import {$, doAfterLoad, footer, header, nav, showPage} from "@fwdekker/template";


const storageKey = "/tools/random-fo76//selected-signatures";
const signatureColCount = 8;


/**
 * Fetches the API response given a query.
 *
 * @param query the query to send to the API
 * @param callback the function to execute with the array of signatures
 * @param handle the function to execute if signatures could not be downloaded
 */
const fetchFromApi = (query, callback, handle) => {
    fetch(`api.php?${query}`)
        .then(response => {
            if (!response.ok) {
                if (handle) handle(response);
                console.error(response);
                throw new Error(`Failed to execute query '${query}' on API.`);
            }

            return response.json();
        })
        .then(response => callback(response));
}


/**
 * Returns an array of the signatures that are currently selected.
 */
const getSelectedSignatures = () => {
    const signatures = [];

    const selectedCheckboxes = document.querySelectorAll("#signatures input:checked");
    for (let i = 0; i < selectedCheckboxes.length; i++) {
        const selectedCheckbox = selectedCheckboxes[i];
        signatures.push(selectedCheckbox.value);
    }

    return signatures;
};

/**
 * Selects the indicated signatures, and deselects all others.
 *
 * @param signatures the array of signatures to select
 */
const setSelectedSignatures = signatures => {
    const checkboxes = document.querySelectorAll("#signatures input");
    for (let i = 0; i < checkboxes.length; i++)
        checkboxes[i].checked = false;

    for (let i = 0; i < signatures.length; i++)
        $(`#signature-${signatures[i]}`).checked = true;

    updateSignatureToggle();
};

/**
 * Selects all signatures.
 */
const setAllSignatures = checked => {
    const checkboxes = document.querySelectorAll("#signatures input");
    for (let i = 0; i < checkboxes.length; i++)
        checkboxes[i].checked = checked;
    saveSelectedSignaturesToStorage();

    updateSignatureToggle();
};

/**
 * (De)selects signatures based on the selection stored in local storage.
 */
const loadSelectedSignaturesFromStorage = () => {
    const item = localStorage.getItem(storageKey);
    let signatures;
    if (item === null)
        signatures = [];
    else
        signatures = item.split(",");

    setSelectedSignatures(signatures);
};

/**
 * Saves the currently-selected signatures to local storage.
 */
const saveSelectedSignaturesToStorage = () => localStorage.setItem(storageKey, getSelectedSignatures().join(","));

/**
 * Updates the button used to toggle all signatures on or off.
 */
const updateSignatureToggle = () => {
    const signatureToggle = $("#signatureToggle");

    if (getSelectedSignatures().length === document.querySelectorAll("#signatures input").length) {
        signatureToggle.innerHTML = "Deselect all signatures";
        signatureToggle.onclick = () => setAllSignatures(false);
    } else {
        signatureToggle.innerHTML = "Select all signatures";
        signatureToggle.onclick = () => setAllSignatures(true);
    }
};


/**
 * Creates buttons for the signatures and adds them to the form.
 *
 * @param signatures an array of signatures to create buttons for
 */
const createSignatureButtons = signatures => {
    const form = $("#signatures");
    form.innerHTML = "";

    let row;
    for (let i = 0; i < signatures.length; i++) {
        const signature = signatures[i];

        if (i % signatureColCount === 0) {
            if (row !== undefined)
                form.appendChild(row);

            row = document.createElement("div");
            row.className = "row";
        }

        const col = document.createElement("div");
        col.className = "column";

        const label = document.createElement("label");
        label.htmlFor = `signature-${signature}`;
        label.innerHTML = signature;
        col.appendChild(label);

        const checkbox = document.createElement("input");
        checkbox.type = "checkbox";
        checkbox.id = `signature-${signature}`;
        checkbox.name = `signature-${signature}`;
        checkbox.value = signature;
        checkbox.onclick = () => {
            updateSignatureToggle();
            saveSelectedSignaturesToStorage();
        };
        col.appendChild(checkbox);

        row.appendChild(col);
    }
    if (row !== undefined)
        form.appendChild(row);
};

/**
 * Displays a record on the page.
 *
 * @param record the record to display
 */
const showRecord = (record) => {
    $("#output").innerHTML = JSON.stringify(record, null, 4);

    const scrollingElement = (document.scrollingElement || document.body);
    scrollingElement.scrollTop = scrollingElement.scrollHeight;
};


// Apply template
doAfterLoad(() => {
    $("#nav").appendChild(nav("/Tools/Random FO76/"));
    $("#header").appendChild(header({
        title: "Random Fallout 76 record",
        description: "Retrieve a random record from the <i>Fallout 76</i> game files"
    }));
    $("#footer").appendChild(footer({
        author: "Felix W. Dekker",
        authorURL: "https://fwdekker.com/",
        license: "MIT License",
        licenseURL: "https://git.fwdekker.com/FWDekker/random-fo76/src/branch/master/LICENSE",
        vcs: "git",
        vcsURL: "https://git.fwdekker.com/FWDekker/random-fo76/",
        version: "v%%VERSION_NUMBER%%"
    }));
    showPage();
});

// Load page from API
doAfterLoad(() => {
    fetchFromApi("action=get-meta",
        meta => {
            $("#gameVersion").innerHTML = meta["game_version"];
            $("#dumpsVersion").innerHTML = meta["dumps_version"];
        },
        () => {
            $("#gameVersion").innerHTML = "Error";
            $("#dumpsVersion").innerHTML = "Error";
        }
    );

    fetchFromApi("action=list-signatures",
        signatures => {
            createSignatureButtons(signatures);
            loadSelectedSignaturesFromStorage();
        },
        () => {
            const form = $("#signatureForm");
            form.style.color = "red";
            form.innerHTML = "Error: Failed to download signatures. Try reloading the page.";
        }
    );
});

// Install handlers
doAfterLoad(() => {
    $("#submit").onclick = () => {
        $("#output").innerHTML = "Fetching record... please wait";

        const selectedSignatures = getSelectedSignatures();
        fetchFromApi(`action=get-random&signatures=${selectedSignatures.join(",")}`,
            record => showRecord(record)
        );
    };
});