/*
 *                    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.ws.alignment.qblast;

import org.biojava.nbio.core.sequence.io.util.IOUtils;
import org.biojava.nbio.core.sequence.template.Compound;
import org.biojava.nbio.core.sequence.template.Sequence;
import org.biojava.nbio.ws.alignment.RemotePairwiseAlignmentOutputProperties;
import org.biojava.nbio.ws.alignment.RemotePairwiseAlignmentProperties;
import org.biojava.nbio.ws.alignment.RemotePairwiseAlignmentService;

import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;
import java.util.Map;

import static org.biojava.nbio.ws.alignment.qblast.BlastAlignmentParameterEnum.*;
import static org.biojava.nbio.ws.alignment.qblast.BlastOutputParameterEnum.RID;

/**
 * Provides a simple way of submitting BLAST request to the QBlast service at NCBI.
 * <p>
 * NCBI provides a Blast server through a CGI-BIN interface. This service simply encapsulates an access to it by giving
 * users access to get/set methods to fix sequence, program and database as well as advanced options.
 * </p>
 * <p>
 * The philosophy behind this service is to disconnect submission of Blast requests from collection of Blast results.
 * This is done so to allow a user to submit multiple Blast requests while allowing recovery of the reports at a later
 * time.
 * </p>
 * <p>
 * Presently, only blastall programs are accessible.
 * </p>
 *
 * @author Sylvain Foisy, Diploide BioIT
 * @author Gediminas Rimsa
 */
public class NCBIQBlastService implements RemotePairwiseAlignmentService {
        /**
         * Number of milliseconds by which expected job execution time is incremented if it is not finished yet. Subsequent
         * calls to {@link #isReady(String, long)} method will return false until at least this much time passes.
         */
        public static final long WAIT_INCREMENT = 3000;

        private static final MapToStringTransformer MAP_TO_STRING_TRANSFORMER = new MapToStringTransformer();
        private static final String SERVICE_URL = "https://blast.ncbi.nlm.nih.gov/Blast.cgi";
        private static final String DEFAULT_EMAIL = "anonymous@biojava.org";
        private static final String DEFAULT_TOOL = "biojava5";

        private URL serviceUrl;
        private String email = DEFAULT_EMAIL;
        private String tool = DEFAULT_TOOL;

        private Map<String, BlastJob> jobs = new HashMap<String, BlastJob>();

    /** Constructs a service object that targets the public NCBI BLAST network
     * service. 
     */
        public NCBIQBlastService() {
        init(SERVICE_URL);
        }

    /** Constructs a service object which targets a custom NCBI BLAST network
     * service (e.g.: an instance of BLAST in the cloud).
     *
         * @param svcUrl : a {@code String} containing the base URL to send requests to,
     *                 e.g.: http://host.my.cloud.service.provider.com/cgi-bin/blast.cgi
     *
     * @see <a href="https://blast.ncbi.nlm.nih.gov/Blast.cgi?PAGE_TYPE=BlastDocs&DOC_TYPE=CloudBlast">BLAST on the cloud documentation</a>
     */
        public NCBIQBlastService(String svcUrl) {
        init(svcUrl);
        }

    /** Initialize the serviceUrl data member 
     * @throws MalformedURLException on invalid URL
     */
    private void init(String svcUrl) {
                try {
                        serviceUrl = new URL(svcUrl);
                } catch (MalformedURLException e) {
            throw new RuntimeException("It looks like the URL for remote NCBI BLAST service (" 
                                       + svcUrl + ") is wrong. Cause: " + e.getMessage(), e);
                }
    }

