const reader = document.getElementById('reader');
const panel = document.getElementById('settings-panel');
const overlay = document.getElementById('overlay');
const settingsBtn = document.getElementById('settings-btn');
const closePanel = document.getElementById('close-panel');
const chapterLabel = document.getElementById('chapter-label');
const prevBtn = document.getElementById('prev-chapter');
const nextBtn = document.getElementById('next-chapter');

const prevUrl = localStorage.getItem('reader_prev_url');

const lnSettings = document.getElementById('ln-settings');
const mangaSettings = document.getElementById('manga-settings');

const config = {
    ln: {
        fontSize: 18,
        lineHeight: 1.8,
        maxWidth: 750,
        fontFamily: '"Georgia", serif',
        textColor: '#e5e7eb',
        bg: '#14141b',
        textAlign: 'justify'
    },
    manga: {
        direction: 'rtl',
        mode: 'auto',
        spacing: 16,
        imageFit: 'screen',
        preloadCount: 3
    }
};

let currentType = null;
let currentPages = [];
let observer = null;

const parts = window.location.pathname.split('/');

const bookId = parts[2];
let chapter = parts[3];
let provider = parts[4];

function loadConfig() {
    try {
        const saved = localStorage.getItem('readerConfig');
        if (saved) {
            const parsed = JSON.parse(saved);
            Object.assign(config.ln, parsed.ln || {});
            Object.assign(config.manga, parsed.manga || {});
        }
    } catch (e) {
        console.error('Error loading config:', e);
    }
    updateUIFromConfig();
}

function saveConfig() {
    try {
        localStorage.setItem('readerConfig', JSON.stringify(config));
    } catch (e) {
        console.error('Error saving config:', e);
    }
}

function updateUIFromConfig() {
    // Light Novel
    document.getElementById('font-size').value = config.ln.fontSize;
    document.getElementById('font-size-value').textContent = config.ln.fontSize + 'px';

    document.getElementById('line-height').value = config.ln.lineHeight;
    document.getElementById('line-height-value').textContent = config.ln.lineHeight;

    document.getElementById('max-width').value = config.ln.maxWidth;
    document.getElementById('max-width-value').textContent = config.ln.maxWidth + 'px';

    document.getElementById('font-family').value = config.ln.fontFamily;
    document.getElementById('text-color').value = config.ln.textColor;
    document.getElementById('bg-color').value = config.ln.bg;

    // Text alignment buttons
    document.querySelectorAll('[data-align]').forEach(btn => {
        btn.classList.toggle('active', btn.dataset.align === config.ln.textAlign);
    });

    // Manga
    document.getElementById('display-mode').value = config.manga.mode;
    document.getElementById('image-fit').value = config.manga.imageFit;
    document.getElementById('page-spacing').value = config.manga.spacing;
    document.getElementById('page-spacing-value').textContent = config.manga.spacing + 'px';
    document.getElementById('preload-count').value = config.manga.preloadCount;

    // Direction buttons
    document.querySelectorAll('[data-direction]').forEach(btn => {
        btn.classList.toggle('active', btn.dataset.direction === config.manga.direction);
    });
}

function applyStyles() {
    if (currentType === 'ln') {
        document.documentElement.style.setProperty('--ln-font-size', config.ln.fontSize + 'px');
        document.documentElement.style.setProperty('--ln-line-height', config.ln.lineHeight);
        document.documentElement.style.setProperty('--ln-max-width', config.ln.maxWidth + 'px');
        document.documentElement.style.setProperty('--ln-font-family', config.ln.fontFamily);
        document.documentElement.style.setProperty('--ln-text-color', config.ln.textColor);
        document.documentElement.style.setProperty('--bg-base', config.ln.bg);
        document.documentElement.style.setProperty('--ln-text-align', config.ln.textAlign);
    }

    if (currentType === 'manga') {
        document.documentElement.style.setProperty('--page-spacing', config.manga.spacing + 'px');
        document.documentElement.style.setProperty('--page-max-width', 900 + 'px');
        document.documentElement.style.setProperty('--manga-max-width', 1400 + 'px');

        const viewportHeight = window.innerHeight - 64 - 32;
        document.documentElement.style.setProperty('--viewport-height', viewportHeight + 'px');
    }
}

function updateSettingsVisibility() {
    lnSettings.classList.toggle('hidden', currentType !== 'ln');
    mangaSettings.classList.toggle('hidden', currentType !== 'manga');
}

