fix: cap camera snap payload size

apps/android/app/src/main/java/com/steipete/clawdis/node/node/CameraCaptureManager.kt

@@ -28,6 +28,7 @@ import kotlinx.coroutines.withContext
 import java.io.ByteArrayOutputStream
 import java.io.File
 import java.util.concurrent.Executor
+import kotlin.math.roundToInt
 import kotlin.coroutines.resume
 import kotlin.coroutines.resumeWithException
 
@@ -99,14 +100,35 @@ class CameraCaptureManager(private val context: Context) {
           decoded
         }
 
-      val out = ByteArrayOutputStream()
-      val jpegQuality = (quality * 100.0).toInt().coerceIn(10, 100)
-      if (!scaled.compress(Bitmap.CompressFormat.JPEG, jpegQuality, out)) {
-        throw IllegalStateException("UNAVAILABLE: failed to encode JPEG")
-      }
-      val base64 = Base64.encodeToString(out.toByteArray(), Base64.NO_WRAP)
+      val maxPayloadBytes = 5 * 1024 * 1024
+      val maxEncodedBytes = (maxPayloadBytes / 4) * 3
+      val result =
+        JpegSizeLimiter.compressToLimit(
+          initialWidth = scaled.width,
+          initialHeight = scaled.height,
+          startQuality = (quality * 100.0).roundToInt().coerceIn(10, 100),
+          maxBytes = maxEncodedBytes,
+          encode = { width, height, q ->
+            val bitmap =
+              if (width == scaled.width && height == scaled.height) {
+                scaled
+              } else {
+                scaled.scale(width, height)
+              }
+            val out = ByteArrayOutputStream()
+            if (!bitmap.compress(Bitmap.CompressFormat.JPEG, q, out)) {
+              if (bitmap !== scaled) bitmap.recycle()
+              throw IllegalStateException("UNAVAILABLE: failed to encode JPEG")
+            }
+            if (bitmap !== scaled) {
+              bitmap.recycle()
+            }
+            out.toByteArray()
+          },
+        )
+      val base64 = Base64.encodeToString(result.bytes, Base64.NO_WRAP)
       Payload(
-        """{"format":"jpg","base64":"$base64","width":${scaled.width},"height":${scaled.height}}""",
+        """{"format":"jpg","base64":"$base64","width":${result.width},"height":${result.height}}""",
       )
     }
 

apps/android/app/src/main/java/com/steipete/clawdis/node/node/JpegSizeLimiter.kt

@@ -0,0 +1,61 @@
+package com.steipete.clawdis.node.node
+
+import kotlin.math.max
+import kotlin.math.min
+import kotlin.math.roundToInt
+
+internal data class JpegSizeLimiterResult(
+  val bytes: ByteArray,
+  val width: Int,
+  val height: Int,
+  val quality: Int,
+)
+
+internal object JpegSizeLimiter {
+  fun compressToLimit(
+    initialWidth: Int,
+    initialHeight: Int,
+    startQuality: Int,
+    maxBytes: Int,
+    minQuality: Int = 20,
+    minSize: Int = 256,
+    scaleStep: Double = 0.85,
+    maxScaleAttempts: Int = 6,
+    maxQualityAttempts: Int = 6,
+    encode: (width: Int, height: Int, quality: Int) -> ByteArray,
+  ): JpegSizeLimiterResult {
+    require(initialWidth > 0 && initialHeight > 0) { "Invalid image size" }
+    require(maxBytes > 0) { "Invalid maxBytes" }
+
+    var width = initialWidth
+    var height = initialHeight
+    val clampedStartQuality = startQuality.coerceIn(minQuality, 100)
+    var best = JpegSizeLimiterResult(bytes = encode(width, height, clampedStartQuality), width = width, height = height, quality = clampedStartQuality)
+    if (best.bytes.size <= maxBytes) return best
+
+    repeat(maxScaleAttempts) {
+      var quality = clampedStartQuality
+      repeat(maxQualityAttempts) {
+        val bytes = encode(width, height, quality)
+        best = JpegSizeLimiterResult(bytes = bytes, width = width, height = height, quality = quality)
+        if (bytes.size <= maxBytes) return best
+        if (quality <= minQuality) return@repeat
+        quality = max(minQuality, (quality * 0.75).roundToInt())
+      }
+
+      val minScale = (minSize.toDouble() / min(width, height).toDouble()).coerceAtMost(1.0)
+      val nextScale = max(scaleStep, minScale)
+      val nextWidth = max(minSize, (width * nextScale).roundToInt())
+      val nextHeight = max(minSize, (height * nextScale).roundToInt())
+      if (nextWidth == width && nextHeight == height) return@repeat
+      width = min(nextWidth, width)
+      height = min(nextHeight, height)
+    }
+
+    if (best.bytes.size > maxBytes) {
+      throw IllegalStateException("CAMERA_TOO_LARGE: ${best.bytes.size} bytes > $maxBytes bytes")
+    }
+
+    return best
+  }
+}

apps/android/app/src/test/java/com/steipete/clawdis/node/node/JpegSizeLimiterTest.kt

@@ -0,0 +1,47 @@
+package com.steipete.clawdis.node.node
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import kotlin.math.min
+
+class JpegSizeLimiterTest {
+  @Test
+  fun compressesLargePayloadsUnderLimit() {
+    val maxBytes = 5 * 1024 * 1024
+    val result =
+      JpegSizeLimiter.compressToLimit(
+        initialWidth = 4000,
+        initialHeight = 3000,
+        startQuality = 95,
+        maxBytes = maxBytes,
+        encode = { width, height, quality ->
+          val estimated = (width.toLong() * height.toLong() * quality.toLong()) / 100
+          val size = min(maxBytes.toLong() * 2, estimated).toInt()
+          ByteArray(size)
+        },
+      )
+
+    assertTrue(result.bytes.size <= maxBytes)
+    assertTrue(result.width <= 4000)
+    assertTrue(result.height <= 3000)
+    assertTrue(result.quality <= 95)
+  }
+
+  @Test
+  fun keepsSmallPayloadsAsIs() {
+    val maxBytes = 5 * 1024 * 1024
+    val result =
+      JpegSizeLimiter.compressToLimit(
+        initialWidth = 800,
+        initialHeight = 600,
+        startQuality = 90,
+        maxBytes = maxBytes,
+        encode = { _, _, _ -> ByteArray(120_000) },
+      )
+
+    assertEquals(800, result.width)
+    assertEquals(600, result.height)
+    assertEquals(90, result.quality)
+  }
+}