feat(rules): add game-specific metadata attachment and unify match metadata initialization

Added AttachGameMetadata to GameRules interface

Implemented metadata setup for Battleship (phase + readiness flags)

Implemented no-op metadata hook for TicTacToe

Moved generic phase/ready metadata out of MatchInit

Added game/mode metadata to match state

Fixed json:"metadata" tag in MatchState

plugins/games/battleship.go

@@ -6,6 +6,14 @@ import (
     "localrepo/plugins/structs"
 )
 
+var Fleet = map[string]int{
+  "carrier":    5,
+  "battleship": 4,
+  "cruiser":    3,
+  "submarine":  3,
+  "destroyer":  2,
+}
+
 //
 // BATTLESHIP RULES IMPLEMENTATION
 //
@@ -62,26 +70,35 @@ type BattleshipRules struct{}
 
 func (b *BattleshipRules) MaxPlayers() int { return 2 }
 
+func (b *BattleshipRules) InitBoards(players []*structs.Player, cfg GameConfiguration) map[string]*structs.Board {
+    boards := make(map[string]*structs.Board)
+    // One ships board and one shots board per player
+    for _, p := range players {
+        pid := fmt.Sprintf("p%d", p.Index)
+
+        // Player's fleet board (ships placement)
+        boards[pid+"_ships"] = structs.NewBoard(cfg.Board.Rows, cfg.Board.Cols)
+
+        // Player's attack tracking board (shots fired at opponent)
+        boards[pid+"_shots"] = structs.NewBoard(cfg.Board.Rows, cfg.Board.Cols)
+    }
+    return boards
+}
+
 // ------------------------------
 // Assign player boards
 // ------------------------------
 func (b *BattleshipRules) AssignPlayerSymbols(players []*structs.Player) {
-    // Battleship has no symbols like X/O,
+    // nothing needed for battleship
-    // but we use this hook to initialize per-player boards.
+}
 
-    for _, p := range players {
+// ------------------------------
-        // 10x10 boards
+// Attach Game Metadata
-        empty := make([][]string, 10)
+// ------------------------------
-        for r := range empty {
+func (b *BattleshipRules) AttachGameMetadata(state *structs.MatchState) {
-            empty[r] = make([]string, 10)
+  state.Metadata["phase"] = "placement"
-        }
+  state.Metadata["p0_ready"] = false
-
+  state.Metadata["p1_ready"] = false
-        // ship board → players place ships manually via a "setup" phase
-        p.Metadata["ship_board"] = encodeBoard(empty)
-
-        // shot board → empty grid that tracks hits/misses
-        p.Metadata["shot_board"] = encodeBoard(empty)
-    }
 }
 
 // ------------------------------
@@ -90,72 +107,226 @@ func (b *BattleshipRules) AssignPlayerSymbols(players []*structs.Player) {
 // ------------------------------
 
 func (b *BattleshipRules) ValidateMove(state *structs.MatchState, playerIdx int, payload MovePayload) bool {
-    rF, ok1 := payload.Data["row"].(float64)
+    switch payload.Action {
-    cF, ok2 := payload.Data["col"].(float64)
+    case "place":
+        return b.ValidatePlacementMove(state, playerIdx, payload)
+    case "shoot":
+        return b.ValidateShotMove(state, playerIdx, payload)
+    default:
+        return false
+    }
+}
+
+func (b *BattleshipRules) ValidatePlacementMove(state *structs.MatchState, playerIdx int, payload MovePayload) bool {
+    // Allow placement until player placed all ships
+    if state.Metadata["phase"] != "placement" {
+        return false
+    }
+    key := fmt.Sprintf("p%d_placed", playerIdx)
+    placed := 0
+    if state.Metadata[key] != nil {
+        placed = state.Metadata[key].(int)
+    }
+    return placed < len(Fleet)
+}
+
+func (b *BattleshipRules) ValidateShotMove(state *structs.MatchState, playerIdx int, payload MovePayload) bool {
+    if state.Metadata["phase"] != "battle" {
+        return false
+    }
+    rf, ok1 := payload.Data["row"].(float64)
+    cf, ok2 := payload.Data["col"].(float64)
     if !ok1 || !ok2 {
         return false
     }
 
