// ==UserScript==
// @name         antisocial.moe - youtube music scrobbler
// @namespace    http://tampermonkey.net/
// @version      2.1
// @description  Scrobbles songs from YouTube Music to antisocial.moe, with progress bar monitoring
// @match        https://music.youtube.com/*
// @grant        GM_xmlhttpRequest
// @grant        GM_setValue
// @grant        GM_getValue
// @grant        GM_registerMenuCommand
// @connect      antisocial.moe
// ==/UserScript==

(function() {
    'use strict';

    /**
     * ============================
     * Helper Functions
     * ============================
     */

    /**
     * Recursively searches for elements matching the selector within shadow DOMs.
     * @param {string} selector - The CSS selector to match.
     * @param {Document|ShadowRoot} root - The root to start searching from.
     * @returns {Element|null} - The first matching element or null if not found.
     */
    function querySelectorDeep(selector, root = document) {
        const result = root.querySelector(selector);
        if (result) return result;

        // Traverse shadow roots
        const allElements = root.querySelectorAll('*');
        for (let el of allElements) {
            if (el.shadowRoot) {
                const shadowResult = querySelectorDeep(selector, el.shadowRoot);
                if (shadowResult) return shadowResult;
            }
        }
        return null;
    }

    /**
     * Extracts the current song information from the YouTube Music player bar.
     * Implements multiple extraction methods to handle different HTML structures.
     * @returns {Object|null} An object containing title, author, and album, or null if not found.
     */
    function getSongInfo() {
        // Primary Extraction Method
        let titleElement = querySelectorDeep('.ytmusic-player-bar .title');
        let bylineElement = querySelectorDeep('.ytmusic-player-bar .byline');

        if (titleElement && bylineElement) {
            const title = titleElement.textContent.trim();

            // The byline typically has the format: "Author • Album • Year"
            const bylineText = bylineElement.textContent.trim();
            const parts = bylineText.split('•').map(part => part.trim());

            const author = parts[0] || 'Unknown Artist';
            const album = parts[1] || 'Unknown Album';

            return { title, author, album };
        }

        // Fallback Extraction Method: Parse from 'title' attribute of byline
        if (bylineElement && bylineElement.getAttribute('title')) {
            const bylineTitle = bylineElement.getAttribute('title').trim();
            const parts = bylineTitle.split('•').map(part => part.trim());

            const author = parts[0] || 'Unknown Artist';
            const album = parts[1] || 'Unknown Album';

            // Attempt to find the song title from an alternative element or attribute
            let title = 'Unknown Title';
            if (titleElement) {
                title = titleElement.textContent.trim();
            } else {
                // Try to extract from other possible attributes or elements if available
                const parent = bylineElement.parentElement;
                if (parent && parent.getAttribute('title')) {
                    title = parent.getAttribute('title').trim();
                }
            }

            return { title, author, album };
        }

        // Additional Fallbacks can be added here as needed

        return null;
    }

    /**
     * Determines whether the current song is playing.
     * @returns {boolean} True if playing, false if paused or unable to determine.
     */
    function isPlaying() {
        // The play/pause button has id="play-pause-button"
        const playPauseButton = querySelectorDeep('#play-pause-button');

        if (playPauseButton) {
            const titleAttr = playPauseButton.getAttribute('title');
            const ariaLabel = playPauseButton.getAttribute('aria-label');

            // If the button's title or aria-label is "Pause", it means the song is currently playing
            if (titleAttr && titleAttr.toLowerCase() === 'pause') {
                return true;
            }
            if (ariaLabel && ariaLabel.toLowerCase() === 'pause') {
                return true;
            }
        }

        return false;
    }

    /**
     * Sends a scrobble request to the specified endpoint.
     * @param {string} title - The title of the song.
     * @param {string} author - The author/artist of the song.
     * @param {string} album - The album name of the song.
     */
    function scrobble(title, author, album) {
        const AUTH_KEY = GM_getValue('AUTH_KEY', '');
        if (!AUTH_KEY) {
            console.error('AUTH_KEY is not set. Please set it using the Tampermonkey menu.');
            return;
        }

        const url = 'https://antisocial.moe/wp-json/image-scrobble/v1/scrobble';
        const payload = {
            song_name: title,
            author: author,
            album_name: album
        };

        GM_xmlhttpRequest({
            method: 'POST',
            url: url,
            headers: {
                'Content-Type': 'application/json',
                'Authorization': `Bearer ${AUTH_KEY}`
            },
            data: JSON.stringify(payload),
            onload: function(response) {
                if (response.status >= 200 && response.status < 300) {
                    console.log(`Scrobble successful: "${title}" by ${author} from "${album}"`);
                } else {
                    console.error(`Scrobble failed with status ${response.status}:`, response.responseText);
                    console.debug('Payload:', payload);
                }
                // Update lastScrobbledSong regardless of scrobble success to prevent duplicate attempts
                lastScrobbledSong = { title, author, album };
                // Reset scrobbleScheduled
                scrobbleScheduled = false;
            },
            onerror: function(error) {
                console.error('Scrobble request error:', error);
                // Update lastScrobbledSong to prevent further attempts
                lastScrobbledSong = { title, author, album };
                // Reset scrobbleScheduled
                scrobbleScheduled = false;
            }
        });
    }

