/*
 *                    BioJava development code
 *
 * This code may be freely distributed and modified under the
 * terms of the GNU Lesser General Public Licence.  This should
 * be distributed with the code.  If you do not have a copy,
 * see:
 *
 *      http://www.gnu.org/copyleft/lesser.html
 *
 * Copyright for this code is held jointly by the individual
 * authors.  These should be listed in @author doc comments.
 *
 * For more information on the BioJava project and its aims,
 * or to join the biojava-l mailing list, visit the home page
 * at:
 *
 *      http://www.biojava.org/
 *
 */
package org.biojava.nbio.structure.align.client;


import java.io.File;
import java.io.IOException;
import java.io.Serializable;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.biojava.nbio.structure.BioAssemblyIdentifier;
import org.biojava.nbio.structure.ResidueRange;
import org.biojava.nbio.structure.Structure;
import org.biojava.nbio.structure.StructureException;
import org.biojava.nbio.structure.StructureIdentifier;
import org.biojava.nbio.structure.SubstructureIdentifier;
import org.biojava.nbio.structure.URLIdentifier;
import org.biojava.nbio.structure.align.util.AtomCache;
import org.biojava.nbio.structure.cath.CathDomain;
import org.biojava.nbio.structure.cath.CathFactory;
import org.biojava.nbio.structure.domain.PDPDomain;
import org.biojava.nbio.structure.domain.PDPProvider;
import org.biojava.nbio.structure.domain.RemotePDPProvider;
import org.biojava.nbio.structure.ecod.EcodFactory;
import org.biojava.nbio.structure.io.util.FileDownloadUtils;
import org.biojava.nbio.structure.scop.ScopDatabase;
import org.biojava.nbio.structure.scop.ScopDomain;
import org.biojava.nbio.structure.scop.ScopFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * A utility class that makes working with names of structures, domains and ranges easier.
 *
 * Accepts a wide range of identifier formats, including {@link ScopDomain},
 * {@link CathDomain}, PDP domains, and {@link SubstructureIdentifier} residue
 * ranges.
 *
 * Where possible, data is extracted from the input string. Otherwise, range
 * information may be loaded from one of the factory classes:
 * {@link CathFactory},{@link ScopFactory}, etc.
 *
 * @see #getName the name. e.g. 4hhb, 4hhb.A, d4hhba_, PDP:4HHBAa etc.
 */

public class StructureName implements Comparable<StructureName>, Serializable, StructureIdentifier {
        private static final long serialVersionUID = 4021229518711762957L;
        private static final Logger logger = LoggerFactory.getLogger(StructureName.class);

        protected String name;
        protected String pdbId;
        protected String chainId;

        private static final Pattern cathPattern = Pattern.compile("^(?:CATH:)?([0-9][a-z0-9]{3})(\\w)([0-9]{2})$",Pattern.CASE_INSENSITIVE);
        // ds046__ is a special case with no PDB entry
        private static final Pattern scopPattern = Pattern.compile("^(?:SCOP:)?d([0-9][a-z0-9]{3}|s046)(\\w|\\.)(\\w)$",Pattern.CASE_INSENSITIVE);
        // ECOD chains and domains can't be automatically distinguished. Ex: e3j9zS13 is chain 'S1', e1wz2B14 is chain 'B'
        private static final Pattern ecodPattern = Pattern.compile("^(?:ECOD:)?e([0-9][a-z0-9]{3})(?:\\w|\\.)\\w+$",Pattern.CASE_INSENSITIVE);

        // Names are automatically used as prefixes
        public enum Source {
                PDB,
                SCOP,
                PDP,
                CATH,
                URL,
                FILE,
                ECOD,
                BIO,
        };

        private Source mySource = null;

        // cache for getBaseIdentifier() method
        private StructureIdentifier base = null;

