// WorkTables.java
// (C) 2010 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 04.02.2010 on http://yacy.net
//
// This is a part of YaCy, a peer-to-peer based web search engine
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// LICENSE
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program 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 for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

package net.yacy.data;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.TreeMap;

import org.apache.http.Header;
import org.apache.http.HttpStatus;
import org.apache.http.entity.mime.content.ContentBody;

import net.yacy.cora.date.GenericFormatter;
import net.yacy.cora.document.encoding.ASCII;
import net.yacy.cora.document.encoding.UTF8;
import net.yacy.cora.document.id.DigestURL;
import net.yacy.cora.document.id.MultiProtocolURL;
import net.yacy.cora.order.Base64Order;
import net.yacy.cora.protocol.ClientIdentification;
import net.yacy.cora.protocol.HeaderFramework;
import net.yacy.cora.protocol.http.HTTPClient;
import net.yacy.cora.storage.HandleSet;
import net.yacy.cora.util.ConcurrentLog;
import net.yacy.cora.util.SpaceExceededException;
import net.yacy.kelondro.blob.Tables;
import net.yacy.kelondro.data.word.WordReference;
import net.yacy.kelondro.rwi.IndexCell;
import net.yacy.search.Switchboard;
import net.yacy.server.serverObjects;

public class WorkTables extends Tables {

    public final static String TABLE_API_NAME = "api";
    public final static String TABLE_API_TYPE_STEERING = "steering";
    public final static String TABLE_API_TYPE_CONFIGURATION = "configuration";
    public final static String TABLE_API_TYPE_CRAWLER = "crawler";
    public final static String TABLE_API_TYPE_DELETION = "deletion";
    public final static String TABLE_API_TYPE_DUMP = "dump";

    public final static String TABLE_API_COL_TYPE = "type";
    public final static String TABLE_API_COL_COMMENT = "comment";
    public final static String TABLE_API_COL_DATE_RECORDING = "date_recording"; // if not present default to old date field
    public final static String TABLE_API_COL_DATE_LAST_EXEC = "date_last_exec"; // if not present default to old date field
    public final static String TABLE_API_COL_DATE_NEXT_EXEC = "date_next_exec"; // if not present default to zero
    public final static String TABLE_API_COL_DATE = "date"; // old date; do not set in new records
    public final static String TABLE_API_COL_URL = "url";
    public final static String TABLE_API_COL_APICALL_PK = "apicall_pk"; // the primary key for the table entry of that api call (not really a database field, only a name in the apicall)
    public final static String TABLE_API_COL_APICALL_COUNT = "apicall_count"; // counts how often the API was called (starts with 1)
    public final static String TABLE_API_COL_APICALL_SCHEDULE_TIME = "apicall_schedule_time"; // factor for SCHEULE_UNIT time units
    public final static String TABLE_API_COL_APICALL_SCHEDULE_UNIT = "apicall_schedule_unit"; // may be 'minutes', 'hours', 'days'
    public final static String TABLE_API_COL_APICALL_EVENT_KIND = "apicall_event_kind"; //
    public final static String TABLE_API_COL_APICALL_EVENT_ACTION = "apicall_event_action"; //

    public final static String TABLE_ROBOTS_NAME = "robots";

    public final static String TABLE_ACTIVECRAWLS_NAME = "crawljobsActive";
    public final static String TABLE_PASSIVECRAWLS_NAME = "crawljobsPassive";


    public WorkTables(final File workPath) {
        super(workPath, 12);
    }

    /**
     *
     * @param post the api call eventual request parameters.
     * @param servletName the name of the servlet. Must not be null.
     * @return the API URL to be recorded, formatted to include request parameters as URL query parameters
     */
    public static String generateRecordedURL(final serverObjects post, final String servletName) {
        /* Before API URL serialization, we set any eventual transaction token value to empty :
         * this will later help identify a new valid transaction token will be necessary,
         * but prevents revealing it in the URL displayed in the process scheduler and prevents storing an outdated value */
        final String transactionToken;
        if(post != null) {
            transactionToken = post.get(TransactionManager.TRANSACTION_TOKEN_PARAM, "");
        } else {
            transactionToken = null;
        }
        if(transactionToken != null && post != null) {
            post.put(TransactionManager.TRANSACTION_TOKEN_PARAM, "");
        }

