/* jslint node: true */
'use strict';

//	ENiGMA½
const msgDb						= require('./database.js').dbs.message;
const Config					= require('./config.js').get;
const Message					= require('./message.js');
const Log						= require('./logger.js').log;
const msgNetRecord				= require('./msg_network.js').recordMessage;
const sortAreasOrConfs			= require('./conf_area_util.js').sortAreasOrConfs;

//	deps
const async			= require('async');
const _				= require('lodash');
const assert		= require('assert');

exports.getAvailableMessageConferences      = getAvailableMessageConferences;
exports.getSortedAvailMessageConferences	= getSortedAvailMessageConferences;
exports.getAvailableMessageAreasByConfTag   = getAvailableMessageAreasByConfTag;
exports.getSortedAvailMessageAreasByConfTag = getSortedAvailMessageAreasByConfTag;
exports.getDefaultMessageConferenceTag      = getDefaultMessageConferenceTag;
exports.getDefaultMessageAreaTagByConfTag   = getDefaultMessageAreaTagByConfTag;
exports.getMessageConferenceByTag			= getMessageConferenceByTag;
exports.getMessageAreaByTag					= getMessageAreaByTag;
exports.changeMessageConference				= changeMessageConference;
exports.changeMessageArea					= changeMessageArea;
exports.tempChangeMessageConfAndArea		= tempChangeMessageConfAndArea;
exports.getMessageListForArea				= getMessageListForArea;
exports.getNewMessageCountInAreaForUser		= getNewMessageCountInAreaForUser;
exports.getNewMessagesInAreaForUser			= getNewMessagesInAreaForUser;
exports.getMessageIdNewerThanTimestampByArea	= getMessageIdNewerThanTimestampByArea;
exports.getMessageAreaLastReadId			= getMessageAreaLastReadId;
exports.updateMessageAreaLastReadId			= updateMessageAreaLastReadId;
exports.persistMessage						= persistMessage;
exports.trimMessageAreasScheduledEvent		= trimMessageAreasScheduledEvent;

function getAvailableMessageConferences(client, options) {
    options = options || { includeSystemInternal : false };

    assert(client || true === options.noClient);

    //	perform ACS check per conf & omit system_internal if desired
    return _.omitBy(Config().messageConferences, (conf, confTag) => {
        if(!options.includeSystemInternal && 'system_internal' === confTag) {
            return true;
        }

        return client && !client.acs.hasMessageConfRead(conf);
    });
}

function getSortedAvailMessageConferences(client, options) {
    const confs = _.map(getAvailableMessageConferences(client, options), (v, k) => {
        return {
            confTag : k,
            conf	: v,
        };
    });

    sortAreasOrConfs(confs, 'conf');

    return confs;
}

//  Return an *object* of available areas within |confTag|
function getAvailableMessageAreasByConfTag(confTag, options) {
    options = options || {};

    //  :TODO: confTag === "" then find default

    const config = Config();
    if(_.has(config.messageConferences, [ confTag, 'areas' ])) {
        const areas = config.messageConferences[confTag].areas;

        if(!options.client || true === options.noAcsCheck) {
            //	everything - no ACS checks
            return areas;
        } else {
            //	perform ACS check per area
            return _.omitBy(areas, area => {
                return !options.client.acs.hasMessageAreaRead(area);
            });
        }
    }
}

function getSortedAvailMessageAreasByConfTag(confTag, options) {
    const areas = _.map(getAvailableMessageAreasByConfTag(confTag, options), (v, k) => {
        return  {
            areaTag	: k,
            area	: v,
        };
    });

    sortAreasOrConfs(areas, 'area');

    return areas;
}

function getDefaultMessageConferenceTag(client, disableAcsCheck) {
    //
    //	Find the first conference marked 'default'. If found,
    //	inspect |client| against *read* ACS using defaults if not
    //	specified.
    //
    //	If the above fails, just go down the list until we get one
    //	that passes.
    //
    //	It's possible that we end up with nothing here!
    //
    //	Note that built in 'system_internal' is always ommited here
    //
    const config = Config();
    let defaultConf = _.findKey(config.messageConferences, o => o.default);
    if(defaultConf) {
        const conf = config.messageConferences[defaultConf];
        if(true === disableAcsCheck || client.acs.hasMessageConfRead(conf)) {
            return defaultConf;
        }
    }

