main.go

package main

import (
	"fmt"
	"os"

	tea "github.com/charmbracelet/bubbletea"
)

type model struct {
	cursor int
}

func newModel() model {
	return model{}
}

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

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {

	// Is it a key press?
	case tea.KeyMsg:

		// Cool, what was the actual key pressed?
		switch msg.String() {

		// These keys should exit the program.
		case "ctrl+c", "q":
			return m, tea.Quit

		// The "up" and "k" keys move the cursor up
		case "up", "k":
			if m.cursor > 0 {
				m.cursor--
			}

		// The "down" and "j" keys move the cursor down
		case "down", "j":
			if m.cursor < 11 {
				m.cursor++
			}
		}
	}

	// Return the updated model to the Bubble Tea runtime for processing.
	// Note that we're not returning a command.
	return m, nil
}

func (m model) View() string {
	s := ""
	for i := 0; i <= m.cursor; i++ {
		s += "\n"
	}
	s += "<>"
	return s
}

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