/**
 * Copyright 2011 Bill Brown
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.colorfulsoftware.rss;

import java.io.Serializable;
import java.util.LinkedList;
import java.util.List;

/**
 * <p>
 * The &lt;channel> element.
 * </p>
 * <p>
 * From the <a href="http://cyber.law.harvard.edu/rss/rss.html">RSS 2.0
 * specification</a>...
 * </p>
 * <p>
 * A channel may contain any number of &lt;item>s. An item may represent a
 * "story" -- much like a story in a newspaper or magazine; if so its
 * description is a synopsis of the story, and the link points to the full
 * story. An item may also be complete in itself, if so, the description
 * contains the text (entity-encoded HTML is allowed; see examples), and the
 * link and title may be omitted. All elements of an item are optional, however
 * at least one of title or description must be present.
 * </p>
 * 
 * @author Bill Brown
 * 
 */
public class Channel implements Serializable {

        /**
         * 
         */
        private static final long serialVersionUID = -6193654133883709775L;

        /* required fields */
        private final Title title;

        private final Link link;

        private final Description description;

        /* optional fields */
        private final Language language;

        private final Copyright copyright;

        private final ManagingEditor managingEditor;

        private final WebMaster webMaster;

        private final PubDate pubDate;

        private final LastBuildDate lastBuildDate;

        private final List<Category> categories;

        private final Generator generator;

        private final Docs docs;

        private final Cloud cloud;

        private final TTL ttl;

        private final Image image;

        private final Rating rating;

        private final TextInput textInput;

        private final SkipHours skipHours;

        private final SkipDays skipDays;

        private final List<Item> items;

        private final List<Extension> extensions;

        private List<String> unboundPrefixes;

        Channel(Title title, Link link, Description description, Language language,
                        Copyright copyright, ManagingEditor managingEditor,
                        WebMaster webMaster, PubDate pubDate, LastBuildDate lastBuildDate,
                        List<Category> categories, Generator generator, Docs docs,
                        Cloud cloud, TTL ttl, Image image, Rating rating,
                        TextInput textInput, SkipHours skipHours, SkipDays skipDays,
                        List<Extension> extensions, List<Item> items)
                        throws RSSpectException {

                // make sure title is present
                if (title == null) {
                        throw new RSSpectException(
                                        "channel elements MUST contain a title element.");
                }
                this.title = new Title(title);

                // make sure link is present
                if (link == null) {
                        throw new RSSpectException(
                                        "channel elements MUST contain a link element.");
                }
                this.link = new Link(link);

                // make sure description is present
                if (description == null) {
                        throw new RSSpectException(
                                        "channel elements MUST contain a description element.");
                }
                this.description = new Description(description);

                this.language = (language == null) ? null : new Language(language);
                this.copyright = (copyright == null) ? null : new Copyright(copyright);
                this.managingEditor = (managingEditor == null) ? null
                                : new ManagingEditor(managingEditor);
                this.webMaster = (webMaster == null) ? null : new WebMaster(webMaster);
                this.pubDate = (pubDate == null) ? null : new PubDate(pubDate
                                .getDateTime());
                this.lastBuildDate = (lastBuildDate == null) ? null
                                : new LastBuildDate(lastBuildDate.getDateTime());
                if (categories == null) {
                        this.categories = null;
                } else {
                        this.categories = new LinkedList<Category>();
                        for (Category category : categories) {
                                this.categories.add(new Category(category));
                        }
                }
                this.generator = (generator == null) ? null : new Generator(generator
                                .getGenerator());
                this.docs = (docs == null) ? null : new Docs(docs.getDocs());
                this.cloud = (cloud == null) ? null : new Cloud(cloud);
                this.ttl = (ttl == null) ? null : new TTL(ttl.getTtl());
                this.image = (image == null) ? null : new Image(image);
                this.rating = (rating == null) ? null : new Rating(rating.getRating());
                this.textInput = (textInput == null) ? null : new TextInput(textInput);
                this.skipHours = (skipHours == null) ? null : new SkipHours(skipHours);
                this.skipDays = (skipDays == null) ? null : new SkipDays(skipDays);

