MMPCreator

assets/js/creations/state.js

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+// js/state.js
+import { DEFAULT_VOLUME, DEFAULT_PAN } from "./config.js";
+import {
+  initializeAudioContext,
+  getAudioContext,
+  getMainGainNode,
+} from "./audio.js";
+import { renderApp } from "./ui.js";
+
+// O "cérebro" da aplicação
+export let appState = {
+  tracks: [],
+  isPlaying: false,
+  playbackIntervalId: null,
+  currentStep: 0,
+  metronomeEnabled: false,
+  originalXmlDoc: null,
+};
+
+export function addTrackToState() {
+  initializeAudioContext();
+  const audioContext = getAudioContext();
+  const mainGainNode = getMainGainNode();
+
+  const newTrack = {
+    id: Date.now(),
+    name: "novo instrumento",
+    samplePath: null,
+    steps: [],
+    volume: DEFAULT_VOLUME,
+    pan: DEFAULT_PAN,
+    gainNode: audioContext.createGain(),
+    pannerNode: audioContext.createStereoPanner(),
+  };
+  newTrack.gainNode.connect(newTrack.pannerNode);
+  newTrack.pannerNode.connect(mainGainNode);
+  newTrack.gainNode.gain.value = newTrack.volume;
+  newTrack.pannerNode.pan.value = newTrack.pan;
+
+  appState.tracks.push(newTrack);
+  renderApp();
+}
+
+export function removeLastTrackFromState() {
+  appState.tracks.pop();
+  renderApp();
+}
+
+export function updateTrackSample(trackId, samplePath) {
+  const track = appState.tracks.find((t) => t.id == trackId);
+  if (track) {
+    track.samplePath = samplePath;
+    track.name = samplePath.split("/").pop();
+  }
+  renderApp();
+}
+
+export function toggleStepState(trackId, stepIndex) {
+  const track = appState.tracks.find((t) => t.id == trackId);
+  if (track) {
+    track.steps[stepIndex] = !track.steps[stepIndex];
+  }
+}
+
+export function updateTrackVolume(trackId, volume) {
+  const track = appState.tracks.find((t) => t.id == trackId);
+  const audioContext = getAudioContext();
+  if (track) {
+    const clampedVolume = Math.max(0, Math.min(1.5, volume));
+    track.volume = clampedVolume;
+    if (track.gainNode) {
+      track.gainNode.gain.setValueAtTime(
+        clampedVolume,
+        audioContext.currentTime
+      );
+    }
+  }
+}
+
+export function updateTrackPan(trackId, pan) {
+  const track = appState.tracks.find((t) => t.id == trackId);
+  const audioContext = getAudioContext();
+  if (track) {
+    const clampedPan = Math.max(-1, Math.min(1, pan));
+    track.pan = clampedPan;
+    if (track.pannerNode) {
+      track.pannerNode.pan.setValueAtTime(clampedPan, audioContext.currentTime);
+    }
+  }
+}