    /**
     * ============================
     * Scrobbling Logic
     * ============================
     */

    function areSongsEqual(song1, song2) {
        if (!song1 || !song2) return false;
        return song1.title.toLowerCase() === song2.title.toLowerCase() &&
               song1.author.toLowerCase() === song2.author.toLowerCase() &&
               song1.album.toLowerCase() === song2.album.toLowerCase();
    }

    // Variable to keep track of the last scrobbled song
    let lastScrobbledSong = null;
    // Flag to indicate if a scrobble is already scheduled
    let scrobbleScheduled = false;
    // Timer for scrobbling after 10 seconds of playback
    let playbackTimer = null;

    /**
     * ============================
     * Progress Monitoring Logic
     * ============================
     */

    /**
     * Gets the current progress percentage of the song.
     * @returns {number|null} Progress percentage (0-100) or null if not available.
     */
    function getProgressPercentage() {
        const progressBar = querySelectorDeep('#progress-bar');
        if (progressBar) {
            const valueNow = parseInt(progressBar.getAttribute('aria-valuenow'), 10);
            const valueMax = parseInt(progressBar.getAttribute('aria-valuemax'), 10);
            if (!isNaN(valueNow) && !isNaN(valueMax) && valueMax > 0) {
                return (valueNow / valueMax) * 100;
            }
        }
        return null;
    }

    // Variable to keep track of last progress percentage
    let lastProgressPercentage = null;

    /**
     * Handles progress changes and detects jumps from >95% to <5%.
     * @param {number} newPercentage - The new progress percentage.
     */
    function handleProgressChange(newPercentage) {
        if (lastProgressPercentage === null) {
            lastProgressPercentage = newPercentage;
            return;
        }
        if (lastProgressPercentage > 95 && newPercentage < 5) {
            console.log('Progress jumped from >95% to <5%. Sending new scrobble.');
            const songInfo = getSongInfo();
            if (songInfo) {
                scrobble(songInfo.title, songInfo.author, songInfo.album);
            } else {
                console.warn('Cannot scrobble: song information not found.');
            }
        }
        lastProgressPercentage = newPercentage;
    }

    /**
     * Initializes a MutationObserver to monitor the progress bar's aria-valuenow.
     */
    function initProgressObserver() {
        const progressBar = querySelectorDeep('#progress-bar');
        if (!progressBar) {
            console.error('Progress bar not found. Progress monitoring not initialized.');
            return;
        }

        // Initialize lastProgressPercentage
        lastProgressPercentage = getProgressPercentage();
        console.debug('Initial progress percentage:', lastProgressPercentage);

        // Create observer
        const progressObserver = new MutationObserver((mutations) => {
            for (let mutation of mutations) {
                if (mutation.type === 'attributes' && mutation.attributeName === 'aria-valuenow') {
                    const newPercentage = getProgressPercentage();
                    if (newPercentage !== null) {
                        console.debug(`Progress updated: ${newPercentage.toFixed(2)}%`);
                        handleProgressChange(newPercentage);
                    }
                }
            }
        });

        // Observe aria-valuenow
        progressObserver.observe(progressBar, { attributes: true, attributeFilter: ['aria-valuenow'] });
        console.log('Progress observer initialized.');
    }

    /**
     * ============================
     * Scrobbling Logic (continued)
     * ============================
     */

    /**
     * Handles the scrobbling logic when a song change or playback state change is detected.
     * Scrobbles the song only if it has been playing for more than 10 seconds and is currently playing.
     */
    function handleScrobble() {
        const currentKey = GM_getValue('AUTH_KEY', '');

        if (!currentKey) {
          return;
        }

        const songInfo = getSongInfo();

        if (songInfo) {
            // Log current and detected song information
            console.debug('Current scrobbled song:', lastScrobbledSong);
            console.debug('Detected song:', songInfo);

            // Check if the song has changed to avoid duplicate scrobbles
            if (!areSongsEqual(lastScrobbledSong, songInfo)) {
                console.log(`New song detected: "${songInfo.title}" by ${songInfo.author} from "${songInfo.album}"`);

                // Check if the song is currently playing
                if (isPlaying() && !scrobbleScheduled) {
                      scrobbleScheduled = true;

                      // Update lastScrobbledSong to prevent repeated attempts
                      // Note: We update it here to prevent multiple timers for the same song
                      lastScrobbledSong = songInfo;