-    r := int(rF)
+    r := int(rf)
-    c := int(cF)
+    c := int(cf)
 
-    if r < 0 || r > 9 || c < 0 || c > 9 {
+    shotKey := fmt.Sprintf("p%d_shots", playerIdx)
+    shotBoard := state.Boards[shotKey]
+    if shotBoard == nil {
         return false
     }
 
-    // Check if this spot was already shot before
+    if !shotBoard.InBounds(r, c) {
-    shotBoard := decodeBoard(state.Players[playerIdx].Metadata["shot_board"])
+        return false
-    return shotBoard[r][c] == ""
+    }
+
+    if !shotBoard.IsEmpty(r, c) { // already shot
+        return false
+    }
+
+    return true
 }
 
-// ------------------------------
+// -----------------------------
-// ApplyMove
+// APPLY MOVE (MODE B — CLASSIC)
-// ------------------------------
+// -----------------------------
-func (b *BattleshipRules) ApplyMove(
+func (b *BattleshipRules) ApplyShot(
   state *structs.MatchState,
   playerIdx int,
   payload MovePayload,
-) (bool, bool, int) {
+) (bool, bool, int, bool) {
-  attacker := state.Players[playerIdx]
+  if !b.bothPlayersReady(state) {
-  defenderIdx := 1 - playerIdx
+    return false, false, -1, false
-  defender := state.Players[defenderIdx]
+  }
 
   r := int(payload.Data["row"].(float64))
   c := int(payload.Data["col"].(float64))
 
-  shotBoard := decodeBoard(attacker.Metadata["shot_board"])
+  shotKey := fmt.Sprintf("p%d_shots", playerIdx)
-  shipBoard := decodeBoard(defender.Metadata["ship_board"])
+  shipKey := fmt.Sprintf("p%d_ships", 1-playerIdx)
 
-  if shipBoard[r][c] == "S" {
+  shots := state.Boards[shotKey]
-      shotBoard[r][c] = "H"
+  ships := state.Boards[shipKey]
-      shipBoard[r][c] = "X"
+
+  hit := false
+
+  if ships.Get(r, c) == "S" {
+      // hit
+      hit = true
+      shots.Set(r, c, "H")
+      ships.Set(r, c, "X")   // mark destroyed section
   } else {
-      shotBoard[r][c] = "M"
+      shots.Set(r, c, "M")
   }
 
-  attacker.Metadata["shot_board"] = encodeBoard(shotBoard)
+  // check game over
-  defender.Metadata["ship_board"] = encodeBoard(shipBoard)
-
   over, winner := b.CheckGameOver(state)
 