    //  just use anything we can
    defaultConf = _.findKey(config.messageConferences, (conf, confTag) => {
        return 'system_internal' !== confTag && (true === disableAcsCheck || client.acs.hasMessageConfRead(conf));
    });

    return defaultConf;
}

function getDefaultMessageAreaTagByConfTag(client, confTag, disableAcsCheck) {
    //
    //  Similar to finding the default conference:
    //  Find the first entry marked 'default', if any. If found, check | client| against
    //  *read* ACS. If this fails, just find the first one we can that passes checks.
    //
    //  It's possible that we end up with nothing!
    //
    confTag = confTag || getDefaultMessageConferenceTag(client);

    const config = Config();
    if(confTag && _.has(config.messageConferences, [ confTag, 'areas' ])) {
        const areaPool = config.messageConferences[confTag].areas;
        let defaultArea = _.findKey(areaPool, o => o.default);
        if(defaultArea) {
            const area = areaPool[defaultArea];
            if(true === disableAcsCheck || client.acs.hasMessageAreaRead(area)) {
                return defaultArea;
            }
        }

        defaultArea = _.findKey(areaPool, (area) => {
            return (true === disableAcsCheck || client.acs.hasMessageAreaRead(area));
        });

        return defaultArea;
    }
}

function getMessageConferenceByTag(confTag) {
    return Config().messageConferences[confTag];
}

function getMessageConfTagByAreaTag(areaTag) {
    const confs = Config().messageConferences;
    return Object.keys(confs).find( (confTag) => {
        return _.has(confs, [ confTag, 'areas', areaTag]);
    });
}

function getMessageAreaByTag(areaTag, optionalConfTag) {
    const confs = Config().messageConferences;

    //	:TODO: this could be cached
    if(_.isString(optionalConfTag)) {
        if(_.has(confs, [ optionalConfTag, 'areas', areaTag ])) {
            return confs[optionalConfTag].areas[areaTag];
        }
    } else {
        //
        //  No confTag to work with - we'll have to search through them all
        //
        let area;
        _.forEach(confs, (v) => {
            if(_.has(v, [ 'areas', areaTag ])) {
                area = v.areas[areaTag];
                return false;   //  stop iteration
            }
        });

        return area;
    }
}

function changeMessageConference(client, confTag, cb) {
    async.waterfall(
        [
            function getConf(callback) {
                const conf = getMessageConferenceByTag(confTag);

                if(conf) {
                    callback(null, conf);
                } else {
                    callback(new Error('Invalid message conference tag'));
                }
            },
            function getDefaultAreaInConf(conf, callback) {
                const areaTag 	= getDefaultMessageAreaTagByConfTag(client, confTag);
                const area		= getMessageAreaByTag(areaTag, confTag);

                if(area) {
                    callback(null, conf, { areaTag : areaTag, area : area } );
                } else {
                    callback(new Error('No available areas for this user in conference'));
                }
            },
            function validateAccess(conf, areaInfo, callback) {
                if(!client.acs.hasMessageConfRead(conf) || !client.acs.hasMessageAreaRead(areaInfo.area)) {
                    return callback(new Error('Access denied to message area and/or conference'));
                } else {
                    return callback(null, conf, areaInfo);
                }
            },
            function changeConferenceAndArea(conf, areaInfo, callback) {
                const newProps = {
                    message_conf_tag	: confTag,
                    message_area_tag	: areaInfo.areaTag,
                };
                client.user.persistProperties(newProps, err => {
                    callback(err, conf, areaInfo);
                });
            },
        ],
        function complete(err, conf, areaInfo) {
            if(!err) {
                client.log.info( { confTag : confTag, confName : conf.name, areaTag : areaInfo.areaTag }, 'Current message conference changed');
            } else {
                client.log.warn( { confTag : confTag, error : err.message }, 'Could not change message conference');
            }
            cb(err);
        }
    );
}

function changeMessageAreaWithOptions(client, areaTag, options, cb) {
    options = options || {};	//	:TODO: this is currently pointless... cb is required...

