/*
 * 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.sling.maven.slingstart;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.json.Json;
import javax.json.JsonObject;
import javax.json.JsonReader;
import javax.json.JsonValue;
import javax.json.stream.JsonGenerator;

import org.apache.felix.configurator.impl.json.JSMin;
import org.apache.maven.MavenExecutionException;
import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
import org.apache.maven.artifact.resolver.ArtifactResolver;
import org.apache.maven.artifact.versioning.DefaultArtifactVersion;
import org.apache.maven.execution.MavenSession;
import org.apache.maven.project.MavenProject;
import org.apache.sling.feature.ArtifactId;
import org.apache.sling.feature.Feature;
import org.apache.sling.feature.builder.FeatureProvider;
import org.apache.sling.feature.io.json.FeatureJSONReader;
import org.apache.sling.feature.io.json.FeatureJSONWriter;
import org.apache.sling.feature.modelconverter.FeatureToProvisioning;
import org.apache.sling.maven.slingstart.ModelPreprocessor.Environment;
import org.apache.sling.maven.slingstart.ModelPreprocessor.ProjectInfo;

import aQute.bnd.version.MavenVersion;

public class FeatureModelConverter {
    static final String BUILD_DIR = "provisioning/converted";

    static final String PROVISIONING_MODEL_NAME_VARIABLE = "provisioning.model.name";
    static final String PROVISIONING_RUNMODES = "provisioning.runmodes";

    public static Feature getFeature(ArtifactId id, MavenSession session, MavenProject project, ArtifactHandlerManager manager, ArtifactResolver resolver) {
        try {
            File file = ModelUtils.getArtifact(project, session, manager, resolver, id.getGroupId(), id.getArtifactId(), id.getVersion(), id.getType(), id.getClassifier()).getFile();
            try (Reader reader = new InputStreamReader(new FileInputStream(file), "UTF-8")) {
                return FeatureJSONReader.read(reader, file.toURI().toURL().toString());
            }
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }

    public static void convert(Environment env) throws MavenExecutionException {
        for (ProjectInfo pi : env.modelProjects.values()) {
            convert(env, pi, pi.defaultProvisioningModelName);
        }
    }

    public static class FeatureFileEntry {
        public File file;
        public String runModes;
        public String model;
    }

    public static void convertDirectories(String featuresDirectory, MavenProject project, String defaultProvName,
            FeatureProvider fp) throws MavenExecutionException {
        final List<FeatureFileEntry> featureFiles = FeatureModelConverter.getFeatureFiles(project.getBasedir(),
                featuresDirectory);
        if (!featureFiles.isEmpty()) {
            convert(featureFiles, project, defaultProvName, fp);
        }
    }

    static List<FeatureFileEntry> getFeatureFiles(final File baseDir, final String config) {
        final List<FeatureFileEntry> files = new ArrayList<>();
        for (final ParsedHeaderClause cfg : parseStandardHeader(config)) {
            final String directory = cfg.m_paths.get(0).trim().replace('/', File.separatorChar);

            String runmodes = (String) cfg.m_attrs.get(PROVISIONING_RUNMODES);
            String model = (String) cfg.m_attrs.get(PROVISIONING_MODEL_NAME_VARIABLE);

            final File featuresDir = new File(baseDir, directory);
            final File[] children = featuresDir.listFiles();
            if (children != null) {
                for (final File f : children) {
                    if (f.isFile() && f.getName().endsWith(".json")) {
                        final FeatureFileEntry ff = new FeatureFileEntry();
                        ff.file = f;
                        ff.runModes = runmodes;
                        ff.model = model;
                        files.add(ff);
                    }
                }
            }
        }

