feat(diagnostics): harden ingestion and delivery

shared/src/androidMain/kotlin/com/vnidrop/app/diagnostics/PendingCrashStore.android.kt

@@ -13,8 +13,16 @@ private class AndroidPendingCrashStore(
 
 	@Synchronized
 	override fun write(report: CrashReport) {
+		if (!isValidDiagnosticId(report.id)) return
 		directory.mkdirs()
-		File(directory, "${report.id}.crash").writeText(CrashReportCodec.encode(report), StandardCharsets.UTF_8)
+		val target = File(directory, "${report.id}.crash")
+		val temporary = File(directory, ".${report.id}.tmp")
+		val payload = CrashReportCodec.encode(report)
+		temporary.writeText(payload, StandardCharsets.UTF_8)
+		if (!temporary.renameTo(target)) {
+			target.writeText(payload, StandardCharsets.UTF_8)
+			temporary.delete()
+		}
 	}
 
 	@Synchronized
@@ -31,6 +39,34 @@ private class AndroidPendingCrashStore(
 
 	@Synchronized
 	override fun delete(id: String) {
+		if (!isValidDiagnosticId(id)) return
 		File(directory, "$id.crash").delete()
 	}
+
+	@Synchronized
+	override fun prune(olderThanTimestampMillis: Long, maxCount: Int) {
+		require(maxCount > 0) { "maxCount must be positive" }
+		if (!directory.isDirectory) return
+		directory.listFiles { file -> file.isFile && file.name.endsWith(".tmp") }
+			.orEmpty()
+			.forEach(File::delete)
+		val reports = directory
+			.listFiles { file -> file.isFile && file.name.endsWith(".crash") }
+			.orEmpty()
+			.mapNotNull { file ->
+				val report = runCatching {
+					CrashReportCodec.decode(file.readText(StandardCharsets.UTF_8))
+				}.getOrNull()
+				if (report == null) {
+					file.delete()
+					null
+				} else {
+					file to report
+				}
+			}
+			.sortedByDescending { (_, report) -> report.timestampMillis }
+		reports.forEachIndexed { index, (file, report) ->
+			if (index >= maxCount || report.timestampMillis < olderThanTimestampMillis) file.delete()
+		}
+	}
 }

shared/src/androidMain/kotlin/com/vnidrop/app/diagnostics/PlatformHttp.android.kt

@@ -0,0 +1,37 @@
+package com.vnidrop.app.diagnostics
+
+import java.io.BufferedReader
+import java.io.InputStreamReader
+import java.net.HttpURLConnection
+import java.net.URI
+import java.nio.charset.StandardCharsets
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+
+actual suspend fun platformHttpPost(
+	url: String,
+	headers: Map<String, String>,
+	bodyUtf8: String,
+): PlatformHttpResponse = withContext(Dispatchers.IO) {
+	val connection = (URI(url).toURL().openConnection() as HttpURLConnection).apply {
+		requestMethod = "POST"
+		doOutput = true
+		connectTimeout = 15_000
+		readTimeout = 30_000
+		setRequestProperty("Content-Type", "application/json; charset=utf-8")
+		headers.forEach { (key, value) -> setRequestProperty(key, value) }
+	}
+	try {
+		connection.outputStream.use { output ->
+			output.write(bodyUtf8.toByteArray(StandardCharsets.UTF_8))
+		}
+		val code = connection.responseCode
+		val stream = if (code in 200..299) connection.inputStream else connection.errorStream
+		val body = stream?.use { input ->
+			BufferedReader(InputStreamReader(input, StandardCharsets.UTF_8)).readText()
+		}.orEmpty()
+		PlatformHttpResponse(code, body)
+	} finally {
+		connection.disconnect()
+	}
+}