        /**
         * A simple method to check the availability of the QBlast service. Sends {@code Info} command to QBlast
         *
         * @return QBlast info output concatenated to String
         * @throws Exception if unable to connect to the NCBI QBlast service
         */
        public String getRemoteBlastInfo() throws Exception {
                OutputStreamWriter writer = null;
                BufferedReader reader = null;
                try {
                        URLConnection serviceConnection = setQBlastServiceProperties(serviceUrl.openConnection());
                        writer = new OutputStreamWriter(serviceConnection.getOutputStream());
                        writer.write("CMD=Info");
                        writer.flush();
                        reader = new BufferedReader(new InputStreamReader(serviceConnection.getInputStream()));
                        StringBuilder sb = new StringBuilder();
                        String line;
                        while ((line = reader.readLine()) != null) {
                                sb.append(line);
                                sb.append(System.getProperty("line.separator"));
                        }
                        return sb.toString();
                } catch (IOException e) {
                        throw new Exception("Impossible to get info from QBlast service at this time. Cause: " + e.getMessage(), e);
                } finally {
                        IOUtils.close(reader);
                        IOUtils.close(writer);
                }
        }

        /**
         * Converts given sequence to String and calls
         * {@link #sendAlignmentRequest(String, RemotePairwiseAlignmentProperties)}
         */
        @Override
        public String sendAlignmentRequest(Sequence<Compound> seq, RemotePairwiseAlignmentProperties rpa) throws Exception {
                return sendAlignmentRequest(seq.getSequenceAsString(), rpa);
        }

        /**
         * Converts given GenBank GID to String and calls
         * {@link #sendAlignmentRequest(String, RemotePairwiseAlignmentProperties)}
         */
        public String sendAlignmentRequest(int gid, RemotePairwiseAlignmentProperties rpa) throws Exception {
                return sendAlignmentRequest(Integer.toString(gid), rpa);
        }

        /**
         * Sends the Blast request via the Put command of the CGI-BIN interface. Uses all of the parameters specified in
         * {@code alignmentProperties} (parameters PROGRAM and DATABASE are required).
         *
         * @param query : a {@code String} representing a sequence or Genbank ID
         * @param alignmentProperties : a {@code RemotePairwiseAlignmentProperties} object representing alignment properties
         * @return the request id for this sequence, necessary to fetch results after completion
         * @throws Exception if unable to connect to the NCBI QBlast service or if no sequence or required parameters
         *             PROGRAM and DATABASE are not set
         */
        @Override
        public String sendAlignmentRequest(String query, RemotePairwiseAlignmentProperties alignmentProperties) throws Exception {
                Map<String, String> params = new HashMap<String, String>();
                for (String key : alignmentProperties.getAlignmentOptions()) {
                        params.put(key, alignmentProperties.getAlignmentOption(key));
                }

                if (query == null || query.isEmpty()) {
                        throw new IllegalArgumentException("Impossible to execute QBlast request. The sequence has not been set.");
                }
                if (!params.containsKey(PROGRAM.name())) {
                        throw new IllegalArgumentException("Impossible to execute QBlast request. Parameter PROGRAM has not been set.");
                }
                if (!params.containsKey(DATABASE.name())) {
                        throw new IllegalArgumentException("Impossible to execute QBlast request. Parameter DATABASE has not been set.");
                }

                params.put(CMD.name(), "Put");
                params.put(QUERY.name(), query);
                params.put(TOOL.name(), getTool());
                params.put(EMAIL.name(), getEmail());

                String putCmd = MAP_TO_STRING_TRANSFORMER.transform(params);

                OutputStreamWriter writer = null;
                BufferedReader reader = null;
                try {
                        URLConnection serviceConnection = setQBlastServiceProperties(serviceUrl.openConnection());
                        writer = new OutputStreamWriter(serviceConnection.getOutputStream());
                        writer.write(putCmd);
                        writer.flush();

                        // Get the response
                        reader = new BufferedReader(new InputStreamReader(serviceConnection.getInputStream()));

