tic-tac-toe/plugins/games/battleship.go

package games

import (
    "fmt"
    "encoding/json"
    "localrepo/plugins/structs"
)

//
// BATTLESHIP RULES IMPLEMENTATION
//
// NOTES:
// - 2 players
// - Each player has 2 boards:
//      1. Their own ship board   (state.Board is not reused here)
//      2. Their "shots" board    (hits/misses on opponent)
// - We store boards in Player.Metadata as JSON strings
//   (simplest method without changing your structs).
//

// ShipBoard and ShotBoard are encoded inside Metadata:
//
// Metadata["ship_board"] = JSON string of [][]string
// Metadata["shot_board"] = JSON string of [][]string
//

// ------------------------------
// Helpers: encode/decode
// ------------------------------

func encodeBoard(b [][]string) string {
    out := "["
    for i, row := range b {
        out += "["
        for j, col := range row {
            out += fmt.Sprintf("%q", col)
            if j < len(row)-1 {
                out += ","
            }
        }
        out += "]"
        if i < len(b)-1 {
            out += ","
        }
    }
    out += "]"
    return out
}

func decodeBoard(s string) [][]string {
    var out [][]string
    // should never fail; safe fallback
    _ = json.Unmarshal([]byte(s), &out)
    return out
}

// ------------------------------
// BattleshipRules
// ------------------------------

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) {
    // nothing needed for classic mode
}

// ------------------------------
// ValidateMove
// payload.data = { "row": int, "col": int }
// ------------------------------

func (b *BattleshipRules) ValidateMove(state *structs.MatchState, playerIdx int, payload MovePayload) bool {
    rf, ok1 := payload.Data["row"].(float64)
    cf, ok2 := payload.Data["col"].(float64)
    if !ok1 || !ok2 {
        return false
    }
    r := int(rf)
    c := int(cf)

    shotKey := fmt.Sprintf("p%d_shots", playerIdx)
    shotBoard := state.Boards[shotKey]
    if shotBoard == nil {
        return false
    }

    if !shotBoard.InBounds(r, c) {
        return false
    }

    // can't shoot same cell twice
    if !shotBoard.IsEmpty(r, c) {
        return false
    }

    return true
}

// -----------------------------
// APPLY MOVE (MODE B — CLASSIC)
// -----------------------------
func (b *BattleshipRules) ApplyMove(
  state *structs.MatchState,
  playerIdx int,
  payload MovePayload,
) (bool, bool, int, bool) {

  r := int(payload.Data["row"].(float64))
  c := int(payload.Data["col"].(float64))

  shotKey := fmt.Sprintf("p%d_shots", playerIdx)
  shipKey := fmt.Sprintf("p%d_ships", 1-playerIdx)

  shots := state.Boards[shotKey]
  ships := state.Boards[shipKey]

  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 {
      shots.Set(r, c, "M")
  }

  // check game over
  over, winner := b.CheckGameOver(state)

  // keepTurn = hit (classic rule)
  return true, over, winner, hit
}

// ------------------------------
// CheckGameOver
// ------------------------------
func (b *BattleshipRules) CheckGameOver(state *structs.MatchState) (bool, int) {
    for i := range state.Players {
        shipKey := fmt.Sprintf("p%d_ships", i)
        ships := state.Boards[shipKey]

        alive := false
        for r := 0; r < ships.Rows; r++ {
            for c := 0; c < ships.Cols; c++ {
                if ships.Get(r, c) == "S" {
                    alive = true
                    break
                }
            }
            if alive {
                break
            }
        }

        if !alive {
            // this player has no ships left → opponent wins
            return true, 1 - i
        }
    }

    return false, -1
}

// ------------------------------
// Forfeit Winner
// ------------------------------
func (b *BattleshipRules) ForfeitWinner(state *structs.MatchState, leaverIndex int) int {

    // If player leaves, opponent automatically wins.
    if leaverIndex == 0 {
        return 1
    }
    if leaverIndex == 1 {
        return 0
    }
    return -1
}