// Copyright (c) 2024, snegov
// All rights reserved.

const pathnameRegex = /^\/\w{2}-\w{2}\/n?iv/;
const MAX_SIGNIN_ATTEMPTS = 1;
const PAGE_WAIT_TIME = 3792;
const MINUTE = 60;
const RANDOM_JITTER = 0.1;
const SOFT_BAN_TIMEOUT = 27;
const NOTIF_CHANNEL = "snegov_test"

let config = {
    activate: null,
    username: null,
    password: null,
    frequency: null,
    apptId: null,
    currentAppt: {
        consulate: null,
        date: null,
    },
    signinAttempts: null,
    consulates: null,
    deltaAppt: null,
    deltaNow: null,
};
let isRunning = false;
let msg = "";
let isFoundAppointment = false;

async function delay(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
}

async function sendNotification(message, channel = NOTIF_CHANNEL) {
    await fetch('https://ntfy.sh/' + channel, {
        method: 'POST',
        body: "[US visa bot] " + message,
    })
    .then(() => console.log('Notification sent'))
    .catch(e => console.error(e));
}

function getRandomInt(max) {
    return Math.floor(Math.random() * Math.floor(max));
}


function getJitter(frequency) {
    return frequency * MINUTE * RANDOM_JITTER;
}

function getFutureDate(minutes, maxRandomSeconds = 0) {
    // return date some amount of minutes in future plus random amount of seconds
    let futureDate = new Date();
    futureDate.setSeconds(futureDate.getSeconds() + minutes * MINUTE + getRandomInt(maxRandomSeconds));
    return futureDate.toISOString();
}

function hiddenPassword(config) {
    return {
        ...config,
        password: config.password.replace(/./g, "*"),
    };
}

function diffObjects(obj1, obj2) {
    let diff = {};

    for (let key in obj1) {
        if (typeof obj1[key] === 'object' && obj1[key] !== null && obj2[key]) {
            let nestedDiff = diffObjects(obj1[key], obj2[key]);
            if (Object.keys(nestedDiff).length > 0) {
                diff[key] = nestedDiff;
            }
        } else if (obj2[key] && obj1[key] !== obj2[key]) {
            diff[key] = [obj1[key], obj2[key]];
        }
    }

    for (let key in obj2) {
        if (obj1[key] === undefined && obj2[key] !== undefined) {
            diff[key] = [undefined, obj2[key]];
        }
    }

    return diff;
}

function getPathnameParts(pathname) {
    let pathParts = pathname.split('/');
    let locale = pathParts[1] || 'en-us';
    let visaType = pathParts[2] || 'niv';
    return [ locale, visaType ];
}

function isSignInPage() {
    return Boolean(window.location.pathname.match(/^\/\w{2}-\w{2}\/n?iv\/users\/sign_in/));
}

function isLoggedOutPage() {
    return Boolean(window.location.pathname.match(/^\/\w{2}-\w{2}\/n?iv$/));
}

function isDashboardPage() {
    return Boolean(window.location.pathname.match(/^\/\w{2}-\w{2}\/n?iv\/groups\/\d+/));
}

function isAppointmentPage() {
    return Boolean(window.location.pathname.match(/^\/\w{2}-\w{2}\/n?iv\/schedule\/\d+\/appointment$/));
}

function isConfirmationPage() {
    return Boolean(window.location.pathname.match(/^\/\w{2}-\w{2}\/n?iv\/schedule\/\d+\/appointment\/instructions$/));
}

function isNotEnglishPage() {
    return Boolean(isSignInPage()
            || isLoggedOutPage()
            || isDashboardPage()
            || isAppointmentPage()
            || isConfirmationPage()
        ) && !window.location.pathname.match(/^\/en-/);
}

async function handleHttpError(e) {
    if (e.response && e.response.status === 401) {
        msg = "Unauthorized";
        console.log(msg);
        await sendNotification(msg);
        await logOut();
        return null;
    } else {
        console.error(e);
        return null;
    }
}

async function switchToEnglishPage() {
    window.location.href(window.location.pathname.replace(/^\/\w{2}-{2}/, '/en-us'));
    await delay(PAGE_WAIT_TIME);
    // Should be on English page
}

async function logOut() {
    let [locale, visaType] = getPathnameParts(window.location.pathname);
    let signOutPath = `/${locale}/${visaType}/users/sign_out`;
    window.location.href = window.location.origin + signOutPath;
    await delay(PAGE_WAIT_TIME);
    return isLoggedOutPage();
}

