function humanReadableDate(str) {
    let date = new Date();
    let today = date.toISOString().split("T")[0];
    date.setDate(date.getDate() - 1);
    let yesterday = date.toISOString().split("T")[0];
    date.setDate(date.getDate() + 2);
    let tomorrow = date.toISOString().split("T")[0];
    return str.replace("T", " ").replaceAll(yesterday, "včera").replaceAll(today, "dnes").replaceAll(tomorrow, "zítra");
}

function refreshStatus(data) {
    let status = document.getElementById("status");
    let action, then_action;
    if (data["action"]) {
        action = "Povoleno"
        then_action = "zakázáno"
    } else {
        action = "Zakázáno"
        then_action = "povoleno"
    }
    let text = action;
    if (data["until"]) {
        text += " do " + humanReadableDate(data["until"]) + ", pak " + then_action;
        if (data["then_until"]) {
            text += " do " + humanReadableDate(data["then_until"]);
        } else {
            text += " napořád"
        }
    } else {
        text += " napořád"
    }
    status.textContent = text;
}

function refreshOverrides(data) {
    let overrides = document.getElementById("overrides");
    overrides.innerHTML = "";
    for (const record of data) {
        let overrideText = document.createElement("span");
        overrideText.textContent = (record["action"] ? "Povoleno" : "Zakázáno") + " od " + humanReadableDate(record["start"]) + " do " + humanReadableDate(record["end"]);
        let overrideButton = document.createElement("input");
        overrideButton.type = "button";
        overrideButton.value = "❌";
        overrideButton.addEventListener("click", async () => {
            let response = await fetch("api/delete-override", {
                method: "POST",
                headers: {"Content-Type": "application/json"},
                body: JSON.stringify({
                    action: record["action"],
                    start: record["start"],
                    end: record["end"]
                }),
            });
            await refresh(await response.json());
        })
        overrides.appendChild(overrideText);
        overrides.appendChild(overrideButton);
    }
}

function refreshSchedules(data) {
    for (const [day, entries] of Object.entries(data)) {
        let schedule = "Zakázáno"
        if (entries.length > 0) {
            schedule = entries.map((entry) => entry["start"] + " - " + entry["end"]).join(", ");
        }
        document.getElementById("schedule-" + day).textContent = schedule;
    }
}

async function refresh(data) {
    data = data || await (await fetch("api/data")).json();
    refreshStatus(data["status"]);
    refreshOverrides(data["overrides"]);
    refreshSchedules(data["schedules"]);
}

async function addOverride(e) {
    e.preventDefault();
    let response = await fetch("api/override", {
        method: "POST",
        headers: {"Content-Type": "application/json"},
        body: JSON.stringify({
            action: document.getElementById("override-action").value == "allow",
            start: document.getElementById("override-start").value,
            end: document.getElementById("override-end").value,
        }),
    });
    await refresh(await response.json());
    document.getElementById("add-override").reset();
}

async function updateSchedule(e) {
    e.preventDefault();
    let response = await fetch("api/schedule", {
        method: "POST",
        headers: {"Content-Type": "application/json"},
        body: JSON.stringify({
            action: document.getElementById("schedule-action").value == "allow",
            days: Array.from(document.getElementById("schedule-days").selectedOptions).map(v => parseInt(v.value)),
            start: document.getElementById("schedule-start").value,
            end: document.getElementById("schedule-end").value
        })
    });
    await refresh(await response.json());
    document.getElementById("update-schedule").reset();
}

async function fastAction(e) {
    let response = await fetch("api/fast-action/" + e.target.dataset.mins);
    await refresh(await response.json());
}

window.addEventListener("DOMContentLoaded", () => {
    refresh();
    document.getElementById("add-override").addEventListener("submit", addOverride);
    document.getElementById("update-schedule").addEventListener("submit", updateSchedule);
    Array.from(document.getElementsByClassName("fast-action")).forEach(function(element) {
        element.addEventListener("click", fastAction);
    });
    window.setInterval(refresh, 5000);
});