tictactoe/main.go

package main

import (
	"fmt"
	"os"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
)

var (
	colorRed   = lipgloss.NewStyle().Foreground(lipgloss.Color("#ff0000"))
	colorGreen = lipgloss.NewStyle().Foreground(lipgloss.Color("#76c165"))
	colorBlue  = lipgloss.NewStyle().Foreground(lipgloss.Color("#1a73e8"))
	colorLemon = lipgloss.NewStyle().Foreground(lipgloss.Color("#e7ef80"))
)

type model struct {
	board        [][]int // 2-D game board. 0 for nothing, 1 for o, 2 for x
	turn         int     // who's turn is it
	cursor       []int   // coordinates of cursor position in the board
	msg          string
	moves        int     // number of occupied cells
	movesHistory [][]int // list of coords
}

func initialModel() model {
	board := make([][]int, 3)
	for i := range board {
		board[i] = make([]int, 3)
	}
	return model{
		board:  board,
		turn:   1,
		cursor: make([]int, 2),
		msg:    "",
	}
}

func (m model) Init() tea.Cmd {
	return nil
}

func (m model) getWinner() int {
	return 0
}

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	m.msg = ""

	switch msg := msg.(type) {
	case tea.KeyMsg:
		key := msg.String()
		switch key {
		case "q", "ctrl+c":
			m.msg = "Bye!"
			return m, tea.Quit

		case "u":
			if m.moves == 0 {
				m.msg = "Nothing to undo"
				return m, nil
			}

			last := m.movesHistory[m.moves-1]
			m.board[last[0]][last[1]] = 0
			m.cursor[0] = last[0]
			m.cursor[1] = last[1]
			m.movesHistory = m.movesHistory[:m.moves-1]

			m.turn = 1 - m.turn + 2 // change 1 to 2, 2 to 1
			m.moves--
			m.msg = "Undone"
			return m, nil

		case "enter", " ":
			if m.board[m.cursor[0]][m.cursor[1]] == 0 {
				m.board[m.cursor[0]][m.cursor[1]] = m.turn
				m.turn = 1 - m.turn + 2 // change 1 to 2, 2 to 1
				m.moves++
				m.movesHistory = append(m.movesHistory, []int{m.cursor[0], m.cursor[1]})
			} else {
				m.msg = "That cell is already occupied!"
			}

		case "up", "k":
			if m.cursor[0] > 0 {
				m.cursor[0]--
			}

		case "down", "j":
			if m.cursor[0] < 2 {
				m.cursor[0]++
			}

		case "left", "h":
			if m.cursor[1] > 0 {
				m.cursor[1]--
			}

		case "right", "l":
			if m.cursor[1] < 2 {
				m.cursor[1]++
			}
		}
	}
	winner := m.getWinner()
	if winner != 0 {
		if winner == 1 {
			m.msg = "o wins!"
		} else {
			m.msg = "x wins!"
		}
		return m, tea.Quit
	}
	if m.moves == 9 {
		m.msg = "It's a tie!"
		m.turn = 1 - m.turn + 2 // show last turn
		return m, tea.Quit
	}

	return m, nil
}

func (m model) View() (s string) {
	s = "\n"
	// s += fmt.Sprintf("%v", m.cursor)
	indent := "    "

	for x, row := range m.board {
		var v string
		s += indent
		for y, cell := range row {
			switch cell {
			case 0:
				v = "_"
			case 1:
				v = colorGreen.Render("o")
			case 2:
				v = colorBlue.Render("x")
			}
			if x == m.cursor[0] && y == m.cursor[1] {
				s += fmt.Sprintf(" [%s] ", v)
			} else {
				s += fmt.Sprintf("  %s  ", v)
			}
		}
		s += "\n\n"
	}

	if m.turn == 1 {
		s += fmt.Sprintf("\n  %s turn\n", colorGreen.Render("o"))
	} else {
		s += fmt.Sprintf("\n  %s turn\n", colorBlue.Render("x"))
	}
	s += "\n  " + colorLemon.Render(m.msg) + "\n\n"

	s += "[enter/space] select;  [hjkl/arrows] move around;  [u]ndo;  [q/ctrl-c] quit"

	return
}

func main() {
	p := tea.NewProgram(initialModel())
	if err := p.Start(); err != nil {
		fmt.Printf("Alas, there's been an error: %v", err)
		os.Exit(1)
	}
}