/*

 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package javax.xml.catalog;

import java.net.URI;

import java.nio.file.Files;

import java.nio.file.Paths;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

/**

 * Represents a group entry.

 *

 * @since 9

 */

class GroupEntry extends BaseEntry {

    static final int ATTRIBUTE_PREFER = 0;

    static final int ATTRIBUTE_DEFFER = 1;

    static final int ATTRIBUTE_RESOLUTION = 2;

    //Unmodifiable features when the Catalog is created

    CatalogFeatures features;

    //Value of the prefer attribute

    boolean isPreferPublic = true;

    //The catalog instance this group belongs to

    CatalogImpl catalog;

    //A list of all entries in a catalog or group

    List<BaseEntry> entries = new ArrayList<>();

    //loaded delegated catalog by system id

    Map<String, Catalog> delegateCatalogs = new HashMap<>();

    //A list of all loaded Catalogs, including this, and next catalogs

    Map<String, Catalog> loadedCatalogs = new HashMap<>();

    /*

     A list of Catalog Ids that have already been searched in a matching

     operation. Check this list before constructing new Catalog to avoid circular

     reference.

     */

    List<String> catalogsSearched = new ArrayList<>();

    //A flag to indicate whether the current match is a system or uri

    boolean isInstantMatch = false;

    //A match of a rewrite type

    String rewriteMatch = null;

    //The length of the longest match of a rewrite type

    int longestRewriteMatch = 0;

    //A match of a suffix type

    String suffixMatch = null;

    //The length of the longest match of a suffix type

    int longestSuffixMatch = 0;

    /**

     * PreferType represents possible values of the prefer property

     */

    public static enum PreferType {

        PUBLIC("public"),

        SYSTEM("system");

        final String literal;

        PreferType(String literal) {

            this.literal = literal;

        }

        public boolean prefer(String prefer) {

            return literal.equals(prefer);

        }

    }

    /**

     * PreferType represents possible values of the resolve property

     */

    public static enum ResolveType {

        STRICT(CatalogFeatures.RESOLVE_STRICT),

        CONTINUE(CatalogFeatures.RESOLVE_CONTINUE),

        IGNORE(CatalogFeatures.RESOLVE_IGNORE);

        final String literal;

        ResolveType(String literal) {

            this.literal = literal;

        }

        static public ResolveType getType(String resolveType) {

            for (ResolveType type : ResolveType.values()) {

                if (type.isType(resolveType)) {

                    return type;

                }

            }

            return null;

        }

        public boolean isType(String type) {

            return literal.equals(type);

        }

    }

    /**

     * Constructs a GroupEntry

     *

     * @param type The type of the entry

     */

    public GroupEntry(CatalogEntryType type) {

        super(type);

    }

    /**

     * Constructs a group entry.

     *

     * @param base The baseURI attribute

     * @param attributes The attributes

     */

    public GroupEntry(String base, String... attributes) {

        this(null, base, attributes);

    }

    /**

     * Resets the group entry to its initial state.

     */

    public void reset() {

        isInstantMatch = false;

        rewriteMatch = null;

        longestRewriteMatch = 0;

        suffixMatch = null;

        longestSuffixMatch = 0;

    }

    /**

     * Constructs a group entry.

     * @param catalog The parent catalog

     * @param base The baseURI attribute

     * @param attributes The attributes

     */

    public GroupEntry(CatalogImpl catalog, String base, String... attributes) {

        super(CatalogEntryType.GROUP, base);

        setPrefer(attributes[ATTRIBUTE_PREFER]);

        this.catalog = catalog;

    }

    /**

     * Adds an entry.

     *

     * @param entry The entry to be added.

     */

    public void addEntry(BaseEntry entry) {

        entries.add(entry);

    }

    /**

     * Sets the prefer property. If the value is null or empty, or any String

     * other than the defined, it will be assumed as the default value.

     *

     * @param value The value of the prefer attribute

     */

    public final void setPrefer(String value) {

        isPreferPublic = PreferType.PUBLIC.prefer(value);

    }

    /**

     * Queries the prefer attribute

     *

     * @return true if the prefer attribute is set to system, false if not.

     */

    public boolean isPreferPublic() {

        return isPreferPublic;

    }

    /**

     * Attempt to find a matching entry in the catalog by systemId.

     *

     * <p>

     * The method searches through the system-type entries, including system,

     * rewriteSystem, systemSuffix, delegateSystem, and group entries in the

     * current catalog in order to find a match.

     *

     *

     * @param systemId The system identifier of the external entity being

     * referenced.

