var SEVERITY_COLORS = [
    '#97AAB3', '#7499FF', '#FFC859',
    '#FFA059', '#E97659', '#E45959'
];

var RESOLVE_COLOR = '#009900';

var SLACK_MODE_HANDLERS = {
    alarm: handlerAlarm,
    event: handlerEvent
};

var EVENT_STATUS = {
    PROBLEM: 'PROBLEM',
    UPDATE: 'UPDATE',
    RESOLVE: 'OK'
};

if (!String.prototype.format) {
    String.prototype.format = function() {
        var args = arguments;

        return this.replace(/{(\d+)}/g, function(match, number) {
            return number in args
                ? args[number]
                : match
            ;
        });
    };
}

function isEventProblem(params) {
    return params.event_value == 1
        && params.event_update_status == 0
    ;
}

function isEventUpdate(params) {
    return params.event_value == 1
        && params.event_update_status == 1
    ;
}

function isEventResolve(params) {
    return params.event_value == 0;
}

function getPermalink(channelId, messageTimestamp) {
    var req = new CurlHttpRequest();

    req.AddHeader('Content-Type: application/x-www-form-urlencoded; charset=utf-8');

    var resp = JSON.parse(req.Get(
        '{0}?token={1}&channel={2}&message_ts={3}'.format(
            Slack.getPermalink,
            params.bot_token,
            channelId,
            messageTimestamp
        )
    ));

    if (req.Status != 200 && !resp.ok) {
        throw resp.error;
    }

    return resp.permalink;
}

function createProblemURL(zabbix_url, triggerid, eventid) {
    var problem_url = '{0}/tr_events.php?triggerid={1}&eventid={2}'
        .format(
            zabbix_url.replace(/\/+$/, ''),
            triggerid,
            eventid
        );

    return problem_url;
}

function createInventoryURL(zabbix_url, hostid) {
    var inventory_url = '{0}/hostinventories.php?hostid={1}'
        .format(
            zabbix_url.replace(/\/+$/, ''),
            hostid
        );

    return inventory_url;
}

function createHostInfo(region, territory, building, building_code, building_address) {
    var host_info = '{0}, {1}'
        .format(
            building,
            building_code
        );

    return host_info;
}

function getTagValue(event_tags, key) {
    var pattern = new RegExp('(' + key + ':.+)');
    var tag_value = event_tags
        .split(',')
        .filter(function (v) {
            return v.match(pattern);
        })
        .map(function (v) {
            return v.split(':')[1];
        })[0]
        || 0;

    return tag_value;
}

function handlerAlarm(params) {
    var fields = {
        channel: params.channel,
        as_user: params.slack_as_user,
    };

    if (isEventProblem(params)) {
        fields.attachments = [
            createMessage(
                EVENT_STATUS.PROBLEM,
                SEVERITY_COLORS[params.event_nseverity] || 0,
                params.event_date,
                params.event_time,
                createProblemURL(params.zabbix_url, params.trigger_id, params.event_id),
                createInventoryURL(params.zabbix_url, params.host_id),
                createHostInfo(params.region, params.territory, params.building, params.building_code, params.building_address)
            )
        ];

        var resp = JSON.parse(req.Post(Slack.postMessage, JSON.stringify(fields)));

        if (req.Status != 200 && !resp.ok) {
            throw resp.error;
        }

        result.tags['__message_ts_'+params.channel.substring(1)] = resp.ts;
        result.tags['__channel_id_'+params.channel.substring(1)] = resp.channel;
        result.tags.__channel_name = params.channel;
        result.tags.__message_link = getPermalink(resp.channel, resp.ts);
        result.tags['__channel_name_'+params.channel.substring(1)] = params.channel;
        result.tags['__message_link_'+params.channel.substring(1)] = getPermalink(resp.channel, resp.ts);
    }
    else if (isEventUpdate(params)) {
        fields.thread_ts = getTagValue(params.event_tags, 'message_ts_'+params.channel.substring(1));
        fields.attachments = [
            createMessage(
                EVENT_STATUS.UPDATE,
                SEVERITY_COLORS[params.event_nseverity] || 0,
                params.event_update_date,
                params.event_update_time,
                createProblemURL(params.zabbix_url, params.trigger_id, params.event_id),
                createInventoryURL(params.zabbix_url, params.host_id),
                createHostInfo(params.region, params.territory, params.building, params.building_code, params.building_address),
                true,
                params.event_update_message
            )
        ];

        resp = JSON.parse(req.Post(Slack.postMessage, JSON.stringify(fields)));
        if (req.Status != 200 && !resp.ok) {
            throw resp.error;
        }

