TabManager: one GeckoSession per tab

app/src/main/java/dev/nova/browser/TabManager.kt

@@ -0,0 +1,107 @@
+package dev.nova.browser
+
+import androidx.compose.runtime.mutableStateListOf
+import androidx.compose.runtime.mutableStateOf
+import org.mozilla.geckoview.GeckoRuntime
+import org.mozilla.geckoview.GeckoSession
+import org.mozilla.geckoview.WebExtension
+
+/**
+ * Nova's tab model. One GeckoSession per tab; the UI activates a tab by
+ * calling GeckoView.setSession() on the active tab's session.
+ */
+class TabManager(private val runtime: GeckoRuntime) {
+
+    data class Tab(val id: Int, val session: GeckoSession)
+
+    /** Observable tab list for Compose. */
+    val tabs = mutableStateListOf<Tab>()
+    val activeTabId = mutableStateOf<Int?>(null)
+
+    /** Installed built-in extension, wired in once available. */
+    var devExtension: WebExtension? = null
+
+    /** Console lines forwarded from the dev-console extension. */
+    val consoleLines = mutableStateListOf<String>()
+
+    private var nextId = 1
+
+    /** Per-session content-script message delegate ("browser" native app). */
+    private val sessionMessageDelegate = object : WebExtension.MessageDelegate {
+        override fun onMessage(
+            nativeApp: String,
+            message: Any,
+            sender: WebExtension.MessageSender
+        ): GeckoResult<Any>? {
+            recordConsoleMessage(message)
+            return null
+        }
+    }
+
+    fun open(url: String): Tab {
+        val session = GeckoSession()
+
+        session.progressDelegate = object : GeckoSession.ProgressDelegate {
+            override fun onProgressChange(session: GeckoSession, progress: Int) {
+                // Hook for the loading bar (M2 milestone).
+            }
+        }
+        session.navigationDelegate = object : GeckoSession.NavigationDelegate {
+            override fun onLocationChange(session: GeckoSession, url: String?) {
+                // Hook for syncing the URL bar (M2 milestone).
+            }
+        }
+
+        session.open(runtime)
+
+        // Content scripts of the dev-console extension can sendNativeMessage to us.
+        devExtension?.let { ext ->
+            session.webExtensionController.setMessageDelegate(ext, sessionMessageDelegate, "browser")
+        }
+
+        val tab = Tab(nextId++, session)
+        tabs.add(tab)
+        activeTabId.value = tab.id
+        session.loadUri(url)
+        return tab
+    }
+
+    fun activate(id: Int) {
+        if (tabs.any { it.id == id }) activeTabId.value = id
+    }
+
+    fun close(id: Int) {
+        val index = tabs.indexOfFirst { it.id == id }
+        if (index == -1) return
+        tabs[index].session.close()
+        tabs.removeAt(index)
+        if (activeTabId.value == id) {
+            activeTabId.value = tabs.lastOrNull()?.id
+        }
+    }
+
+    fun activeSession(): GeckoSession? =
+        activeTabId.value?.let { id -> tabs.firstOrNull { it.id == id }?.session }
+
+    /** Called once the built-in extension finishes installing. */
+    fun wireExtension(ext: WebExtension) {
+        devExtension = ext
+        // Re-wire existing sessions that opened before the extension was ready.
+        tabs.forEach { tab ->
+            tab.session.webExtensionController.setMessageDelegate(ext, sessionMessageDelegate, "browser")
+        }
+    }
+
+    fun recordConsoleMessage(raw: Any) {
+        val line = when (raw) {
+            is Map<*, *> -> {
+                val type = raw["type"] ?: "log"
+                val payload = raw["payload"]?.toString() ?: ""
+                "[$type] $payload"
+            }
+            else -> raw.toString()
+        }
+        consoleLines.add(line)
+        android.util.Log.i("NovaConsole", line)
+    }
+}