var Itop = {
    params: {},

    setParams: function (params) {
        if (typeof params !== 'object') {
            return;
        }

        if (params.log !== 'private_log' && params.log !== 'public_log') {
            throw 'Incorrect "itop_log" parameter given: ' + params.log + '\\nMust be "private_log" or "public_log".';
        }

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

            Itop.params.url += 'webservices/rest.php?version=' + encodeURIComponent(Itop.params.api_version);
        }
    },

    setProxy: function (HTTPProxy) {
        Itop.HTTPProxy = HTTPProxy;
    },

    setCreatePayload: function () {
        json_data.operation = 'core/create';
        json_data.fields.org_id = Itop.params.organization_id;
        json_data.fields.title = params.alert_subject;
        json_data.fields.description = params.alert_message.replace('<', '&lt;')
            .replace('>', '&gt;')
            .replace(/(?:\\r\\n|\\r|\\n)/g, '<br>');
    },

    setUpdatePayload: function () {
        json_data.operation = 'core/update';
        json_data.key = Itop.params.id;
        json_data.fields.title = params.alert_subject;
        json_data.fields[Itop.params.log] = {
            add_item: {
                message: params.alert_subject + '\\n' + params.alert_message,
                format: 'text'
            }
        };
    },

    request: function (data) {
        ['url', 'user', 'password', 'organization_id', 'class', 'api_version', 'id'].forEach(function (field) {
            if (typeof Itop.params !== 'object' || typeof Itop.params[field] === 'undefined'
                    || Itop.params[field] === '' ) {
                throw 'Required Itop param is not set: "itop_' + field + '".';
            }
        });

        var response,
            url = Itop.params.url,
            request = new HttpRequest(),
            object;

        request.addHeader('Content-Type: multipart/form-data');
        request.addHeader('Authorization: Basic ' + btoa(Itop.params.user + ':' + Itop.params.password));

        if (Itop.HTTPProxy) {
            request.setProxy(Itop.HTTPProxy);
        }

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

        Zabbix.log(4, '[ iTop Webhook ] Sending request: ' + url + '&json_data=' + data);

        response = request.post(url + '&json_data=' + encodeURIComponent(data));

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

        try {
            response = JSON.parse(response);
        }
        catch (error) {
            Zabbix.log(4, '[ iTop Webhook ] Failed to parse response received from iTop');
            throw 'Failed to parse response received from iTop.\\nRequest status code ' +
                    request.getStatus() + '. Check debug log for more information.';
        }

        if (request.getStatus() < 200 || request.getStatus() >= 300) {
            throw 'Request failed with status code ' + request.getStatus() + '. Check debug log for more information.';
        }
        else if (typeof response.code !== 'undefined' && response.code !== 0) {
            throw 'Request failed with iTop code ' + response.code + ': ' +
                    JSON.stringify(response.message) + '. Check debug log for more information.';
        }
        else {
            Object.keys(response.objects)
                .forEach(function (key) {
                    object = response.objects[key];
                });
    
            return {
                status: request.getStatus(),
                response: object.fields
            };
        }
    }
};

try {
    var params = JSON.parse(value),
        json_data = {},
        itop_params = {},
        result = {tags: {}},
        required_params = [
            'alert_subject', 'summary', 'event_recovery_value',
            'event_source', 'event_value', 'action_name'
        ];

    Object.keys(params)
        .forEach(function (key) {
            if (key.startsWith('itop_')) {
                itop_params[key.substring(5)] = params[key];
            }
            else if (required_params.indexOf(key) !== -1 && params[key] === '') {
                throw 'Parameter "' + key + '" can\\'t 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_update_status !== '0' && params.event_update_status !== '1' && params.event_source === '0') {
        throw 'Incorrect "event_update_status" parameter given: ' + params.event_update_status + '\\nMust be 0 or 1.';
    }

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

    Itop.setParams(itop_params);
    Itop.setProxy(params.HTTPProxy);

    json_data.operation = '';
    json_data.class = Itop.params.class;
    json_data.comment = Itop.params.comment;
    json_data.output_fields = 'id, friendlyname';
    json_data.fields = {};

    // Create issue for non trigger-based events.
    if (params.event_source !== '0' && params.event_recovery_value !== '0') {
        Itop.setCreatePayload();
        Itop.request(json_data);
    }
    // Create issue for trigger-based events.
    else if (params.event_value === '1' && params.event_update_status === '0'
            && Itop.params.id === '{EVENT.TAGS.__zbx_itop_id}') {
        Itop.setCreatePayload();

        var response = Itop.request(json_data);

        result.tags.__zbx_itop_id = response.response.id;
        result.tags.__zbx_itop_key = response.response.friendlyname;
        result.tags.__zbx_itop_link = params.itop_url + (params.itop_url.endsWith('/') ? '' : '/') +
                'pages/UI.php?operation=details&class=' + encodeURIComponent(Itop.params.class) + '&id=' +
                encodeURIComponent(response.response.id);
    }
    // Update created issue for trigger-based event.
    else {
        if (Itop.params.id === '{EVENT.TAGS.__zbx_itop_id}') {
            throw 'Incorrect iTop ticket ID given: ' + Itop.params.id;
        }
        Itop.setUpdatePayload();
        Itop.request(json_data);
    }

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