        /**
         * Create a new StructureName from the given identifier, which may be a
         * domain name, a substructure identifier, etc.
         * <p>
         * The source and PDB-Id are extracted at compile time, but fully
         * interpreting the ID, which may require additional parsing or remote
         * calls, is done lazily.
         * <p>
         * The following sources are supported. Any may be prefixed by the source
         * name followed by a colon (e.g. PDB:4HHB). In this case, that source will be used
         * unequivocally. If no source is specified, StructureName will make a
         * (usually reliable) guess as to which source was intended.
         * <ul>
         * <li><b>PDB</b>PDB identifier, optionally followed by chain and/or residue
         *     ranges. Internally represented by a {@link SubstructureIdentifier};
         *     see that class for the full format specification.
         *     Examples: 4hhb, 4hhb.A, 4hhb.A:1-50.
         * <li><b>SCOP</b> SCOP domain (or SCOPe, depending on the
         *     {@link ScopFactory#getSCOP()} version). Example: d1h6w.2
         * <li><b>PDP</b> Protein Domain Parser domain. PDP domains are not guessed,
         *     making the PDP: prefix obligatory. Example: PDP:4HHBAa
         * <li><b>CATH</b> Cath domains. Example: 1qvrC03
         * <li><b>URL</b> Arbitrary URLs. Most common protocols are handled,
         *     including http://, ftp://, and file://. Some parsing information can
         *     be passed as custom query parameters. Example:
         *     http://www.rcsb.org/pdb/files/1B8G.pdb.gz
         * <li><b>FILE</b> A file path. Supports relative paths and expands ~ to
         *     the user's home directory. Only existing files will be automatically
         *     detected; to refer to a potentially not-yet existing file, prepend
         *     the prefix. Internally represented as a {@link URLIdentifier}
         *     after path expansion. Example: ~/custom_protein.pdb
         * <li><b>ECOD</b> ECOD domain. Example: e1lyw.1
         * <li><b>BIO</b> Biological assembly. These are not guessed, making
         *     the BIO: prefix obligatory. Example: BIO:2ehz:1
         * </ul>
         * @param name An identifier string
         * @throws IllegalArgumentException if the name has a recognizable source but is semantically invalid
         */
        public StructureName(String name){
                this.name = name;

                init();//sets pdbId and mySource
        }


        /**
         * Tries to determine the source and pdbId without fully realizing the identifier,
         * which could require I/O depending on the source
         * @throws IllegalArgumentException if the source is recognizable but invalid
         */
        private void init(){

                // First try identifying a prefix
                String[] prefix = name.split(":", 2);
                mySource = null;
                if(prefix.length > 1) {
                        // Match Source prefixes
                        String suffix = prefix[1];
                        try {
                                mySource = Source.valueOf(prefix[0].toUpperCase());
                        } catch( IllegalArgumentException e ) {
                                // unrecognized prefix; fall back on guessing
                                mySource = null;
                        }
                        if(mySource != null) {
                                switch( mySource) {
                                case SCOP:
                                        if( ! initFromScop(suffix) )
                                                throw new IllegalArgumentException("Malformed SCOP domain name:"+suffix);
                                        return;
                                case PDP:
                                        if( ! initFromPDP(name) )
                                                throw new IllegalArgumentException("Malformed PDP domain name:"+suffix);
                                        return;
                                case CATH:
                                        if( ! initFromCATH(suffix) )
                                                throw new IllegalArgumentException("Malformed CATH domain name:"+suffix);
                                        return;
                                case BIO:
                                        if( ! initFromBIO(name) )
                                                throw new IllegalArgumentException("Malformed BIO name:"+suffix);
                                        return;
                                case ECOD:
                                        if( ! initFromECOD(suffix) )
                                                throw new IllegalArgumentException("Malformed ECOD domain name:"+suffix);
                                        return;
                                case PDB:
                                        if( ! initFromPDB(suffix) )
                                                throw new IllegalArgumentException("Malformed PDB specification:"+suffix);
                                        return;
                                case FILE:
                                        // Treat file:/ prefixes as URLs
                                        if( ! suffix.startsWith("/")) {
                                                // Otherwise, treat as file
                                                initFromFile();
                                                return;
                                        }
                                        // fall through to URL case
                                case URL:
                                        if( ! initFromURL(name))
                                                throw new IllegalArgumentException("Malformed URL specification:"+suffix);
                                        return;
                                default:
                                        throw new IllegalStateException("Unimplemented Source "+mySource);
                                }
                        }
                }

                // No known prefix, so revert to guessing

                // First guess regex-based identifiers
                // SCOP domain
                if( initFromScop(name) )
                        return;
                // CATH
                if( initFromCATH(name) )
                        return;
                // ECOD
                if( initFromECOD(name) )
                        return;
                // Never guess BIO or PDP

                // URL
                if( initFromURL(name) )
                        return;