        // generate the apicall url - without the apicall attributes
        StringBuilder apiurl = new StringBuilder("/").append(servletName);
        if(post != null) {
            apiurl.append("?").append(post.toString());
        }

        /* Now restore the eventual transaction token to prevent side effects on the post object eventually still used by the caller */
        if(post != null) {
            if(transactionToken != null) {
                post.put(TransactionManager.TRANSACTION_TOKEN_PARAM, transactionToken);
            } else {
                post.remove(TransactionManager.TRANSACTION_TOKEN_PARAM);
            }
        }

        return apiurl.toString();
    }

    /**
     * @param servletName the servlet name used to identify the API when the call is recorded.
     * @param post Servlet request parameters. Must not be null.
     * @param sb the {@link Switchboard} instance. Must not be null.
     * @return the most recently recorded call to the given API with the same parameters, or null when no one was found or data is not accessible
     */
    public static Row selectLastExecutedApiCall(final String servletName, final serverObjects post, final Switchboard sb) {
        Row lastRecordedCall = null;
        if (servletName != null && sb != null && sb.tables != null) {
            try {
                if (post != null && post.containsKey(WorkTables.TABLE_API_COL_APICALL_PK)) {
                    /*
                     * Search the table on the primary key when when present (re-execution of a
                     * recorded call)
                     */
                    lastRecordedCall = sb.tables.select(WorkTables.TABLE_API_NAME, post.getBytes(WorkTables.TABLE_API_COL_APICALL_PK));
                } else {
                    /* Else search the table on the API URL as recorded (including parameters) */
                    final String apiURL = WorkTables.generateRecordedURL(post, servletName);
                    final Iterator<Row> rowsIt = sb.tables.iterator(WorkTables.TABLE_API_NAME,
                            WorkTables.TABLE_API_COL_URL, UTF8.getBytes(apiURL));
                    while (rowsIt.hasNext()) {
                        final Row currentRow = rowsIt.next();
                        if (currentRow != null) {
                            final Date currentLastExec = currentRow.get(WorkTables.TABLE_API_COL_DATE_LAST_EXEC,
                                    (Date) null);
                            if (currentLastExec != null) {
                                if (lastRecordedCall == null) {
                                    /*
                                     * Do not break now the loop : we are looking for the most recent API call on
                                     * the same URL
                                     */
                                    lastRecordedCall = currentRow;
                                } else if (lastRecordedCall.get(WorkTables.TABLE_API_COL_DATE_LAST_EXEC, (Date) null)
                                        .before(currentLastExec)) {
                                    lastRecordedCall = currentRow;
                                }
                            }
                        }
                    }
                }

            } catch (final IOException e) {
                ConcurrentLog.logException(e);
            } catch (final SpaceExceededException e) {
                ConcurrentLog.logException(e);
            }
        }
        return lastRecordedCall;
    }

    /**
     * recording of a api call. stores the call parameters into the API database table
     * @param post the post arguments of the api call. Must not be null.
     * @param servletName the name of the servlet
     * @param type name of the servlet category
     * @param comment visual description of the process
     * @return the pk of the new entry in the api table
     */
    public byte[] recordAPICall(final serverObjects post, final String servletName, final String type, final String comment) {
        // remove the apicall attributes from the post object
        String[] pks = post.remove(TABLE_API_COL_APICALL_PK);

        byte[] pk = pks == null || pks.length == 0 ? null : UTF8.getBytes(pks[0]);

        // generate the apicall url - without the apicall attributes
        final String apiurl = generateRecordedURL(post, servletName);