    async.waterfall(
        [
            function getArea(callback) {
                const area = getMessageAreaByTag(areaTag);
                return callback(area ? null : new Error('Invalid message areaTag'), area);
            },
            function validateAccess(area, callback) {
                //
                //  Need at least *read* to access the area
                //
                if(!client.acs.hasMessageAreaRead(area)) {
                    return callback(new Error('Access denied to message area'));
                } else {
                    return callback(null, area);
                }
            },
            function changeArea(area, callback) {
                if(true === options.persist) {
                    client.user.persistProperty('message_area_tag', areaTag, function persisted(err) {
                        return callback(err, area);
                    });
                } else {
                    client.user.properties['message_area_tag'] = areaTag;
                    return callback(null, area);
                }
            }
        ],
        function complete(err, area) {
            if(!err) {
                client.log.info( { areaTag : areaTag, area : area }, 'Current message area changed');
            } else {
                client.log.warn( { areaTag : areaTag, area : area, error : err.message }, 'Could not change message area');
            }

            return cb(err);
        }
    );
}

//
//	Temporairly -- e.g. non-persisted -- change to an area and it's
//	associated underlying conference. ACS is checked for both.
//
//	This is useful for example when doing a new scan
//
function tempChangeMessageConfAndArea(client, areaTag) {
    const area		= getMessageAreaByTag(areaTag);
    const confTag	= getMessageConfTagByAreaTag(areaTag);

    if(!area || !confTag) {
        return false;
    }

    const conf = getMessageConferenceByTag(confTag);

    if(!client.acs.hasMessageConfRead(conf) || !client.acs.hasMessageAreaRead(area)) {
        return false;
    }

    client.user.properties.message_conf_tag	= confTag;
    client.user.properties.message_area_tag = areaTag;

    return true;
}

function changeMessageArea(client, areaTag, cb) {
    changeMessageAreaWithOptions(client, areaTag, { persist : true }, cb);
}

function getNewMessageCountInAreaForUser(userId, areaTag, cb) {
    getMessageAreaLastReadId(userId, areaTag, (err, lastMessageId) => {
        lastMessageId = lastMessageId || 0;

        const filter = {
            areaTag,
            newerThanMessageId	: lastMessageId,
            resultType			: 'count',
        };

        if(Message.isPrivateAreaTag(areaTag)) {
            filter.privateTagUserId = userId;
        }

        Message.findMessages(filter, (err, count) => {
            return cb(err, count);
        });
    });
}

function getNewMessagesInAreaForUser(userId, areaTag, cb) {
    getMessageAreaLastReadId(userId, areaTag, (err, lastMessageId) => {
        lastMessageId = lastMessageId || 0;

        const filter = {
            areaTag,
            resultType			: 'messageList',
            newerThanMessageId	: lastMessageId,
            sort				: 'messageId',
            order				: 'ascending',
        };

        if(Message.isPrivateAreaTag(areaTag)) {
            filter.privateTagUserId = userId;
        }

        return Message.findMessages(filter, cb);
    });
}

function getMessageListForArea(client, areaTag, cb) {
    const filter = {
        areaTag,
        resultType	: 'messageList',
        sort		: 'messageId',
        order		: 'ascending',
    };

    if(Message.isPrivateAreaTag(areaTag)) {
        filter.privateTagUserId = client.user.userId;
    }

