package org.apidesign.bck2brwsr.dew;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.URI;

import java.net.URISyntaxException;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import javax.tools.Diagnostic;

import javax.tools.DiagnosticListener;

import javax.tools.FileObject;

import javax.tools.ForwardingJavaFileManager;

import javax.tools.JavaFileManager;

import javax.tools.JavaFileObject;

import javax.tools.JavaFileObject.Kind;

import javax.tools.SimpleJavaFileObject;

import javax.tools.StandardJavaFileManager;

import javax.tools.StandardLocation;

import javax.tools.ToolProvider;

/**

 *

 * @author Jaroslav Tulach <jtulach@netbeans.org>

 */

final class Compile implements DiagnosticListener<JavaFileObject> {

    private final List<Diagnostic<? extends JavaFileObject>> errors = new ArrayList<>();

    private final Map<String, byte[]> classes;

    private final String pkg;

    private final String cls;

    private Compile(String html, String code) throws IOException {

        this.pkg = findPkg(code);

        this.cls = findCls(code);

        classes = compile(html, code);

    }

    /** Performs compilation of given HTML page and associated Java code

     */

    public static Compile create(String html, String code) throws IOException {

        return new Compile(html, code);

    }

    /** Checks for given class among compiled resources */

    public byte[] get(String res) {

        return classes.get(res);

    }

    /** Obtains errors created during compilation.

     */

    public List<Diagnostic<? extends JavaFileObject>> getErrors() {

        List<Diagnostic<? extends JavaFileObject>> err = new ArrayList<>();

        for (Diagnostic<? extends JavaFileObject> diagnostic : errors) {

            if (diagnostic.getKind() == Diagnostic.Kind.ERROR) {

                err.add(diagnostic);

            }

        }

        return err;

    }

    private Map<String, byte[]> compile(final String html, final String code) throws IOException {

        StandardJavaFileManager sjfm = ToolProvider.getSystemJavaCompiler().getStandardFileManager(this, null, null);

        final Map<String, ByteArrayOutputStream> class2BAOS = new HashMap<>();

        JavaFileObject file = new SimpleJavaFileObject(URI.create("mem://mem"), Kind.SOURCE) {

            @Override

            public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

                return code;

            }

        };

        final JavaFileObject htmlFile = new SimpleJavaFileObject(URI.create("mem://mem2"), Kind.OTHER) {

            @Override

            public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

                return html;

            }

            @Override

            public InputStream openInputStream() throws IOException {

                return new ByteArrayInputStream(html.getBytes());

            }

        };

        final URI scratch;

        try {

            scratch = new URI("mem://mem3");

        } catch (URISyntaxException ex) {

            throw new IOException(ex);

        }

        JavaFileManager jfm = new ForwardingJavaFileManager<JavaFileManager>(sjfm) {

            @Override

            public JavaFileObject getJavaFileForOutput(Location location, String className, Kind kind, FileObject sibling) throws IOException {

                if (kind  == Kind.CLASS) {

                    final ByteArrayOutputStream buffer = new ByteArrayOutputStream();

                    class2BAOS.put(className.replace('.', '/') + ".class", buffer);

                    return new SimpleJavaFileObject(sibling.toUri(), kind) {

                        @Override

                        public OutputStream openOutputStream() throws IOException {

                            return buffer;

                        }

                    };

                }

                if (kind == Kind.SOURCE) {

                    return new SimpleJavaFileObject(scratch/*sibling.toUri()*/, kind) {

                        private final ByteArrayOutputStream data = new ByteArrayOutputStream();

                        @Override

                        public OutputStream openOutputStream() throws IOException {

                            return data;

                        }

                        @Override

                        public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

                            data.close();

                            return new String(data.toByteArray());

                        }

                    };

                }

                throw new IllegalStateException();

            }

            @Override

            public FileObject getFileForInput(Location location, String packageName, String relativeName) throws IOException {

                if (location == StandardLocation.SOURCE_PATH) {

                    if (packageName.equals(pkg)) {

                        return htmlFile;

                    }

                }

                return null;

            }

        };

        ToolProvider.getSystemJavaCompiler().getTask(null, jfm, this, /*XXX:*/Arrays.asList("-source", "1.7", "-target", "1.7"), null, Arrays.asList(file)).call();

        Map<String, byte[]> result = new HashMap<>();

        for (Map.Entry<String, ByteArrayOutputStream> e : class2BAOS.entrySet()) {

            result.put(e.getKey(), e.getValue().toByteArray());

        }

        return result;

    }

    @Override

    public void report(Diagnostic<? extends JavaFileObject> diagnostic) {

        errors.add(diagnostic);

    }

    private static String findPkg(String java) throws IOException {

        Pattern p = Pattern.compile("package\\p{javaWhitespace}*([\\p{Alnum}\\.]+)\\p{javaWhitespace}*;", Pattern.MULTILINE);

        Matcher m = p.matcher(java);

        if (!m.find()) {

            throw new IOException("Can't find package declaration in the java file");

        }

        String pkg = m.group(1);

        return pkg;

    }

    private static String findCls(String java) throws IOException {

        Pattern p = Pattern.compile("class\\p{javaWhitespace}*([\\p{Alnum}\\.]+)\\p{javaWhitespace}", Pattern.MULTILINE);

        Matcher m = p.matcher(java);

        if (!m.find()) {

            throw new IOException("Can't find package declaration in the java file");

        }

        String cls = m.group(1);

        return cls;

    }

}