script.js

function castSpell() {
    const birthDateInput = document.getElementById("birthDate").value;
    const resultBox = document.getElementById("result");

    if (!birthDateInput) {
        resultBox.innerHTML = "請先輸入妙麗的誕生魔法時刻，方能啟動歲月咒語。";
        return;
    }

    const birthDate = new Date(birthDateInput);
    const now = new Date();

    const diffTime = now.getTime() - birthDate.getTime();
    const dogAge = diffTime / (1000 * 60 * 60 * 24 * 365.25);

    if (dogAge <= 0 || isNaN(dogAge)) {
        resultBox.innerHTML = "時間魔法發生錯亂，請確認誕生魔法時刻。";
        return;
    }

    const humanAge = 16 * Math.log(dogAge) + 31;
    const humanAgeRounded = Math.round(humanAge);

    const resultText = `
        水晶球顯示——<br><br>
        妙麗如今約 ${dogAge.toFixed(2)} 歲狗狗年齡，<br>
        換算成校長年齡，大約是 ${humanAgeRounded} 歲。
    `;

    resultBox.innerHTML = resultText;

    saveHistory(birthDateInput, dogAge.toFixed(2), humanAgeRounded);
}

function clearMagic() {
    document.getElementById("birthDate").value = "";
    document.getElementById("result").innerHTML = "";
}

function toggleReference() {
    document.getElementById("referenceBox").classList.toggle("hidden");
}

function toggleHistory() {
    const box = document.getElementById("historyBox");
    box.classList.toggle("hidden");
    loadHistory();
}

function saveHistory(date, dogAge, humanAge) {
    const history = JSON.parse(localStorage.getItem("magicHistory")) || [];

    history.push({
        date: date,
        dogAge: dogAge,
        humanAge: humanAge,
        time: new Date().toLocaleString()
    });

    localStorage.setItem("magicHistory", JSON.stringify(history));
}

function loadHistory() {
    const historyContent = document.getElementById("historyContent");
    const history = JSON.parse(localStorage.getItem("magicHistory")) || [];

    if (history.length === 0) {
        historyContent.innerHTML = "水晶球尚未記錄任何歲月痕跡。";
        return;
    }

    historyContent.innerHTML = history
        .slice()
        .reverse()
        .map(item => `
            <div style="margin-bottom:10px;">
                ✨ 記錄時間：${item.time}<br>
                誕生魔法時刻：${item.date}<br>
                狗狗年齡：約 ${item.dogAge} 歲<br>
                校長年齡：約 ${item.humanAge} 歲
            </div>
        `)
        .join("");
}