     *

     * @return An URI string if a mapping is found, or null otherwise.

     */

    public String matchSystem(String systemId) {

        String match = null;

        for (BaseEntry entry : entries) {

            switch (entry.type) {

                case SYSTEM:

                    match = ((SystemEntry) entry).match(systemId);

                    //if there's a matching system entry, use it

                    if (match != null) {

                        isInstantMatch = true;

                        return match;

                    }

                    break;

                case REWRITESYSTEM:

                    match = ((RewriteSystem) entry).match(systemId, longestRewriteMatch);

                    if (match != null) {

                        rewriteMatch = match;

                        longestRewriteMatch = ((RewriteSystem) entry).getSystemIdStartString().length();

                    }

                    break;

                case SYSTEMSUFFIX:

                    match = ((SystemSuffix) entry).match(systemId, longestSuffixMatch);

                    if (match != null) {

                        suffixMatch = match;

                        longestSuffixMatch = ((SystemSuffix) entry).getSystemIdSuffix().length();

                    }

                    break;

                case GROUP:

                    GroupEntry grpEntry = (GroupEntry) entry;

                    match = grpEntry.matchSystem(systemId);

                    if (grpEntry.isInstantMatch) {

                        //use it if there is a match of the system type

                        return match;

                    } else if (grpEntry.longestRewriteMatch > longestRewriteMatch) {

                        rewriteMatch = match;

                    } else if (grpEntry.longestSuffixMatch > longestSuffixMatch) {

                        suffixMatch = match;

                    }

                    break;

            }

        }

        if (longestRewriteMatch > 0) {

            return rewriteMatch;

        } else if (longestSuffixMatch > 0) {

            return suffixMatch;

        }

        //if no single match is found, try delegates

        return matchDelegate(CatalogEntryType.DELEGATESYSTEM, systemId);

    }

    /**

     * Attempt to find a matching entry in the catalog by publicId.

     *

     * <p>

     * The method searches through the public-type entries, including public,

     * delegatePublic, and group entries in the current catalog in order to find

     * a match.

     *

     *

     * @param publicId The public identifier of the external entity being

     * referenced.

     *

     * @return An URI string if a mapping is found, or null otherwise.

     */

    public String matchPublic(String publicId) {

        //as the specification required

        if (!isPreferPublic) {

            return null;

        }

        //match public entries

        String match = null;

        for (BaseEntry entry : entries) {

            switch (entry.type) {

                case PUBLIC:

                    match = ((PublicEntry) entry).match(publicId);

                    break;

                case GROUP:

                    match = ((GroupEntry) entry).matchPublic(publicId);

                    break;

            }

            if (match != null) {

                return match;

            }

        }

        //if no single match is found, try delegates

        return matchDelegate(CatalogEntryType.DELEGATEPUBLIC, publicId);

    }

    /**

     * Attempt to find a matching entry in the catalog by the uri element.

     *

     * <p>

     * The method searches through the uri-type entries, including uri,

     * rewriteURI, uriSuffix, delegateURI and group entries in the current

     * catalog in order to find a match.

     *

     *

     * @param uri The URI reference of a resource.

     *

     * @return An URI string if a mapping is found, or null otherwise.

     */

    public String matchURI(String uri) {

        String match = null;

        for (BaseEntry entry : entries) {

            switch (entry.type) {

                case URI:

                    match = ((UriEntry) entry).match(uri);

                    if (match != null) {

                        isInstantMatch = true;

                        return match;

                    }

                    break;

                case REWRITEURI:

                    match = ((RewriteUri) entry).match(uri, longestRewriteMatch);

                    if (match != null) {

                        rewriteMatch = match;

                        longestRewriteMatch = ((RewriteUri) entry).getURIStartString().length();

                    }

                    break;

                case URISUFFIX:

                    match = ((UriSuffix) entry).match(uri, longestSuffixMatch);

                    if (match != null) {

                        suffixMatch = match;

                        longestSuffixMatch = ((UriSuffix) entry).getURISuffix().length();

                    }

                    break;

                case GROUP:

                    GroupEntry grpEntry = (GroupEntry) entry;

                    match = grpEntry.matchURI(uri);

                    if (grpEntry.isInstantMatch) {

                        //use it if there is a match of the uri type

                        return match;

                    } else if (grpEntry.longestRewriteMatch > longestRewriteMatch) {

                        rewriteMatch = match;

                    } else if (grpEntry.longestSuffixMatch > longestSuffixMatch) {

                        suffixMatch = match;

                    }

                    break;

            }

        }

        if (longestRewriteMatch > 0) {

            return rewriteMatch;

        } else if (longestSuffixMatch > 0) {

            return suffixMatch;

        }

        //if no single match is found, try delegates

        return matchDelegate(CatalogEntryType.DELEGATEURI, uri);

    }

    /**

     * Matches delegatePublic or delegateSystem against the specified id

     *

     * @param isSystem The flag to indicate whether the delegate is system or

     * public

     * @param id The system or public id to be matched

     * @return The URI string if a mapping is found, or null otherwise.

