feat(android): back text messages up, in a build Play does not get

A Messages section sends the SMS added since the last copy, as restorable
<smses> XML, into <folder>/<account>-messages/YYYY. A play flavor has neither
READ_SMS nor the code that reads messages; full is the default.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

4 files changed, 84 insertions, 3 deletions

diff --git a/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/MainActivity.kt b/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/MainActivity.kt
index 3fa1146..0545ead 100644
--- a/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/MainActivity.kt
+++ b/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/MainActivity.kt
@@ -39,6 +39,7 @@ import org.meshbay.client.photos.BackupService
 import org.meshbay.client.phonesync.ContactSource
 import org.meshbay.client.phonesync.DestinationChannels
 import org.meshbay.client.phonesync.DocChannels
+import org.meshbay.client.phonesync.Flavor
 import org.meshbay.client.photos.PhotoChannels
 import org.meshbay.client.save.SaveSinks
 import org.meshbay.client.shell.Pickers
@@ -108,7 +109,11 @@ class MainActivity : Activity() {
             DocChannels("contactsync", this, getSharedPreferences("contactsync", Context.MODE_PRIVATE), destinations,
                         java.io.File(cacheDir, "contactsync"), ContactSource(this),
                         notifyId = 10, permissionRequest = 4209),
-        )
+        ) + listOfNotNull(Flavor.messageSource(this)?.let { source ->
+            DocChannels("messagesync", this, getSharedPreferences("messagesync", Context.MODE_PRIVATE), destinations,
+                        java.io.File(cacheDir, "messagesync"), source,
+                        notifyId = 11, permissionRequest = 4210)
+        })
         channels = Channels(hub, onHubChanged = { runOnUiThread { reloadForHub() } },
                             hasCatalogue = { code -> hasAsset("ui/locales/$code.js") }, keys = keys, saves = saves,
                             cast = cast, onPlayback = { on -> runOnUiThread { playing = on; keepAlive() } },
@@ -247,7 +252,8 @@ class MainActivity : Activity() {
         val source = assets.open("bridge/meshbay-bridge.js").bufferedReader().use { it.readText() }
         val binary = WebViewFeature.isFeatureSupported(WebViewFeature.WEB_MESSAGE_ARRAY_BUFFER)
         val prelude = "const HUB_BASE = ${JSONObject.quote(hub.base)};\nconst BINARY = $binary;\n" +
-            "const CAST = ${cast.control.available()};\n"
+            "const CAST = ${cast.control.available()};\n" +
+            "const MESSAGES = ${docs.any { it.handles("messagesync:") }};\n"
         shim = WebViewCompat.addDocumentStartJavaScript(web, "(function(){$prelude$source\n})();", setOf(UiAssets.ORIGIN))
     }
 
diff --git a/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/DocChannels.kt b/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/DocChannels.kt
index 6877912..2efe558 100644
--- a/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/DocChannels.kt
+++ b/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/DocChannels.kt
@@ -124,7 +124,8 @@ class DocChannels(
         val token = PhotoChannels.hex(ByteArray(16).also { random.nextBytes(it) })
         issued = Issued(token, export, c.ledgerKey)
         return JSONObject().put("item", JSONObject()
-            .put("token", token).put("name", export.name).put("dir", DocPlan.dirFor(c, source.suffix))
+            .put("token", token).put("name", export.name)
+            .put("dir", DocPlan.dirFor(c, source.suffix) + (if (export.subdir.isEmpty()) "" else "/${export.subdir}"))
             .put("size", export.file.length()).put("count", export.count))
     }
 
diff --git a/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/DocPlan.kt b/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/DocPlan.kt
index b1563da..1a2a359 100644
--- a/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/DocPlan.kt
+++ b/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/DocPlan.kt
@@ -15,6 +15,8 @@ data class Export(
     val marker: String,
     /** Contacts or messages in it, for the page to say. */
     val count: Int,
+    /** A folder under the kind's own, such as the year, or empty. */
+    val subdir: String = "",
 )
 