-  return true, over, winner
+  // keepTurn = hit (classic rule)
+  return true, over, winner, hit
+}
+
+func (b *BattleshipRules) ApplyMove(
+    state *structs.MatchState,
+    playerIdx int,
+    payload MovePayload,
+) (bool, bool, int, bool) {
+
+    switch payload.Action {
+    case "place":
+        return b.ApplyPlacement(state, playerIdx, payload)
+    case "shoot":
+        return b.ApplyShot(state, playerIdx, payload)
+    default:
+        return false, false, -1, false
+    }
+}
+
+func (b *BattleshipRules) ApplyPlacement(
+    state *structs.MatchState,
+    playerIdx int,
+    payload MovePayload,
+) (bool, bool, int, bool) {
+
+    shipName, _ := payload.Data["ship"].(string)
+    rf, _ := payload.Data["row"].(float64)
+    cf, _ := payload.Data["col"].(float64)
+    dir, _ := payload.Data["dir"].(string)
+
+    r := int(rf)
+    c := int(cf)
+
+    size, ok := Fleet[shipName]
+    if !ok {
+        return false, false, -1, false // invalid ship name
+    }
+
+    shipKey := fmt.Sprintf("p%d_ships", playerIdx)
+    shipBoard := state.Boards[shipKey]
+
+    // Validate placement
+    if !b.validatePlacement(shipBoard, r, c, size, dir) {
+        return false, false, -1, false
+    }
+
+    // Place the ship
+    if dir == "h" {
+        for i := 0; i < size; i++ {
+            shipBoard.Set(r, c+i, "S")
+        }
+    } else { // vertical
+        for i := 0; i < size; i++ {
+            shipBoard.Set(r+i, c, "S")
+        }
+    }
+
+    // Track ships placed by player
+    placedCountKey := fmt.Sprintf("p%d_placed", playerIdx)
+    count := state.Metadata[placedCountKey]
+    if count == nil {
+        state.Metadata[placedCountKey] = 1
+    } else {
+        state.Metadata[placedCountKey] = count.(int) + 1
+    }
+
+    // If all 5 ships placed → ready
+    if state.Metadata[placedCountKey].(int) == len(Fleet) {
+        readyKey := fmt.Sprintf("p%d_ready", playerIdx)
+        state.Metadata[readyKey] = true
+    }
+
+    // Check if both players are ready
+    if b.bothPlayersReady(state) {
+        state.Metadata["phase"] = "battle"
+    }
+
+    return true, false, -1, false
+}
+
+func (b *BattleshipRules) validatePlacement(board *structs.Board, r, c, size int, dir string) bool {
+    rows, cols := board.Rows, board.Cols
+
+    if dir == "h" {
+        if c+size > cols {
+            return false
+        }
+        for i := 0; i < size; i++ {
+            if board.Get(r, c+i) != "" {
+                return false
+            }
+        }
+    } else {
+        if r+size > rows {
+            return false
+        }
+        for i := 0; i < size; i++ {
+            if board.Get(r+i, c) != "" {
+                return false
+            }
+        }
+    }
+    return true
+}
+
+func (b *BattleshipRules) bothPlayersReady(state *structs.MatchState) bool {
+    r0 := state.Metadata["p0_ready"]
+    r1 := state.Metadata["p1_ready"]
+
+    return r0 == true && r1 == true
 }
 
 // ------------------------------
 // CheckGameOver
 // ------------------------------
 func (b *BattleshipRules) CheckGameOver(state *structs.MatchState) (bool, int) {
-
+    for i := range state.Players {
-    for i, p := range state.Players {
+        shipKey := fmt.Sprintf("p%d_ships", i)
-        ships := decodeBoard(p.Metadata["ship_board"])
+        ships := state.Boards[shipKey]
 
         alive := false
-        for r := range ships {
+        for r := 0; r < ships.Rows; r++ {
-            for c := range ships[r] {
+            for c := 0; c < ships.Cols; c++ {
-                if ships[r][c] == "S" {
+                if ships.Get(r, c) == "S" {
                     alive = true
+                    break
                 }
             }
+            if alive {
+                break
+            }
         }
 
         if !alive {

plugins/games/rules.go

@@ -2,11 +2,18 @@ package games
 
 import "localrepo/plugins/structs"
 
-// MovePayload is used for incoming move data from clients.
+// MovePayload is the decoded payload sent from clients.
+// It is intentionally untyped (map[string]interface{}) so each game
+// can define its own move structure (e.g., row/col, coordinate, action type, etc.)
 type MovePayload struct {
-    Data map[string]interface{} `json:"data"`
+    Action string                 `json:"action"` // "place" or "shoot"
+    Data map[string]interface{}   `json:"data"`
 }
 
+// GameRules defines a generic interface for match logic.
+//
+// Each game (TicTacToe, Battleship, Chess, etc.) must implement this interface.
+// The Nakama match handler delegates all game-specific behavior to these methods.
 type GameRules interface {
     // Number of players needed to start.
     MaxPlayers() int
@@ -14,9 +21,15 @@ type GameRules interface {
     // Assign symbols/colors/pieces at start.
     AssignPlayerSymbols(players []*structs.Player)
 
+    // Attach Game Metadata
+    AttachGameMetadata(state *structs.MatchState)
     // Apply a move.
     // Returns: (changed, gameOver, winnerIndex)
-    ApplyMove(state *structs.MatchState, playerIdx int, payload MovePayload) (bool, bool, int)
+    ApplyMove(
+        state *structs.MatchState,
+        playerIdx int,
+        payload MovePayload,
+    ) (changed bool, gameOver bool, winnerIdx int, keepTurn bool)
 