        return files;
    }

    public static void convert(Environment env, ProjectInfo info, String defaultProvName)
            throws MavenExecutionException {
        final String config = ModelPreprocessor.nodeValue(info.plugin, "featuresDirectory", "src/main/features");
        final List<FeatureFileEntry> files = getFeatureFiles(info.project.getBasedir(), config);
        if (!files.isEmpty()) {
            try {
                convert(files, info.project, defaultProvName,
                        id -> getFeature(id, env.session, info.project, env.artifactHandlerManager, env.resolver));
            } catch (RuntimeException ex) {
                throw new MavenExecutionException(ex.getMessage(), ex);
            }
        }
    }

    static void convert(List<FeatureFileEntry> files, MavenProject project, String defaultProvName, FeatureProvider fp)
            throws MavenExecutionException {
        File processedFeaturesDir = new File(project.getBuild().getDirectory(), "features/processed");
        processedFeaturesDir.mkdirs();

        List<File> substedFiles = new ArrayList<>();
        for (FeatureFileEntry featureFile : files) {
            final File f = featureFile.file;
            File outFile = new File(processedFeaturesDir, f.getName());
            if (!outFile.exists() || outFile.lastModified() <= f.lastModified()) {
                try {
                    final String suggestedClassifier;
                    if (!f.getName().equals("feature.json")) {
                        final int lastDot = f.getName().lastIndexOf('.');
                        suggestedClassifier = f.getName().substring(0, lastDot);
                    } else {
                        suggestedClassifier = null;
                    }
                    String json = readFeatureFile(project, f, suggestedClassifier);

                    // check for prov model name
                    if (defaultProvName != null || featureFile.runModes != null || featureFile.model != null) {
                        try (final Reader reader = new StringReader(json)) {
                            final Feature feature = FeatureJSONReader.read(reader, f.getAbsolutePath());
                            boolean update = false;
                            if (featureFile.runModes != null) {
                                String oldValue = feature.getVariables().get(PROVISIONING_RUNMODES);
                                String newValue;
                                if (oldValue == null) {
                                    newValue = featureFile.runModes;
                                } else {
                                    newValue = oldValue.concat(",").concat(featureFile.runModes);
                                }
                                feature.getVariables().put(PROVISIONING_RUNMODES, newValue);
                                update = true;
                            }

                            if (feature.getVariables().get(PROVISIONING_MODEL_NAME_VARIABLE) == null) {
                                boolean updateInner = true;
                                if (featureFile.model != null) {
                                    feature.getVariables().put(PROVISIONING_MODEL_NAME_VARIABLE, featureFile.model);
                                }
                                else if (defaultProvName != null) {
                                    feature.getVariables().put(PROVISIONING_MODEL_NAME_VARIABLE, defaultProvName);
                                }
                                else {
                                    updateInner = update;
                                }
                                update = updateInner;
                            }

                            if (update) {
                                try (final Writer writer = new StringWriter()) {
                                    FeatureJSONWriter.write(writer, feature);
                                    writer.flush();
                                    json = writer.toString();
                                }
                            }
                        }
                    }
                    try (final Writer fileWriter = new FileWriter(outFile)) {
                        fileWriter.write(json);
                    }
                } catch (IOException e) {
                    throw new MavenExecutionException("Problem processing feature file " + f.getAbsolutePath(), e);
                }
            }
            substedFiles.add(outFile);
        }

        File targetDir = new File(project.getBuild().getDirectory(), BUILD_DIR);
        targetDir.mkdirs();

        try {
            for (File f : substedFiles) {
                File genFile = new File(targetDir, f.getName() + ".txt");
                FeatureToProvisioning.convert(f, genFile, fp, substedFiles.toArray(new File[] {}));
            }
        } catch (Exception e) {
            throw new MavenExecutionException("Cannot convert feature files to provisioning model", e);
        }
    }

    /**
     * Read the json file, minify it, add id if missing and replace variables
     *
     * @param file The json file
     * @return The read and minified JSON
     */
    public static String readFeatureFile(final MavenProject project, final File file,
            final String suggestedClassifier) {
        final StringBuilder sb = new StringBuilder();
        try (final Reader reader = new FileReader(file)) {
            final char[] buf = new char[4096];
            int l = 0;

            while ((l = reader.read(buf)) > 0) {
                sb.append(buf, 0, l);
            }
        } catch (final IOException io) {
            throw new RuntimeException("Unable to read feature " + file.getAbsolutePath(), io);
        }
        final String readJson = sb.toString();