async function loadChapter() {
    reader.innerHTML = `
        <div class="loading-container">
            <div class="loading-spinner"></div>
            <span>Loading chapter...</span>
        </div>
    `;

    try {
        const res = await fetch(`/api/book/${bookId}/${chapter}/${provider}`);
        const data = await res.json();

        if (data.title) {
            chapterLabel.textContent = data.title;
            document.title = data.title;
        } else {
            chapterLabel.textContent = `Chapter ${chapter}`;
            document.title = `Chapter ${chapter}`;
        }

        if (data.error) {
            reader.innerHTML = `
                <div class="loading-container">
                    <span style="color: #ef4444;">Error: ${data.error}</span>
                </div>
            `;
            return;
        }

        currentType = data.type;
        updateSettingsVisibility();
        applyStyles();
        reader.innerHTML = '';

        if (data.type === 'manga') {
            currentPages = data.pages || [];
            loadManga(currentPages);
        } else if (data.type === 'ln') {
            loadLN(data.content);
        }
    } catch (error) {
        reader.innerHTML = `
            <div class="loading-container">
                <span style="color: #ef4444;">Error loading chapter: ${error.message}</span>
            </div>
        `;
    }
}

function loadManga(pages) {
    if (!pages || pages.length === 0) {
        reader.innerHTML = '<div class="loading-container"><span>No pages found</span></div>';
        return;
    }

    const container = document.createElement('div');
    container.className = 'manga-container';

    let isLongStrip = false;

    if (config.manga.mode === 'longstrip') {
        isLongStrip = true;
    } else if (config.manga.mode === 'auto' && detectLongStrip(pages)) {
        isLongStrip = true;
    }


    const useDouble = config.manga.mode === 'double' ||
        (config.manga.mode === 'auto' && !isLongStrip && shouldUseDoublePage(pages));

    if (useDouble) {
        loadDoublePage(container, pages);
    } else {
        loadSinglePage(container, pages);
    }

    reader.appendChild(container);
    setupLazyLoading();
    enableMangaPageNavigation();
}

function shouldUseDoublePage(pages) {
    if (pages.length <= 5) return false;

    const widePages = pages.filter(p => {
        if (!p.height || !p.width) return false;
        const ratio = p.width / p.height;
        return ratio > 1.3;
    });

    if (widePages.length > pages.length * 0.3) return false;

    return true;
}

function loadSinglePage(container, pages) {
    pages.forEach((page, index) => {
        const img = createImageElement(page, index);
        container.appendChild(img);
    });
}

function loadDoublePage(container, pages) {
    let i = 0;
    while (i < pages.length) {
        const currentPage = pages[i];
        const nextPage = pages[i + 1];

        const isWide = currentPage.width && currentPage.height &&
            (currentPage.width / currentPage.height) > 1.1;

        if (isWide) {
            const img = createImageElement(currentPage, i);
            container.appendChild(img);
            i++;
        } else {
            const doubleContainer = document.createElement('div');
            doubleContainer.className = 'double-container';

            const leftPage = createImageElement(currentPage, i);

            if (nextPage) {
                const nextIsWide = nextPage.width && nextPage.height &&
                    (nextPage.width / nextPage.height) > 1.3;

                if (nextIsWide) {
                    const singleImg = createImageElement(currentPage, i);
                    container.appendChild(singleImg);
                    i++;
                } else {
                    const rightPage = createImageElement(nextPage, i + 1);

                    if (config.manga.direction === 'rtl') {
                        doubleContainer.appendChild(rightPage);
                        doubleContainer.appendChild(leftPage);
                    } else {
                        doubleContainer.appendChild(leftPage);
                        doubleContainer.appendChild(rightPage);
                    }

                    container.appendChild(doubleContainer);
                    i += 2;
                }
            } else {
                const singleImg = createImageElement(currentPage, i);
                container.appendChild(singleImg);
                i++;
            }
        }
    }
}

function createImageElement(page, index) {
    const img = document.createElement('img');
    img.className = 'page-img';
    img.dataset.index = index;

    const url = buildProxyUrl(page.url, page.headers);

    if (config.manga.mode === 'longstrip' && index > 0) {
        img.classList.add('longstrip-fit');
    } else {
        if (config.manga.imageFit === 'width') img.classList.add('fit-width');
        else if (config.manga.imageFit === 'height') img.classList.add('fit-height');
        else if (config.manga.imageFit === 'screen') img.classList.add('fit-screen');
    }

