const request = {
            get: function (url, callback) {
                let xmlHttp = new XMLHttpRequest();
                xmlHttp.onreadystatechange = function() {
                    if (xmlHttp.readyState === 4 && xmlHttp.status === 200)
                        callback(xmlHttp.responseText);
                };
                xmlHttp.open("GET", url, true);
                xmlHttp.send();
            },

            post: function (url, callback, data) {
                let xmlHttp = new XMLHttpRequest();
                xmlHttp.onreadystatechange = function() {
                    if (xmlHttp.readyState === 4 && xmlHttp.status === 200)
                        callback(xmlHttp.responseText);
                };
                xmlHttp.open("POST", url, true);
                xmlHttp.send(this.formatParams(data));
            },

            formatParams: function (params) {
                return Object.keys(params).map((key) => {
                    return key+"="+encodeURIComponent(params[key])
                }).join("&")
            }
        };

const defaultColumnInputs = {
    'service_id': `<input type="text">`,
    'servtype': `<input type="text">`,
    'subtype': `<input type="text">`,
    'user_id': `<input type="text">`,
    'referrer_user_id': `<input type="text">`,
    'state': `<select>
        <option>N</option>
        <option>A</option>
        <option>S</option>
        <option>D</option>
        <option>O</option>
    </select>`,

    'creation_date': `<input type="date">`,
    'creation_time': `<input type="time">`,
    'creation_request_sent_date': `<input type="date"><input type="time">`,
    'notified_about_expiration': `<input type="text">`
};

const baseFormFields = `<form id="tableForm" action="/api/update" method="post">
    <div class="formRow">
        <div class="formRow-label">service_id</div>
        <div class="formRow-input"><input type="text" name="service_id" class="formInput" id="formServiceId" disabled></div>
    </div>
    
    <div class="formRow">
        <div class="formRow-label"> servtype </div>
        <div class="formRow-input">
            <input type="text" name="servtype" class="formInput">
        </div>
    </div>

    <div class="formRow">
        <div class="formRow-label"> subtype </div>
        <div class="formRow-input">
            <input type="text" name="subtype" class="formInput">
        </div>
    </div>

    <div class="formRow">
        <div class="formRow-label"> user_id </div>
        <div class="formRow-input">
            <input type="text" name="user_id" class="formInput">
        </div>
    </div>

    <div class="formRow">
        <div class="formRow-label"> referrer_user_id </div>
        <div class="formRow-input">
            <input type="text" name="referrer_user_id" class="formInput">
        </div>
    </div>

    <div class="formRow">
        <div class="formRow-label"> state </div>
        <div class="formRow-input">
            <select name="state">
                <option>N</option>
                <option>A</option>
                <option>S</option>
                <option>D</option>
                <option>O</option>
            </select>
        </div>
    </div>

    <div class="formRow">
        <div class="formRow-label"> creation_date </div>
        <div class="formRow-input">
            <input type="date" name="creation_date" class="formInput">
        </div>
    </div>
    <div class="formRow">
        <div class="formRow-label"> creation_time </div>
        <div class="formRow-input">
            <input type="time" name="creation_time" class="formInput">
        </div>
    </div>

    <div class="formRow">
        <div class="formRow-label"> creation_request_sent_date </div>
        <div class="formRow-input" style="display: flex; flex-direction: row">
            <input type="date" name="creation_request_sent_date" class="formInput" style="width: 50%;">
            <input type="time" name="creation_request_sent_time" class="formInput" style="width: 50%;">
        </div>
    </div>

    <div class="formRow">
        <div class="formRow-label"> notified_about_expiration </div>
        <div class="formRow-input">
            <input type="text" name="notified_about_expiration" class="formInput">
        </div>
    </div>
</form>`;

const formCreateButtons = `<div class="formButtons">
    <button type="button" onclick="hideForm()">Cancel</button>
    <button type="submit">Create</button>
</div>`;

const formEditButtons = `<div class="formButtons">
    <button type="button" onclick="hideForm()">Cancel</button>
    <button type="submit">Update</button>
</div>`;

const uploadFileHtml = '<img src="/static/images/upload_icon.png" alt="" style="width: 70%;height: 70%;">';