const imperialUnitNames = ["cup", "ounce", "teaspoon", "pound"];

function findImperialUnitIndex(text) {
    return imperialUnitNames.findIndex(unitName => text.includes(unitName))
}

function textToNumber(text) {
    if (text == "¼") {
        return 0.25
    } else if (text == "½") {
        return 0.5
    } else if (text.includes("/")) {
        const [beforeSlash, afterSlash] = text.split("/")
        return Number(beforeSlash) / Number(afterSlash)
    } else {
        return Number(text)
    }
}

function convertUnits(amount, unitName) {
    if (unitName.includes("cup")) {
        amount = textToNumber(amount)
        const mlAmount = Math.round(amount*236.5882365)
        const gramsAmount = Math.round(amount*201.6)
        return ["~" + mlAmount, "ml or (~" + gramsAmount + " g)" ]

    } else if (unitName.includes("teaspoon")) {
        amount = textToNumber(amount)
        const mlAmount = Math.round(amount*5.919388)
        const gramsAmount = Math.round(amount*4.2605668424239)
        return ["~" + mlAmount, "ml or (~" + gramsAmount + " g)" ]

    } else if (unitName.includes("pound")) {
        return ["~" + Math.round(amount*453.59237), "grams"]

    } else if (unitName.includes("ounce")) {
        //amount = textToNumber(amount)
        //const gramsAmount = Math.fround(amount * 28.34952);
        return [amount, unitName]
        //return ["~" + , "grams"]

    } else {
        return [amount, unitName]
    }
}

function textNodesUnder(node) {
    var n, a=[], walk=document.createTreeWalker(node,NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_TEXT,null,false)
    while(n=walk.nextNode()) a.push(n)
    return a
}

function replaceImperialUnitsInText(text) {
    const words = text.split(" ")
    for (let i = 1; i < words.length; i++) {
        if (findImperialUnitIndex(words[i]) != -1) {
            const [newAmount, newUnitName] = convertUnits(words[i-1], words[i]);
            words[i-1] = newAmount
            words[i] = newUnitName
            updated = true
        }
    }

    return words.join(" ")
}

const content = document.getElementsByClassName("loc article-content")[0]
for (const textNode of textNodesUnder(content)) {
    if (!textNode.parentElement) continue;

    if (textNode.parentElement.classList.contains("mntl-structured-ingredients__list-item")) {
        let quantityChild;
        let unitNameChild;
        for (const child of textNode.childNodes) {
            if (!child.dataset) continue

            if ("ingredientQuantity" in child.dataset) {
                quantityChild = child
            } else if ("ingredientUnit" in child.dataset) {
                unitNameChild = child
            }
        }
        if (unitNameChild && quantityChild && quantityChild.textContent.length > 0) {
            if (findImperialUnitIndex(unitNameChild.textContent) == 0) {
                const [newAmount, newUnitName] = convertUnits(quantityChild.textContent, unitNameChild.textContent);
                quantityChild.textContent = newAmount
                unitNameChild.textContent = newUnitName
            } else {

            }
        }
    } else if (textNode.nodeValue && findImperialUnitIndex(textNode.nodeValue) != -1) {
        textNode.nodeValue = replaceImperialUnitsInText(textNode.nodeValue)
    }
}