/**
 *    Copyright (C) 2015 MongoDB Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    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 Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplication

#include "mongo/platform/basic.h"

#include "mongo/db/repl/repl_set_html_summary.h"

#include <string>
#include <sstream>

#include "mongo/util/mongoutils/html.h"
#include "mongo/util/mongoutils/str.h"


namespace mongo {
namespace repl {

    ReplSetHtmlSummary::ReplSetHtmlSummary() : _selfIndex(-1), _primaryIndex(-1), _selfUptime(0) {}

namespace {

    /**
     * Turns an unsigned int representing a duration of time in milliseconds and turns it into
     * a human readable time string representation.
     */
    std::string ago(unsigned int duration) {
        std::stringstream s;
        if( duration < 180 ) {
            s << duration << " sec";
            if( duration != 1 ) s << 's';
        }
        else if( duration < 3600 ) {
            s.precision(2);
            s << duration / 60.0 << " mins";
        }
        else {
            s.precision(2);
            s << duration / 3600.0 << " hrs";
        }
        return s.str();
    }

    unsigned int timeDifference(Date_t now, Date_t past) {
        return static_cast<unsigned int>(past != Date_t() ? durationCount<Seconds>(now - past) : 0);
    }

    std::string stateAsHtml(const MemberState& s) {
        using namespace html;

        if( s.s == MemberState::RS_STARTUP )
            return a("",
                     "server still starting up, or still trying to initiate the set",
                     "STARTUP");
        if( s.s == MemberState::RS_PRIMARY )
            return a("", "this server thinks it is primary", "PRIMARY");
        if( s.s == MemberState::RS_SECONDARY )
            return a("", "this server thinks it is a secondary (slave mode)", "SECONDARY");
        if( s.s == MemberState::RS_RECOVERING )
            return a("",
                     "recovering/resyncing; after recovery usually auto-transitions to secondary",
                     "RECOVERING");
        if( s.s == MemberState::RS_STARTUP2 )
            return a("", "loaded config, still determining who is primary", "STARTUP2");
        if( s.s == MemberState::RS_ARBITER )
            return a("", "this server is an arbiter only", "ARBITER");
        if( s.s == MemberState::RS_DOWN )
            return a("", "member is down, slow, or unreachable", "DOWN");
        if( s.s == MemberState::RS_ROLLBACK )
            return a("", "rolling back operations to get in sync", "ROLLBACK");
        if( s.s == MemberState::RS_UNKNOWN)
            return a("", "we do not know what state this node is in", "UNKNOWN");
        if( s.s == MemberState::RS_REMOVED)
            return a("", "this server has been removed from the replica set config", "ROLLBACK");
        return "";
    }
}

    const std::string ReplSetHtmlSummary::toHtmlString() const {
        using namespace html;

        std::stringstream s;

        if (!_config.isInitialized()) {
            s << p("Still starting up, or else replset is not yet initiated.");
            return s.str();
        }
        if (_selfIndex < 0) {
            s << p("This node is not a member of its replica set configuration, it most likely was"
                    " removed recently");
            return s.str();
        }

        int votesUp = 0;
        int totalVotes = 0;
        // Build table of node information.
        std::stringstream memberTable;
        const char *h[] =
            {"Member",
             "<a title=\"member id in the replset config\">id</a>",
             "Up",
             "<a title=\"length of time we have been continuously connected to the other member "
                     "with no reconnects (for self, shows uptime)\">cctime</a>",
             "<a title=\"when this server last received a heartbeat response - includes error code "
                     "responses\">Last heartbeat</a>",
             "Votes",
             "Priority",
             "State",
             "Messages",
             "<a title=\"how up to date this server is.  this value polled every few seconds so "
                     "actually lag is typically lower than value shown here.\">optime</a>",
             0
            };
        memberTable << table(h);

        for (int i = 0; i < _config.getNumMembers(); ++i) {
            const MemberConfig& memberConfig = _config.getMemberAt(i);
            const MemberHeartbeatData& memberHB = _hbData[i];
            bool isSelf = _selfIndex == i;
            bool up = memberHB.getHealth() > 0;

            totalVotes += memberConfig.getNumVotes();
            if (up || isSelf) {
                votesUp += memberConfig.getNumVotes();
            }

            memberTable << tr();
            if (isSelf) {
                memberTable << td(memberConfig.getHostAndPort().toString() + " (me)");
                memberTable << td(memberConfig.getId());
                memberTable << td("1"); // up
                memberTable << td(ago(_selfUptime));
                memberTable << td(""); // last heartbeat
                memberTable << td(std::to_string(memberConfig.getNumVotes()));
                memberTable << td(std::to_string(memberConfig.getPriority()));
                memberTable << td(stateAsHtml(_selfState) +
                                  (memberConfig.isHidden() ? " (hidden)" : ""));
                memberTable << td(_selfHeartbeatMessage);
                memberTable << td(_selfOptime.toString());
            }
            else {
                std::stringstream link;
                link << "http://" << memberConfig.getHostAndPort().host() << ':' <<
                        (memberConfig.getHostAndPort().port() + 1000) << "/_replSet";
                memberTable << td( a(link.str(), "", memberConfig.getHostAndPort().toString()) );
                memberTable << td(memberConfig.getId());
                memberTable << td(red(str::stream() << memberHB.getHealth(), !up));
                const unsigned int uptime = timeDifference(_now, memberHB.getUpSince());
                memberTable << td(ago(uptime));
                if (memberHB.getLastHeartbeat() == Date_t()) {
                    memberTable << td("never");
                }
                else {
                    memberTable << td(ago(timeDifference(_now, memberHB.getLastHeartbeat())));
                }
                memberTable << td(std::to_string(memberConfig.getNumVotes()));
                memberTable << td(std::to_string(memberConfig.getPriority()));
                std::string state = memberHB.getState().toString() +
                        (memberConfig.isHidden() ? " (hidden)" : "");
                if (up) {
                    memberTable << td(state);
                }
                else {
                    memberTable << td( grey(str::stream() << "(was " << state << ')', true) );
                }
                memberTable << td(grey(memberHB.getLastHeartbeatMsg(), !up));
                // TODO(dannenberg): change timestamp to optime in V1
                memberTable << td(memberHB.getLastHeartbeat() == Date_t() ?
                        "?" : memberHB.getOpTime().toString());
            }
            memberTable << _tr();
        }
        memberTable << _table();

        s << table(0, false);
        s << tr("Set name:", _config.getReplSetName());
        bool majorityUp = votesUp * 2 > totalVotes;
        s << tr("Majority up:", majorityUp ? "yes" : "no" );

        const MemberConfig& selfConfig = _config.getMemberAt(_selfIndex);

        if (_primaryIndex >= 0 && _primaryIndex != _selfIndex && !selfConfig.isArbiter()) {
            int lag = _hbData[_primaryIndex].getOpTime().getTimestamp().getSecs() -
                _selfOptime.getTimestamp().getSecs();
            s << tr("Lag: ", str::stream() << lag << " secs");
        }

        s << _table();

        s << memberTable.str();

        return s.str();
    }

} // namespace repl
} // namespace mongo