    if (index < config.manga.preloadCount) {
        img.src = url;
    } else {
        img.dataset.src = url;
        img.loading = 'lazy';
    }

    img.alt = `Page ${index + 1}`;

    return img;
}

function buildProxyUrl(url, headers = {}) {
    const params = new URLSearchParams({
        url
    });

    if (headers.referer) params.append('referer', headers.referer);
    if (headers['user-agent']) params.append('ua', headers['user-agent']);
    if (headers.cookie) params.append('cookie', headers.cookie);

    return `/api/proxy?${params.toString()}`;
}

function detectLongStrip(pages) {
    if (!pages || pages.length === 0) return false;

    const relevant = pages.slice(1);
    const tall = relevant.filter(p => p.height && p.width && (p.height / p.width) > 2);
    return tall.length >= 2 || (tall.length / relevant.length) > 0.3;
}

function setupLazyLoading() {
    if (observer) observer.disconnect();

    observer = new IntersectionObserver((entries) => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                const img = entry.target;
                if (img.dataset.src) {
                    img.src = img.dataset.src;
                    delete img.dataset.src;
                    observer.unobserve(img);
                }
            }
        });
    }, {
        rootMargin: '200px'
    });

    document.querySelectorAll('img[data-src]').forEach(img => observer.observe(img));
}

function loadLN(html) {
    const div = document.createElement('div');
    div.className = 'ln-content';
    div.innerHTML = html;
    reader.appendChild(div);
}

// Event Listeners - Light Novel
document.getElementById('font-size').addEventListener('input', (e) => {
    config.ln.fontSize = parseInt(e.target.value);
    document.getElementById('font-size-value').textContent = e.target.value + 'px';
    applyStyles();
    saveConfig();
});

document.getElementById('line-height').addEventListener('input', (e) => {
    config.ln.lineHeight = parseFloat(e.target.value);
    document.getElementById('line-height-value').textContent = e.target.value;
    applyStyles();
    saveConfig();
});

document.getElementById('max-width').addEventListener('input', (e) => {
    config.ln.maxWidth = parseInt(e.target.value);
    document.getElementById('max-width-value').textContent = e.target.value + 'px';
    applyStyles();
    saveConfig();
});

document.getElementById('font-family').addEventListener('change', (e) => {
    config.ln.fontFamily = e.target.value;
    applyStyles();
    saveConfig();
});

document.getElementById('text-color').addEventListener('change', (e) => {
    config.ln.textColor = e.target.value;
    applyStyles();
    saveConfig();
});

document.getElementById('bg-color').addEventListener('change', (e) => {
    config.ln.bg = e.target.value;
    applyStyles();
    saveConfig();
});

// Text alignment
document.querySelectorAll('[data-align]').forEach(btn => {
    btn.addEventListener('click', () => {
        document.querySelectorAll('[data-align]').forEach(b => b.classList.remove('active'));
        btn.classList.add('active');
        config.ln.textAlign = btn.dataset.align;
        applyStyles();
        saveConfig();
    });
});

// Presets
document.querySelectorAll('[data-preset]').forEach(btn => {
    btn.addEventListener('click', () => {
        const preset = btn.dataset.preset;

        const presets = {
            dark: { bg: '#14141b', textColor: '#e5e7eb' },
            sepia: { bg: '#f4ecd8', textColor: '#5c472d' },
            light: { bg: '#fafafa', textColor: '#1f2937' },
            amoled: { bg: '#000000', textColor: '#ffffff' }
        };

        if (presets[preset]) {
            Object.assign(config.ln, presets[preset]);
            document.getElementById('bg-color').value = config.ln.bg;
            document.getElementById('text-color').value = config.ln.textColor;
            applyStyles();
            saveConfig();
        }
    });
});

// Event Listeners - Manga

document.getElementById('display-mode').addEventListener('change', (e) => {
    config.manga.mode = e.target.value;
    saveConfig();
    loadChapter();
});

document.getElementById('image-fit').addEventListener('change', (e) => {
    config.manga.imageFit = e.target.value;
    saveConfig();
    loadChapter();
});

document.getElementById('page-spacing').addEventListener('input', (e) => {
    config.manga.spacing = parseInt(e.target.value);
    document.getElementById('page-spacing-value').textContent = e.target.value + 'px';
    applyStyles();
    saveConfig();
});

document.getElementById('preload-count').addEventListener('change', (e) => {
    config.manga.preloadCount = parseInt(e.target.value);
    saveConfig();
});

