Add Rock Paper Scissors game implementation with CLI support

Author: chrisreddington

cmd/rockpaperscissors.go

@@ -0,0 +1,26 @@
+// This file is an entrypoint for the Rock Paper Scissors game. It uses the cobra cmd to execute the game.
+// The game logic is in the internal/rockpaperscissors package.
+
+// This file sets up the command line interface for the game. It should call the PlayGame function from the rockpaperscissors package.
+
+package cmd
+
+import (
+	"os"
+
+	"github.com/chrisreddington/gh-game/internal/rockpaperscissors"
+	userPrompt "github.com/cli/go-gh/v2/pkg/prompter"
+	"github.com/spf13/cobra"
+)
+
+// rootCmd represents the base command when called without any subcommands
+var rockPaperScissorsCmd = &cobra.Command{
+	Use:   "rockpaperscissors",
+	Short: "A simple Rock Paper Scissors game",
+	Long: `A simple Rock Paper Scissors game that allows you to play against the computer.
+You can choose from rock, paper, or scissors. The computer will randomly choose its move and the winner will be determined based on the rules of the game.`,
+	Run: func(cmd *cobra.Command, args []string) {
+		input := userPrompt.New(os.Stdin, os.Stdout, os.Stderr)
+		rockpaperscissors.PlayGame(input)
+	},
+}

cmd/root.go

@@ -18,4 +18,5 @@ func init() {
 	rootCmd.AddCommand(whoamiCmd)
 	rootCmd.AddCommand(cointossCmd)
 	rootCmd.AddCommand(tictactoeCmd)
+	rootCmd.AddCommand(rockPaperScissorsCmd)
 }

