// Storage for the options that the server gives us. This will define our filters.
var options = {};
// Last time we updated the spots/alerts list on display.
var lastUpdateTime;


// For a parameter, such as dx_continent, get the query string for the current filter options.
function getQueryStringFor(parameter) {
    return parameter + "=" + encodeURIComponent(getSelectedFilterOptions(parameter));
}

// For a parameter, such as dx_continent, get the filter options that are currently selected in the UI.
function getSelectedFilterOptions(parameter) {
    return $(".filter-button-" + parameter).filter(function() {
        return this.checked;
    }).map(function() {
        return this.value;
    }).get().join(",");
}

// For a parameter, such as dx_continent, return true if all possible options are enabled. (In this case, we don't need
// to bother sending this as one of the query parameters to the API; no parameter provided implies "send everything".)
function allFilterOptionsSelected(parameter) {
    var filter = $(".filter-button-" + parameter).filter(function() {
        return !this.checked;
    }).get();
    return filter.length == 0;
}


// Generate a filter card with multiple toggle buttons plus All/None buttons
function generateMultiToggleFilterCard(displayName, filterQuery, options) {
    let $col = $("<div class='col'>")
    let $card = $("<div class='card'>");
    let $card_body = $("<div class='card-body'>");
    $card_body.append(`<h5 class='card-title'>${displayName}</h5>`);
    $p = $("<p class='card-text filter-card-text'>");
    // Create a button for each option
    options.forEach(o => {
        $p.append(`<input type="checkbox" class="btn-check filter-button-${filterQuery} storeable-checkbox" name="options" id="filter-button-${filterQuery}-${o}" value="${o}" autocomplete="off" onClick="filtersUpdated()" checked><label class="btn btn-outline-primary" for="filter-button-${filterQuery}-${o}">${o}</label> `);
    });
    // Create All/None buttons
    $p.append(` <span style="display: inline-block"><button id="filter-button-${filterQuery}-all" type="button" class="btn btn-outline-secondary" onclick="toggleFilterButtons('${filterQuery}', true);">All</button>&nbsp;<button id="filter-button-${filterQuery}-none" type="button" class="btn btn-outline-secondary" onclick="toggleFilterButtons('${filterQuery}', false);">None</button></span>`);
    // Compile HTML elements to return
    $card_body.append($p);
    $card.append($card_body);
    $col.append($card);
    return $col;
}

// Method called when "All" or "None" is clicked
function toggleFilterButtons(filterQuery, state) {
    $(".filter-button-" + filterQuery).each(function() {
        $(this).prop('checked', state);
    });
    filtersUpdated();
}

// Update the refresh timing display
function updateRefreshDisplay() {
    if (lastUpdateTime != null) {
        let count = REFRESH_INTERVAL_SEC;
        let secSinceUpdate = moment.duration(moment().diff(lastUpdateTime)).asSeconds();
        updatingString = "Updating..."
        if (secSinceUpdate < REFRESH_INTERVAL_SEC) {
            count = REFRESH_INTERVAL_SEC - secSinceUpdate;
            if (count <= 60) {
                var number = count.toFixed(0);
                updatingString = "Updating in <span class='nowrap'>" + number + " second" + (number != "1" ? "s" : "") + ".</span>";
            } else {
                var number = Math.round(count / 60.0).toFixed(0);
                updatingString = "Updating in <span class='nowrap'>" + number + " minute" + (number != "1" ? "s" : "") + ".</span>";
            }
        }
        $("#timing-container").html("Last updated at " + lastUpdateTime.format('HH:mm') + " UTC. " + updatingString);
    }
}

// Utility function to escape HTML characters from a string.
function escapeHtml(str) {
    if (typeof str !== 'string') {
        return '';
    }

    const escapeCharacter = (match) => {
        switch (match) {
            case '&': return '&amp;';
            case '<': return '&lt;';
            case '>': return '&gt;';
            case '"': return '&quot;';
            case '\'': return '&#039;';
            case '`': return '&#096;';
            default: return match;
        }
    };

    return str.replace(/[&<>"'`]/g, escapeCharacter);
}

// When the "use local time" field is changed, reload the table and save settings
function localTimeUpdated() {
    updateTable();
    saveSettings();
}

// Save settings to local storage
function saveSettings() {
    // Find all storeable UI elements, store a key of "element id:property name" mapped to the value of that
    // property. For a checkbox, that's the "checked" property.
    $(".storeable-checkbox").each(function() {
        localStorage.setItem("#" + $(this)[0].id + ":checked", $(this)[0].checked);
    });
    $(".storeable-select").each(function() {
        localStorage.setItem("#" + $(this)[0].id + ":value", $(this)[0].value);
    });
}

// Load settings from local storage and set up the filter selectors
function loadSettings() {
    // Find all local storage entries and push their data to the corresponding UI element
    Object.keys(localStorage).forEach(function(key) {
        if (key.startsWith("#") && key.includes(":")) {
            // Split the key back into an element ID and a property
            var split = key.split(":");
            $(split[0]).prop(split[1], JSON.parse(localStorage.getItem(key)));
        }
    });
}