var SysAid = {
    params: {},

    setParams: function (params) {
        var required = ['url', 'auth_user', 'auth_password', 'category_level_1', 'category_level_2',
            'category_level_3', 'incident_id', 'template_id', 'urgency_id', 'incident_state',
            'default_priority_id'
        ];

        required.forEach(function (field) {
            if (typeof params !== 'object' || typeof params[field] === 'undefined' || params[field] === '') {
                throw 'Required param is not set: "' + field + '".';
            }
        });

        SysAid.params = params;
        if (typeof SysAid.params.url === 'string' && !SysAid.params.url.endsWith('/')) {
            SysAid.params.url += '/';
        }
    },

    login: function () {
        var result = SysAid.request('post', 'api/v1/login', {
            user_name: SysAid.params.auth_user,
            password: SysAid.params.auth_password
        });

        return result.response.user.id;
    },

    request: function (method, query, data) {
        var response,
            request = SysAid.req || (SysAid.req = new HttpRequest()),
            url = SysAid.params.url + query;

        if (typeof SysAid.HTTPProxy !== 'undefined' && SysAid.HTTPProxy.trim() !== '') {
            request.setProxy(SysAid.HTTPProxy);
        }

        if (typeof data !== 'undefined') {
            data = JSON.stringify(data);
        }

        Zabbix.log(4, '[ SysAid Webhook ] Sending request: ' +
            url + ((typeof data === 'string') ? (' ' + data) : ''));

        switch (method) {
            case 'get':
                response = request.get(url, data);
                break;

            case 'post':
                response = request.post(url, data);
                break;

            case 'put':
                response = request.put(url, data);
                break;

            default:
                throw 'Unsupported HTTP request method: ' + method;
        }

        Zabbix.log(4, '[ SysAid Webhook ] Received response with status code ' + request.getStatus() + ': ' + response);

        if (request.getStatus() !== 200) {
            var message = 'Request failed with status code ' + request.getStatus();

            message += ': ' + response;
            throw message + ' Check debug log for more information.';
        }

        if (response !== null) {
            try {
                response = JSON.parse(response);
            }
            catch (error) {
                Zabbix.log(4, '[ SysAid Webhook ] Failed to parse response received from SysAid');
                response = null;
            }
        }

        if (response === null || (typeof response.Error !== 'undefined' && Object.keys(response.Error).length > 0)) {
            throw 'Request failed: ' + JSON.stringify(response.Error);
        }

        return {
            status: request.getStatus(),
            response: response
        };
    },

    createIncident: function(subject, message, priority) {
        var result = SysAid.request('post', 'api/v1/sr/?template=' + encodeURIComponent(SysAid.params.template_id), {
            info: [
                {
                    key: 'problem_type',
                    value: [
                        SysAid.params.category_level_1,
                        SysAid.params.category_level_2,
                        SysAid.params.category_level_3
                    ].join('_')
                },
                {
                    key: 'title',
                    value: subject
                },
                {
                    key: 'description',
                    value: message
                },
                {
                    key: 'status',
                    value: '1'
                },
                {
                    key: 'urgency',
                    value: SysAid.params.urgency_id
                },
                {
                    key: 'priority',
                    value: priority || SysAid.params.default_priority_id,
                }
            ]
        });

        if (result.response.id === 'undefined') {
            throw 'Cannot create SysAid incident. Check debug log for more information.';
        }

        return result.response.id;
    },

    updateTicket: function(note) {
        var date = new Date().getTime();

        SysAid.request('put', 'api/v1/sr/' + encodeURIComponent(SysAid.params.incident_id), {
            id: SysAid.params.incident_id,
            info: [
                {
                    key: 'update_time',
                    value: date
                },
                {
                    key: 'notes',
                    value: [
                        {
                            userName: 'Zabbix',
                            createDate: date,
                            text: note
                        }
                    ]
                }
            ]
        });
    }
};

try {
    var params = JSON.parse(value),
        params_sysaid = {},
        params_update = {},
        result = {tags: {}},
        required_params = ['alert_subject', 'event_source', 'event_value',  'event_update_status'],
        severities = [
            {name: 'not_classified', color: '#97AAB3'},
            {name: 'information', color: '#7499FF'},
            {name: 'warning', color: '#FFC859'},
            {name: 'average', color: '#FFA059'},
            {name: 'high', color: '#E97659'},
            {name: 'disaster', color: '#E45959'},
            {name: 'resolved', color: '#009900'},
            {name: null, color: '#000000'}
        ],
        priority;

