feat: Add Checkers game realm

packages/r/karma1337/checkers/checkers.gno

@@ -0,0 +1,136 @@
+package checkers
+
+import (
+	"strings"
+
+	"chain/runtime"
+)
+
+// CreateGame starts a new game where the caller plays RED and the provided
+// address plays BLACK. Returns the game id (e.g. "game_0").
+//
+// Usage: CreateGame("g1opponentaddress...")
+// You can use your own address to play both sides for testing.
+func CreateGame(_ realm, black string) string {
+	if black == "" {
+		panic("opponent address is required")
+	}
+
+	black = strings.TrimSpace(black)
+	if black == "" {
+		panic("opponent address cannot be empty")
+	}
+
+	caller := runtime.PreviousRealm().Address().String()
+
+	id := newGameID()
+	g := &Game{
+		ID:     id,
+		Red:    caller,
+		Black:  black,
+		Board:  initialBoard(),
+		Turn:   RED,
+		Status: StatusActive,
+	}
+	saveGame(g)
+	return id
+}
+
+// Move performs a single piece move. Coordinates are 0-based.
+func Move(_ realm, gameID string, fromRow, fromCol, toRow, toCol int) MoveRecord {
+	g := mustGetGame(gameID)
+	record := applyMove(g, fromRow, fromCol, toRow, toCol, runtime.PreviousRealm().Address().String())
+	return record
+}
+
+// GetGameInfo returns a copy of the game.
+func GetGameInfo(gameID string) Game {
+	g := mustGetGame(gameID)
+	return copyGame(g)
+}
+
+// GetMoveHistory returns the recorded move history.
+func GetMoveHistory(gameID string) []MoveRecord {
+	g := mustGetGame(gameID)
+	history := make([]MoveRecord, len(g.History))
+	copy(history, g.History)
+	return history
+}
+
+// ListGames returns the ids of all games.
+func ListGames() []string {
+	out := make([]string, 0, len(games))
+	for id := range games {
+		out = append(out, id)
+	}
+	return out
+}
+
+// GamesByAddress returns games where the address participates.
+func GamesByAddress(addr string) []string {
+	out := []string{}
+	for id, g := range games {
+		if g.Red == addr || g.Black == addr {
+			out = append(out, id)
+		}
+	}
+	return out
+}
+
+// Render implements gnoweb entry point.
+func Render(path string) string {
+	normalizedPath, queryParams := parsePath(path)
+	callerAddr := getCallerAddress()
+
+	// Check query params FIRST (they take precedence)
+	if gameID := queryParams["game"]; gameID != "" {
+		// View specific game
+		g, ok := games[gameID]
+		if !ok {
+			return "# Game Not Found\n\nThe game `" + gameID + "` does not exist.\n\n[← Back to Home](?)\n"
+		}
+		return renderGame(g, queryParams, callerAddr)
+	}
+
+	if queryParams["list"] != "" {
+		// List all games
+		var output strings.Builder
+		output.WriteString("# All Games\n\n")
+		output.WriteString(renderList())
+		return output.String()
+	}
+
+	if queryParams["mygames"] != "" {
+		// User's games
+		var output strings.Builder
+		output.WriteString(renderMyGames(callerAddr))
+		output.WriteString("\n\n")
+		output.WriteString("[← Back to Home](?)\n")
+		return output.String()
+	}
+
+	// Then check path-based routes
+	switch normalizedPath {
+	case "", "/":
+		// Home page
+		return renderHome(callerAddr)
+
+	case "/list", "/games":
+		// List all games
+		var output strings.Builder
+		output.WriteString("# All Games\n\n")
+		output.WriteString(renderList())
+		return output.String()
+
+	case "/mygames":
+		// User's games
+		var output strings.Builder
+		output.WriteString(renderMyGames(callerAddr))
+		output.WriteString("\n\n")
+		output.WriteString("[← Back to Home](?)\n")
+		return output.String()
+
+	default:
+		return "# Page Not Found\n\nThe requested page does not exist.\n\n[← Back to Home](?)\n"
+	}
+}