PleromaModPlayer = function (attachment) {
  this.file = attachment.querySelector("a").href;
  this.attachment = attachment.cloneNode(true);
  this.attachment.setAttribute("class", "mod-player");
  attachment.parentNode.replaceChild(this.attachment, attachment);
  this.initComponents();
  this.module = null;
  this.replay = null;
  this.patternDisplay = null;
  this.samplePosition = 0;
  this.channel = 0;
  this.patternDisplay = new PatternDisplay(PleromaModTracker.chars.sheet, PleromaModTracker.chars.x, PleromaModTracker.chars.y);
  this.patternCanvas.width = this.patternDisplay.getMaxWidth(PleromaModTracker.chars.x);
  this.patternCanvas.height = this.patternDisplay.getMaxHeight();
  this.loadFile();
};
[
  function initComponents () {
    if (!window.CompatAudioContext) {
      const error = document.createElement("div");
      error.setAttribute("class", "alert error");
      error.innerText = "can't use webaudio. check if webaudio is enabled.";
      this.attachment.appendChild(error);
      return;
    }

    this.songName = this.attachment.querySelector("a");
    this.songName.setAttribute("class", "mod-title");

    const controls = document.createElement("div");
    controls.setAttribute("class", "mod-controls");
    
    this.playButton = document.createElement("button");
    this.playButton.onclick = () => { this.play() };
    this.playButton.innerText = " ▶ ";
    this.playButton.disabled = !window.CompatAudioContext;
    controls.appendChild(this.playButton);

    this.stopButton = document.createElement("button");
    this.stopButton.onclick = () => { this.stop() };
    this.stopButton.innerText = " ■ ";
    controls.appendChild(this.stopButton);

    this.seekBar = document.createElement("input");
    this.seekBar.setAttribute("class", "mod-seekbar");
    this.seekBar.setAttribute("type", "range");
    this.seekBar.onmousedown = () => { this.stop() };
    this.seekBar.onmouseup = () => { this.play() };
    controls.appendChild(this.seekBar);

    this.attachment.appendChild(controls);

    this.patternCanvas = document.createElement("canvas");
    this.patternCanvas.setAttribute("class", "mod-patterns");
    this.attachment.appendChild(this.patternCanvas);

    this.instruments = document.createElement("div");
    this.instruments.setAttribute("class", "mod-instruments");
    this.attachment.appendChild(this.instruments);
  },

  function play () {
    this.stop();
    PleromaModTracker.currentDisplay = this;
    PleromaModTracker.player.setAudioSource(this.replay);
    this.samplePosition = this.replay.seek(this.seekBar.value * PleromaModTracker.player.getSamplingRate());
    PleromaModTracker.setReverb(50);
    PleromaModTracker.player.play();
  },
  function stop () {
    PleromaModTracker.player.stop();
    PleromaModTracker.currentDisplay = null;
  },

  function loadFile () {
    window.fetch(this.file).then((response) => {
      if (response.ok) {
        response.arrayBuffer().then((buffer) => {
          this.setModule(new Int8Array(buffer));
        }).catch((error) => {
          console.error("can't read module data");
          console.error(error);
        });
      }
    }).catch((error) => {
      console.warn("can't load module");
      console.warn(error);
    });
  },

  function setModule (moduleData) {
    this.module = new IBXMModule(moduleData);
    const rate = PleromaModTracker.player.getSamplingRate();
    this.replay = new IBXMReplay(this.module, rate);
    const duration = Math.round(this.replay.calculateSongDuration() / rate);
    this.samplePosition = 0;
    this.seekBar.value = 0;
    this.seekBar.max = duration;
    this.songName.innerText = this.module.songName;
    let instruments = "";
    for (let idx = 1; idx < this.module.instruments.length; idx++) {
      const name = this.module.instruments[idx].name;
      if (name.trim().length > 0) {
        const instrument = (idx < 16 ? "&nbsp;" : "") + idx.toString(16);
        instruments = instruments + instrument + " " + name.replace(/\s/g, "&nbsp;") + "<br/>";
      }
    }
    this.instruments.innerHTML = instruments;
    this.channel = 0;
    this.clearDisplay();
    this.updateDisplay();
  },

  function updateDisplay (count) {
    if (count) {
      this.samplePosition += count;
    }
    this.seekBar.value = this.samplePosition / PleromaModTracker.player.getSamplingRate();
    this.patternDisplay.display(this.module, this.replay, this.channel, this.patternCanvas);
  },

  function clearDisplay () {
    const context = this.patternCanvas.getContext("2d");
    context.fillStyle = "black";
    context.fillRect(0, 0, this.patternCanvas.width, this.patternCanvas.height);
  },
].forEach((fn) => { PleromaModPlayer.prototype[fn.name] = fn; });

