package org.simantics.scl.osgi.internal;

import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;

import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.BundleEvent;
import org.osgi.service.component.ComponentContext;
import org.osgi.service.component.annotations.Activate;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Deactivate;
import org.osgi.util.tracker.BundleTracker;
import org.simantics.scl.compiler.module.repository.UpdateListener;
import org.simantics.scl.compiler.source.ModuleSource;
import org.simantics.scl.compiler.source.repository.ModuleSourceRepository;

import gnu.trove.map.hash.THashMap;
import gnu.trove.procedure.TObjectObjectProcedure;
import gnu.trove.set.hash.THashSet;

@Component
public class BundleModuleSourceRepository implements ModuleSourceRepository {
    
    Tracker tracker;
    THashMap<String, BundleModuleSource> modules = new THashMap<String, BundleModuleSource>();
    THashMap<Bundle, ArrayList<String>> modulesPerBundle = new THashMap<Bundle, ArrayList<String>>();
    THashMap<String, BundleDocumentationSource> documentations = new THashMap<String, BundleDocumentationSource>();
    THashMap<Bundle, ArrayList<String>> documentationsPerBundle = new THashMap<Bundle, ArrayList<String>>();
            
    class Tracker extends BundleTracker<Bundle> {
        public Tracker(BundleContext context) {
            super(context, 0xffffffff, null);
        }
        
        @Override
        public Bundle addingBundle(Bundle bundle, BundleEvent event) {
            synchronized(BundleModuleSourceRepository.this) {
                Enumeration<URL> moduleEntries = bundle.findEntries("scl", "*.scl", true);
                if(moduleEntries != null) {
                    ArrayList<String> modulesInThisBundle = new ArrayList<String>();
                    while(moduleEntries.hasMoreElements()) {
                        URL url = moduleEntries.nextElement();
                        String path = url.getPath();
                        String moduleName = path.substring(5, path.length()-4);
                        modules.put(moduleName, new BundleModuleSource(moduleName, bundle, url));
                        modulesInThisBundle.add(moduleName);
                    }
                    modulesPerBundle.put(bundle, modulesInThisBundle);
                }
                else
                    modulesPerBundle.put(bundle, new ArrayList<String>(0));
                
                Enumeration<URL> documentationEntries = bundle.findEntries("scl", "*.md", true);
                if(documentationEntries != null) {
                    ArrayList<String> documentationsInThisBundle = new ArrayList<String>();
                    while(documentationEntries.hasMoreElements()) {
                        URL url = documentationEntries.nextElement();
                        String path = url.getPath();
                        String documentationName = path.substring(5, path.length()-3);
                        documentations.put(documentationName, new BundleDocumentationSource(documentationName, bundle, url));
                        documentationsInThisBundle.add(documentationName);
                    }
                    documentationsPerBundle.put(bundle, documentationsInThisBundle);
                }
                else
                    documentationsPerBundle.put(bundle, new ArrayList<String>(0));
                
                return bundle;
            }
        }
        
        @Override
        public void removedBundle(Bundle bundle, BundleEvent event,
                Bundle object) {
            synchronized(BundleModuleSourceRepository.this) {
                ArrayList<String> moduleList = modulesPerBundle.get(bundle);
                if(moduleList != null)
                    for(String moduleName : moduleList)
                        modules.remove(moduleName);
                ArrayList<String> documentationsList = documentationsPerBundle.get(bundle);
                if(documentationsList != null)
                    for(String documentation : documentationsList)
                        documentations.remove(documentation);
            }
        }
    };
    
    @Activate
    public void activate(ComponentContext context) {
        tracker = new Tracker(context.getBundleContext());
        tracker.open();
    }
    
    @Deactivate
    public void deactivate(ComponentContext context) {
        tracker.close();
    }

    @Override
    synchronized public ModuleSource getModuleSource(String moduleName,
            UpdateListener listener) {
        return modules.get(moduleName);
    }

    @Override
    public synchronized Collection<String> getModuleNames() {
        return new ArrayList<String>(modules.keySet());
    }
    
    @Override
    public synchronized Collection<String> getDocumentationNames() {
        return new ArrayList<String>(documentations.keySet());
    }
    
    @Override
    synchronized public String getDocumentation(String documentationName) {
        BundleDocumentationSource source = documentations.get(documentationName);
        if(source == null)
            return null;
        else
            return source.getText();
    }
    
    @Override
    public void checkUpdates() {
        synchronized(this) {
            modulesPerBundle.forEachEntry(new TObjectObjectProcedure<Bundle, ArrayList<String>>() {
                @Override
                public boolean execute(Bundle bundle, ArrayList<String> oldModules) {
                    Enumeration<URL> moduleEntries = bundle.findEntries("scl", "*.scl", true);
                    if(moduleEntries != null) {
                        THashSet<String> oldModuleSet = new THashSet<String>(oldModules);
                        ArrayList<String> modulesInThisBundle = new ArrayList<String>();
                        while(moduleEntries.hasMoreElements()) {
                            URL url = moduleEntries.nextElement();
                            String path = url.getPath();
                            String moduleName = path.substring(5, path.length()-4);
                            if(!oldModuleSet.remove(moduleName))
                                modules.put(moduleName, new BundleModuleSource(moduleName, bundle, url));
                            modulesInThisBundle.add(moduleName);
                        }
                        for(String oldModule : oldModuleSet)
                            modules.remove(oldModule);
                        modulesPerBundle.put(bundle, modulesInThisBundle);
                    }
                    else {
                        for(String oldModule : oldModules)
                            modules.remove(oldModule);
                        modulesPerBundle.put(bundle, new ArrayList<String>(0));
                    }
                    return true;
                }
            });
            documentationsPerBundle.forEachEntry(new TObjectObjectProcedure<Bundle, ArrayList<String>>() {
                @Override
                public boolean execute(Bundle bundle, ArrayList<String> oldDocumentations) {
                    Enumeration<URL> documentationEntries = bundle.findEntries("scl", "*.md", true);
                    if(documentationEntries != null) {
                        THashSet<String> oldDocSet = new THashSet<String>(oldDocumentations);
                        ArrayList<String> documentationsInThisBundle = new ArrayList<String>();
                        while(documentationEntries.hasMoreElements()) {
                            URL url = documentationEntries.nextElement();
                            String path = url.getPath();
                            String documentationName = path.substring(5, path.length()-3);
                            if(!oldDocSet.remove(documentationName))
                                documentations.put(documentationName, new BundleDocumentationSource(documentationName, bundle, url));
                            documentationsInThisBundle.add(documentationName);
                        }
                        for(String oldDocumentation : oldDocSet)
                            documentations.remove(oldDocumentation);
                        documentationsPerBundle.put(bundle, documentationsInThisBundle);
                    }
                    else {
                        for(String oldDocumentation : oldDocumentations)
                            documentations.remove(oldDocumentation);
                        documentationsPerBundle.put(bundle, new ArrayList<String>(0));
                    }
                    return true;
                }
            });
        }
        for(BundleModuleSource source : modules.values())
            source.checkUpdates();
    }

    @Override
    public void clear() {
        for (BundleModuleSource source : modules.values()) {
            source.clear();
        }
    }

}