Fix VideoTile bug and improve screen sharing

shared/src/lib.rs

@@ -0,0 +1,80 @@
+use serde::{Deserialize, Serialize};
+
+pub type UserId = u32; // Unique identifier for a user within a room
+pub type StreamId = u16; // Typically mapped to User + Media Source
+
+#[derive(Debug, Serialize, Deserialize, Clone, Copy, PartialEq, Eq, Hash)]
+#[repr(u8)]
+pub enum MediaType {
+    Audio = 0,
+    Video = 1,
+    Screen = 2,
+    Command = 3, // For handshake/keepalive
+    Unknown = 255,
+}
+
+/// UDP Packet Header (fixed size binary struct)
+#[derive(Debug, Serialize, Deserialize, Clone)]
+pub struct PacketHeader {
+    pub version: u8, // Protocol version (v1)
+    pub media_type: MediaType,
+    pub user_id: UserId, // Identifies the source user (was stream_id)
+    pub sequence: u32, // User-defined sequence number (for reordering/loss)
+    pub timestamp: u32, // RTP-like timestamp
+    pub fragment_index: u16, // If packet is fragmented (0 if not)
+    pub fragment_count: u16, // Total fragments (1 if not)
+    pub flags: u8, // Bitmask: 0x01 = Keyframe, etc.
+}
+
+pub const FLAG_KEYFRAME: u8 = 0x01;
+
+/// Signaling Messages (WebSocket - JSON)
+#[derive(Debug, Serialize, Deserialize, Clone)]
+#[serde(tag = "type", content = "data")]
+pub enum ControlMsg {
+    /// Client -> Server: Request to join a room
+    Join {
+        room_code: String,
+        display_name: String,
+    },
+    /// Server -> Client: Join success
+    Joined {
+        self_id: UserId,
+        room_code: String,
+        peers: Vec<PeerInfo>,
+    },
+    /// Server -> Client: New peer joined
+    PeerJoined {
+        user_id: UserId,
+        display_name: String,
+    },
+    /// Server -> Client: Peer left
+    PeerLeft {
+        user_id: UserId,
+    },
+    /// Client -> Server: Update stream status (e.g. camera on/off)
+    UpdateStream {
+        user_id: UserId,
+        stream_id: StreamId,
+        active: bool,
+        media_type: MediaType,
+    },
+    /// Client <-> Server: Chat message
+    ChatMessage {
+        user_id: UserId,
+        display_name: String,
+        message: String,
+        timestamp: u64,
+    },
+    /// General Error
+    Error {
+        message: String,
+    },
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone)]
+pub struct PeerInfo {
+    pub user_id: UserId,
+    pub display_name: String,
+    // Could include active streams etc.
+}