    return Message.findMessages(filter, cb);
}

function getMessageIdNewerThanTimestampByArea(areaTag, newerThanTimestamp, cb) {
    Message.findMessages(
        {
            areaTag,
            newerThanTimestamp,
            sort 	: 'modTimestamp',
            order	: 'ascending',
            limit	: 1,
        },
        (err, id) => {
            if(err) {
                return cb(err);
            }
            return cb(null, id ? id[0] : null);
        }
    );
}

function getMessageAreaLastReadId(userId, areaTag, cb) {
    msgDb.get(
        'SELECT message_id '					+
		'FROM user_message_area_last_read '		+
		'WHERE user_id = ? AND area_tag = ?;',
        [ userId, areaTag.toLowerCase() ],
        function complete(err, row) {
            cb(err, row ? row.message_id : 0);
        }
    );
}

function updateMessageAreaLastReadId(userId, areaTag, messageId, allowOlder, cb) {
    if(!cb && _.isFunction(allowOlder)) {
        cb = allowOlder;
        allowOlder = false;
    }

    //	:TODO: likely a better way to do this...
    async.waterfall(
        [
            function getCurrent(callback) {
                getMessageAreaLastReadId(userId, areaTag, function result(err, lastId) {
                    lastId = lastId || 0;
                    callback(null, lastId);	//	ignore errors as we default to 0
                });
            },
            function update(lastId, callback) {
                if(allowOlder || messageId > lastId) {
                    msgDb.run(
                        'REPLACE INTO user_message_area_last_read (user_id, area_tag, message_id) '	+
						'VALUES (?, ?, ?);',
                        [ userId, areaTag, messageId ],
                        function written(err) {
                            callback(err, true);    //  true=didUpdate
                        }
                    );
                } else {
                    callback(null);
                }
            }
        ],
        function complete(err, didUpdate) {
            if(err) {
                Log.debug(
                    { error : err.toString(), userId : userId, areaTag : areaTag, messageId : messageId },
                    'Failed updating area last read ID');
            } else {
                if(true === didUpdate) {
                    Log.trace(
                        { userId : userId, areaTag : areaTag, messageId : messageId },
                        'Area last read ID updated');
                }
            }
            cb(err);
        }
    );
}

function persistMessage(message, cb) {
    async.series(
        [
            function persistMessageToDisc(callback) {
                return message.persist(callback);
            },
            function recordToMessageNetworks(callback) {
                return msgNetRecord(message, callback);
            }
        ],
        cb
    );
}

//	method exposed for event scheduler
function trimMessageAreasScheduledEvent(args, cb) {

    function trimMessageAreaByMaxMessages(areaInfo, cb) {
        if(0 === areaInfo.maxMessages) {
            return cb(null);
        }

        msgDb.run(
            `DELETE FROM message
			WHERE message_id IN(
				SELECT message_id
				FROM message
				WHERE area_tag = ?
				ORDER BY message_id DESC
				LIMIT -1 OFFSET ${areaInfo.maxMessages}
			);`,
            [ areaInfo.areaTag.toLowerCase() ],
            function result(err) {	//	no arrow func; need this
                if(err) {
                    Log.error( { areaInfo : areaInfo, error : err.message, type : 'maxMessages' }, 'Error trimming message area');
                } else {
                    Log.debug( { areaInfo : areaInfo, type : 'maxMessages', count : this.changes }, 'Area trimmed successfully');
                }
                return cb(err);
            }
        );
    }

    function trimMessageAreaByMaxAgeDays(areaInfo, cb) {
        if(0 === areaInfo.maxAgeDays) {
            return cb(null);
        }

        msgDb.run(
            `DELETE FROM message
			WHERE area_tag = ? AND modified_timestamp < date('now', '-${areaInfo.maxAgeDays} days');`,
            [ areaInfo.areaTag ],
            function result(err) {	//	no arrow func; need this
                if(err) {
                    Log.warn( { areaInfo : areaInfo, error : err.message, type : 'maxAgeDays' }, 'Error trimming message area');
                } else {
                    Log.debug( { areaInfo : areaInfo, type : 'maxAgeDays', count : this.changes }, 'Area trimmed successfully');
                }
                return cb(err);
            }
        );
    }

    async.waterfall(
        [
            function getAreaTags(callback) {
                const areaTags = [];