async function goToSignInPage() {
    let [locale, visaType] = getPathnameParts(window.location.pathname);
    let signInPath = `/${locale}/${visaType}/users/sign_in`;
    window.location.href = window.location.origin + signInPath;
    await delay(PAGE_WAIT_TIME);
    return isSignInPage();
}

async function goToDashboardPage() {
    let [locale, visaType] = getPathnameParts(window.location.pathname);
    let dashboardPath = `/${locale}/${visaType}/account`;
    window.location.href = window.location.origin + dashboardPath;
    await delay(PAGE_WAIT_TIME);
    return isDashboardPage();
}

async function enterCredentials() {
    document.getElementById("user_email").value = config.username;
    document.getElementById("user_password").value = config.password;
    let policyConfirmed = document.querySelector('[for="policy_confirmed"]');
    if (!policyConfirmed.getElementsByTagName('input')[0].checked) {
        policyConfirmed.click();
    }
    document.querySelector("#sign_in_form input[type=submit]").click();

    await delay(PAGE_WAIT_TIME);
    return isDashboardPage();
}

async function getAppointmentId() {
    let appointments = document.querySelectorAll("p.consular-appt [href]")
    if (appointments.length > 1) {
        console.log("Multiple appointments found, taking the first one");
    }

    let apptId = appointments[0].href.replace(/\D/g, "");
    return apptId;
}

async function getConsulates() {
    let consulatesSelect = document.querySelector("#appointments_consulate_appointment_facility_id")
    let consulatesDict = {};

    for (let option of consulatesSelect.options) {
        if (!option.value) continue;    // skip empty option
        consulatesDict[option.text] = {
            "id": parseInt(option.value),
            "isSelected": option.selected,
            "bestDate": null,
            "currentDate": null,
            "nextCheckAt": getFutureDate(0, getJitter(config.frequency)),
            "autobook": false,
        };
    }
    return consulatesDict;
}

async function getAvailableDates(consulateId) {
    let uri = window.location.pathname + `/days/${consulateId}.json?appointments[expedite]=false`
    let dates = fetch(uri, { headers: { "x-requested-with": "XMLHttpRequest" }})
        .then(d => d.json())
        .then(data => {
            let dateList = data.map(item => item.date);
            dateList.sort();
            return dateList;
        })
        .catch(async e => handleHttpError(e));
    return dates;
}

async function filterDates(dates, currentAppt, deltaFromAppt, deltaFromNow) {
    let maxDate = new Date(currentAppt);
    // let maxDate = new Date("2029-09-09");
    maxDate.setDate(maxDate.getDate() - deltaFromAppt);
    let minDate = new Date();
    minDate.setDate(minDate.getDate() + deltaFromNow);
    let availableDates = dates.filter(d => new Date(d) >= minDate && new Date(d) < maxDate);
    return availableDates;
}

async function getAvailableTimes(consulateId, date) {
    let uri = window.location.pathname + `/times/${consulateId}.json?date=${date}&appointments[expedite]=false`
    let times = await fetch(uri, { headers: { "x-requested-with": "XMLHttpRequest" } })
        .then(d => d.json())
        .then(data => data.available_times)
        .catch(e => handleHttpError(e));
    return times;
}

async function runner() {
    if (isRunning) {
        return;
    }
    isRunning = true;
    // console.log('runner start');

    let prev_config = Object.assign({}, config);

    let result = await new Promise(resolve => chrome.storage.local.get(null, resolve));
    config.activate = result['__activate'] || false;
    config.username = result['__username'] || "";
    config.password = result['__password'] || "";
    config.frequency = parseFloat(result['__frequency'] || 1);
    config.signinAttempts = result['__signinAttempts'] || 0;
    config.apptId = result['__apptId'] || null;
    config.currentAppt = result['__currentAppt'] || { consulate: null, date: null };
    config.consulates = result['__consulates'] || null;
    config.deltaAppt = result['__deltaAppt'] || 1;
    config.deltaNow = result['__deltaNow'] || 1;

    if (prev_config.activate === null) {
        console.log('Reading config: ' + JSON.stringify(hiddenPassword(config)));
        isRunning = false;
        return;
    }

    for (let key in config) {
        if (config.hasOwnProperty(key)
                && !_.isEqual(config[key], prev_config[key])) {
            msg = `Config change: ${key}`
            if (key === 'password') {
                msg += ', ******** => ********';
            } else if (key === 'consulates') {
                msg += `, ${JSON.stringify(diffObjects(config[key], prev_config[key]))}`;
            } else {
                msg += `, ${prev_config[key]} => ${config[key]}`;
            }   
            console.log(msg);

