package org.simantics.scl.osgi.internal;

import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.BundleException;
import org.osgi.framework.wiring.BundleWiring;
import org.simantics.scl.compiler.common.exceptions.InternalCompilerError;
import org.simantics.scl.compiler.internal.codegen.types.JavaReferenceValidator;
import org.simantics.scl.compiler.internal.codegen.types.JavaReferenceValidatorFactory;
import org.simantics.scl.compiler.internal.codegen.types.RuntimeJavaReferenceValidator;
import org.simantics.scl.compiler.types.Type;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@SuppressWarnings("restriction")
public class OsgiJavaReferenceValidatorFactory implements JavaReferenceValidatorFactory {

    private static final Logger LOGGER = LoggerFactory.getLogger(OsgiJavaReferenceValidatorFactory.class);

    private final Bundle bundle;

    public OsgiJavaReferenceValidatorFactory(Bundle bundle) {
        this.bundle = bundle;
    }

    private static ClassLoader getClassLoader(Bundle bundle) {
        if (bundle.getSymbolicName().equals("org.simantics.scl.runtime"))
            return Type.class.getClassLoader();
        else {
            BundleWiring wiring = bundle.adapt(BundleWiring.class);
            if (wiring == null && bundle.getState() == Bundle.INSTALLED) {
                LOGGER.info("Starting bundle {} with state {}", bundle.getSymbolicName(), BundleUtils.resolveBundleState(bundle));
                try {
                    bundle.start();
                } catch (BundleException e) {
                    throw new InternalCompilerError("Couldn't activate bundle " + bundle.getSymbolicName() + ". Bundle state is " + BundleUtils.resolveBundleState(bundle));
                }
                wiring = bundle.adapt(BundleWiring.class);
            }
            if (wiring != null)
                return wiring.getClassLoader();
            else
                throw new InternalCompilerError("Cannot get the class loader for bundle " + bundle.getSymbolicName() + ". Bundle state is " + BundleUtils.resolveBundleState(bundle));
        }
    }

    @SuppressWarnings("unchecked")
    private static JavaReferenceValidator<Object, Object, Object, Object> getJavaReferenceValidator(Bundle bundle) {
        if(bundle == null)
            return null;
        return (JavaReferenceValidator<Object, Object, Object, Object>)
                (JavaReferenceValidator<?, ?, ?, ?>)new RuntimeJavaReferenceValidator(getClassLoader(bundle));
    }

    private static Bundle getBundle(BundleContext bundleContext, String symbolicName) {
        Bundle result = null;
        for (Bundle candidate : bundleContext.getBundles())
            if (candidate.getSymbolicName().equals(symbolicName))
                if (result == null || result.getVersion().compareTo(candidate.getVersion()) < 0)
                    result = candidate;
        return result;
    }
    
    @Override
    public JavaReferenceValidator<Object, Object, Object, Object> getJavaReferenceValidator(String bundleName) {
        LOGGER.info("getJavaReferenceValidator(" + bundleName + ")");
        return getJavaReferenceValidator(getBundle(bundle.getBundleContext(), bundleName));
    }

    @Override
    public JavaReferenceValidator<Object, Object, Object, Object> getDefaultJavaReferenceValidator() {
        return getJavaReferenceValidator(bundle);
    }

}