// AbortController is used for aborting fetch calls. This allows us to prevent future HTTP requests from going out if a previous HTTP request failed.
// https://javascript.info/fetch-abort
const abortController = new AbortController();
const httpMethods = {
    GET: 'GET',
    POST: 'POST',
    PATCH: 'PATCH'
};

var abortSignal = abortController.signal;
const rootEndpoint = 'https://gyt1ihav1i.execute-api.us-east-2.amazonaws.com/prod/';
// const rootEndpoint = 'https://3k07mdhq8k.execute-api.us-east-1.amazonaws.com/';

function ParseResponse(responsePayload)
{
    let status = responsePayload["status"];

    if (status === "fail")
    {
        console.log("FAILED");
        abortController.abort();
    }
    else if (status === "error")
    {
        console.log("ERROR");
        abortController.abort();
    }
    else if (status === "success")
    {
        console.log("SUCCESS");
    }

    if (responsePayload['data'].hasOwnProperty('sqlErrorCode'))
    {
        if (responsePayload['data']['sqlErrorCode'] == 1062)
            console.log("USER ALREADY EXISTS");
        else
            console.log("SQL Error " + responsePayload['data']['sqlErrorCode']);
    }

    console.log(responsePayload);
}

async function CreatePortalUser(payload)
{
    // TEST PORTAL USER CREATION
    let response = await fetch(rootEndpoint + 'PortalUser', {
        method: 'POST',
        body: JSON.stringify(payload),
        headers: {
            'Content-Type': 'application/json'
        },
        signal: abortSignal
    });

    let responsePayload = await response.json();

    // ParseResponse(responsePayload);

    return response;
}

async function SubmitRegistration(payload)
{

    let response = await fetch(rootEndpoint + 'SubmitRegistration', {
        method: 'POST',
        body: JSON.stringify(payload),
        headers: {
            'Content-Type': 'application/json'
        },
        signal: abortSignal
    });

    let responsePayload = await response.json();

    // ParseResponse(responsePayload);

    return responsePayload;
}

async function GenerateReport(studyID, acronym, jwtAccessToken, redirectCallback)
{
    let endpoint = `${rootEndpoint}GenerateReport?studyID=${studyID}&acronym=${acronym}`;

    console.log("Sending Request");
    let response = await fetch(endpoint, {
        method: 'GET',
        headers: {
            'Content-Type': 'application/json',
            "Authorization": 'Bearer ' + jwtAccessToken
        }
    });

    console.log("Received Response. Parsing JSON.");
    let responsePayload = await response.json();
    console.log("JSON Parsed");

    if (response.status == 401)
    {
        // Unauthorized so redirect
        redirectCallback();
    }

    return responsePayload;
}


async function ProcessUser(confirmationID)
{
    let payload = {
        "confirmationID": confirmationID
    };

    let response = await fetch(rootEndpoint + "ConfirmUser", {
        method: 'POST',
        body: JSON.stringify(payload),
        headers: {
            'Content-Type': 'application/json'
        },
        signal: abortSignal
    });

    let responsePayload = await response.json();
    // ParseResponse(responsePayload);

    return responsePayload;
}

async function SubmitSurvey(subjectID, sendScheduling)
{
    let payload = {
        "subjectID": subjectID,
        "sendScheduling": sendScheduling
    };

    let response = await fetch(rootEndpoint + "SubmitSurvey", {
        method: 'PATCH',
        body: JSON.stringify(payload),
        headers: {
            'Content-Type': 'application/json'
        },
        signal: abortSignal
    });

    let responsePayload = await response.json();
    // ParseResponse(responsePayload);

    return responsePayload;
}

// Returns all study data
async function GetStudyData(jwtAccessToken, redirectCallback)
{
    let response = await fetch(rootEndpoint + "GetStudies", {
        method: 'GET',
        headers: {
            'Content-Type': 'application/json',
            "Authorization": 'Bearer ' + jwtAccessToken
        },
        signal: abortSignal
    });

    let responsePayload = await response.json();

    if (response.status == 401)
    {
        // Unauthorized so redirect
        redirectCallback();
    }

