/*******************************************************************************
 * Copyright (c) 2012, Directors of the Tyndale STEP Project
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met:
 * 
 * Redistributions of source code must retain the above copyright 
 * notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the following disclaimer in 
 * the documentation and/or other materials provided with the 
 * distribution.
 * Neither the name of the Tyndale House, Cambridge (www.TyndaleHouse.com)  
 * nor the names of its contributors may be used to endorse or promote 
 * products derived from this software without specific prior written 
 * permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
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 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
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 * THE POSSIBILITY OF SUCH DAMAGE.
 ******************************************************************************/
package com.tyndalehouse.step.core.service.impl;

import static com.tyndalehouse.step.core.utils.JSwordUtils.getSortedSerialisableList;

import java.util.*;

import javax.inject.Inject;
import javax.inject.Provider;
import javax.inject.Singleton;

import org.crosswire.jsword.book.Book;
import org.crosswire.jsword.book.BookCategory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.tyndalehouse.step.core.models.BibleVersion;
import com.tyndalehouse.step.core.models.ClientSession;
import com.tyndalehouse.step.core.service.ModuleService;
import com.tyndalehouse.step.core.service.helpers.VersionResolver;
import com.tyndalehouse.step.core.service.jsword.JSwordModuleService;

/**
 * Looks up module information, for example lexicon definitions for particular references
 * 
 * @author chrisburrell
 * 
 */
@Singleton
public class ModuleServiceImpl implements ModuleService {
    private static final Logger LOGGER = LoggerFactory.getLogger(ModuleServiceImpl.class);
    private final JSwordModuleService jswordModuleService;
    private final Provider<ClientSession> clientSession;
    private final VersionResolver resolver;

    /**
     * constructs a service to give module information and content.
     * 
     * @param jswordModuleService the service to register and manipulate modules
     * @param clientSession the client session to validate security
     */
    @Inject
    public ModuleServiceImpl(final JSwordModuleService jswordModuleService,
            final Provider<ClientSession> clientSession, final VersionResolver resolver) {
        this.jswordModuleService = jswordModuleService;
        this.clientSession = clientSession;
        this.resolver = resolver;
    }

    @Override
    public List<BibleVersion> getAvailableModules() {
        LOGGER.debug("Getting bible versions");
        return getSortedSerialisableList(this.jswordModuleService.getInstalledModules(BookCategory.BIBLE,
                BookCategory.COMMENTARY), this.clientSession.get().getLocale(),
                this.resolver);
    }

    @Override
    public List<BibleVersion> getAllInstallableModules(int installerIndex, final BookCategory... categories) {
        final BookCategory[] selected = categories.length == 0 ? new BookCategory[] { BookCategory.BIBLE,
                BookCategory.COMMENTARY } : categories;

        LOGGER.info("Returning all modules currently not installed");
        final List<Book> installedVersions = this.jswordModuleService.getInstalledModules(selected);
        final List<Book> allModules = this.jswordModuleService.getAllModules(installerIndex, selected);

        return getSortedSerialisableList(subtract(allModules, installedVersions),
                this.clientSession.get().getLocale(), this.resolver);
    }

    /**
     *
     * @param originalBooks list a the master list
     * @param booksToRemove list b the list of items to take out
     * @return the trimmed list
     */
    public static Collection<Book> subtract(final List<Book> originalBooks, final List<Book> booksToRemove) {
        //unfortunately, can't use Book.equals(), and therefore normal sets, because
        //Book.equals() compares all of the SwordBookMetaData, which can be different
        //if STEP has its own version of the books.
        //convert the first list to a map, keyed by version intials
        Map<String, Book> books = new HashMap<String, Book>(originalBooks.size()*2);
        for(Book b : originalBooks) {
            books.put(b.getInitials(), b);
        }

        for(Book b : booksToRemove) {
            books.remove(b.getInitials());
        }

        return books.values();
    }
}