            // reduce wait times for consulates if frequency is increased
            if (key === 'frequency') {
                let wasChanged = false;
                for (let consulate in config.consulates) {
                    let newNextCheckAt = getFutureDate(config.frequency, getJitter(config.frequency));
                    if (config.consulates[consulate].nextCheckAt > newNextCheckAt) {
                        config.consulates[consulate].nextCheckAt = newNextCheckAt;
                        wasChanged = true;
                        console.log(`Reducing wait time for ${consulate} from ${config.consulates[consulate].nextCheckAt} to ${newNextCheckAt}`);
                    }
                }
                // TODO maybe causes additional requests
                if (wasChanged) {
                    await chrome.storage.local.set({ "__consulates": config.consulates });
                }
            }

            if (key === 'activate') {
                if (config[key]) {
                    console.log('Activating extension');
                } else {
                    console.log('Deactivating extension');
                    await chrome.storage.local.set({ "__status": "inactive" });
                }
            }

            // clear signin attempts when credentials are changed
            if (key === 'username' && config[key]
                    || key === 'password' && config[key]) {
                config.signinAttempts = 0;
                await chrome.storage.local.set({ "__signinAttempts": config.signinAttempts });
            }
        }
    }

    if (!config.activate) {
        isRunning = false;
        return;
    }

    if (config.username === "" || config.password === "") {
        console.log('Username or password is empty');
        await chrome.storage.local.set({ "__status": "missing credentials" });
        isRunning = false;
        return;
    }

    if (config.frequency <= 0) {
        console.log('Frequency is 0 or negative');
        await chrome.storage.local.set({ "__status": "invalid frequency" });
        isRunning = false;
        return;
    }

    // Check if current time is between 11pm and 9am UTC (4pm - 2am PST)
    let now = new Date();
    let currentHourUTC = now.getUTCHours();
    if (currentHourUTC >= 23 || currentHourUTC < 9) {
        // Continue running the code
    } else {
        await chrome.storage.local.set({ "__status": "not operational hours" });
        isRunning = false;
        return;
    }

    if (isFoundAppointment) {
        // don't do anything if appointment is found and manual booking is required
        if (isAppointmentPage()) {
            isRunning = false;
            return;
        // we're not on an appointment page, so seems like we're done, and we can check dates again
        } else {
            isFoundAppointment = false;
        }
    }

    if (isNotEnglishPage()) {
        await switchToEnglishPage();
    }

    if (isLoggedOutPage()) {
        if (!await goToSignInPage()) {
            msg = 'Failed to go to sign in page';
            console.log(msg);
            await chrome.storage.local.set({ "__status": msg });
            isRunning = false;
            return;
        };

    }
    
    else if (isSignInPage()) {
        // Prevent brute forcing
        if (config.signinAttempts >= MAX_SIGNIN_ATTEMPTS) {
            await chrome.storage.local.set({ "__status": "too many sign in attempts" });
            isRunning = false;
            return;
        }
    
        // Sign in
        msg = 'Signing in attempt: ' + config.signinAttempts;
        console.log(msg)
        await chrome.storage.local.set({ "__status": msg });
        let signedIn = await enterCredentials();
        config.signinAttempts += 1;
        await chrome.storage.local.set({ "__signinAttempts": config.signinAttempts });
        if (!signedIn) {
            msg = 'Failed to sign in';
            console.log(msg);
            await chrome.storage.local.set({ "__status": msg });
            isRunning = false;
            return;
        };
    
    }
    
    else if (isDashboardPage()) {
        // reset signin attempts when successfully logged in
        config.signinAttempts = 0;
        await chrome.storage.local.set({ "__status": "fetching appointment info" });
        await chrome.storage.local.set({ "__signinAttempts": config.signinAttempts });

        // get appointmentId
        if (!config.apptId) {
            config.apptId = await getAppointmentId();
            if (config.apptId) {
                console.log(`Appointment ID: ${config.apptId}`);
                await chrome.storage.local.set({ "__apptId": config.apptId });            
            } else {
                msg = 'No appointments found';
                console.log(msg);
                await chrome.storage.local.set({ "__status": msg });
                isRunning = false;
                return;
            }
        }