        // read old entry from the apicall table (if exists)
        Row row = null;
        try {
            row = (pk == null) ? null : super.select(TABLE_API_NAME, pk);
        } catch (final IOException e) {
            ConcurrentLog.logException(e);
        } catch (final SpaceExceededException e) {
            ConcurrentLog.logException(e);
        }

        // insert or update entry
        try {
            if (row == null) {
                // create and insert new entry
                Data data = new Data();
                data.put(TABLE_API_COL_TYPE, UTF8.getBytes(type));
                data.put(TABLE_API_COL_COMMENT, UTF8.getBytes(comment));
                byte[] date = UTF8.getBytes(GenericFormatter.SHORT_MILSEC_FORMATTER.format());
                data.put(TABLE_API_COL_DATE_RECORDING, date);
                data.put(TABLE_API_COL_DATE_LAST_EXEC, date);
                data.put(TABLE_API_COL_URL, UTF8.getBytes(apiurl));

                // insert APICALL attributes
                data.put(TABLE_API_COL_APICALL_COUNT, "1");
                pk = super.insert(TABLE_API_NAME, data);
            } else {
                // modify and update existing entry

                // modify date attributes and patch old values
                row.put(TABLE_API_COL_DATE_LAST_EXEC, UTF8.getBytes(GenericFormatter.SHORT_MILSEC_FORMATTER.format()));
                if (!row.containsKey(TABLE_API_COL_DATE_RECORDING)) row.put(TABLE_API_COL_DATE_RECORDING, row.get(TABLE_API_COL_DATE));
                row.remove(TABLE_API_COL_DATE);

                // insert APICALL attributes
                row.put(TABLE_API_COL_APICALL_COUNT, row.get(TABLE_API_COL_APICALL_COUNT, 1) + 1);
                calculateAPIScheduler(row, false); // set next execution time (as this might be a forward existing entry with schedule data)
                super.update(TABLE_API_NAME, row);
                assert pk != null;
            }
        } catch (final IOException e) {
            ConcurrentLog.logException(e);
        } catch (final SpaceExceededException e) {
            ConcurrentLog.logException(e);
        }
        ConcurrentLog.info("APICALL", apiurl);
        return pk;
    }

    /**
     * store a API call and set attributes to schedule a re-call of that API call according to a given frequence
     * This is the same as the previous method but it also computes a re-call time and stores that additionally
     * @param post the post arguments of the api call
     * @param servletName the name of the servlet
     * @param type name of the servlet category
     * @param comment visual description of the process
     * @param time the time until next scheduled execution of this api call
     * @param unit the time unit for the scheduled call
     * @return the pk of the new entry in the api table
     */
    public byte[] recordAPICall(final serverObjects post, final String servletName, final String type, final String comment, int time, String unit) {
        if (post.containsKey(TABLE_API_COL_APICALL_PK)) {
            // this api call has already been stored somewhere.
            return this.recordAPICall(post, servletName, type, comment);
        }
        if (time < 0 || unit == null || unit.isEmpty() || "minutes,hours,days".indexOf(unit) < 0) {
            time = 0; unit = "";
        } else {
            if (unit.equals("minutes") && time < 10) time = 10;
        }


        /* Before API URL serialization, we set any eventual transaction token value to empty :
         * this will later help identify a new valid transaction token will be necessary,
         * but without revealing it in the URL displayed in the process scheduler and storing an invalid value */
        final String transactionToken = post.get(TransactionManager.TRANSACTION_TOKEN_PARAM, "");
        if(transactionToken != null) {
            post.put(TransactionManager.TRANSACTION_TOKEN_PARAM, "");
        }

        // generate the apicall url - without the apicall attributes
        final String apiurl = /*"http://localhost:" + getConfig("port", "8090") +*/ "/" + servletName + "?" + post.toString();