                // Guess FILE based on file existence
                File file = new File(FileDownloadUtils.expandUserHome(name));
                if( file.canRead() && !file.isDirectory() ) {
                        // an attempt to mitigate issue #398. It doesn't fix it but it catches the most common case of passing a pdb id and finding a file in working dir matching it
                        if (name.matches("\\d\\w\\w\\w")) {
                                // the plain pdb id case, this is unlikely to be what the user wants: let's let it through but warn about it
                                logger.warn("Provided 4-letter structure name '{}' matches "
                                                + "file name in directory {}. Will read structure "
                                                + "data from file {} and not consider the name as a "
                                                + "structure identifier. If this is not what you "
                                                + "want, use 'FILE:{}'",
                                                name, file.getAbsoluteFile().getParent(),
                                                file.getAbsolutePath(), name);
                        } else {
                                logger.info("Provided structure name '{}' matches "
                                                + "file name in directory {}. Will read structure "
                                                + "data from file {}.",
                                                name, file.getAbsoluteFile().getParent(),
                                                file.getAbsolutePath());
                        }

                        initFromFile();
                        return;
                }

                // Default to PDB
                initFromPDB( name );
        }

        private boolean initFromScop(String name) {
                Matcher matcher = scopPattern.matcher(name);
                if ( matcher.matches() ) {
                        mySource = Source.SCOP;
                        pdbId = matcher.group(1).toUpperCase();
                        chainId = matcher.group(2);
                        return true;
                }
                return false;
        }
        private boolean initFromPDP(String name) {
                Matcher matcher = PDPDomain.PDP_NAME_PATTERN.matcher(name);
                if( matcher.matches() ) {
                        pdbId = matcher.group(1).toUpperCase();
                        chainId = matcher.group(2);
                        return true;
                }
                return false;
        }
        private boolean initFromCATH(String name) {
                Matcher matcher = cathPattern.matcher(name);
                if ( matcher.matches() ){
                        mySource = Source.CATH;
                        pdbId = matcher.group(1).toUpperCase();
                        chainId = matcher.group(2);
                        return true;
                }
                return false;
        }
        private boolean initFromECOD(String name) {
                Matcher matcher = ecodPattern.matcher(name);
                if ( matcher.matches() ){
                        mySource = Source.ECOD;
                        pdbId = matcher.group(1).toUpperCase();
                        chainId = null;
                        return true;
                }
                return false;
        }
        private boolean initFromBIO(String name) {
                Matcher matcher = BioAssemblyIdentifier.BIO_NAME_PATTERN.matcher(name);
                if( matcher.matches() ) {
                        pdbId = matcher.group(1).toUpperCase();
                        return true;
                }
                return false;
        }
        private boolean initFromPDB(String suffix) {
                mySource = Source.PDB;
                SubstructureIdentifier si = new SubstructureIdentifier(suffix);
                base = si; // Safe to realize immediately

                pdbId = si.getPdbId();
                // Set chainId if unique
                Set<String> chains = getChainIds(si);
                if(chains.size() == 1) {
                        this.chainId = chains.iterator().next();
                } else if(chains.size() > 1) {
                        this.chainId = ".";
                } else {
                        this.chainId = null;
                }
                return true;
        }
        private boolean initFromURL(String suffix) {
                try {
                        URL url = new URL(suffix);
                        String path = url.getPath();
                        mySource = Source.URL;
                        pdbId = URLIdentifier.guessPDBID( path.substring(path.lastIndexOf('/')+1) );
                        chainId = null; // Don't bother checking query params here
                        return true;
                } catch(MalformedURLException e) {
                        return false;
                }
        }
        private boolean initFromFile() {
                mySource = Source.FILE;
                pdbId = null;
                chainId = null;
                return true;
        }

        private static Set<String> getChainIds(SubstructureIdentifier si) {
                Set<String> chains = new TreeSet<String>();
                List<ResidueRange> ranges = si.getResidueRanges();
                for(ResidueRange range : ranges) {
                        String chain = range.getChainId();
                        if(chain != null) {
                                chains.add(chain);
                        }
                }
                return chains;
        }

        /**
         * Get the PDB ID for this name, if any.
         *
         * Equivalent to {@link SubstructureIdentifier#getPdbId()
         * toCanonical().getPdbId()}
         * @return The upper-case PDB Name, or null if not applicable
         * @throws StructureException Wraps errors which occur when converting to canonical form
         */
        public String getPdbId() throws StructureException {
                if( pdbId == null) {
                        pdbId = toCanonical().getPdbId();
                }
                return pdbId;
        }

