const pageLabel = document.getElementById("pageLabel");
const statusText = document.getElementById("status");
const slideImage = document.getElementById("slideImage");
const imageFallback = document.getElementById("imageFallback");
const slideTitle = document.getElementById("slideTitle");
const slideScript = document.getElementById("slideScript");

const prevBtn = document.getElementById("prevBtn");
const playBtn = document.getElementById("playBtn");
const stopBtn = document.getElementById("stopBtn");
const nextBtn = document.getElementById("nextBtn");
const player = document.getElementById("player");

const workspace = document.getElementById("workspace");
const slidePane = document.getElementById("slidePane");
const scriptPane = document.getElementById("scriptPane");
const resizer = document.getElementById("resizer");

let slides = [];
let currentIndex = 0;

let isPlaying = false;
let isPaused = false;

let isDragging = false;
let pointerId = null;

function setStatus(text) {
    statusText.textContent = text;
}

function updatePlayButton() {
    if (isPlaying && !isPaused) {
        playBtn.textContent = "⏸ Pause";
        return;
    }

    if (isPlaying && isPaused) {
        playBtn.textContent = "▶ Resume";
        return;
    }

    playBtn.textContent = "▶ Play";
}

function updateButtons() {
    prevBtn.disabled = currentIndex <= 0;
    nextBtn.disabled = currentIndex >= slides.length - 1;
}

function renderSlide(index) {
    if (!slides.length) {
        pageLabel.textContent = "No slides";
        slideTitle.textContent = "";
        slideScript.textContent = "No script data was loaded.";
        setStatus("No slides");
        updateButtons();
        return;
    }

    if (index < 0) index = 0;
    if (index >= slides.length) index = slides.length - 1;

    currentIndex = index;

    const slide = slides[currentIndex];

    pageLabel.textContent = `Slide ${currentIndex} / ${slides.length - 1}`;
    slideTitle.textContent = slide.title || `Slide ${currentIndex}`;
    slideScript.textContent = slide.speech || "";

    imageFallback.hidden = true;
    slideImage.hidden = false;

    slideImage.onerror = () => {
        slideImage.hidden = true;
        imageFallback.hidden = false;
    };

    slideImage.src = `${slide.image}?t=${Date.now()}`;

    updateButtons();

    if (!isPlaying) {
        setStatus("Ready");
    }
}

async function loadSlides() {
    try {
        const response = await fetch("/api/slides");

        if (!response.ok) {
            throw new Error(`Failed to load slides: ${response.status}`);
        }

        slides = await response.json();

        if (!Array.isArray(slides) || slides.length === 0) {
            throw new Error("No slides found. Check scripts.txt.");
        }

        renderSlide(0);
        setStatus(`Ready · ${slides.length} slides`);
        updatePlayButton();

    } catch (error) {
        console.error(error);

        pageLabel.textContent = "Load failed";
        slideTitle.textContent = "Error";
        slideScript.textContent = String(error.message || error);

        setStatus("Error");
    }
}

function stopAudio(status = "Stopped") {

    isPlaying = false;
    isPaused = false;

    player.pause();
    player.removeAttribute("src");
    player.load();

    setStatus(status);
    updatePlayButton();
}

function playCurrent() {

    if (!slides.length) return;

    isPlaying = true;
    isPaused = false;

    const slide = slides[currentIndex];

    setStatus(`Reading ${currentIndex + 1}/${slides.length}`);

    player.pause();
    player.currentTime = 0;

    player.src = `${slide.audio}?t=${Date.now()}`;

    updatePlayButton();

    player.play().catch(error => {
        console.error(error);
        stopAudio("Audio play failed");
    });
}

function goToSlide(index, keepPlaying = false) {

    const wasPlaying =
        (isPlaying && !isPaused) || keepPlaying;

    player.pause();
    player.currentTime = 0;

    renderSlide(index);

    if (wasPlaying) {
        playCurrent();
    } else {
        isPlaying = false;
        isPaused = false;
        updatePlayButton();
    }
}

prevBtn.addEventListener("click", () => {
    if (currentIndex <= 0) return;
    goToSlide(currentIndex - 1, isPlaying && !isPaused);
});

nextBtn.addEventListener("click", () => {
    if (currentIndex >= slides.length - 1) return;
    goToSlide(currentIndex + 1, isPlaying && !isPaused);
});

playBtn.addEventListener("click", () => {

    if (!isPlaying) {
        playCurrent();
        return;
    }

    if (isPlaying && !isPaused) {

        player.pause();

        isPaused = true;

        setStatus("Paused");
        updatePlayButton();

        return;
    }

    if (isPlaying && isPaused) {

        player.play()
            .then(() => {

                isPaused = false;

                setStatus(
                    `Reading ${currentIndex + 1}/${slides.length}`
                );

                updatePlayButton();
            })
            .catch(error => {

                console.error(error);

                stopAudio(
                    "Audio play failed"
                );
            });
    }
});

stopBtn.addEventListener("click", () => {
    stopAudio("Stopped");
});

player.addEventListener("ended", () => {

    if (!isPlaying) return;
    if (isPaused) return;

    if (currentIndex < slides.length - 1) {

        goToSlide(
            currentIndex + 1,
            true
        );

    } else {

        stopAudio(
            "Finished"
        );
    }
});

document.addEventListener("keydown", event => {

    if (event.key === "ArrowLeft") {
        prevBtn.click();
    }

    if (event.key === "ArrowRight") {
        nextBtn.click();
    }

    if (event.key === " ") {

        event.preventDefault();

        playBtn.click();
    }
});

function startResize(event) {

    if (window.innerWidth <= 900)
        return;

    isDragging = true;

    pointerId = event.pointerId;

    document.body.classList.add(
        "dragging"
    );

    try {

        resizer.setPointerCapture(
            pointerId
        );

    } catch (error) {
        // ignore
    }
}

function resizePanes(clientX) {

    if (!isDragging)
        return;

    if (window.innerWidth <= 900)
        return;

    const rect =
        workspace.getBoundingClientRect();

    const x =
        clientX - rect.left;

    const percent =
        (x / rect.width) * 100;

    const scriptWidth =
        Math.max(
            18,
            Math.min(
                58,
                percent
            )
        );

    const slideWidth =
        100 - scriptWidth;

    scriptPane.style.flexBasis =
        `${scriptWidth}%`;

    scriptPane.style.width =
        `${scriptWidth}%`;

    slidePane.style.flexBasis =
        `${slideWidth}%`;
}

function stopResize() {

    if (!isDragging)
        return;

    isDragging = false;

    pointerId = null;

    document.body.classList.remove(
        "dragging"
    );
}

resizer.addEventListener(
    "pointerdown",
    event => {
        startResize(event);
    }
);

window.addEventListener(
    "pointermove",
    event => {
        resizePanes(event.clientX);
    }
);

window.addEventListener(
    "pointerup",
    () => {
        stopResize();
    }
);

window.addEventListener(
    "pointercancel",
    () => {
        stopResize();
    }
);

window.addEventListener(
    "resize",
    () => {

        if (
            window.innerWidth <= 900
        ) {

            slidePane.style.flexBasis = "";
            scriptPane.style.flexBasis = "";
            scriptPane.style.width = "";

            stopResize();
        }
    }
);

loadSlides();