     */

    private String matchDelegate(CatalogEntryType type, String id) {

        String match = null;

        int longestMatch = 0;

        URI catalogId = null;

        URI temp;

        //Check delegate types in the current catalog

        for (BaseEntry entry : entries) {

            if (entry.type == type) {

                if (type == CatalogEntryType.DELEGATESYSTEM) {

                    temp = ((DelegateSystem)entry).matchURI(id, longestMatch);

                } else if (type == CatalogEntryType.DELEGATEPUBLIC) {

                    temp = ((DelegatePublic)entry).matchURI(id, longestMatch);

                } else {

                    temp = ((DelegateUri)entry).matchURI(id, longestMatch);

                }

                if (temp != null) {

                    longestMatch = entry.getMatchId().length();

                    catalogId = temp;

                }

            }

        }

        //Check delegate Catalogs

        if (catalogId != null) {

            Catalog delegateCatalog = loadCatalog(catalogId);

            if (delegateCatalog != null) {

                if (type == CatalogEntryType.DELEGATESYSTEM) {

                    match = delegateCatalog.matchSystem(id);

                } else if (type == CatalogEntryType.DELEGATEPUBLIC) {

                    match = delegateCatalog.matchPublic(id);

                } else {

                    match = delegateCatalog.matchURI(id);

                }

            }

        }

        return match;

    }

    /**

     * Loads all delegate catalogs.

     */

    void loadDelegateCatalogs() {

        entries.stream()

                .filter((entry) -> (entry.type == CatalogEntryType.DELEGATESYSTEM ||

                        entry.type == CatalogEntryType.DELEGATEPUBLIC ||

                        entry.type == CatalogEntryType.DELEGATEURI))

                .map((entry) -> (AltCatalog)entry)

                .forEach((altCatalog) -> {

                        loadCatalog(altCatalog.getCatalogURI());

        });

    }

    /**

     * Loads a delegate catalog by the catalogId specified.

     * @param catalogId the catalog Id

     */

    Catalog loadCatalog(URI catalogURI) {

        Catalog delegateCatalog = null;

        if (catalogURI != null) {

            String catalogId = catalogURI.toASCIIString();

            delegateCatalog = getLoadedCatalog(catalogId);

            if (delegateCatalog == null) {

                if (verifyCatalogFile(catalogURI)) {

                    delegateCatalog = new CatalogImpl(catalog, features, catalogId);

                    delegateCatalogs.put(catalogId, delegateCatalog);

                }

            }

        }

        return delegateCatalog;

    }

    /**

     * Returns a previously loaded Catalog object if found.

     *

     * @param catalogId The systemId of a catalog

     * @return a Catalog object previously loaded, or null if none in the saved

     * list

     */

    Catalog getLoadedCatalog(String catalogId) {

        Catalog c = null;

        //checl delegate Catalogs

        c = delegateCatalogs.get(catalogId);

        if (c == null) {

            //check other loaded Catalogs

            c = loadedCatalogs.get(catalogId);

        }

        return c;

    }

    /**

     * Verifies that the catalog file represented by the catalogId exists. If it

     * doesn't, returns false to ignore it as specified in the Catalog

     * specification, section 8. Resource Failures.

     * <p>

     * Verifies that the catalog represented by the catalogId has not been

     * searched or is not circularly referenced.

     *

     * @param catalogId The URI to a catalog

     * @throws CatalogException if circular reference is found.

     * @return true if the catalogId passed verification, false otherwise

     */

    final boolean verifyCatalogFile(URI catalogURI) {

        if (catalogURI == null) {

            return false;

        }

        //Ignore it if it doesn't exist

        if (!Files.exists(Paths.get(catalogURI))) {

            return false;

        }

        String catalogId = catalogURI.toASCIIString();

        if (catalogsSearched.contains(catalogId)) {

            CatalogMessages.reportRunTimeError(CatalogMessages.ERR_CIRCULAR_REFERENCE,

                    new Object[]{CatalogMessages.sanitize(catalogId)});

        }

        return true;

    }

}