const ANILIST_API = 'https://graphql.anilist.co';
const CACHE_NAME = 'waifuboard-schedule-v1';
const CACHE_DURATION = 5 * 60 * 1000;

const state = {
    currentDate: new Date(),
    viewType: 'MONTH',
    mode: 'SUB',
    loading: false,
    abortController: null,
    refreshInterval: null
};

document.addEventListener('DOMContentLoaded', () => {
    renderHeader();
    fetchSchedule();

    state.refreshInterval = setInterval(() => {
        console.log("Auto-refreshing schedule...");
        fetchSchedule(true);
    }, CACHE_DURATION);
});

async function getCache(key) {
    try {
        const cache = await caches.open(CACHE_NAME);

        const response = await cache.match(`/schedule-cache/${key}`);

        if (!response) return null;

        const cached = await response.json();
        const age = Date.now() - cached.timestamp;

        if (age < CACHE_DURATION) {
            console.log(`[Cache Hit] Loaded ${key} (Age: ${Math.round(age / 1000)}s)`);
            return cached.data;
        }

        console.log(`[Cache Stale] ${key} expired.`);

        cache.delete(`/schedule-cache/${key}`);
        return null;
    } catch (e) {
        console.error("Cache read failed", e);
        return null;
    }
}

async function setCache(key, data) {
    try {
        const cache = await caches.open(CACHE_NAME);
        const payload = JSON.stringify({
            timestamp: Date.now(),
            data: data
        });

        const response = new Response(payload, {
            headers: { 'Content-Type': 'application/json' }
        });
        await cache.put(`/schedule-cache/${key}`, response);
    } catch (e) {
        console.warn("Cache write failed", e);
    }
}

function getCacheKey() {
    if (state.viewType === 'MONTH') {
        return `M_${state.currentDate.getFullYear()}_${state.currentDate.getMonth()}`;
    } else {
        const start = getWeekStart(state.currentDate);
        return `W_${start.toISOString().split('T')[0]}`;
    }
}

function navigate(delta) {
    if (state.abortController) state.abortController.abort();

    if (state.viewType === 'MONTH') {
        state.currentDate.setMonth(state.currentDate.getMonth() + delta);
    } else {
        state.currentDate.setDate(state.currentDate.getDate() + (delta * 7));
    }

    renderHeader();
    fetchSchedule();
}

function setViewType(type) {
    if (state.viewType === type) return;
    state.viewType = type;

    document.getElementById('btnViewMonth').classList.toggle('active', type === 'MONTH');
    document.getElementById('btnViewWeek').classList.toggle('active', type === 'WEEK');

    if (state.abortController) state.abortController.abort();

    renderHeader();
    fetchSchedule();
}

function setMode(mode) {
    if (state.mode === mode) return;
    state.mode = mode;
    document.getElementById('btnSub').classList.toggle('active', mode === 'SUB');
    document.getElementById('btnDub').classList.toggle('active', mode === 'DUB');

    fetchSchedule();
}

function renderHeader() {
    const options = { month: 'long', year: 'numeric' };
    let title = state.currentDate.toLocaleDateString('en-US', options);

    if (state.viewType === 'WEEK') {
        const start = getWeekStart(state.currentDate);
        const end = new Date(start);
        end.setDate(end.getDate() + 6);

        const startStr = start.toLocaleDateString('en-US', { month: 'short', day: 'numeric' });
        const endStr = end.toLocaleDateString('en-US', { month: 'short', day: 'numeric' });
        title = `Week of ${startStr} - ${endStr}`;
    }

    document.getElementById('monthTitle').textContent = title;
}

function getWeekStart(date) {
    const d = new Date(date);
    const day = d.getDay();
    const diff = d.getDate() - day + (day === 0 ? -6 : 1);
    return new Date(d.setDate(diff));
}

async function fetchSchedule(forceRefresh = false) {
    const key = getCacheKey();

    if (!forceRefresh) {
        const cachedData = await getCache(key);
        if (cachedData) {
            renderGrid(cachedData);
            updateAmbient(cachedData);
            return;
        }
    }

    if (state.abortController) state.abortController.abort();
    state.abortController = new AbortController();
    const signal = state.abortController.signal;

    if (!forceRefresh) setLoading(true);

    let startTs, endTs;
    if (state.viewType === 'MONTH') {
        const year = state.currentDate.getFullYear();
        const month = state.currentDate.getMonth();
        startTs = Math.floor(new Date(year, month, 1).getTime() / 1000);
        endTs = Math.floor(new Date(year, month + 1, 0, 23, 59, 59).getTime() / 1000);
    } else {
        const start = getWeekStart(state.currentDate);
        start.setHours(0, 0, 0, 0);
        const end = new Date(start);
        end.setDate(end.getDate() + 7);
        startTs = Math.floor(start.getTime() / 1000);
        endTs = Math.floor(end.getTime() / 1000);
    }

    const query = `
                query ($start: Int, $end: Int, $page: Int) {
                    Page(page: $page, perPage: 50) {
                        pageInfo { hasNextPage }
                        airingSchedules(airingAt_greater: $start, airingAt_lesser: $end, sort: TIME) {
                            airingAt
                            episode
                            media {
                                id
                                title { userPreferred english }
                                coverImage { large }
                                bannerImage
                                isAdult
                                countryOfOrigin
                                popularity
                            }
                        }
                    }
                }
            `;