        /**
         * Gets the chain ID, for structures where it is unique and well-defined.
         * May return '.' for multi-chain ranges, '_' for wildcard chains, or
         * null if the information is unavailable.
         *
         * <p>This method should only be used casually. For precise chainIds, it
         * is better to use {@link #toCanonical()} and iterate through the
         * residue ranges.
         * @return
         */
        public String getChainId() {
                return chainId;
        }
        /**
         *
         * @return the identifier string
         * @deprecated use {@link #getIdentifier()}
         */
        @Deprecated
        public String getName(){

                return getIdentifier();
        }

        /**
         * Get the original form of the identifier
         */
        @Override
        public String getIdentifier() {
                return name;
        }

        @Override
        public String toString(){

                return name;
        }


        public boolean isScopName() {
                return mySource == Source.SCOP;
        }

        public boolean isPDPDomain(){
                return mySource == Source.PDP;
        }

        public boolean isCathID(){
                return mySource == Source.CATH;
        }

        public boolean isPdbId(){
                return mySource == Source.PDB;
        }

        public boolean isURL() {
                return mySource == Source.URL;
        }

        /**
         * Indicates that the identifier was determined to correspond to a file.
         * Note that some file identifiers may also be valid URLs; in that case,
         * the URL source is preferred.
         * @return
         */
        public boolean isFile() {
                return mySource == Source.FILE;
        }

        public boolean isEcodDomain() {
                return mySource == Source.ECOD;
        }

        public boolean isBioAssembly() {
                return mySource == Source.BIO;
        }

        public Source getSource() {
                return mySource;
        }

        /**
         * StructureName wraps another StructureIdentifier. The type of the base
         * identifier depends on the {@link #getSource() source}. Most StructureName
         * methods deligate to the base identifier.
         *
         * <p>It is possible that future versions of StructureName might change the
         * return type. Except for some specialized uses, it is probably better
         * to create the correct type of identifier directly, rather than creating
         * a StructureName and casting the result of this method.
         * @return A Str
         * @throws StructureException Wraps exceptions that may be thrown by
         *  individual implementations. For example, a SCOP identifier may require
         *  that the domain definitions be available for download.
         */
        public StructureIdentifier getBaseIdentifier() throws StructureException {
                if( base == null ) {

                        switch(mySource) {
                        case CATH:
                                base = CathFactory.getCathDatabase().getDescriptionByCathId(getIdentifier());
                                break;
                        case ECOD:
                                try {
                                        base = EcodFactory.getEcodDatabase().getDomainsById(name);
                                } catch (IOException e) {
                                        throw new StructureException("Unable to get ECOD domain "+name,e);
                                }
                                break;
                        case SCOP:
                                // Fuzzy matching of the domain name to the current default factory
                                base = guessScopDomain(getIdentifier(),ScopFactory.getSCOP());
                                if(base == null) {
                                        // Guessing didn't work, so just use the PDBID and Chain from name
                                        // Guess that '_' means 'whole structure'
                                        if (chainId.equals("_")) {
                                                base = new SubstructureIdentifier(pdbId);
                                        } else {
                                                base = new SubstructureIdentifier(pdbId,ResidueRange.parseMultiple(chainId));
                                        }
                                        logger.error("Unable to find {}, so using {}",name,base);
                                }
                                break;
                        case FILE:
                                try {
                                        String[] prefix = name.split(":", 2);
                                        String filename;
                                        if(prefix.length > 1) {
                                                filename = prefix[1];
                                        } else {
                                                filename = name;
                                        }
                                        filename = FileDownloadUtils.expandUserHome(filename);
                                        base = new URLIdentifier(new File(filename).toURI().toURL());
                                } catch (MalformedURLException e) {
                                        // Should never happen
                                        throw new StructureException("Unable to get URL for file: "+name,e);
                                }
                                break;
                        case URL:
                                try {
                                        base = new URLIdentifier(name);
                                } catch (MalformedURLException e) {
                                        throw new StructureException("Invalid URL: "+name,e);
                                }
                                break;
                        case PDP:
                                try {
                                        PDPProvider provider = new RemotePDPProvider(false);
                                        base = provider.getPDPDomain(name);
                                } catch (IOException e) {
                                        throw new StructureException("Unable to fetch PDP domain "+name, e);
                                }
                                break;
                        case BIO:
                                base = new BioAssemblyIdentifier(name);
                                break;
                        case PDB:
                                base = new SubstructureIdentifier(getIdentifier());
                                break;
                        default:
                                throw new IllegalStateException("Unimplemented source: "+mySource);
                        }
                }
                return base;
        }

        @Override
        public SubstructureIdentifier toCanonical() throws StructureException {
                return getBaseIdentifier().toCanonical();
        }

