From aa125d2f46dabca608422ed2a90f4b06d3b7f52a Mon Sep 17 00:00:00 2001
From: onyx-and-iris <code@onyxandiris.online>
Date: Fri, 11 Jul 2025 18:41:03 +0100
Subject: [PATCH] add audio gain command

---
 bin/index.js |  8 +++++++-
 src/audio.js | 46 +++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/bin/index.js b/bin/index.js
index 5ed6275..c3dd962 100755
--- a/bin/index.js
+++ b/bin/index.js
@@ -13,7 +13,7 @@ import WebSocket from 'ws'
 import cli from '../src/cli.js'
 import style from '../src/style.js'
 import { sceneHelp, sceneList, sceneSwitch, sceneCurrent } from '../src/scene.js'
-import { audioHelp, audioList, audioMute, audioUnmute, audioToggle, audioStatus } from '../src/audio.js'
+import { audioHelp, audioList, audioMute, audioUnmute, audioToggle, audioStatus, audioGain } from '../src/audio.js'
 import { streamHelp, streamStart, streamStop, streamToggle, streamStatus } from '../src/stream.js'
 import { recordHelp, recordStart, recordStop, recordToggle, recordStatus } from '../src/record.js'
 import { clipHelp, clipSave } from '../src/clip.js'
@@ -138,6 +138,12 @@ socket.onopen = function () {
             }
             withChannel(socket, (channel) => audioStatus(channel, audioArguments[0]))
             break
+          case 'gain':
+            if (!audioArguments[0] || isNaN(audioArguments[1])) {
+              printError('Error: Audio name and gain value are required for the gain command.')
+            }
+            withChannel(socket, (channel) => audioGain(channel, audioArguments[0], parseFloat(audioArguments[1])))
+            break
           default:
             printHelp(audioHelp)
         }
diff --git a/src/audio.js b/src/audio.js
index 50189bc..059cf76 100644
--- a/src/audio.js
+++ b/src/audio.js
@@ -27,6 +27,9 @@ const commands = {
   },
   status: {
     desc: 'Show current audio status'
+  },
+  gain: {
+    desc: 'Adjust the audio gain'
   }
 }
 
@@ -238,11 +241,52 @@ function audioStatus (channel, audioName) {
   })
 }
 
+/**
+ * Adjust the gain of a specific audio track by name.
+ * @param {Object} channel - The channel object containing Meld session data.
+ * @param {string} audioName - The name of the audio track to adjust.
+ * @param {number} gainValue - The gain value to set (-60.0 to 0.0).
+ * @returns {Promise<string>} Resolves with a success message or rejects with an error.
+ */
+function audioGain (channel, audioName, gainValue) {
+  if (!channel.objects || !channel.objects.meld) {
+    return Promise.reject(new Error('Meld object not found in channel.'))
+  }
+  const meld = channel.objects.meld
+  let itemId
+  for (const [key, value] of Object.entries(meld.session.items)) {
+    if (value.type === 'track' && value.name === audioName) {
+      itemId = key
+      break
+    }
+  }
+  if (!itemId) {
+    return Promise.reject(new Error(`No audio device with name ${style.errHighlight(audioName)} found.`))
+  }
+
+  if (typeof gainValue !== 'number' || gainValue < -60.0 || gainValue > 0.0) {
+    return Promise.reject(new Error('Gain value must be between -60.0 and 0.0.'))
+  }
+  // Convert dB (-60.0 to 0.0) to linear gain (0 to 1)
+  const dbDisplay = Math.pow(10, gainValue / 20)
+
+  return new Promise((resolve, reject) => {
+    meld.setGain(itemId, dbDisplay)
+      .then(() => {
+        resolve(`Audio track ${style.highlight(audioName)} gain set to ${gainValue}.`)
+      })
+      .catch((err) => {
+        reject(new Error(`Error setting audio gain: ${err.message}`))
+      })
+  })
+}
+
 export {
   audioHelp,
   audioList,
   audioMute,
   audioUnmute,
   audioToggle,
-  audioStatus
+  audioStatus,
+  audioGain
 }