -1) {
            end = source.length();
        }
        int startsAt = -1;
        int pattern = -1;
        for (int i = 0; i < linePatterns.length; i++) {
            String linePattern = linePatterns[i];
            int currentStartsAt = source.lastIndexOf(linePattern, end);
            if (currentStartsAt > startsAt) {
                startsAt = currentStartsAt;
                pattern = i;
            }
        }
        return new int[] {startsAt, pattern};
    }
}