        @Override
        public Structure reduce(Structure input) throws StructureException {
                return getBaseIdentifier().reduce(input);
        }

        @Override
        public Structure loadStructure(AtomCache cache) throws StructureException,
        IOException {
                return getBaseIdentifier().loadStructure(cache);
        }

        @Override
        public int hashCode() {
                final int prime = 31;
                int result = 1;
                result = prime * result + ((name == null) ? 0 : name.hashCode());
                return result;
        }

        @Override
        public boolean equals(Object obj) {
                if (this == obj)
                        return true;
                if (obj == null)
                        return false;
                if (getClass() != obj.getClass())
                        return false;
                StructureName other = (StructureName) obj;
                if (name == null) {
                        if (other.name != null)
                                return false;
                } else if (!name.equals(other.name))
                        return false;
                return true;
        }

        /**
         * Orders identifiers lexicographically by PDB ID and then full Identifier
         */
        @Override
        public int compareTo(StructureName o) {
                if ( this.equals(o))
                        return 0;

                String pdb1 = null;
                String pdb2 = null;
                try {
                        pdb1 = this.getPdbId();
                } catch (StructureException e) {}
                try {
                        pdb2 = this.getPdbId();
                } catch (StructureException e) {}

                int comp = 0;

                // Sort those with PDBIDs before those without
                if( pdb1 == null ) {
                        if( pdb2 != null) {
                                return 1; // this > o
                        }
                        // both null
                } else if( pdb2 == null){
                        return -1; // this < o
                } else {
                        // neither null
                        comp = pdb1.compareTo(pdb2);
                }
                if( comp != 0 ) {
                        return comp;
                }

                // break tie with full identifiers
                pdb1 = this.getIdentifier();
                pdb2 = o.getIdentifier();

                // Throws NPE for nulls
                return pdb1.compareTo(pdb2);
        }

        /**
         * <p>
         * Guess a scop domain. If an exact match is found, return that.
         *
         * <p>
         * Otherwise, return the first scop domain found for the specified protein such that
         * <ul>
         * <li>The chains match, or one of the chains is '_' or '.'.
         * <li>The domains match, or one of the domains is '_'.
         * </ul>
         *
         * In some cases there may be several valid matches. In this case a warning
         * will be logged.
         *
         * @param name SCOP domain name, or a guess thereof
         * @param scopDB SCOP domain provider
         * @return The best match for name among the domains of scopDB, or null if none match.
         */
        public static ScopDomain guessScopDomain(String name, ScopDatabase scopDB) {
                List<ScopDomain> matches = new LinkedList<ScopDomain>();

                // Try exact match first
                ScopDomain domain = scopDB.getDomainByScopID(name);
                if (domain != null) {
                        return domain;
                }

                // Didn't work. Guess it!
                logger.warn("Warning, could not find SCOP domain: " + name);

                Matcher scopMatch = scopPattern.matcher(name);
                if (scopMatch.matches()) {
                        String pdbID = scopMatch.group(1);
                        String chainID = scopMatch.group(2);
                        String domainID = scopMatch.group(3);

                        for (ScopDomain potentialSCOP : scopDB.getDomainsForPDB(pdbID)) {
                                Matcher potMatch = scopPattern.matcher(potentialSCOP.getScopId());
                                if (potMatch.matches()) {
                                        if (chainID.equals(potMatch.group(2)) || chainID.equals("_") || chainID.equals(".")
                                                        || potMatch.group(2).equals("_") || potMatch.group(2).equals(".")) {
                                                if (domainID.equals(potMatch.group(3)) || domainID.equals("_") || potMatch.group(3).equals("_")) {
                                                        // Match, or near match
                                                        matches.add(potentialSCOP);
                                                }
                                        }
                                }
                        }
                }

                Iterator<ScopDomain> match = matches.iterator();
                if (match.hasNext()) {
                        ScopDomain bestMatch = match.next();
                        if(logger.isWarnEnabled()) {
                                StringBuilder warnMsg = new StringBuilder();
                                warnMsg.append("Trying domain " + bestMatch.getScopId() + ".");
                                if (match.hasNext()) {
                                        warnMsg.append(" Other possibilities: ");
                                        while (match.hasNext()) {
                                                warnMsg.append(match.next().getScopId() + " ");
                                        }
                                }
                                warnMsg.append(System.getProperty("line.separator"));
                                logger.warn(warnMsg.toString());
                        }
                        return bestMatch;
                } else {
                        return null;
                }
        }



}