package org.simantics.scl.osgi.internal;

import java.util.ArrayList;
import java.util.Collection;

import org.osgi.framework.BundleContext;
import org.osgi.util.tracker.ServiceTracker;
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.procedure.TObjectProcedure;

public class ServiceBasedModuleSourceRepository implements ModuleSourceRepository {

    ServiceTracker<ModuleSourceRepository, ModuleSourceRepository> sourceRepositories;

    public ServiceBasedModuleSourceRepository(BundleContext context) {
        sourceRepositories = new ServiceTracker<ModuleSourceRepository, ModuleSourceRepository>(
                context, ModuleSourceRepository.class, null);
        sourceRepositories.open();
    }

    @Override
    public ModuleSource getModuleSource(String moduleName,
            UpdateListener listener) {
        ModuleSource result = null;
        ModuleSourceRepository resultRepository = null;
        Object[] services = sourceRepositories.getServices();
        if(services != null)
            for(Object sourceRepository_ : services) {
                ModuleSourceRepository sourceLoader = (ModuleSourceRepository)sourceRepository_;
                ModuleSource source = sourceLoader.getModuleSource(moduleName, listener);
                if(source != null) {
                    if(result != null) {
                        double resultPriority = result.getPriority();
                        double sourcePriority = source.getPriority();
                        if(resultPriority > sourcePriority)
                            continue;
                        if(resultPriority == sourcePriority)
                            throw new RuntimeException("Module " + moduleName + " has two sources " + result + " (from "+resultRepository+"), " +
                                    source + " (from "+sourceLoader+")  with the same priority.");
                    }
                    result = source;
                    resultRepository = sourceLoader;
                }
            }
        return result;
    }
    
    @Override
    public String getDocumentation(String documentationName) {
        // getServices is internally synchronized, so no need to synchronize here
        Object[] services = sourceRepositories.getServices();
        if(services != null)
            for(Object sourceRepository_ : services) {
                ModuleSourceRepository sourceLoader = (ModuleSourceRepository)sourceRepository_;
                String documentation = sourceLoader.getDocumentation(documentationName);
                if(documentation != null)
                    return documentation;
            }
        return null;
    }

    @Override
    public void forAllModules(TObjectProcedure<String> procedure) {
        // getServices is internally synchronized, so no need to synchronize here
        Object[] services = sourceRepositories.getServices();
        if(services != null)
            for(Object sourceRepository_ : services) {
                ModuleSourceRepository sourceLoader = (ModuleSourceRepository)sourceRepository_;
                sourceLoader.forAllModules(procedure);
            }
    }
    
    @Override
    public Collection<String> getModuleNames() {
        ArrayList<String> result = new ArrayList<>();
        forAllModules((String name) -> {
            result.add(name);
            return true;
        });
        return result;
    }
    
    @Override
    public void forAllDocumentations(TObjectProcedure<String> procedure) {
        Object[] services = sourceRepositories.getServices();
        if(services != null)
            for(Object sourceRepository_ : services) {
                ModuleSourceRepository sourceLoader = (ModuleSourceRepository)sourceRepository_;
                sourceLoader.forAllDocumentations(procedure);
            }
    }
    
    @Override
    public Collection<String> getDocumentationNames() {
        ArrayList<String> result = new ArrayList<>();
        forAllDocumentations((String name) -> {
            result.add(name);
            return true;
        });
        return result;
    }

    @Override
    public void checkUpdates() {
        for(Object service_ : sourceRepositories.getServices()) {
            ModuleSourceRepository service = (ModuleSourceRepository)service_;
            service.checkUpdates();
        }
    }

}