        // get current appointment date
        let apptInfoCard = document.querySelector("p.consular-appt [href*='" + config.apptId + "']").parentNode.parentNode.parentNode
        if (!apptInfoCard.querySelector("h4").innerText.match(/Attend Appointment/)) {
            msg = 'Appointment not available';
            console.log(msg);
            await chrome.storage.local.set({ "__status": msg });
            isRunning = false;
            return;
        }
        let apptInfo = apptInfoCard.querySelector("p.consular-appt").innerText;
        let apptConsulate = (apptInfo.match(/at (\w+)/) || [])[1];
        let apptDate = new Date(apptInfo.match(/\d{1,2} \w+, \d{4}/)[0]);
        apptDate = apptDate.toISOString().slice(0, 10);
        if (apptDate && apptConsulate
                && (apptDate != config.currentAppt.date
                    || apptConsulate != config.currentAppt.consulate)) {
            console.log(`New appointment date: ${apptDate} at ${apptConsulate},
                            old: ${config.currentAppt.consulate} at ${config.currentAppt.date}`);
            config.currentAppt.date = apptDate;
            config.currentAppt.consulate = apptConsulate;
            await chrome.storage.local.set({ "__currentAppt": config.currentAppt });
        }

        // go to appointment page
        let apptLink = apptInfoCard.querySelector("p.consular-appt [href]")
            .getAttribute("href").replace("/addresses/consulate", "/appointment");
        window.location.href = apptLink;
        await delay(PAGE_WAIT_TIME);
    }

    else if (isAppointmentPage()) {
        // if no apptDate, fetch it from dashboard page
        if (!config.currentAppt.date) {
            console.log('No appointment date is set, going back to dashboard');
            await goToDashboardPage();
            isRunning = false;
            return;
        }

        // await chrome.storage.local.set({ "__status": "fetching consulates" });
        let applicantForm = document.querySelector('form[action*="' + window.location.pathname + '"]');
        if (applicantForm && applicantForm.method.toLowerCase() == "get") {
            applicantForm.submit();
            await delay(PAGE_WAIT_TIME);
            isRunning = false;
            return;
        }

        if (!document.getElementById("consulate_date_time")) {
            msg = 'No available appointments';
            console.log(msg);
            await chrome.storage.local.set({ "__status": msg });
            isRunning = false;
            return;
        };

        if (!config.consulates) {
            config.consulates = await getConsulates();
            await chrome.storage.local.set({ "__consulates": config.consulates });
        }
        if (!config.consulates) {
            console.log('No consulates found');
            await chrome.storage.local.set({ "__status": "no consulates found" });
            isRunning = false;
            return;
        }

        // TODO choose ASC facility
        // document.querySelector("#appointments_asc_appointment_facility_id [selected]").innerText

        // for each selected consulate check available dates
        let selectedConsulates = Object.keys(config.consulates).filter(c => config.consulates[c].isSelected);
        if (selectedConsulates.length == 0) {
            msg = 'No selected consulates found';
            console.log(msg);
            await chrome.storage.local.set({ "__status": msg });
            isRunning = false;
            return;
        }

        let processedConsulates = 0;
        for (let consulate of selectedConsulates) {
            // only one consulate per run
            if (processedConsulates > 0) {
                break;
            }
            // skip if not time to check
            if (config.consulates[consulate].nextCheckAt > new Date().toISOString()) {
                continue;
            }

            processedConsulates += 1;

            msg = `Checking dates for ${consulate}`;
            console.log(msg);
            await chrome.storage.local.set({ "__status": msg });
            let availDates = await getAvailableDates(config.consulates[consulate].id);
            config.consulates[consulate].nextCheckAt = getFutureDate(config.frequency, getJitter(config.frequency));

            if (!availDates) {
                msg = `Failed to fetch available dates in ${consulate}`;
                console.log(msg);
                await chrome.storage.local.set({ "__status": msg });
                continue;
            }

            // if empty list, either we're banned or non operational hours or dead consulate
            // wait for some time before checking again
            let now = new Date();
            let currentHourUTC = now.getUTCHours();
            let currentMinuteUTC = now.getUTCMinutes();

            if (availDates.length == 0) {
                msg = `No available dates in ${consulate}, probably banned`;
                console.log(msg);
                await chrome.storage.local.set({ "__status": msg });

