package org.apidesign.vm4brwsr;

import java.io.BufferedWriter;

import java.io.FileWriter;

import java.io.IOException;

import java.io.InputStream;

import java.io.Writer;

import java.util.Arrays;

import java.util.HashSet;

import java.util.LinkedList;

import java.util.List;

import java.util.Set;

/** Generator of JavaScript from bytecode of classes on classpath of the VM.

 *

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

 */

final class GenJS {

    private GenJS() {}

    public static void main(String... args) throws IOException {

        if (args.length < 2) {

            System.err.println("Usage: java -cp ... -jar ... <file_to_generate_js_code_to> java/lang/Class org/your/App ...");

            return;

        }

        Writer w = new BufferedWriter(new FileWriter(args[0]));

        List<String> classes = Arrays.asList(args).subList(1, args.length);

        compile(w, classes);

        w.close();

    }

    static void compile(Appendable out, String... names) throws IOException {

        compile(out, Arrays.asList(names));

    }

    static void compile(Appendable out, List<String> names) throws IOException {

        Set<String> processed = new HashSet<String>();

        LinkedList<String> toProcess = new LinkedList<String>(names);

        for (;;) {

            toProcess.removeAll(processed);

            if (toProcess.isEmpty()) {

                break;

            }

            String name = toProcess.getFirst();

            processed.add(name);

            if (name.startsWith("java/") && !name.equals("java/lang/Object")) {

                continue;

            }

            InputStream is = GenJS.class.getClassLoader().getResourceAsStream(name + ".class");

            if (is == null) {

                throw new IOException("Can't find class " + name); 

            }

            try {

                ByteCodeToJavaScript.compile(is, out, toProcess);

            } catch (RuntimeException ex) {

                if (out instanceof CharSequence) {

                    CharSequence seq = (CharSequence)out;

                    int lastBlock = seq.length();

                    while (lastBlock-- >= 0) {

                        if (seq.charAt(lastBlock) == '{') {

                            break;

                        }

                    }

                    throw new IOException("Error while compiling " + name + "\n" 

                        + seq.subSequence(lastBlock + 1, seq.length()), ex

                    );

                } else {

                    throw new IOException("Error while compiling " + name + "\n" 

                        + out, ex

                    );

                }

            }

        }

    }

}