        /* Now restore the eventual transaction token to prevent side effects on the post object eventually still used by the caller */
        if(transactionToken != null) {
            post.put(TransactionManager.TRANSACTION_TOKEN_PARAM, transactionToken);
        } else {
            post.remove(TransactionManager.TRANSACTION_TOKEN_PARAM);
        }

        byte[] pk = null;
        // insert entry
        try {
            // create and insert new entry
            Data data = new Data();
            data.put(TABLE_API_COL_TYPE, UTF8.getBytes(type));
            data.put(TABLE_API_COL_COMMENT, UTF8.getBytes(comment));
            byte[] date = ASCII.getBytes(GenericFormatter.SHORT_MILSEC_FORMATTER.format());
            data.put(TABLE_API_COL_DATE_RECORDING, date);
            data.put(TABLE_API_COL_DATE_LAST_EXEC, date);
            data.put(TABLE_API_COL_URL, UTF8.getBytes(apiurl));

            // insert APICALL attributes
            data.put(TABLE_API_COL_APICALL_COUNT, UTF8.getBytes("1"));
            data.put(TABLE_API_COL_APICALL_SCHEDULE_TIME, ASCII.getBytes(Integer.toString(time)));
            data.put(TABLE_API_COL_APICALL_SCHEDULE_UNIT, UTF8.getBytes(unit));
            calculateAPIScheduler(data, false); // set next execution time
            pk = super.insert(TABLE_API_NAME, data);
        } catch (final IOException e) {
            ConcurrentLog.logException(e);
        } catch (final SpaceExceededException e) {
            ConcurrentLog.logException(e);
        }
        ConcurrentLog.info("APICALL", apiurl);
        return pk;
    }

    /**
     * execute an API call using a api table row which contains all essentials
     * to access the server also the host and port must be given
     * @param pks a collection of primary keys denoting the rows in the api table
     * @param host the host where the api shall be called
     * @param port the port on the host
     * @return a map of the called urls and the http status code of the api call or -1 if any other IOException occurred
     */
    public Map<String, Integer> execAPICalls(String host, int port, Collection<String> pks, final String username, final String pass) {
        LinkedHashMap<String, Integer> l = new LinkedHashMap<>();
        // now call the api URLs and store the result status
        try (final HTTPClient client = new HTTPClient(ClientIdentification.yacyInternetCrawlerAgent)) {
            client.setTimout(120000);
            Tables.Row row;
            for (final String pk: pks) {
                row = null;
                try {
                    row = this.select(WorkTables.TABLE_API_NAME, UTF8.getBytes(pk));
                } catch (final IOException e) {
                    ConcurrentLog.logException(e);
                } catch (final SpaceExceededException e) {
                    ConcurrentLog.logException(e);
                }
                if (row == null) continue;
                String theapicall = UTF8.String(row.get(WorkTables.TABLE_API_COL_URL)) + "&" + WorkTables.TABLE_API_COL_APICALL_PK + "=" + UTF8.String(row.getPK());
                try {
                    MultiProtocolURL url = new MultiProtocolURL("http", host, port, theapicall);
                    final Map<String, String> attributes = url.getAttributes();
                    final boolean isTokenProtectedAPI = attributes.containsKey(TransactionManager.TRANSACTION_TOKEN_PARAM);
                    // use 4 param MultiProtocolURL to allow api_row_url with searchpart (like url?p=a&p2=b ) in client.GETbytes()
                    if (theapicall.length() > 1000 || isTokenProtectedAPI) {
                        // use a POST to execute the call
                        this.execPostAPICall(host, port, username, pass, client, l, url, isTokenProtectedAPI);
                    } else {
                        // use a GET to execute the call
                        ConcurrentLog.info("WorkTables", "executing url: " + url.toNormalform(true));
                        try {
                            client.GETbytes(url, username, pass, false); // use GETbytes(MultiProtocolURL,..) form to allow url in parameter (&url=path%
                            if(client.getStatusCode() == HttpStatus.SC_METHOD_NOT_ALLOWED) {
                                /* GET method not allowed (HTTP 450 status) : this may be an old API entry,
                                 * now restricted to HTTP POST and requiring a transaction token. We try now with POST. */
                                this.execPostAPICall(host, port, username, pass, client, l, url, true);
                            } else {
                                l.put(url.toNormalform(true), client.getStatusCode());
                            }
                        } catch (final IOException e) {
                            ConcurrentLog.logException(e);
                            l.put(url.toString(), -1);
                        }
                    }
                } catch (MalformedURLException ex) {
                    ConcurrentLog.warn("APICALL", "wrong url in apicall " + theapicall);
                }
            }
        } catch (IOException e) {
            ConcurrentLog.logException(e);
        }
        return l;
    }