 /**
@@ -46,6 +48,9 @@ object DocPlan {
      * `<stem>-YYYY-MM-DD-HHmm.<ext>`, in the phone's time: a run never replaces
      * an earlier file, and the name says when it was taken.
      */
+    fun yearOf(now: Long, zone: TimeZone): String =
+        SimpleDateFormat("yyyy", Locale.ROOT).apply { timeZone = zone }.format(Date(now))
+
     fun nameFor(stem: String, ext: String, now: Long, zone: TimeZone): String =
         "$stem-" + SimpleDateFormat("yyyy-MM-dd-HHmm", Locale.ROOT).apply { timeZone = zone }.format(Date(now)) + ".$ext"
 }
diff --git a/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/SmsXml.kt b/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/SmsXml.kt
new file mode 100644
index 0000000..624e1f1
--- /dev/null
+++ b/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/phonesync/SmsXml.kt
@@ -0,0 +1,69 @@
+package org.meshbay.client.phonesync
+
+import java.io.Writer
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+import java.util.TimeZone
+
+/** One text message, as the platform's SMS provider stores it. */
+data class Sms(
+    val id: Long,
+    val address: String,
+    /** Milliseconds, received or sent. */
+    val date: Long,
+    val dateSent: Long,
+    /** 1 received, 2 sent, 3 draft, 4 outbox, 5 failed, 6 queued. */
+    val type: Int,
+    val body: String,
+    val read: Int,
+    val status: Int,
+    val locked: Int,
+    val protocol: Int,
+    val subject: String?,
+    val serviceCenter: String?,
+    val contactName: String?,
+)
+
+/**
+ * Messages written as the `<smses>` XML that SMS backup applications read and
+ * restore, so a copy on the node goes back onto a phone with tools that exist.
+ * Pure, so the JVM tests hold the format and its escaping.
+ */
+object SmsXml {
+    fun write(messages: List<Sms>, out: Writer, zone: TimeZone) {
+        val readable = SimpleDateFormat("d MMM yyyy HH:mm:ss", Locale.ROOT).apply { timeZone = zone }
+        out.write("<?xml version='1.0' encoding='UTF-8' standalone='yes' ?>\n")
+        out.write("<smses count=\"${messages.size}\">\n")
+        for (m in messages) {
+            out.write("  <sms protocol=\"${m.protocol}\" address=${q(m.address)} date=\"${m.date}\"" +
+                " type=\"${m.type}\" subject=${q(m.subject ?: "null")} body=${q(m.body)}" +
+                " toa=\"null\" sc_toa=\"null\" service_center=${q(m.serviceCenter ?: "null")}" +
+                " read=\"${m.read}\" status=\"${m.status}\" locked=\"${m.locked}\" date_sent=\"${m.dateSent}\"" +
+                " readable_date=${q(readable.format(Date(m.date)))}" +
+                " contact_name=${q(m.contactName ?: "(Unknown)")} />\n")
+        }
+        out.write("</smses>\n")
+    }
+
+    /**
+     * A quoted attribute value. Line breaks are kept as character references,
+     * which an attribute would otherwise fold into spaces; characters XML 1.0
+     * cannot carry at all, even escaped, are left out.
+     */
+    fun q(text: String): String {
+        val b = StringBuilder(text.length + 2).append('"')
+        for (c in text) when {
+            c == '&' -> b.append("&amp;")
+            c == '<' -> b.append("&lt;")
+            c == '>' -> b.append("&gt;")
+            c == '"' -> b.append("&quot;")
+            c == '\n' -> b.append("&#10;")
+            c == '\r' -> b.append("&#13;")
+            c == '\t' -> b.append("&#9;")
+            c < ' ' || c == '￾' || c == '￿' -> {}
+            else -> b.append(c)
+        }
+        return b.append('"').toString()
+    }
+}