                      // Clear any existing timer
                      if (playbackTimer) {
                          clearTimeout(playbackTimer);
                          playbackTimer = null;
                          scrobbleScheduled = false;
                      }

                      playbackTimer = setTimeout(() => {
                          if (isPlaying()) {
                              scrobble(songInfo.title, songInfo.author, songInfo.album);
                              playbackTimer = null;
                          } else {
                              console.log('Playback stopped before scrobble threshold.');
                              scrobbleScheduled = false;
                          }
                      }, 10000); // 10 seconds
                      console.log('Started 10-second timer for scrobble.');
                } else {
                  console.debug(`isPlaying: ${isPlaying()} scrobbleScheduled: ${scrobbleScheduled}`)
                }
            } else {
                console.debug('Same song, no action needed.');
            }
        } else {
            console.warn('Song information not found.');
        }
    }

    /**
     * ============================
     * Debouncing Mechanism
     * ============================
     */

    /**
     * Debounce mechanism to prevent rapid consecutive scrobbles.
     * Waits for 1 second after the last mutation before handling scrobble.
     */
    let debounceTimeout = null;

    function debouncedHandleScrobble() {
        if (debounceTimeout) {
            clearTimeout(debounceTimeout);
        }
        debounceTimeout = setTimeout(() => {
            handleScrobble();
        }, 1000); // 1 second debounce
    }

    /**
     * ============================
     * MutationObserver Setup
     * ============================
     */

    /**
     * Initializes the MutationObserver to monitor changes in the player bar and play/pause button.
     */
    function initObserver() {
        const observer = new MutationObserver((mutations) => {
            for (let mutation of mutations) {
                // Detect changes in child elements (e.g., song title updates)
                if (mutation.type === 'childList' && mutation.addedNodes.length > 0) {
                    debouncedHandleScrobble();
                    break; // No need to process further mutations for this batch
                }

                // Detect attribute changes (e.g., play/pause button title changes)
                if (mutation.type === 'attributes' && (mutation.attributeName === 'title' || mutation.attributeName === 'aria-label')) {
                    debouncedHandleScrobble();
                    break;
                }
            }
        });

        // Configuration for the observer
        const config = { childList: true, subtree: true, attributes: true, attributeFilter: ['title', 'aria-label'] };

        // Start observing the entire document
        observer.observe(document.body, config);

        console.log('YouTube Music Scrobbler with Conditional Scrobbling is now active.');
    }

    /**
     * ============================
     * Initialization
     * ============================
     */

    /**
     * Waits for the player bar to be available in the DOM before initializing the observer.
     */
    function waitForPlayerBar() {
        const interval = setInterval(() => {
            const playerBar = querySelectorDeep('.ytmusic-player-bar');
            if (playerBar) {
                clearInterval(interval);
                initObserver();
                // Initial scrobble handling
                handleScrobble();

                // Initialize progress observer
                initProgressObserver();
            }
        }, 1000); // Check every second

        // Optionally, add a timeout to stop checking after a certain period
        // setTimeout(() => {
        //     clearInterval(interval);
        //     console.error('Player bar not found. Scrobbler not initialized.');
        // }, 30000); // 30 seconds
    }

    /**
     * Prompts the user to enter their AUTH_KEY and stores it using GM_setValue.
     */
    function setAuthKey() {
        const currentKey = GM_getValue('AUTH_KEY', '');
        const newKey = prompt('Enter your AUTH_KEY for antisocial.moe:', currentKey);
        if (newKey !== null) { // User didn't cancel
            if (newKey.trim() === '') {
                alert('AUTH_KEY cannot be empty.');
                return;
            }
            GM_setValue('AUTH_KEY', newKey.trim());
            alert('AUTH_KEY has been updated.');
            console.log('AUTH_KEY has been set/updated.');
        }
    }

    /**
     * Registers a menu command to allow users to set/edit the AUTH_KEY.
     */
    function registerMenuCommands() {
        GM_registerMenuCommand('Set antisocial.moe Auth Key', setAuthKey);
    }

    /**
     * Optionally, prompt the user to set the AUTH_KEY if it's not already set.
     */
    function promptForAuthKeyIfNeeded() {
        const authKey = GM_getValue('AUTH_KEY', '');
        if (!authKey) {
            alert('Please set your antisocial.moe AUTH_KEY using the Tampermonkey menu (right-click the Tampermonkey icon > Your Script > "Set antisocial.moe Auth Key").');
        }
    }

    // Register the menu command for setting the AUTH_KEY
    registerMenuCommands();

    // Start the script by waiting for the player bar to load
    waitForPlayerBar();

    // Prompt the user to set the AUTH_KEY if it's not set
    promptForAuthKeyIfNeeded();

})();