                //
                //	We use SQL here vs API such that no-longer-used tags are picked up
                //
                msgDb.each(
                    `SELECT DISTINCT area_tag
					FROM message;`,
                    (err, row) => {
                        if(err) {
                            return callback(err);
                        }

                        //	We treat private mail special
                        if(!Message.isPrivateAreaTag(row.area_tag)) {
                            areaTags.push(row.area_tag);
                        }
                    },
                    err => {
                        return callback(err, areaTags);
                    }
                );
            },
            function prepareAreaInfo(areaTags, callback) {
                let areaInfos = [];

                //	determine maxMessages & maxAgeDays per area
                const config = Config();
                areaTags.forEach(areaTag => {

                    let maxMessages = config.messageAreaDefaults.maxMessages;
                    let maxAgeDays	= config.messageAreaDefaults.maxAgeDays;

                    const area = getMessageAreaByTag(areaTag);	//	note: we don't know the conf here
                    if(area) {
                        maxMessages = area.maxMessages || maxMessages;
                        maxAgeDays	= area.maxAgeDays || maxAgeDays;
                    }

                    areaInfos.push( {
                        areaTag		: areaTag,
                        maxMessages	: maxMessages,
                        maxAgeDays	: maxAgeDays,
                    } );
                });

                return callback(null, areaInfos);
            },
            function trimGeneralAreas(areaInfos, callback) {
                async.each(
                    areaInfos,
                    (areaInfo, next) => {
                        trimMessageAreaByMaxMessages(areaInfo, err => {
                            if(err) {
                                return next(err);
                            }

                            trimMessageAreaByMaxAgeDays(areaInfo, err => {
                                return next(err);
                            });
                        });
                    },
                    callback
                );
            },
            function trimExternalPrivateSentMail(callback) {
                //
                //	*External* (FTN, email, ...) outgoing is cleaned up *after export*
                //	if it is older than the configured |maxExternalSentAgeDays| days
                //
                //	Outgoing externally exported private mail is:
                //	- In the 'private_mail' area
                //	- Marked exported (state_flags0 exported bit set)
                //	- Marked with any external flavor (we don't mark local)
                //
                const maxExternalSentAgeDays = _.get(
                    Config,
                    'messageConferences.system_internal.areas.private_mail.maxExternalSentAgeDays',
                    30
                );

                msgDb.run(
                    `DELETE FROM message
					WHERE message_id IN (
						SELECT m.message_id
						FROM message m
						JOIN message_meta mms
							ON m.message_id = mms.message_id AND
							(mms.meta_category='System' AND mms.meta_name='${Message.SystemMetaNames.StateFlags0}' AND (mms.meta_value & ${Message.StateFlags0.Exported} = ${Message.StateFlags0.Exported}))
						JOIN message_meta mmf
							ON m.message_id = mmf.message_id AND
							(mmf.meta_category='System' AND mmf.meta_name='${Message.SystemMetaNames.ExternalFlavor}')
						WHERE m.area_tag='${Message.WellKnownAreaTags.Private}' AND	DATETIME('now') > DATETIME(m.modified_timestamp, '+${maxExternalSentAgeDays} days')
					);`,
                    function results(err) {	//	no arrow func; need this
                        if(err) {
                            Log.warn( { error : err.message }, 'Error trimming private externally sent messages');
                        } else {
                            Log.debug( { count : this.changes }, 'Private externally sent messages trimmed successfully');
                        }
                    }
                );

                return callback(null);
            }
        ],
        err => {
            return cb(err);
        }
    );
}