     // If a player leaves, who wins?
     // Return:
@@ -24,4 +37,17 @@ type GameRules interface {
     //   -1 → draw
     //   -2 → invalid
     ForfeitWinner(state *structs.MatchState, leaverIndex int) int
+
+    // InitBoards initializes all the boards required for the game.
+    //
+    // This is called AFTER all players have joined the match.
+    //
+    // Examples:
+    // - TicTacToe → 1 board shared by both players:   {"tictactoe": 3x3}
+    // - Battleship → 2 boards per player:
+    //       {"p0_ships":10x10, "p0_shots":10x10, "p1_ships":..., "p1_shots":...}
+    //
+    // The returned map is stored in MatchState.Boards.
+    InitBoards(players []*structs.Player, cfg GameConfiguration) map[string]*structs.Board
+
 }

plugins/games/tictactoe.go

@@ -15,6 +15,12 @@ func (t *TicTacToeRules) MaxPlayers() int {
     return 2
 }
 
+func (t *TicTacToeRules) InitBoards(players []*structs.Player, cfg GameConfiguration) map[string]*structs.Board {
+    return map[string]*structs.Board{
+        "tictactoe": structs.NewBoard(cfg.Board.Rows, cfg.Board.Cols),
+    }
+}
+
 // Assign player symbols: X and O
 func (t *TicTacToeRules) AssignPlayerSymbols(players []*structs.Player) {
     if len(players) < 2 {
@@ -25,6 +31,13 @@ func (t *TicTacToeRules) AssignPlayerSymbols(players []*structs.Player) {
     players[1].Metadata["symbol"] = "O"
 }
 
+// ------------------------------
+// Attach Game Metadata
+// ------------------------------
+func (b *TicTacToeRules) AttachGameMetadata(state *structs.MatchState) {
+    // nothing needed for tictactoe
+}
+
 // ValidateMove checks bounds and empty cell.
 func (t *TicTacToeRules) ValidateMove(state *structs.MatchState, playerIdx int, payload MovePayload) bool {
 
@@ -45,13 +58,18 @@ func (t *TicTacToeRules) ValidateMove(state *structs.MatchState, playerIdx int,
     r := int(row)
     c := int(col)
 
+    b := state.Boards["tictactoe"]
+    if b == nil {
+        return false
+    }
+
     // bounds
-    if !state.Board.InBounds(r, c) {
+    if !b.InBounds(r, c) {
         return false
     }
 
     // empty?
-    return state.Board.IsEmpty(r, c)
+    return b.IsEmpty(r, c)
 }
 
 // ApplyMove writes X or O to the board.
@@ -59,24 +77,33 @@ func (t *TicTacToeRules) ApplyMove(
   state *structs.MatchState,
   playerIdx int,
   payload MovePayload,
-) (bool, bool, int) {
+) (bool, bool, int, bool) {
+  b := state.Boards["tictactoe"]
+  if b == nil {
+      return false, false, -1, false
+  }
+
   symbol := state.Players[playerIdx].Metadata["symbol"]
 
   r := int(payload.Data["row"].(float64))
   c := int(payload.Data["col"].(float64))
 
-  state.Board.Set(r, c, symbol)
+  b.Set(r, c, symbol)
 
   over, winner := t.CheckGameOver(state)
 
-  return true, over, winner
+  return true, over, winner, false
 }
 
 
 // CheckGameOver determines win/draw state.
 func (t *TicTacToeRules) CheckGameOver(state *structs.MatchState) (bool, int) {
+    b := state.Boards["tictactoe"]
+    if b == nil {
+        return true, -1 // fallback safety
+    }
 
-    winnerSymbol := t.findWinner(state.Board)
+    winnerSymbol := t.findWinner(b)
 
     if winnerSymbol != "" {
         // find the player with this symbol
@@ -88,7 +115,7 @@ func (t *TicTacToeRules) CheckGameOver(state *structs.MatchState) (bool, int) {
         return true, -1
     }
 
-    if state.Board.Full() {
+    if b.Full() {
         return true, -1 // draw
     }
 

plugins/modules/match.go

@@ -63,18 +63,6 @@ func indexOfPlayerByID(players []*structs.Player, userID string) int {
 	return -1
 }
 