PleromaModTracker = function () {
  this.config = {
    stylesheet: "style.css",
    pattern: "\\.(xm|mod|s3m)$"
  };
  this.toUpdate = [];
  this.ready = false;
};
[
  function onMutation (mutation, observer) {
    for (const addedNode of mutation.addedNodes) {
      this.handlePost(addedNode);
    }
  },

  function onReady () {
    const posts = document.querySelectorAll(".status");
    for (const post of posts) {
      this.handlePost(post);
    }
  },

  function handlePost (postElement) {
    if (
      postElement.querySelectorAll &&
      postElement.querySelectorAll(".attachments").length > 0
    ) {
      const attachments = this.getModuleAttachments(postElement);
      for (const attachment of attachments) {
        if (this.ready) {
          new PleromaModPlayer(attachment);
        } else {
          this.toUpdate.push(attachment);
        }
      }
    }
  },

  function getModuleAttachments (postElement) {
    const result = [];
    const nonGalleryElements = postElement.querySelectorAll(".non-gallery");
    const regex = new RegExp(this.config.pattern, "i");
    for (const nonGalleryElement of nonGalleryElements) {
      if (
        regex.test(nonGalleryElement.querySelector("a").href)
      ) {
        result.push(nonGalleryElement);
      }
    }
    return result;
  },

  function catchUp () {
    for (const attachment of this.toUpdate) {
      new PleromaModPlayer(attachment);
    }
    this.toUpdate = [];
  },

  function run () {
    PleromaModLoader.includeModCss("pleroma-mod-tracker/" + this.config.stylesheet);
    PleromaModTracker.chars = {
      x: 8,
      y: 16
    };
    if (!window.CompatAudioContext) {
      this.ready = true;
      this.catchUp();
      return;
    }
    Promise.all([
      PleromaModLoader.includeModScript("pleroma-mod-tracker/audio-player.js"),
      PleromaModLoader.includeModScript("pleroma-mod-tracker/ibxm.js"),
      PleromaModLoader.includeModScript("pleroma-mod-tracker/pattern-display.js"),
    ]).then(() => {
      const imageCharset = new Image();
      imageCharset.src = PleromaModLoader.getModDir() + "pleroma-mod-tracker/topaz8.png";
      imageCharset.addEventListener("load", () => {
        initCharset(imageCharset, PleromaModTracker.chars.x, PleromaModTracker.chars.y, (chs) => {
          PleromaModTracker.chars.sheet = chs;
          PleromaModTracker.player = new AudioPlayer(
            PleromaModTracker.onPlayerUpdate,
            PleromaModTracker.onEffect
          );
          this.ready = true;
          this.catchUp();
        });
      });
    });
  },
].forEach((fn) => { PleromaModTracker.prototype[fn.name] = fn; });

window.CompatAudioContext = window.AudioContext || window.webkitAudioContext;
PleromaModTracker.currentDisplay = null;

[
  function onPlayerUpdate (count) {
    if (PleromaModTracker.currentDisplay) {
      PleromaModTracker.currentDisplay.updateDisplay(count);
    }
  },

  function setReverb (milliSeconds) {
    const length = Math.round(PleromaModTracker.player.getSamplingRate() * milliSeconds / 1000);
    PleromaModTracker.reverb = {
      idx: 0,
      length: length,
      bufferLeft: new Float32Array(length),
      bufferRight: new Float32Array(length)
    };
  },

  function onEffect (mixBufferLeft, mixBufferRight, count) {
    if (PleromaModTracker.reverb.length) {
      const reverb = PleromaModTracker.reverb;
      for (let mixIdx = 0; mixIdx < count; mixIdx++) {
        mixBufferLeft[mixIdx] = (mixBufferLeft[mixIdx] * 3 + reverb.bufferRight[reverb.idx]) * 0.25;
        mixBufferRight[mixIdx] = (mixBufferRight[mixIdx] * 3 + reverb.bufferLeft[reverb.idx]) * 0.25;
        reverb.bufferLeft[reverb.idx] = mixBufferLeft[mixIdx];
        reverb.bufferRight[reverb.idx] = mixBufferRight[mixIdx];
        reverb.idx++;
        if (reverb.idx >= reverb.length) {
          reverb.idx = 0;
        }
      }
    }
  }
].forEach((fn) => { PleromaModTracker[fn.name] = fn; });

PleromaModLoader.registerMod(PleromaModTracker);