fetch relay list from the internet

app/src/main/java/com/bitchat/android/nostr/RelayDirectory.kt

@@ -1,10 +1,24 @@
 package com.bitchat.android.nostr
 
 import android.app.Application
+import android.content.SharedPreferences
 import android.util.Log
 import java.io.BufferedReader
+import java.io.File
+import java.io.FileInputStream
+import java.io.FileOutputStream
+import java.io.InputStream
 import java.io.InputStreamReader
+import java.security.MessageDigest
+import java.util.concurrent.TimeUnit
 import kotlin.math.*
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import okhttp3.OkHttpClient
+import okhttp3.Request
 
 /**
  * Loads relay coordinates from assets and provides nearest-relay lookup by geohash.
@@ -12,7 +26,21 @@ import kotlin.math.*
 object RelayDirectory {
 
     private const val TAG = "RelayDirectory"
+    private const val ASSET_FILE_URL = "https://raw.githubusercontent.com/permissionlesstech/georelays/refs/heads/main/nostr_relays.csv"
     private const val ASSET_FILE = "nostr_relays.csv"
+    private const val DOWNLOADED_FILE = "nostr_relays_latest.csv"
+    private const val PREFS_NAME = "relay_directory_prefs"
+    private const val KEY_LAST_UPDATE_MS = "last_update_ms"
+    private val ONE_DAY_MS = TimeUnit.DAYS.toMillis(1)
+
+    private val ioScope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+    private val httpClient: OkHttpClient by lazy {
+        OkHttpClient.Builder()
+            .callTimeout(15, TimeUnit.SECONDS)
+            .connectTimeout(10, TimeUnit.SECONDS)
+            .readTimeout(15, TimeUnit.SECONDS)
+            .build()
+    }
 
     data class RelayInfo(
         val url: String,
@@ -24,35 +52,35 @@ object RelayDirectory {
     private var initialized: Boolean = false
 
     private val relays: MutableList<RelayInfo> = mutableListOf()
+    private val relaysLock = Any()
 
     fun initialize(application: Application) {
         if (initialized) return
         synchronized(this) {
             if (initialized) return
             try {
-                val input = application.assets.open(ASSET_FILE)
-                BufferedReader(InputStreamReader(input)).use { reader ->
-                    var line: String?
-                    var numLoaded = 0
-                    while (true) {
-                        line = reader.readLine()
-                        if (line == null) break
-                        val trimmed = line!!.trim()
-                        if (trimmed.isEmpty()) continue
-                        // Skip header if present
-                        if (trimmed.lowercase().startsWith("relay url")) continue
-                        val parts = trimmed.split(",")
-                        if (parts.size < 3) continue
-                        val url = normalizeRelayUrl(parts[0].trim())
-                        val lat = parts[1].trim().toDoubleOrNull()
-                        val lon = parts[2].trim().toDoubleOrNull()
-                        if (url.isEmpty() || lat == null || lon == null) continue
-                        relays.add(RelayInfo(url = url, latitude = lat, longitude = lon))
-                        numLoaded += 1
-                    }
-                    Log.i(TAG, "📥 Loaded $numLoaded relay entries from assets/$ASSET_FILE")
+                val downloaded = getDownloadedFile(application)
+                val loadedFromDownloaded = if (downloaded.exists() && downloaded.canRead()) {
+                    loadFromFile(downloaded, sourceLabel = "downloaded")
+                } else {
+                    false
                 }
+
+                if (!loadedFromDownloaded) {
+                    loadFromAssets(application)
+                }
+
                 initialized = true
+
+                // Trigger an immediate fetch if the data is stale (older than 24h)
+                ioScope.launch {
+                    if (isStale(application)) {
+                        fetchAndMaybeSwap(application)
+                    }
+                }
+
+                // Start periodic staleness check every minute
+                startPeriodicRefresh(application)
             } catch (e: Exception) {
                 Log.e(TAG, "Failed to initialize RelayDirectory: ${e.message}")
             }
@@ -63,7 +91,8 @@ object RelayDirectory {
      * Return up to nRelays closest relay URLs to the geohash center.
      */
     fun closestRelaysForGeohash(geohash: String, nRelays: Int): List<String> {
-        if (relays.isEmpty()) return emptyList()
+        val snapshot = synchronized(relaysLock) { relays.toList() }
+        if (snapshot.isEmpty()) return emptyList()
         val center = try {
             val c = com.bitchat.android.geohash.Geohash.decodeToCenter(geohash)
             c
@@ -73,7 +102,7 @@ object RelayDirectory {
         }
 