    /**
     * Executes an API call using HTTP POST method to the YaCy peer with the given parameters
     * @param host the peer host name
     * @param port the peer port
     * @param username authentication user name
     * @param pass authentication encoded password
     * @param client the HTTP client to use
     * @param results the results map to update
     * @param apiURL the full API URL with all parameters
     * @param isTokenProtectedAPI set to true when the API is protected by a transaction token
     * @throws MalformedURLException when the HTTP POST url could not be derived from apiURL
     */
    private void execPostAPICall(String host, int port, final String username, final String pass,
            final HTTPClient client, final LinkedHashMap<String, Integer> results,
            final MultiProtocolURL apiURL, final boolean isTokenProtectedAPI) throws MalformedURLException {
        Map<String, ContentBody> post = new HashMap<>();
        for (Map.Entry<String, String> a: apiURL.getAttributes().entrySet()) {
            post.put(a.getKey(), UTF8.StringBody(a.getValue()));
        }

        final MultiProtocolURL url = new MultiProtocolURL("http", host, port, apiURL.getPath());

        try {
            if (isTokenProtectedAPI) {
                // Eventually acquire first a new valid transaction token before posting data
                client.GETbytes(url, username, pass, false);
                if (client.getStatusCode() != HttpStatus.SC_OK) {
                    /* Do not fail immediately, the token may be no more necessary on this API :
                     * let's log a warning but try anyway the POST call that will eventually reject the request */
                    ConcurrentLog.warn("APICALL", "Could not retrieve a transaction token for " + apiURL.toNormalform(true));
                } else {

                    final Header transactionTokenHeader = client.getHttpResponse()
                            .getFirstHeader(HeaderFramework.X_YACY_TRANSACTION_TOKEN);
                    if (transactionTokenHeader == null) {
                        /*
                         * Do not fail immediately, the token may be no more
                         * necessary on this API : let's log a warning but try
                         * anyway the POST call that will eventually reject the
                         * request
                         */
                        ConcurrentLog.warn("APICALL",
                                "Could not retrieve a transaction token for " + apiURL.toNormalform(true));
                    } else {
                        post.put(TransactionManager.TRANSACTION_TOKEN_PARAM,
                                UTF8.StringBody(transactionTokenHeader.getValue()));
                    }
                }

            }

            client.POSTbytes(url, "localhost", post, username, pass, false, false);

            results.put(apiURL.toNormalform(true), client.getStatusCode());
        } catch (final IOException e) {
            ConcurrentLog.logException(e);
            results.put(apiURL.toNormalform(true), -1);
        }
    }

    /**
     * Executes an HTTP GET API call
     * @param host target host name
     * @param port target port
     * @param path target path
     * @param pk the primary key of the api call
     * @param username authentication user name
     * @param pass authentication encoded password
     * @return the API response HTTP status, or -1 when an error occured
     */
    public static int execGetAPICall(String host, int port, String path, byte[] pk, final String username, final String pass) {
        // now call the api URLs and store the result status
        StringBuilder url = new StringBuilder("http://").append(host).append(":").append(port).append(path);
        if (pk != null) url.append("&").append(WorkTables.TABLE_API_COL_APICALL_PK).append("=").append(UTF8.String(pk));
        try (final HTTPClient client = new HTTPClient(ClientIdentification.yacyInternetCrawlerAgent)) {
            client.setTimout(120000);
            client.GETbytes(url.toString(), username, pass, false);
            return client.getStatusCode();
        } catch (final IOException e) {
            ConcurrentLog.logException(e);
            return -1;
        }
    }

