function writeClipboard(value) {
    if (navigator.clipboard && window.isSecureContext) {
        return navigator.clipboard.writeText(value);
    }

    const textarea = document.createElement("textarea");
    textarea.value = value;
    textarea.setAttribute("readonly", "");
    textarea.style.position = "fixed";
    textarea.style.top = "-1000px";
    document.body.appendChild(textarea);
    textarea.select();
    document.execCommand("copy");
    document.body.removeChild(textarea);
    return Promise.resolve();
}

function nearestCopyValue(button) {
    if (button.dataset.copyValue) {
        return button.dataset.copyValue;
    }

    const scopes = [
        button.closest(".copy-row"),
        button.closest(".cmd-row"),
        button.closest("td"),
        button.parentElement,
    ];

    for (const scope of scopes) {
        if (!scope) {
            continue;
        }

        const target = scope.querySelector("input, textarea, pre, code");
        if (target) {
            return "value" in target ? target.value : target.textContent;
        }
    }

    return "";
}

function showCopied(button, ok) {
    const label = button.textContent;
    button.textContent = ok ? "Zkopírováno" : "Nelze kopírovat";
    window.setTimeout(() => {
        button.textContent = label;
    }, 1200);
}

function copyValue(idOrButton) {
    const target = typeof idOrButton === "string" ? document.getElementById(idOrButton) : idOrButton;
    if (!target) {
        return false;
    }

    const value = "value" in target ? target.value : nearestCopyValue(target);
    if ("select" in target) {
        target.select();
        target.setSelectionRange(0, target.value.length);
    }

    writeClipboard(value)
        .then(() => {
            if (!("value" in target)) {
                showCopied(target, true);
            }
        })
        .catch(() => {
            if (!("value" in target)) {
                showCopied(target, false);
            }
        });
    return false;
}

function copyText(button) {
    const value = nearestCopyValue(button);
    writeClipboard(value)
        .then(() => showCopied(button, true))
        .catch(() => showCopied(button, false));
    return false;
}