        // minify JSON (remove comments)
        String json;
        try (final Writer out = new StringWriter(); final Reader in = new StringReader(readJson)) {
            final JSMin min = new JSMin(in, out);
            min.jsmin();
            json = out.toString();
        } catch (final IOException e) {
            throw new RuntimeException("Unable to read feature file " + file.getAbsolutePath(), e);
        }

        // check if "id" is set
        try (final JsonReader reader = Json.createReader(new StringReader(json))) {
            final JsonObject obj = reader.readObject();
            if (!obj.containsKey("id")) {
                final StringBuilder isb = new StringBuilder();
                isb.append(project.getGroupId());
                isb.append(':');
                isb.append(project.getArtifactId());
                isb.append(':');
                isb.append("slingosgifeature");

                if (suggestedClassifier != null) {
                    isb.append(':');
                    isb.append(suggestedClassifier);
                }
                isb.append(':');
                isb.append(project.getVersion());

                final StringWriter writer = new StringWriter();

                try (final JsonGenerator generator = Json.createGenerator(writer)) {
                    generator.writeStartObject();

                    generator.write("id", isb.toString());

                    for (final Map.Entry<String, JsonValue> entry : obj.entrySet()) {
                        generator.write(entry.getKey(), entry.getValue());
                    }
                    generator.writeEnd();
                }

                json = writer.toString();
            }
        }

        // replace variables
        return Substitution.replaceMavenVars(project, json);
    }

    /**
     * Remove leading zeros for a version part
     */
    private static String cleanVersionString(final String version) {
        final StringBuilder sb = new StringBuilder();
        boolean afterDot = false;
        for(int i=0;i<version.length(); i++) {
            final char c = version.charAt(i);
            if ( c == '.' ) {
                if (afterDot == true ) {
                    sb.append('0');
                }
                afterDot = true;
                sb.append(c);
            } else if ( afterDot && c == '0' ) {
                // skip
            } else if ( afterDot && c == '-' ) {
                sb.append('0');
                sb.append(c);
                afterDot = false;
            } else {
                afterDot = false;
                sb.append(c);
            }
        }
        return sb.toString();
    }

    public static String getOSGiVersion(final String version) {
        final DefaultArtifactVersion dav = new DefaultArtifactVersion(cleanVersionString(version));
        final StringBuilder sb = new StringBuilder();
        sb.append(dav.getMajorVersion());
        sb.append('.');
        sb.append(dav.getMinorVersion());
        sb.append('.');
        sb.append(dav.getIncrementalVersion());
        if ( dav.getQualifier() != null ) {
            sb.append('.');
            sb.append(dav.getQualifier());
        }
        final MavenVersion mavenVersion = new MavenVersion(sb.toString());
        return mavenVersion.getOSGiVersion().toString();
    }

    private static class ParsedHeaderClause
    {
        public final List<String> m_paths;
        public final Map<String, String> m_dirs;
        public final Map<String, Object> m_attrs;
        public final Map<String, String> m_types;

        public ParsedHeaderClause(
            List<String> paths, Map<String, String> dirs, Map<String, Object> attrs,
            Map<String, String> types)
        {
            m_paths = paths;
            m_dirs = dirs;
            m_attrs = attrs;
            m_types = types;
        }
    }

    private static final char EOF = (char) -1;

    private static char charAt(int pos, String headers, int length)
    {
        if (pos >= length)
        {
            return EOF;
        }
        return headers.charAt(pos);
    }

    private static final int CLAUSE_START = 0;
    private static final int PARAMETER_START = 1;
    private static final int KEY = 2;
    private static final int DIRECTIVE_OR_TYPEDATTRIBUTE = 4;
    private static final int ARGUMENT = 8;
    private static final int VALUE = 16;