// Direction
document.querySelectorAll('[data-direction]').forEach(btn => {
    btn.addEventListener('click', () => {
        document.querySelectorAll('[data-direction]').forEach(b => b.classList.remove('active'));
        btn.classList.add('active');
        config.manga.direction = btn.dataset.direction;
        saveConfig();
        loadChapter();
    });
});

// Navigation
prevBtn.addEventListener('click', () => {
    const newChapter = String(parseInt(chapter) - 1);
    updateURL(newChapter);
    window.scrollTo(0, 0);
    loadChapter();
});

nextBtn.addEventListener('click', () => {
    const newChapter = String(parseInt(chapter) + 1);
    updateURL(newChapter);
    window.scrollTo(0, 0);
    loadChapter();
});

function updateURL(newChapter) {
    chapter = newChapter;
    const newUrl = `/reader/${bookId}/${chapter}/${provider}`;
    window.history.pushState({}, '', newUrl);
}

document.getElementById('back-btn').addEventListener('click', () => {
    const prev = localStorage.getItem('reader_prev_url');
    if (prev) {
        window.location.href = prev;
    } else {
        history.back();
    }
});

settingsBtn.addEventListener('click', () => {
    panel.classList.add('open');
    overlay.classList.add('active');
});

closePanel.addEventListener('click', closeSettings);
overlay.addEventListener('click', closeSettings);

function closeSettings() {
    panel.classList.remove('open');
    overlay.classList.remove('active');
}

document.addEventListener('keydown', (e) => {
    if (e.key === 'Escape' && panel.classList.contains('open')) {
        closeSettings();
    }
});

function enableMangaPageNavigation() {
    if (currentType !== 'manga') return;
    const logicalPages = [];

    document.querySelectorAll('.manga-container > *').forEach(el => {
        if (el.classList.contains('double-container')) {
            logicalPages.push(el);
        } else if (el.tagName === 'IMG') {
            logicalPages.push(el);
        }
    });

    if (logicalPages.length === 0) return;

    function scrollToLogical(index) {
        if (index < 0 || index >= logicalPages.length) return;

        const topBar = document.querySelector('.top-bar');
        const offset = topBar ? -topBar.offsetHeight : 0;

        const y = logicalPages[index].getBoundingClientRect().top
            + window.pageYOffset
            + offset;

        window.scrollTo({
            top: y,
            behavior: 'smooth'
        });
    }

    function getCurrentLogicalIndex() {
        let closest = 0;
        let minDist = Infinity;

        logicalPages.forEach((el, i) => {
            const rect = el.getBoundingClientRect();
            const dist = Math.abs(rect.top);
            if (dist < minDist) {
                minDist = dist;
                closest = i;
            }
        });

        return closest;
    }

    const rtl = () => config.manga.direction === 'rtl';

    document.addEventListener('keydown', (e) => {
        if (currentType !== 'manga') return;
        if (e.target.tagName === 'INPUT' || e.target.tagName === 'SELECT') return;

        const index = getCurrentLogicalIndex();

        if (e.key === 'ArrowLeft') {
            scrollToLogical(rtl() ? index + 1 : index - 1);
        }
        if (e.key === 'ArrowRight') {
            scrollToLogical(rtl() ? index - 1 : index + 1);
        }
    });

    reader.addEventListener('click', (e) => {
        if (currentType !== 'manga') return;

        const bounds = reader.getBoundingClientRect();
        const x = e.clientX - bounds.left;
        const half = bounds.width / 2;

        const index = getCurrentLogicalIndex();

        if (x < half) {
            scrollToLogical(rtl() ? index + 1 : index - 1);
        } else {
            scrollToLogical(rtl() ? index - 1 : index + 1);
        }
    });
}

let resizeTimer;
window.addEventListener('resize', () => {
    clearTimeout(resizeTimer);
    resizeTimer = setTimeout(() => {
        applyStyles();
    }, 250);
});

if (!bookId || !chapter || !provider) {
    reader.innerHTML = `
        <div class="loading-container">
            <span style="color: #ef4444;">Missing required parameters (bookId, chapter, provider)</span>
        </div>
    `;
} else {
    loadConfig();
    loadChapter();
}