                        // find request id and time of execution
                        BlastJob job = new BlastJob();
                        String line;
                        while ((line = reader.readLine()) != null) {
                                if (!line.contains("class=\"error\"") && !line.contains("Message ID#")) {
                                        // if there is no error, capture RID and RTOE
                                        if (line.contains("RID = ")) {
                                                String[] arr = line.split("=");
                                                job.setId(arr[1].trim());
                                        } else if (line.contains("RTOE = ")) {
                                                String[] arr = line.split("=");
                                                job.setStartTimestamp(System.currentTimeMillis());
                                                job.setExpectedExecutionTime(Long.parseLong(arr[1].trim()) * 1000);
                                        }
                                        jobs.put(job.getId(), job);
                                } else {
                                        // handle QBlast error message

                                        // Capture everything to the left of this HTML statement...
                                        String[] tmp = line.split("</p></li></ul>");

                                        // Only the error message is on the right side of this...
                                        String[] moreTmp = tmp[0].split("<p class=\"error\">");
                                        throw new Exception("NCBI QBlast refused this request because: " + moreTmp[1].trim());
                                }

                        }
                        if (job != null && job.getId() != null) {
                                return job.getId();
                        } else {
                                throw new Exception("Unable to retrieve request ID");
                        }
                } catch (IOException e) {
                        throw new IOException("An error occured submiting sequence to BLAST server. Cause: " + e.getMessage(), e);
                } finally {
                        IOUtils.close(reader);
                        IOUtils.close(writer);
                }
        }

        /**
         * Wrapper method for {@link #isReady(String, long)}, omitting unnecessary {@code present} property.
         *
         * @see #isReady(String, long)
         */
        public boolean isReady(String id) throws Exception {
                return isReady(id, 0);
        }

        /**
         * Checks for completion of request.
         * <p/>
         * If expected execution time (RTOE) is available for request, this method will always return false until that time
         * passes. This is done to prevent sending unnecessary requests to the server.
         *
         * @param id : request id, which was returned by {@code sendAlignmentRequest} method
         * @param present : is not used, can be any value
         * @return a boolean value telling if the request has been completed
         */
        @Override
        public boolean isReady(String id, long present) throws Exception {
                BlastJob job = jobs.get(id);
                if (job != null) {
                        long expectedJobFinishTime = job.getStartTimestamp() + job.getExpectedExecutionTime();
                        if (System.currentTimeMillis() < expectedJobFinishTime) {
                                return false;
                        }
                } else {
                        // it might be a valid job from another session
                        job = new BlastJob();
                        job.setId(id);
                        job.setStartTimestamp(System.currentTimeMillis());
                        job.setExpectedExecutionTime(0);
                }

                OutputStreamWriter writer = null;
                BufferedReader reader = null;
                try {
                        String checkRequest = "CMD=Get&RID=" + job.getId() + "&FORMAT_OBJECT=SearchInfo";
                        URLConnection serviceConnection = setQBlastServiceProperties(serviceUrl.openConnection());
                        writer = new OutputStreamWriter(serviceConnection.getOutputStream());
                        writer.write(checkRequest);
                        writer.flush();
                        reader = new BufferedReader(new InputStreamReader(serviceConnection.getInputStream()));

                        String line;
                        while ((line = reader.readLine()) != null) {
                                if (line.contains("READY")) {
                                        jobs.put(job.getId(), job);
                                        return true;
                                } else if (line.contains("WAITING")) {
                                        job.setExpectedExecutionTime(job.getExpectedExecutionTime() + WAIT_INCREMENT);
                                        jobs.put(job.getId(), job);
                                        return false;
                                } else if (line.contains("UNKNOWN")) {
                                        throw new IllegalArgumentException("Unknown request id - no results exist for it. Given id = " + id);
                                }
                        }
                        return false;
                } catch (IOException ioe) {
                        throw new Exception("It is not possible to fetch Blast report from NCBI at this time. Cause: " + ioe.getMessage(), ioe);
                } finally {
                        IOUtils.close(reader);
                        IOUtils.close(writer);
                }
        }