    @SuppressWarnings({ "unchecked", "rawtypes" })
    private static List<ParsedHeaderClause> parseStandardHeader(String header)
    {
        List<ParsedHeaderClause> clauses = new ArrayList<ParsedHeaderClause>();
        if (header == null)
        {
            return clauses;
        }
        ParsedHeaderClause clause = null;
        String key = null;
        Map targetMap = null;
        int state = CLAUSE_START;
        int currentPosition = 0;
        int startPosition = 0;
        int length = header.length();
        boolean quoted = false;
        boolean escaped = false;

        char currentChar = EOF;
        do
        {
            currentChar = charAt(currentPosition, header, length);
            switch (state)
            {
                case CLAUSE_START:
                    clause = new ParsedHeaderClause(
                        new ArrayList<String>(),
                        new HashMap<String, String>(),
                        new HashMap<String, Object>(),
                        new HashMap<String, String>());
                    clauses.add(clause);
                    state = PARAMETER_START;
                case PARAMETER_START:
                    startPosition = currentPosition;
                    state = KEY;
                case KEY:
                    switch (currentChar)
                    {
                        case ':':
                        case '=':
                            key = header.substring(startPosition, currentPosition).trim();
                            startPosition = currentPosition + 1;
                            targetMap = clause.m_attrs;
                            state = currentChar == ':' ? DIRECTIVE_OR_TYPEDATTRIBUTE : ARGUMENT;
                            break;
                        case EOF:
                        case ',':
                        case ';':
                            clause.m_paths.add(header.substring(startPosition, currentPosition).trim());
                            state = currentChar == ',' ? CLAUSE_START : PARAMETER_START;
                            break;
                        default:
                            break;
                    }
                    currentPosition++;
                    break;
                case DIRECTIVE_OR_TYPEDATTRIBUTE:
                    switch(currentChar)
                    {
                        case '=':
                            if (startPosition != currentPosition)
                            {
                                clause.m_types.put(key, header.substring(startPosition, currentPosition).trim());
                            }
                            else
                            {
                                targetMap = clause.m_dirs;
                            }
                            state = ARGUMENT;
                            startPosition = currentPosition + 1;
                            break;
                        default:
                            break;
                    }
                    currentPosition++;
                    break;
                case ARGUMENT:
                    if (currentChar == '\"')
                    {
                        quoted = true;
                        currentPosition++;
                    }
                    else
                    {
                        quoted = false;
                    }
                    if (!Character.isWhitespace(currentChar)) {
                        state = VALUE;
                    }
                    else {
                        currentPosition++;
                    }
                    break;
                case VALUE:
                    if (escaped)
                    {
                        escaped = false;
                    }
                    else
                    {
                        if (currentChar == '\\' )
                        {
                            escaped = true;
                        }
                        else if (quoted && currentChar == '\"')
                        {
                            quoted = false;
                        }
                        else if (!quoted)
                        {
                            String value = null;
                            switch(currentChar)
                            {
                                case EOF:
                                case ';':
                                case ',':
                                    value = header.substring(startPosition, currentPosition).trim();
                                    if (value.startsWith("\"") && value.endsWith("\""))
                                    {
                                        value = value.substring(1, value.length() - 1);
                                    }
                                    if (targetMap.put(key, value) != null)
                                    {
                                        throw new IllegalArgumentException(
                                            "Duplicate '" + key + "' in: " + header);
                                    }
                                    state = currentChar == ';' ? PARAMETER_START : CLAUSE_START;
                                    break;
                                default:
                                    break;
                            }
                        }
                    }
                    currentPosition++;
                    break;
                default:
                    break;
            }
        } while ( currentChar != EOF);

        if (state > PARAMETER_START)
        {
            throw new IllegalArgumentException("Unable to parse header: " + header);
        }
        return clauses;
    }
}