// Typeahead for the search box. Rather than ship 3,500 item names to every visitor, the input asks
// for the handful matching what has been typed and drops them into its <datalist>.
//
// Not importing /common.module.js: that module binds to a #log element on load, which this page
// does not have.

const input = document.getElementById("q");
const names = document.getElementById("drop-names");

/** The request whose answer is still wanted; any earlier one is stale. */
let inFlight = null;

if (input && names) {
    input.addEventListener("input", debounce(suggest, 150));

    // Someone arriving on ?q=… already has a query typed; offer the list for it straight away.
    if (input.value.trim()) suggest();
}

async function suggest() {
    const query = input.value.trim();
    if (query.length < 2) {
        names.replaceChildren();
        return;
    }

    // A slow response for "ni" must not overwrite the suggestions for "nikana p".
    inFlight?.abort();
    const request = inFlight = new AbortController();

    try {
        const response = await fetch(`/api/warframe/names?q=${encodeURIComponent(query)}`, {signal: request.signal});
        if (!response.ok) return;

        const suggestions = await response.json();
        names.replaceChildren(...suggestions.map(name => {
            const option = document.createElement("option");
            option.value = name;
            return option;
        }));
    } catch (error) {
        // An abort is this function doing its job; any other failure just means no suggestions,
        // and the form still submits.
        if (error.name !== "AbortError") console.debug("suggest failed", error);
    }
}

function debounce(callback, wait) {
    let timeoutId = null;
    return (...args) => {
        window.clearTimeout(timeoutId);
        timeoutId = window.setTimeout(() => callback(...args), wait);
    };
}