-func newEmptyBoard(rows, cols int) *structs.Board {
-	b := &structs.Board{
-		Rows: rows,
-		Cols: cols,
-		Grid: make([][]string, rows),
-	}
-	for r := 0; r < rows; r++ {
-		b.Grid[r] = make([]string, cols)
-	}
-	return b
-}
-
 // -------------------------
 // Match interface methods
 // -------------------------
@@ -136,11 +124,15 @@ func (m *GenericMatch) MatchInit(
 	// ---- 6. create initial state (board from config) ----
 	state := &structs.MatchState{
 		Players:  []*structs.Player{},
-		Board:    newEmptyBoard(cfg.Board.Rows, cfg.Board.Cols),
+    Boards:   map[string]*structs.Board{}, // empty, will be filled later
 		Turn:     0,
 		Winner:   -1,
 		GameOver: false,
+		Metadata: map[string]interface{}{},
 	}
+  state.Metadata["game"] = m.GameName
+  state.Metadata["mode"] = m.Mode
+	m.Rules.AttachGameMetadata(state)
 
 	label := fmt.Sprintf("%s:%s", m.GameName, m.Mode)
 
@@ -217,6 +209,9 @@ func (m *GenericMatch) MatchJoin(
 		// Assign player symbols/colors/etc. Pass structs.Player directly.
 		m.Rules.AssignPlayerSymbols(s.Players)
 
+    // Initialize boards using game rules
+    s.Boards = m.Rules.InitBoards(s.Players, m.Config)
+
 		// Broadcast initial state
 		if data, err := json.Marshal(s); err == nil {
 			if err := dispatcher.BroadcastMessage(OpState, data, nil, nil, true); err != nil {
@@ -321,13 +316,14 @@ func (m *GenericMatch) MatchLoop(
 
 		// Turn enforcement — keep this here for turn-based games. If you want per-game control,
 		// move this check into the game's ApplyMove implementation or toggle via config.
-		if playerIdx != s.Turn {
+		phase := s.Metadata["phase"]
+    if phase == "battle" && playerIdx != s.Turn {
 			logger.Warn("Move rejected: not player's turn (idx=%d turn=%d)", playerIdx, s.Turn)
 			continue
 		}
 
 		// Delegate to rules.ApplyMove which returns (changed, gameOver, winnerIndex)
-		stateChanged, gameOver, winnerIdx := m.Rules.ApplyMove(s, playerIdx, payload)
+		stateChanged, gameOver, winnerIdx, keepTurn := m.Rules.ApplyMove(s, playerIdx, payload)
 
 		if stateChanged {
 			changed = true
@@ -337,7 +333,7 @@ func (m *GenericMatch) MatchLoop(
 			s.GameOver = true
 			s.Winner = winnerIdx
 		} else {
-			if len(s.Players) > 0 {
+      if !keepTurn && len(s.Players) > 0 {
 				s.Turn = (s.Turn + 1) % len(s.Players)
 			}
 		}
@@ -347,6 +343,7 @@ func (m *GenericMatch) MatchLoop(
 
 	if changed {
 		if data, err := json.Marshal(s); err == nil {
+		  logger.Info("Broadcasting state update (op=%d): %v", OpState, data)
 			if err := dispatcher.BroadcastMessage(OpState, data, nil, nil, true); err != nil {
 				logger.Error("BroadcastMessage failed: %v", err)
 			}

plugins/structs/match_state.go

@@ -2,9 +2,10 @@ package structs
 
 // MatchState holds the full game session state.
 type MatchState struct {
-    Players  []*Player `json:"players"`
+  Players  []*Player              `json:"players"`
-    Board    *Board    `json:"board"`
+  Boards   map[string]*Board      `json:"boards"`      // Multiple named boards:
-    Turn     int       `json:"turn"`       // index in Players[]
+  Turn     int                    `json:"turn"`        // index in Players[]
-    Winner   int       `json:"winner"`     // -1 = none, >=0 = winner index
+  Winner   int                    `json:"winner"`      // -1 = none, >=0 = winner index
-    GameOver bool      `json:"game_over"`  // true when the match ends
+  GameOver bool                   `json:"game_over"`   // true when the match ends
+  Metadata map[string]interface{} `json:"metadata"`      // metadata
 }