        /**
         * Extracts the actual Blast report for given request id according to options provided in {@code outputProperties}
         * argument.
         * <p/>
         * If the results are not ready yet, sleeps until they are available. If sleeping is not desired, call this method
         * after {@code isReady} returns true
         *
         * @param id : request id, which was returned by {@code sendAlignmentRequest} method
         * @param outputProperties : an object specifying output formatting options
         * @return an {@code InputStream} of results
         * @throws Exception if it is not possible to recover the results
         */
        @Override
        public InputStream getAlignmentResults(String id, RemotePairwiseAlignmentOutputProperties outputProperties) throws Exception {
                Map<String, String> params = new HashMap<String, String>();
                for (String key : outputProperties.getOutputOptions()) {
                        params.put(key, outputProperties.getOutputOption(key));
                }
                OutputStreamWriter writer = null;

                while (!isReady(id)) {
                        Thread.sleep(WAIT_INCREMENT + 100);
                }

                params.put(CMD.name(), "Get");
                params.put(RID.name(), id);
                params.put(TOOL.name(), getTool());
                params.put(EMAIL.name(), getEmail());
                String getCmd = MAP_TO_STRING_TRANSFORMER.transform(params);

                try {
                        URLConnection serviceConnection = setQBlastServiceProperties(serviceUrl.openConnection());
                        writer = new OutputStreamWriter(serviceConnection.getOutputStream());
                        writer.write(getCmd);
                        writer.flush();
                        return serviceConnection.getInputStream();
                } catch (IOException ioe) {
                        throw new Exception("It is not possible to fetch Blast report from NCBI at this time. Cause: " + ioe.getMessage(), ioe);
                } finally {
                        IOUtils.close(writer);
                }
        }

        /**
         * Sends a delete request for given request id. Optional operation, ignores IOExceptions.<br/>
         * Can be used after results of given search are no longer needed to be kept on Blast server
         *
         * @param id request id, as returned by {@code sendAlignmentRequest} method
         */
        public void sendDeleteRequest(String id) {
                OutputStreamWriter writer = null;
                try {
                        String deleteRequest = "CMD=Delete&RID=" + id;
                        URLConnection serviceConnection = setQBlastServiceProperties(serviceUrl.openConnection());
                        writer = new OutputStreamWriter(serviceConnection.getOutputStream());
                        writer.write(deleteRequest);
                        writer.flush();
                } catch (IOException ignore) {
                        // ignore it this is an optional operation
                } finally {
                        IOUtils.close(writer);
                }
        }

        /**
         * Sets properties for given URLConnection
         *
         * @param conn URLConnection to set properties for
         * @return given object after setting properties
         */
        private URLConnection setQBlastServiceProperties(URLConnection conn) {
                conn.setDoOutput(true);
                conn.setUseCaches(false);
                conn.setRequestProperty("User-Agent", "Biojava/NCBIQBlastService");
                conn.setRequestProperty("Connection", "Keep-Alive");
                conn.setRequestProperty("Content-type", "application/x-www-form-urlencoded");
                conn.setRequestProperty("Content-length", "200");
                return conn;
        }

        /**
         * Set the tool identifier for QBlast. Defaults to {@value #DEFAULT_TOOL}
         *
         * @param tool the new identifier
         */
        public void setTool(String tool) {
                this.tool = tool;
        }

        /**
         * Get the tool identifier for QBlast. Defaults to {@value #DEFAULT_TOOL}
         *
         * @return the identifier
         */
        public String getTool() {
                return this.tool;
        }

        /**
         * Set the email for QBlast. Defaults to {@value #DEFAULT_EMAIL}
         *
         * @param email the new email
         */
        public void setEmail(String email) {
                this.email = email;
        }

        /**
         * Get the email for QBlast. Defaults to {@value #DEFAULT_EMAIL}.
         *
         * @return the email
         */
        public String getEmail() {
                return this.email;
        }
}