    Object.keys(params)
        .forEach(function (key) {
            if (key.startsWith('sysaid_')) {
                params_sysaid[key.substring(7)] = params[key];
            }
            else if (key.startsWith('event_update_')) {
                params_update[key.substring(13)] = params[key];
            }
            else if (required_params.indexOf(key) !== -1 && params[key].trim() === '') {
                throw 'Parameter "' + key + '" cannot be empty.';
            }
        });

    if ([0, 1, 2, 3].indexOf(parseInt(params.event_source)) === -1) {
        throw 'Incorrect "event_source" parameter given: ' + params.event_source + '\\nMust be 0-3.';
    }

    // Check {EVENT.VALUE} for trigger-based and internal events.
    if (params.event_value !== '0' && params.event_value !== '1'
        && (params.event_source === '0' || params.event_source === '3')) {
        throw 'Incorrect "event_value" parameter given: ' + params.event_value + '\\nMust be 0 or 1.';
    }

    // Check {EVENT.UPDATE.STATUS} only for trigger-based events.
    if (params.event_source === '0' && params.event_update_status !== '0' && params.event_update_status !== '1') {
        throw 'Incorrect "event_update_status" parameter given: ' + params.event_update_status + '\\nMust be 0 or 1.';
    }

    if (params.event_source !== '0' && params.event_value === '0') {
        throw 'Recovery operations are supported only for trigger-based actions.';
    }

    if (params.event_source === '0' && ((params.event_value === '1' && params.event_update_status === '1')
            || (params.event_value === '0' && (params.event_update_status === '0' || params.event_update_status === '1')))
            && (isNaN(parseInt(params.sysaid_incident_id)) || parseInt(params.sysaid_incident_id) < 1 )) {
        throw 'Incorrect "sysaid_incident_id" parameter given: ' + params.sysaid_incident_id + '\\nMust be positive integer.';
    }

    if ([0, 1, 2, 3, 4, 5].indexOf(parseInt(params.event_nseverity)) === -1) {
        params.event_nseverity = '7';
    }

    if (params.event_value === '0') {
        params.event_nseverity = '6';
    }

    priority = params['severity_' + severities[params.event_nseverity].name];
    priority = priority && priority.trim() || severities[7].name;

    SysAid.setParams(params_sysaid);
    SysAid.HTTPProxy = params.HTTPProxy;
    SysAid.login();

    if (params.event_source !== '0' && params.event_value !== '0') {
        // Create ticket for non trigger-based events.
        SysAid.createIncident(params.alert_subject, params.alert_message, priority);
    }
    else if (params.event_value === '1' && params_update.status === '0') {
        // Create ticket for trigger-based events.
        var incident_id = SysAid.createIncident(params.alert_subject, params.alert_subject + '\\n' + params.alert_message +
                '\\n' + params.zabbix_url + (params.zabbix_url.endsWith('/') ? '' : '/') + 'tr_events.php?triggerid=' +
                params.trigger_id + '&eventid=' + params.event_id + '\\n', priority
        );

        result.tags.__zbx_sysaid_incident_id = incident_id;
        result.tags.__zbx_sysaid_incidentlink = params.sysaid_url +
            (params.sysaid_url.endsWith('/') ? '' : '/') + 'SREdit.jsp?id=' + incident_id + '&fromId=IncidentsList';
    }
    else {
        // Update created ticket for trigger-based event.
        SysAid.updateTicket(params.alert_subject + '\\n' + params.alert_message);
    }

    return JSON.stringify(result);
}
catch (error) {
    Zabbix.log(3, '[ SysAid Webhook ] ERROR: ' + error);
    throw 'Sending failed: ' + error;
}