                // check that the extension prefixes are bound to a namespace
                this.unboundPrefixes = new LinkedList<String>();

                if (items == null) {
                        this.items = null;
                } else {
                        this.items = new LinkedList<Item>();
                        for (Item item : items) {
                                // add any unbound prefixes to test.
                                if (item.getUnboundPrefixes() != null) {
                                        this.unboundPrefixes.addAll(item.getUnboundPrefixes());
                                }
                                this.items.add(new Item(item));
                        }
                }

                if (extensions == null) {
                        this.extensions = null;
                } else {
                        this.extensions = new LinkedList<Extension>();

                        for (Extension extension : extensions) {
                                // check that the extension prefix is bound to a namespace
                                String namespacePrefix = extension.getNamespacePrefix();
                                if (namespacePrefix != null) {
                                        this.unboundPrefixes.add(namespacePrefix);
                                }
                                this.extensions.add(new Extension(extension));
                        }
                }

                this.unboundPrefixes = (this.unboundPrefixes.size() == 0) ? null
                                : this.unboundPrefixes;
        }

        Channel(Channel channel) {
                this.title = channel.getTitle();
                this.link = channel.getLink();
                this.description = channel.getDescription();
                this.language = channel.getLanguage();
                this.copyright = channel.getCopyright();
                this.managingEditor = channel.getManagingEditor();
                this.webMaster = channel.getWebMaster();
                this.pubDate = channel.getPubDate();
                this.lastBuildDate = channel.getLastBuildDate();
                this.categories = channel.getCategories();
                this.generator = channel.getGenerator();
                this.docs = channel.getDocs();
                this.cloud = channel.getCloud();
                this.ttl = channel.getTtl();
                this.image = channel.getImage();
                this.rating = channel.getRating();
                this.textInput = channel.getTextInput();
                this.skipHours = channel.getSkipHours();
                this.skipDays = channel.getSkipDays();
                this.items = channel.getItems();
                this.extensions = channel.getExtensions();
                this.unboundPrefixes = channel.getUnboundPrefixes();
        }

        /**
         * @return the title.
         */
        public Title getTitle() {
                return new Title(title);
        }

        /**
         * @return the link element.
         */
        public Link getLink() {
                return new Link(link);
        }

        /**
         * @return the description element.
         */
        public Description getDescription() {
                return new Description(description.getDescription());
        }

        /**
         * @return the language element.
         */
        public Language getLanguage() {
                return (language == null) ? null : new Language(language);
        }

        /**
         * @return the copyright element
         */
        public Copyright getCopyright() {
                return (copyright == null) ? null : new Copyright(copyright);
        }

        /**
         * @return the managing editor element.
         */
        public ManagingEditor getManagingEditor() {
                return (managingEditor == null) ? null : new ManagingEditor(
                                managingEditor);
        }

        /**
         * @return the webmaster element.
         */
        public WebMaster getWebMaster() {
                return (webMaster == null) ? null : new WebMaster(webMaster);
        }

        /**
         * @return the pubDate element.
         */
        public PubDate getPubDate() {
                return (pubDate == null) ? null : new PubDate(pubDate.getDateTime());
        }

        /**
         * @return the last build date element.
         */
        public LastBuildDate getLastBuildDate() {
                return (lastBuildDate == null) ? null : new LastBuildDate(lastBuildDate
                                .getDateTime());
        }

        /**
         * @return the list of categories.
         */
        public List<Category> getCategories() {
                if (categories == null) {
                        return null;
                } else {
                        List<Category> catsCopy = new LinkedList<Category>();
                        for (Category category : this.categories) {
                                catsCopy.add(new Category(category));
                        }
                        return catsCopy;
                }
        }

        /**
         * @return the generator element.
         */
        public Generator getGenerator() {
                return (generator == null) ? null : new Generator(generator);
        }

        /**
         * @return the docs element.
         */
        public Docs getDocs() {
                return (docs == null) ? null : new Docs(docs);
        }

        /**
         * @return the cloud element.
         */
        public Cloud getCloud() {
                return (cloud == null) ? null : new Cloud(cloud);
        }

        /**
         * @return the ttl element.
         */
        public TTL getTtl() {
                return (ttl == null) ? null : new TTL(ttl);
        }

        /**
         * @return the image element.
         */
        public Image getImage() {
                return (image == null) ? null : new Image(image);
        }

        /**
         * @return the rating element.
         */
        public Rating getRating() {
                return (rating == null) ? null : new Rating(rating);
        }

        /**
         * @return the textInput element.
         */
        public TextInput getTextInput() {
                return (textInput == null) ? null : new TextInput(textInput);
        }