         val (lat, lon) = center
-        return relays
+        return snapshot
             .asSequence()
             .sortedBy { haversineMeters(lat, lon, it.latitude, it.longitude) }
             .take(nRelays.coerceAtLeast(0))
@@ -95,6 +124,186 @@ object RelayDirectory {
         if (trimmed.isEmpty()) return trimmed
         return if ("://" in trimmed) trimmed else "wss://$trimmed"
     }
+
+    // ===== Implementation details =====
+
+    private fun getPrefs(application: Application): SharedPreferences =
+        application.getSharedPreferences(PREFS_NAME, Application.MODE_PRIVATE)
+
+    private fun getDownloadedFile(application: Application): File =
+        File(application.filesDir, DOWNLOADED_FILE)
+
+    private fun isStale(application: Application): Boolean {
+        val last = getPrefs(application).getLong(KEY_LAST_UPDATE_MS, 0L)
+        val now = System.currentTimeMillis()
+        return now - last >= ONE_DAY_MS
+    }
+
+    private fun startPeriodicRefresh(application: Application) {
+        ioScope.launch {
+            while (true) {
+                try {
+                    if (isStale(application)) {
+                        fetchAndMaybeSwap(application)
+                    }
+                } catch (e: Exception) {
+                    Log.w(TAG, "Periodic refresh encountered an error: ${e.message}")
+                }
+                delay(TimeUnit.MINUTES.toMillis(1))
+            }
+        }
+    }
+
+    private fun fetchAndMaybeSwap(application: Application) {
+        try {
+            val tmpFile = File.createTempFile("relays_", ".csv", application.cacheDir)
+            val ok = downloadToFile(ASSET_FILE_URL, tmpFile)
+            if (!ok) {
+                Log.w(TAG, "Failed to fetch latest relays; keeping current list (will fallback to bundled if none)")
+                tmpFile.delete()
+                return
+            }
+
+            val parsed = parseCsv(FileInputStream(tmpFile))
+            if (parsed.isEmpty()) {
+                Log.w(TAG, "Downloaded relay CSV parsed to 0 entries; ignoring")
+                tmpFile.delete()
+                return
+            }
+
+            val dest = getDownloadedFile(application)
+            tmpFile.inputStream().use { input ->
+                FileOutputStream(dest, false).use { output ->
+                    input.copyTo(output)
+                }
+            }
+            tmpFile.delete()
+
+            val hash = fileSha256Hex(dest)
+            val entries = parsed.size
+
+            synchronized(relaysLock) {
+                relays.clear()
+                relays.addAll(parsed)
+            }
+
+            getPrefs(application).edit().putLong(KEY_LAST_UPDATE_MS, System.currentTimeMillis()).apply()
+
+            Log.i(TAG, "✅ Using downloaded relay list (${dest.absolutePath}), entries=$entries, sha256=$hash, updatedAtMs=${getPrefs(application).getLong(KEY_LAST_UPDATE_MS, 0L)}")
+        } catch (e: Exception) {
+            Log.w(TAG, "Failed to fetch and swap relay list: ${e.message}")
+        }
+    }
+
+    private fun downloadToFile(url: String, dest: File): Boolean {
+        return try {
+            val req = Request.Builder().url(url).get().build()
+            httpClient.newCall(req).execute().use { resp ->
+                if (!resp.isSuccessful) {
+                    Log.w(TAG, "HTTP ${'$'}{resp.code} when fetching $url")
+                    return false
+                }
+                val body = resp.body ?: return false
+                FileOutputStream(dest).use { out ->
+                    body.byteStream().use { input ->
+                        input.copyTo(out)
+                    }
+                }
+                true
+            }
+        } catch (e: Exception) {
+            Log.w(TAG, "Download error: ${e.message}")
+            false
+        }
+    }
+
+    private fun loadFromFile(file: File, sourceLabel: String): Boolean {
+        return try {
+            val list = parseCsv(FileInputStream(file))
+            if (list.isEmpty()) {
+                Log.w(TAG, "${sourceLabel} relay CSV has 0 entries; ignoring")
+                false
+            } else {
+                synchronized(relaysLock) {
+                    relays.clear()
+                    relays.addAll(list)
+                }
+                val hash = fileSha256Hex(file)
+                Log.i(TAG, "📄 Loaded ${list.size} relay entries from ${sourceLabel} file (${file.absolutePath}), sha256=$hash")
+                true
+            }
+        } catch (e: Exception) {
+            Log.w(TAG, "Failed loading ${sourceLabel} relay file: ${e.message}")
+            false
+        }
+    }
+
+    private fun loadFromAssets(application: Application) {
+        val list = try {
+            parseCsv(application.assets.open(ASSET_FILE))
+        } catch (e: Exception) {
+            Log.e(TAG, "Failed to open asset $ASSET_FILE: ${e.message}")
+            emptyList()
+        }
+        synchronized(relaysLock) {
+            relays.clear()
+            relays.addAll(list)
+        }
+        // Compute asset hash for logging
+        val hash = try {
+            application.assets.open(ASSET_FILE).use { input ->
+                streamSha256Hex(input)
+            }
+        } catch (e: Exception) {
+            "error:${'$'}{e.message}"
+        }
+        Log.i(TAG, "📦 Loaded ${list.size} relay entries from assets/$ASSET_FILE, sha256=$hash")
+    }
+
+    private fun parseCsv(input: InputStream): List<RelayInfo> {
+        val result = mutableListOf<RelayInfo>()
+        BufferedReader(InputStreamReader(input)).use { reader ->
+            var line: String?
+            while (true) {
+                line = reader.readLine()
+                if (line == null) break
+                val trimmed = line!!.trim()
+                if (trimmed.isEmpty()) continue
+                if (trimmed.lowercase().startsWith("relay url")) continue
+                val parts = trimmed.split(",")
+                if (parts.size < 3) continue
+                val url = normalizeRelayUrl(parts[0].trim())
+                val lat = parts[1].trim().toDoubleOrNull()
+                val lon = parts[2].trim().toDoubleOrNull()
+                if (url.isEmpty() || lat == null || lon == null) continue
+                result.add(RelayInfo(url = url, latitude = lat, longitude = lon))
+            }
+        }
+        return result
+    }
+
+    private fun fileSha256Hex(file: File): String = try {
+        FileInputStream(file).use { input ->
+            streamSha256Hex(input)
+        }
+    } catch (_: Exception) { "error" }
+
+    private fun streamSha256Hex(input: InputStream): String {
+        val digest = MessageDigest.getInstance("SHA-256")
+        val buf = ByteArray(8192)
+        var read: Int
+        while (true) {
+            read = input.read(buf)
+            if (read <= 0) break
+            digest.update(buf, 0, read)
+        }
+        val bytes = digest.digest()
+        return bytes.joinToString("") { b ->
+            val v = b.toInt() and 0xff
+            val s = Integer.toHexString(v)
+            if (s.length == 1) "0$s" else s
+        }
+    }
 }