const isOldIE = function isOldIE() {
    let memo;
    return function memorize() {
        if (typeof memo === "undefined") {
            // Test for IE <= 9 as proposed by Browserhacks
            // @see http://browserhacks.com/#hack-e71d8692f65334173fee715c222cb805
            // Tests for existence of standard globals is to allow style-loader
            // to operate correctly into non-standard environments
            // @see https://github.com/webpack-contrib/style-loader/issues/177
            memo = Boolean(window && document && document.all && !window.atob);
        }
        return memo;
    };
}();
const getTargetElement = function() {
    const memo = {};
    return function memorize(target) {
        if (typeof memo[target] === "undefined") {
            let styleTarget = document.querySelector(target);
            // Special case to return head of iframe instead of iframe itself
            if (window.HTMLIFrameElement && styleTarget instanceof window.HTMLIFrameElement) {
                try {
                    // This will throw an exception if access to iframe is blocked
                    // due to cross-origin restrictions
                    styleTarget = styleTarget.contentDocument.head;
                } catch (e) {
                    // istanbul ignore next
                    styleTarget = null;
                }
            }
            memo[target] = styleTarget;
        }
        return memo[target];
    };
}();
const stylesInDom = [];
function getIndexByIdentifier(identifier) {
    let result = -1;
    for(let i = 0; i < stylesInDom.length; i++){
        if (stylesInDom[i].identifier === identifier) {
            result = i;
            break;
        }
    }
    return result;
}
function modulesToDom(list, options) {
    const idCountMap = {};
    const identifiers = [];
    for(let i = 0; i < list.length; i++){
        const item = list[i];
        const id = options.base ? item[0] + options.base : item[0];
        const count = idCountMap[id] || 0;
        const identifier = id + " " + count.toString();
        idCountMap[id] = count + 1;
        const index = getIndexByIdentifier(identifier);
        const obj = {
            css: item[1],
            media: item[2],
            sourceMap: item[3]
        };
        if (index !== -1) {
            stylesInDom[index].references++;
            stylesInDom[index].updater(obj);
        } else {
            stylesInDom.push({
                identifier: identifier,
                // eslint-disable-next-line @typescript-eslint/no-use-before-define
                updater: addStyle(obj, options),
                references: 1
            });
        }
        identifiers.push(identifier);
    }
    return identifiers;
}
function insertStyleElement(options) {
    const style = document.createElement("style");
    const attributes = options.attributes || {};
    if (typeof attributes.nonce === "undefined") {
        const nonce = // eslint-disable-next-line no-undef
        typeof __webpack_nonce__ !== "undefined" ? __webpack_nonce__ : null;
        if (nonce) {
            attributes.nonce = nonce;
        }
    }
    Object.keys(attributes).forEach(function(key) {
        style.setAttribute(key, attributes[key]);
    });
    if (typeof options.insert === "function") {
        options.insert(style);
    } else {
        const target = getTargetElement(options.insert || "head");
        if (!target) {
            throw new Error("Couldn't find a style target. This probably means that the value for the 'insert' parameter is invalid.");
        }
        target.appendChild(style);
    }
    return style;
}
function removeStyleElement(style) {
    // istanbul ignore if
    if (style.parentNode === null) {
        return false;
    }
    style.parentNode.removeChild(style);
}
/* istanbul ignore next  */ const replaceText = function replaceText() {
    const textStore = [];
    return function replace(index, replacement) {
        textStore[index] = replacement;
        return textStore.filter(Boolean).join("\n");
    };
}();
function applyToSingletonTag(style, index, remove, obj) {
    const css = remove ? "" : obj.media ? "@media " + obj.media + " {" + obj.css + "}" : obj.css;
    // For old IE
    /* istanbul ignore if  */ if (style.styleSheet) {
        style.styleSheet.cssText = replaceText(index, css);
    } else {
        const cssNode = document.createTextNode(css);
        const childNodes = style.childNodes;
        if (childNodes[index]) {
            style.removeChild(childNodes[index]);
        }
        if (childNodes.length) {
            style.insertBefore(cssNode, childNodes[index]);
        } else {
            style.appendChild(cssNode);
        }
    }
}
function applyToTag(style, _options, obj) {
    let css = obj.css;
    const media = obj.media;
    const sourceMap = obj.sourceMap;
    if (media) {
        style.setAttribute("media", media);
    } else {
        style.removeAttribute("media");
    }
    if (sourceMap && typeof btoa !== "undefined") {
        css += "\n/*# sourceMappingURL=data:application/json;base64," + btoa(unescape(encodeURIComponent(JSON.stringify(sourceMap)))) + " */";
    }
    // For old IE
    /* istanbul ignore if  */ if (style.styleSheet) {
        style.styleSheet.cssText = css;
    } else {
        while(style.firstChild){
            style.removeChild(style.firstChild);
        }
        style.appendChild(document.createTextNode(css));
    }
}
let singleton = null;
let singletonCounter = 0;
function addStyle(obj, options) {
    let style;
    let update;
    let remove;
    if (options.singleton) {
        const styleIndex = singletonCounter++;
        style = singleton || (singleton = insertStyleElement(options));
        update = applyToSingletonTag.bind(null, style, styleIndex, false);
        remove = applyToSingletonTag.bind(null, style, styleIndex, true);
    } else {
        style = insertStyleElement(options);
        update = applyToTag.bind(null, style, options);
        remove = function() {
            removeStyleElement(style);
        };
    }
    update(obj);
    return function updateStyle(newObj) {
        if (newObj) {
            if (newObj.css === obj.css && newObj.media === obj.media && newObj.sourceMap === obj.sourceMap) {
                return;
            }
            update(obj = newObj);
        } else {
            remove();
        }
    };
}
module.exports = function(list, options) {
    options = options || {};
    // Force single-tag solution on IE6-9, which has a hard limit on the # of <style>
    // tags it will allow on a page
    if (!options.singleton && typeof options.singleton !== "boolean") {
        options.singleton = isOldIE();
    }
    list = list || [];
    let lastIdentifiers = modulesToDom(list, options);
    return function update(newList) {
        newList = newList || [];
        if (Object.prototype.toString.call(newList) !== "[object Array]") {
            return;
        }
        for(let i = 0; i < lastIdentifiers.length; i++){
            const identifier = lastIdentifiers[i];
            const index = getIndexByIdentifier(identifier);
            stylesInDom[index].references--;
        }
        const newLastIdentifiers = modulesToDom(newList, options);
        for(let i = 0; i < lastIdentifiers.length; i++){
            const identifier = lastIdentifiers[i];
            const index = getIndexByIdentifier(identifier);
            if (stylesInDom[index].references === 0) {
                stylesInDom[index].updater();
                stylesInDom.splice(index, 1);
            }
        }
        lastIdentifiers = newLastIdentifiers;
    };
};

//# sourceMappingURL=injectStylesIntoStyleTag.js.map