internal/rockpaperscissors/rockpaperscissors.go

@@ -0,0 +1,174 @@
+package rockpaperscissors
+
+import (
+	"fmt"
+	"math/rand"
+	"time"
+)
+
+// Game options
+var (
+	options = []string{"rock", "paper", "scissors", "exit"}
+)
+
+// Game represents a single game of Rock Paper Scissors.
+type Game struct {
+	// PlayerChoice is the choice made by the player.
+	PlayerChoice string
+	// ComputerChoice is the choice made by the computer.
+	ComputerChoice string
+	// Winner is the winner of the current round.
+	Winner string
+	// PlayerScore tracks the player's wins
+	PlayerScore int
+	// ComputerScore tracks the computer's wins
+	ComputerScore int
+	// BestOf determines how many games to play (e.g., best of 3, 5, 7)
+	BestOf int
+	// GameOver is a flag to indicate if the game is over.
+	GameOver bool
+	// GameOverMessage is the message to display when the game is over.
+	GameOverMessage string
+	// GamesPlayed tracks the number of games played
+	GamesPlayed int
+}
+
+// Prompter defines an interface for getting user input
+type Prompter interface {
+	Select(prompt, defaultValue string, options []string) (int, error)
+}
+
+func NewGame(bestOf int) *Game {
+	if bestOf%2 == 0 {
+		bestOf++ // Ensure we have an odd number for "best of"
+	}
+	return &Game{
+		PlayerChoice:    "",
+		ComputerChoice:  "",
+		Winner:          "",
+		GamesPlayed:     0,
+		PlayerScore:     0,
+		ComputerScore:   0,
+		BestOf:          bestOf,
+		GameOver:        false,
+		GameOverMessage: "",
+	}
+}
+
+// Play plays a single round of Rock Paper Scissors.
+func (g *Game) Play(playerChoice string) {
+	if playerChoice == "exit" {
+		g.GameOver = true
+		g.GameOverMessage = "Game ended by player"
+		return
+	}
+
+	g.PlayerChoice = playerChoice
+	g.ComputerChoice = g.getComputerChoice()
+	g.Winner = g.getWinner()
+	g.updateScore()
+	g.GamesPlayed++
+	g.GameOver = g.isGameOver()
+	if g.GameOver {
+		g.GameOverMessage = g.getGameOverMessage()
+	}
+}
+
+// getComputerChoice returns the choice made by the computer.
+func (g *Game) getComputerChoice() string {
+	rand.Seed(time.Now().UnixNano())
+	// Only use the game options excluding "exit"
+	choices := options[:len(options)-1]
+	return choices[rand.Intn(len(choices))]
+}
+
+// getWinner returns the winner of the current round.
+func (g *Game) getWinner() string {
+	if g.PlayerChoice == g.ComputerChoice {
+		return "draw"
+	}
+	if (g.PlayerChoice == "rock" && g.ComputerChoice == "scissors") ||
+		(g.PlayerChoice == "paper" && g.ComputerChoice == "rock") ||
+		(g.PlayerChoice == "scissors" && g.ComputerChoice == "paper") {
+		return "player"
+	}
+	return "computer"
+}
+
+// updateScore updates the score based on the round winner
+func (g *Game) updateScore() {
+	if g.Winner == "player" {
+		g.PlayerScore++
+	} else if g.Winner == "computer" {
+		g.ComputerScore++
+	}
+}
+
+// isGameOver returns true if the game is over.
+func (g *Game) isGameOver() bool {
+	winsNeeded := (g.BestOf / 2) + 1
+
+	// Game is over if:
+	// 1. Either player has reached the required wins, or
+	// 2. We've played all games in the series
+	return g.PlayerScore >= winsNeeded ||
+		g.ComputerScore >= winsNeeded ||
+		g.GamesPlayed >= g.BestOf
+}
+
+// getGameOverMessage returns the message to display when the game is over.
+func (g *Game) getGameOverMessage() string {
+	if g.PlayerScore > g.ComputerScore {
+		return fmt.Sprintf("You win the match! Final score: Player %d - Computer %d", g.PlayerScore, g.ComputerScore)
+	} else if g.ComputerScore > g.PlayerScore {
+		return fmt.Sprintf("Computer wins the match! Final score: Player %d - Computer %d", g.PlayerScore, g.ComputerScore)
+	}
+	return fmt.Sprintf("The match is a draw! Final score: Player %d - Computer %d", g.PlayerScore, g.ComputerScore)
+}
+
+// PlayGame plays a game of Rock Paper Scissors.
+func PlayGame(prompter Prompter) {
+	// Get the number of rounds from the user
+	roundOptions := []string{"3", "5", "7", "9"}
+	roundIndex, err := prompter.Select("How many rounds would you like to play (best of)?", "3", roundOptions)
+	if err != nil {
+		fmt.Printf("Error getting number of rounds: %v\n", err)
+		return
+	}
+	bestOf := 3 // Default value
+	if roundIndex >= 0 && roundIndex < len(roundOptions) {
+		bestOf = parseInt(roundOptions[roundIndex])
+	}
+
+	game := NewGame(bestOf)
+	fmt.Printf("Playing best of %d games\n", bestOf)
+
+	for !game.GameOver {
+		fmt.Printf("\nCurrent score - Player: %d, Computer: %d\n", game.PlayerScore, game.ComputerScore)
+
+		// Get player choice using prompter
+		playerChoiceIndex, err := prompter.Select("Choose your move", "rock", options)
+		if err != nil {
+			fmt.Printf("Error getting player choice: %v\n", err)
+			return
+		}
+		playerChoice := options[playerChoiceIndex]
+
+		game.Play(playerChoice)
+		if playerChoice == "exit" {
+			break
+		}
+
+		fmt.Printf("You chose: %s\n", game.PlayerChoice)
+		fmt.Printf("Computer chose: %s\n", game.ComputerChoice)
+		fmt.Printf("Round result: %s wins!\n", game.Winner)
+	}
+	fmt.Println(game.GameOverMessage)
+}
+
+// parseInt safely converts a string to an integer
+func parseInt(s string) int {
+	val := 3 // Default value
+	fmt.Sscanf(s, "%d", &val)
+	return val
+}