        /**
         * @return the skipHours element.
         */
        public SkipHours getSkipHours() {
                return (skipHours == null) ? null : new SkipHours(skipHours);
        }

        /**
         * @return the skipDays element.
         */
        public SkipDays getSkipDays() {
                return (skipDays == null) ? null : new SkipDays(skipDays);
        }

        /**
         * @return the list of items.
         */
        public List<Item> getItems() {
                if (items == null) {
                        return null;
                } else {
                        List<Item> itemsCopy = new LinkedList<Item>();
                        for (Item item : this.items) {
                                itemsCopy.add(new Item(item));
                        }
                        return itemsCopy;
                }
        }

        /**
         * 
         * @return the extensions for this entry.
         */
        public List<Extension> getExtensions() {
                if (extensions == null) {
                        return null;
                }
                List<Extension> extsCopy = new LinkedList<Extension>();
                for (Extension extension : this.extensions) {
                        extsCopy.add(new Extension(extension));
                }
                return extsCopy;
        }

        /**
         * @param catValue
         *            the value of the category.
         * @return the category name matching this item or null if not found.
         */
        public Category getCategory(String catValue) {
                if (this.categories != null) {
                        for (Category category : this.categories) {
                                if (category.getCategory() != null
                                                && category.getCategory().equals(catValue)) {
                                        return new Category(category);
                                }
                        }
                }
                return null;
        }

        /**
         * @param titleOrDescription
         *            the title or description data.
         * @return the item with this title or description. returns null if not
         *         found.
         */
        public Item getItem(String titleOrDescription) {
                if (this.items != null) {
                        for (Item item : this.items) {
                                if ((item.getTitle() != null
                                                && item.getTitle().getTitle() != null && item
                                                .getTitle().getTitle().equals(titleOrDescription))
                                                || (item.getDescription() != null && item
                                                                .getDescription().getDescription().equals(
                                                                                titleOrDescription))) {
                                        return new Item(item);
                                }
                        }
                }
                return null;
        }

        /**
         * @param extName
         *            the element name of the extension. eg. "atom:link" or
         *            "someExtension"
         * @return the extension matching the element or null if not found.
         */
        public Extension getExtension(String extName) {
                if (this.extensions != null) {
                        for (Extension extension : this.extensions) {
                                if (extension.getElementName().equals(extName)) {
                                        return new Extension(extension);
                                }
                        }
                }
                return null;
        }

        /**
         * Shows the contents of the &lt;channel> element.
         */
        @Override
        public String toString() {
                StringBuilder sb = new StringBuilder("<channel>");

                sb.append(title);

                sb.append(link);

                sb.append(description);

                if (language != null) {
                        sb.append(language);
                }

                if (copyright != null) {
                        sb.append(copyright);
                }

                if (managingEditor != null) {
                        sb.append(managingEditor);
                }

                if (webMaster != null) {
                        sb.append(webMaster);
                }

                if (pubDate != null) {
                        sb.append(pubDate);
                }

                if (lastBuildDate != null) {
                        sb.append(lastBuildDate);
                }

                if (categories != null) {
                        for (Category category : categories) {
                                sb.append(category);
                        }
                }

                if (generator != null) {
                        sb.append(generator);
                }

                if (docs != null) {
                        sb.append(docs);
                }

                if (cloud != null) {
                        sb.append(cloud);
                }

                if (ttl != null) {
                        sb.append(ttl);
                }

                if (image != null) {
                        sb.append(image);
                }

                if (rating != null) {
                        sb.append(rating);
                }

                if (textInput != null) {
                        sb.append(textInput);
                }

                if (skipHours != null) {
                        sb.append(skipHours);
                }

                if (skipDays != null) {
                        sb.append(skipDays);
                }

                if (items != null) {
                        for (Item item : items) {
                                sb.append(item);
                        }
                }

                if (extensions != null) {
                        for (Extension extension : extensions) {
                                sb.append(extension);
                        }
                }

                sb.append("</channel>");
                return sb.toString();
        }

        List<String> getUnboundPrefixes() {
                return unboundPrefixes;
        }
        
        @Override
        public boolean equals(Object obj) {
                if (obj == this) {
                        return true;
                }
                if (!(obj instanceof Channel)) {
                        return false;
                }
                return this.toString().equals(obj.toString());
        }
        
        @Override public int hashCode() {
                return toString().hashCode();
        }
}