                // Only set SOFT_BAN_TIMEOUT if it's not the first 5 minutes of 23pm UTC
                if (!(currentHourUTC === 23 && currentMinuteUTC < 5)) {
                    config.consulates[consulate].nextCheckAt = getFutureDate(SOFT_BAN_TIMEOUT, getJitter(config.frequency));
                }
            
                continue;
            }

            msg = `Available dates for ${consulate}: ${availDates.slice(0, 5)}`;
            if (availDates.length > 5) {
                msg += ` and ${availDates.length - 10} more`;
            }
            console.log(msg);
            config.consulates[consulate].currentDate = availDates[0];
            if (!config.consulates[consulate].bestDate
                    || availDates[0] < config.consulates[consulate].bestDate) {
                console.log(`New record for ${consulate}: ${availDates[0]}`);
                config.consulates[consulate].bestDate = availDates[0];
            }

            // filter dates with our requests
            let filteredDates = await filterDates(availDates, config.currentAppt.date, config.deltaAppt, config.deltaNow);
            if (!filteredDates.length) {
                console.log(`No better dates in ${consulate}, currently available ${availDates[0]}`);
                await chrome.storage.local.set({ "__status": `No better dates in ${consulate}`});
                continue;
            }

            console.log(`Dates worth rescheduling in ${consulate}: ${filteredDates}`);
            let chosenDate = filteredDates[0];
            await chrome.storage.local.set({ "__status": `Found in ${consulate} better date ${chosenDate}`});

            // fill date in reschedule form
            await delay(PAGE_WAIT_TIME);
            document.getElementById("appointments_consulate_appointment_date").value = chosenDate;
            document.getElementById("appointments_consulate_appointment_time").innerHTML = "<option></option>"
    
            let availTimes = await getAvailableTimes(config.consulates[consulate].id, chosenDate);
            if (!availTimes) {
                msg = `Failed to fetch available timeslots in ${consulate} at ${chosenDate}`;
                console.log(msg);
                await chrome.storage.local.set({ "__status": msg});
                continue;
            }
            if (availTimes.length == 0) {
                msg = `No timeslots in ${consulate} at ${chosenDate}`;
                console.log(msg);
                await chrome.storage.local.set({ "__status": msg});
                continue;
            }
            console.log(`Available timeslots in ${consulate} at ${chosenDate}: ${availTimes}`);
            let chosenTime = availTimes[0];
    
            // fill timeslot in reschedule form
            await delay(PAGE_WAIT_TIME);
            document.getElementById("appointments_consulate_appointment_time").innerHTML = `<option value='${chosenTime}'>${chosenTime}</option>`;
            document.getElementById("appointments_consulate_appointment_time").value = chosenTime;

            // TODO process ASC facilities here

            await delay(PAGE_WAIT_TIME);
            document.getElementById("appointments_submit").removeAttribute("disabled");
            document.getElementById("appointments_submit").click();

            msg = `Found better appointment in ${consulate} at ${chosenDate} ${chosenTime}`;
            console.log(msg);
            await sendNotification(msg);

            if (!config.consulates[consulate].autobook) {
                isFoundAppointment = true;
            } else {
                await delay(PAGE_WAIT_TIME);
                msg = `Auto booking in ${consulate} at ${chosenDate} ${chosenTime}`;
                console.log(msg);
                await sendNotification(msg);
                document.querySelector(".reveal-overlay:last-child [data-reveal] .button.alert").click();
            }
        } // end consulates loop

        for (let consulate in config.consulates) {
            if (!prev_config?.consulates?.[consulate]) continue;
            if (config.consulates[consulate].nextCheckAt != prev_config.consulates[consulate].nextCheckAt) {
                console.log(`Next check for ${consulate} at ${config.consulates[consulate].nextCheckAt}`);
            }
        }
        await chrome.storage.local.set({ "__consulates": config.consulates });
        isRunning = false;
        return;
    }
    
    else if (isConfirmationPage) {
        // go back to dashboard after successful reschedule
        await delay(PAGE_WAIT_TIME);
        config.currentAppt = { consulate: null, date: null};
        await chrome.storage.local.set({"__currentAppt": config.currentAppt});
        console.log('Rescheduled successfully');
        
        // switch off autobook for all consulates after successful reschedule
        for (let consulate in config.consulates) {
            config.consulates[consulate].autobook = false;
        }

        await goToDashboardPage();
    }

    // console.log('runner done');
    isRunning = false;
}

setInterval(runner, 1000);