let tsPerBar = 32;
let nBars = 2;
let tssPerStep = 4;

let isDragging = false;
let action = null;

let player;

let isPlaying = false;
let ts = 0;
let lastTime = 0;


document.addEventListener("DOMContentLoaded", function () {

    setupGridListeners();

    // Clear grid on button click
    const clearButton = document.getElementById('clearButton');
    clearButton.addEventListener('click', clearGrid);

    loadGrid();
    setupVisualizer();
    setupPlayer();
    setupGenerationListeners();
});

function setupGridListeners() {
    const grid = document.getElementById('grid');
    const rows = grid.querySelectorAll('tr');

    rows.forEach((row, i) => {
        const cells = row.querySelectorAll('td');
        cells.forEach((cell, j) => {
            setupCellListeners(cell);
        });
    });

    document.addEventListener('mouseup', function () {
        isDragging = false;
    });
}

function setupCellListeners(cell) {
    cell.addEventListener('dragstart', function (e) {
        e.preventDefault();
    });

    cell.addEventListener('mousedown', function (e) {
        if (e.button !== 0) return;

        e.preventDefault();
        isDragging = true;

        // Determine action based on initial cell's state
        action = cell.classList.contains('activated') ? 'deactivate' : 'activate';
        applyAction(cell, action);
    });

    cell.addEventListener('mouseover', function () {
        if (isDragging) applyAction(cell, action);
    });

    cell.addEventListener('mouseup', function () {
        isDragging = false;  // End dragging once mouse is released
    });
}

function applyAction(cell, action) {
    if (action === 'activate') {
        cell.classList.remove('deactivated');
        cell.classList.add('activated');
    } else {
        cell.classList.add('deactivated');
        cell.classList.remove('activated');
    }
}

function clearGrid() {
    const grid = document.getElementById('grid');
    const cells = grid.querySelectorAll('td');

    cells.forEach(cell => {
        cell.classList.add('deactivated');
        cell.classList.remove('activated');
    });
}

function loadGrid() {
    fetch('/load_grid')
        .then(response => response.json())
        .then(data => applyConfiguration(data[0]))
        .catch(error => console.error('Error fetching grid:', error));
}

function applyConfiguration(config) {

    const grid = document.getElementById('grid');
    const rows = grid.querySelectorAll('tr');

    for (let i = 0; i < rows.length && i < config.length; i++) {
        const cells = rows[i].querySelectorAll('td');

        for (let j = 0; j < cells.length && j < config[i].length; j++) {
            const cell = cells[j];

            if (config[i][j] === true) {
                cell.classList.add('activated');
                cell.classList.remove('deactivated');
            } else {
                cell.classList.add('deactivated');
                cell.classList.remove('activated');
            }
        }
    }
}

function setupPlayer() {
    player = document.getElementById('midiplayer');

    player.loop = true;

    player.addEventListener('start', function () {
        isPlaying = true;
        lastTime = -1;
        ts = 0;
        update();
    });

    player.addEventListener('stop', function (event) {
        if (event.detail.finished) isPlaying = false;
    });
}

function update() {

    if (!isPlaying) return;

    currentTime = player.currentTime;
    dur = player.duration;
    if (currentTime != lastTime) {
        tsTime = dur / (nBars * tsPerBar);
        ts = Math.min(nBars * tsPerBar - 1, currentTime / tsTime);
        ts = tssPerStep * Math.floor(ts / tssPerStep);
        pianorollStep(ts);
    }

    lastTime = currentTime;
    requestAnimationFrame(update);
}


function pianorollStep(ts) {
    const grid = document.getElementById('grid');
    const rows = grid.querySelectorAll('tr');

    // Clear previously darkened cells
    const previouslyDarkened = document.querySelectorAll('.darkened');
    previouslyDarkened.forEach(cell => cell.classList.remove('darkened'));

    for (let row of rows) {
        const cell = row.cells[(ts % tsPerBar) + 1];
        if (cell) {
            cell.classList.add('darkened');
        }
    }
}

function setupVisualizer() {
    const visualizer = document.getElementById('midivisualizer');

    visualizer.config = {
        noteHeight: 5,
        pixelsPerTimeStep: 100,
        minPitch: 40,
        maxPitch: 80
    };
}

const emptyMessages = [
    "\"Hello Darkness, my old friend...\"",
]

function setupGenerationListeners() {
    const generateButton = document.getElementById('generate');
    const keepTonality = document.getElementById('keepTonality');
    const useGrid = document.getElementById('useGrid');

    generateButton.addEventListener('click', async function () {
        generateButton.disabled = true;

        const config = getGridConfiguration();

        const emptyMessage = document.getElementById('emptyMessage');
        if (!config) {
            const r = Math.floor(Math.random() * emptyMessages.length);
            emptyMessage.textContent = emptyMessages[r];
            generateButton.disabled = false;
            emptyMessage.style.display = 'block';
            return;
        } else {
            emptyMessage.textContent = '';
            emptyMessage.style.display = 'none';
        }

        sendJSONToBackend(config).then(response => {
            console.log(response.message);
        });

        const shouldKeepTonality = keepTonality.checked;
        let shouldUseGrid;
        if (useGrid != null) {
            shouldUseGrid = useGrid.checked;
        } else {
            shouldUseGrid = true;
        }

        try {
            const response = await fetch('/generate_midi', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({
                    keepTonality: shouldKeepTonality,
                    useGrid: shouldUseGrid
                })
            });

            if (response.ok) {
                const data = await response.json();
                const filename = data.filename;
                reinitializePlayer(filename);
            } else {
                console.error('Failed to generate MIDI.');
            }
        } catch (error) {
            console.error('Error:', error);
        } finally {
            generateButton.disabled = false;
        }
    });
}

async function sendJSONToBackend(data) {
    const response = await fetch('/save_json', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json'
        },
        body: JSON.stringify(data)
    });
    return response.json();
}


function reinitializePlayer(filename) {
    const player = document.getElementById('midiplayer');
    const visualizer = document.getElementById('midivisualizer');
    const staticUrl = document.body.getAttribute('static-url');

    // Reset properties
    player.currentTime = 0;
    player.noteSequence = null;

    // Load the new MIDI file
    path = staticUrl + '0/' + filename;
    player.src = path;

    // Reload the player
    player.reload();

    visualizer.src = path;
    visualizer.noteSequence = null;

    // Reload the player and visualizer
    player.reload();
    visualizer.reload();

    visualizer.clearActiveNotes();
    visualizer.redraw();
}


function getGridConfiguration() {
    const grid = document.getElementById('grid');
    const rows = grid.querySelectorAll('tr');

    let isEmpty = true;
    const config = [];

    rows.forEach(row => {
        const cells = Array.from(row.querySelectorAll('td'));
        const rowData = cells.map(cell => {
            if (cell.classList.contains('activated')) {
                isEmpty = false;
                return 1;
            }
            return 0;
        });
        config.push(rowData);
    });

    return isEmpty ? null : [config];
}