    let allData = [];
    let page = 1;
    let hasNext = true;
    let retries = 0;

    try {
        while (hasNext && page <= 6) {
            if (signal.aborted) throw new DOMException("Aborted", "AbortError");

            try {
                const res = await fetch(ANILIST_API, {
                    method: 'POST',
                    headers: { 'Content-Type': 'application/json', 'Accept': 'application/json' },
                    body: JSON.stringify({
                        query,
                        variables: { start: startTs, end: endTs, page }
                    }),
                    signal: signal
                });

                if (res.status === 429) {
                    if (retries > 2) throw new Error("Rate Limited");
                    console.warn("429 Hit. Waiting...");
                    await delay(4000);
                    retries++;
                    continue;
                }

                const json = await res.json();
                if (json.errors) throw new Error("API Error");

                const data = json.data.Page;
                allData = [...allData, ...data.airingSchedules];
                hasNext = data.pageInfo.hasNextPage;
                page++;

                await delay(600);

            } catch (e) {
                if (e.name === 'AbortError') throw e;
                console.error(e);
                break;
            }
        }

        if (!signal.aborted) {

            await setCache(key, allData);
            renderGrid(allData);
            updateAmbient(allData);
        }

    } catch (e) {
        if (e.name !== 'AbortError') console.error("Fetch failed:", e);
    } finally {
        if (!signal.aborted) {
            setLoading(false);
            state.abortController = null;
        }
    }
}

function renderGrid(data) {
    const grid = document.getElementById('daysGrid');
    grid.innerHTML = '';

    let items = data.filter(i => !i.media.isAdult && i.media.countryOfOrigin === 'JP');
    if (state.mode === 'DUB') {
        items = items.filter(i => i.media.popularity > 20000);
    }

    if (state.viewType === 'MONTH') {
        const year = state.currentDate.getFullYear();
        const month = state.currentDate.getMonth();
        const daysInMonth = new Date(year, month + 1, 0).getDate();
        let firstDayIndex = new Date(year, month, 1).getDay() - 1;
        if (firstDayIndex === -1) firstDayIndex = 6;

        for (let i = 0; i < firstDayIndex; i++) {
            const empty = document.createElement('div');
            empty.className = 'day-cell empty';
            grid.appendChild(empty);
        }

        for (let day = 1; day <= daysInMonth; day++) {
            const dateObj = new Date(year, month, day);
            renderDayCell(dateObj, items, grid);
        }
    } else {
        const start = getWeekStart(state.currentDate);
        for (let i = 0; i < 7; i++) {
            const dateObj = new Date(start);
            dateObj.setDate(start.getDate() + i);
            renderDayCell(dateObj, items, grid);
        }
    }
}

function renderDayCell(dateObj, items, grid) {
    const cell = document.createElement('div');
    cell.className = 'day-cell';

    if (state.viewType === 'WEEK') cell.style.minHeight = '300px';

    const day = dateObj.getDate();
    const month = dateObj.getMonth();
    const year = dateObj.getFullYear();

    const now = new Date();
    if (day === now.getDate() && month === now.getMonth() && year === now.getFullYear()) {
        cell.classList.add('today');
    }

    const dayEvents = items.filter(i => {
        const eventDate = new Date(i.airingAt * 1000);
        return eventDate.getDate() === day && eventDate.getMonth() === month && eventDate.getFullYear() === year;
    });

    dayEvents.sort((a, b) => b.media.popularity - a.media.popularity);

    if (dayEvents.length > 0) {
        const top = dayEvents[0].media;
        const bg = document.createElement('div');
        bg.className = 'cell-backdrop';
        bg.style.backgroundImage = `url('${top.coverImage.large}')`;
        cell.appendChild(bg);
    }

    const header = document.createElement('div');
    header.className = 'day-header';
    header.innerHTML = `
                <span class="day-number">${day}</span>
                <span class="today-label">Today</span>
            `;
    cell.appendChild(header);

    const list = document.createElement('div');
    list.className = 'events-list';

    dayEvents.forEach(evt => {
        const title = evt.media.title.english || evt.media.title.userPreferred;
        const link = `/anime/${evt.media.id}`;

        const chip = document.createElement('a');
        chip.className = 'anime-chip';
        chip.href = link;
        chip.innerHTML = `
                    <span class="chip-title">${title}</span>
                    <span class="chip-ep">Ep ${evt.episode}</span>
                `;
        list.appendChild(chip);
    });

    cell.appendChild(list);
    grid.appendChild(cell);
}

function setLoading(bool) {
    state.loading = bool;
    const loader = document.getElementById('loader');
    if (bool) loader.classList.add('active');
    else loader.classList.remove('active');
}

function delay(ms) { return new Promise(r => setTimeout(r, ms)); }

function updateAmbient(data) {
    if (!data || !data.length) return;
    const top = data.reduce((prev, curr) => (prev.media.popularity > curr.media.popularity) ? prev : curr);
    const img = top.media.bannerImage || top.media.coverImage.large;
    if (img) document.getElementById('ambientBg').style.backgroundImage = `url('${img}')`;
}