    // ParseResponse(responsePayload);

    return responsePayload;
}

/**
 * Generic REST request function. 
 * @param {string} endpointName - name of the method AFTER the root endpoint of the API
 * @param {httpMethods} httpMethod - "GET", "POST", "PATCH", etc.
 * @param {object} payload - Optional payload of data to send to the lambda
 * @param {string} jwtAccessToken - can be defined if needed for authorization
 * @param {method} redirectCallback - optional callback that will redirect the page on failure
 * @returns Parsed JSON Payload containing the response data
 * @public
 * @method
 */
async function RESTRequest(endpointName, httpMethod, payload = undefined, jwtAccessToken = undefined, redirectCallback = undefined)
{
    headerValues = {
        "Content-Type": "application/json"
    };

    if (jwtAccessToken !== undefined)
    {
        headerValues["Authorization"] = 'Bearer ' + jwtAccessToken;
    }

    let response = await fetch(rootEndpoint + endpointName, {
        method: httpMethod,
        headers: headerValues,
        body: payload === undefined ? undefined : JSON.stringify(payload),
        signal: abortSignal
    })
        .catch((error) =>
        {
            alert(error);

            if (redirectCallback !== undefined)
            {
                redirectCallback();
            }

            return {};
        });

    if (redirectCallback !== undefined && response.status == 401)
    {
        // Unauthorized so redirect
        redirectCallback();
    }

    let responsePayload = await response.json();

    return responsePayload;
}

async function UnsubscribeFromStudy(emailAddress, studyID)
{

    let payload = {
        "emailAddress": emailAddress,
        "studyID": studyID
    };

    let response = await fetch(rootEndpoint + "UnsubscribeStudy", {
        method: 'PATCH',
        body: JSON.stringify(payload),
        headers: {
            'Content-Type': 'application/json'
        },
        signal: abortSignal
    });

    let responsePayload = await response.json();

    // ParseResponse(responsePayload);

    return responsePayload;
}

async function GetParticipantData(jwtAccessToken, queryParams)
{

    let response = await fetch(rootEndpoint + "StudyParticipant" + queryParams, {
        method: 'GET',
        headers: {
            'Content-Type': 'application/json',
            "Authorization": 'Bearer ' + jwtAccessToken
        },
        signal: abortSignal
    });

    let responsePayload = await response.json();

    // ParseResponse(responsePayload);

    return responsePayload;
}

// Returns the query parameters of a GET request
// https://dev.to/ganeshmani/how-to-get-query-string-parameters-in-javascript-2019-4dm2
function GetQueryParameters(url)
{
    let queryParams = {};
    //create an anchor tag to use the property called search
    let anchor = document.createElement('a');
    //assigning url to href of anchor tag
    anchor.href = url;
    //search property returns the query string of url
    let queryStrings = anchor.search.substring(1);
    let params = queryStrings.split('&');

    for (var i = 0; i < params.length; i++)
    {
        var pair = params[i].split('=');
        queryParams[pair[0]] = decodeURIComponent(pair[1]);
    }
    return queryParams;
}

// Inserts data into RegistrationAnalytics table.
async function InsertAnalytics(referrerName, referrerGUID, studyID)
{
    let response = await fetch(rootEndpoint + "InsertAnalytics",
        {
            method: 'POST',
            body: JSON.stringify(
                {
                    "referrerName": referrerName,
                    "referrerGUID": referrerGUID,
                    "didRegister": false,
                    "didConfirmRegistration": false,
                    "studyID": studyID
                }
            ),
            headers:
            {
                'Content-Type': 'application/json'
            },
            signal: abortSignal
        });

    let responsePayload = await response.json();

    return responsePayload;
}