    /**
     * simplified call to execute a single entry in the api database table
     * @param pk the primary key of the entry
     * @param host the host where the api shall be called
     * @param port the port on the host
     * @return the http status code of the api call or -1 if any other IOException occurred
     */
    public int execAPICall(String pk, String host, int port, final String username, final String pass) {
        ArrayList<String> pks = new ArrayList<>();
        pks.add(pk);
        Map<String, Integer> m = this.execAPICalls(host, port, pks, username, pass);
        if (m.isEmpty()) return -1;
        return m.values().iterator().next().intValue();
    }

    final static long hour = 1000L * 60L * 60L;
    final static long day = hour * 24L;

    /**
     * calculate the execution time in a api call table based on given scheduling time and last execution time
     * @param row the database row in the api table
     * @param update if true then the next execution time is based on the latest computed execution time; otherwise it is based on the last execution time
     */
    public static void calculateAPIScheduler(Tables.Data row, boolean update) {
        Date date = row.containsKey(WorkTables.TABLE_API_COL_DATE) ? row.get(WorkTables.TABLE_API_COL_DATE, (Date) null) : null;
        date = update ? row.get(WorkTables.TABLE_API_COL_DATE_NEXT_EXEC, date) : row.get(WorkTables.TABLE_API_COL_DATE_LAST_EXEC, date);
        if (date == null) return;
        long d = 0;

        final String kind = row.get(WorkTables.TABLE_API_COL_APICALL_EVENT_KIND, "off");
        if ("off".equals(kind)) {
            int time = row.get(WorkTables.TABLE_API_COL_APICALL_SCHEDULE_TIME, -1);
            if (time <= 0) { // no schedule time
                row.put(WorkTables.TABLE_API_COL_DATE_NEXT_EXEC, "");
                return;
            }
            String unit = row.get(WorkTables.TABLE_API_COL_APICALL_SCHEDULE_UNIT, "days");
            if (unit.equals("minutes")) d = 60000L * Math.max(10, time);
            if (unit.equals("hours"))   d = hour * time;
            if (unit.equals("days"))    d = day * time;
            if ((d + date.getTime()) < System.currentTimeMillis()) { // missed schedule
                d += System.currentTimeMillis(); // advance next exec from now
            } else {
                d += date.getTime(); // advance next exec from last execution
            }
            d -= d % 60000; // remove seconds
        } else {
            String action = row.get(WorkTables.TABLE_API_COL_APICALL_EVENT_ACTION, "startup");
            if (!"startup".equals(action)) try {
                SimpleDateFormat dateFormat  = new SimpleDateFormat("yyyyMMddHHmm");
                d = dateFormat.parse(dateFormat.format(new Date()).substring(0, 8) + action).getTime();
                if (d < System.currentTimeMillis()) d += day;
            } catch (final ParseException e) {} else {
                row.put(WorkTables.TABLE_API_COL_DATE_NEXT_EXEC, "");
                return;
            }
        }
        row.put(WorkTables.TABLE_API_COL_DATE_NEXT_EXEC, new Date(d));
    }

    public void failURLsRegisterMissingWord(IndexCell<WordReference> indexCell, final DigestURL url, HandleSet queryHashes) {

        // remove words from index
        if (indexCell != null) {
            for (final byte[] word: queryHashes) {
                indexCell.removeDelayed(word, url.hash());
            }
        }
    }

    public static Map<byte[], String> commentCache(Switchboard sb) {
        Map<byte[], String> comments = new TreeMap<>(Base64Order.enhancedCoder);
        Iterator<Tables.Row> i;
        try {
            i = sb.tables.iterator(WorkTables.TABLE_API_NAME);
            Tables.Row row;
            while (i.hasNext()) {
                row = i.next();
                comments.put(row.getPK(), UTF8.String(row.get(WorkTables.TABLE_API_COL_COMMENT)));
            }
        } catch (final IOException e) {
            ConcurrentLog.logException(e);
        }
        return comments;
    }
}