    }
    else if (isEventResolve(params)) {
        fields.channel = getTagValue(params.event_tags, 'channel_id_'+params.channel.substring(1));
        fields.text = '';
        fields.ts = getTagValue(params.event_tags, 'message_ts_'+params.channel.substring(1));
        fields.attachments = [
            createMessage(
                EVENT_STATUS.RESOLVE,
                RESOLVE_COLOR,
                params.event_date,
                params.event_time,
                createProblemURL(params.zabbix_url, params.trigger_id, params.event_id),
                createInventoryURL(params.zabbix_url, params.host_id),
                createHostInfo(params.region, params.territory, params.building, params.building_code, params.building_address)
            )
        ];

        resp = JSON.parse(req.Post(Slack.chatUpdate, JSON.stringify(fields)));
        if (req.Status != 200 && !resp.ok) {
            throw resp.error;
        }
    }
}

function handlerEvent(params) {
    var fields = {
        channel: params.channel,
        as_user: params.slack_as_user
    };

    if (isEventProblem(params)) {
        fields.attachments = [
            createMessage(
                EVENT_STATUS.PROBLEM,
                SEVERITY_COLORS[params.event_nseverity] || 0,
                params.event_date,
                params.event_time,
                createProblemURL(params.zabbix_url, params.trigger_id, params.event_id),
                createInventoryURL(params.zabbix_url, params.host_id),
                createHostInfo(params.region, params.territory, params.building, params.building_code, params.building_address)
            )
        ];

        var resp = JSON.parse(req.Post(Slack.postMessage, JSON.stringify(fields)));

        if (req.Status != 200 && !resp.ok) {
            throw resp.error;
        }

        result.tags.__channel_name = params.channel;
        result.tags.__message_link = getPermalink(resp.channel, resp.ts);
        result.tags['__channel_name_'+params.channel.substring(1)] = params.channel;
        result.tags['__message_link_'+params.channel.substring(1)] = getPermalink(resp.channel, resp.ts);

    }
    else if (isEventUpdate(params)) {
        fields.attachments = [
            createMessage(
                EVENT_STATUS.UPDATE,
                SEVERITY_COLORS[params.event_nseverity] || 0,
                params.event_update_date,
                params.event_update_time,
                createProblemURL(params.zabbix_url, params.trigger_id, params.event_id),
                createInventoryURL(params.zabbix_url, params.host_id),
                createHostInfo(params.region, params.territory, params.building, params.building_code, params.building_address),
                false,
                params.event_update_message
            )
        ];

        resp = JSON.parse(req.Post(Slack.postMessage, JSON.stringify(fields)));

        if (req.Status != 200 && !resp.ok) {
            throw resp.error;
        }

    }
    else if (isEventResolve(params)) {
        fields.attachments = [
            createMessage(
                EVENT_STATUS.RESOLVE,
                RESOLVE_COLOR,
                params.event_recovery_date,
                params.event_recovery_time,
                createProblemURL(params.zabbix_url, params.trigger_id, params.event_id),
                createInventoryURL(params.zabbix_url, params.host_id),
                createHostInfo(params.region, params.territory, params.building, params.building_code, params.building_address)
            )
        ];

        resp = JSON.parse(req.Post(Slack.postMessage, JSON.stringify(fields)));

        if (req.Status != 200 && !resp.ok) {
            throw resp.error;
        }
    }
}

function createMessage(
    status,
    event_severity_color,
    event_date,
    event_time,
    problem_url,
    inventory_url,
    host_info,
    isShort,
    messageText
) {
    var message = {
        fallback: '{0}: {1}'.format(status, params.event_name),
        title: '{0}: {1}'.format(status, params.event_name),
        color: event_severity_color,
        title_link: problem_url,
        pretext: messageText || '',

        fields: [
            {
                title: 'Building',
                value: host_info,
                short: true
            },
            {
                title: 'Host',
                value: '{0} [{1}]'.format(params.host_name, params.host_ip),
                short: true
            },
            {
                title: 'Region',
                value: params.region,
                short: true
            },
            {
                title: 'Event time',
                value: '{0} {1}'.format(event_date, event_time),
                short: true
            },
            {
                title: 'Opdata',
                value: params.event_opdata,
                short: true
            },
            {
                title: 'Severity',
                value: params.event_severity,
                short: true
            }
        ],
    };

    if (!isShort) {
        message['actions'] = [
            {
                type: 'button',
                text: 'Open in Zabbix',
                url: problem_url
            },
            {
                type: 'button',
                text: 'Host inventory',
                url: inventory_url
            }
        ];

        message.fields.push(
            {
                title: ' Trigger description',
                value: params.trigger_description,
                short: true
            },
            {
                title: 'Event tags',
                value: params.event_tags.replace(/__.+?:(.+?,|.+)/g, '') || 'None',
                short: true
            }
        );
    }

    return message;
}