package main

import (
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"os"

	tea "github.com/charmbracelet/bubbletea"
)

const help = `go-sh-manymanuals: ???

???

Options:
	-h    output help
`

var portFlag int
var helpFlag bool

func handleCliFlags() {
	flag.BoolVar(&helpFlag, "h", false, "output help")
	flag.Parse()
}

type model struct {
	manuals []string
	cursor  int
}

func initialModel() model {
	manuals, err := gatherManuals()
	if err != nil {
		log.Fatalf("unable to read manuals: %s", err)
		os.Exit(1)
	}

	return model{
		manuals: manuals,
	}
}

func gatherManuals() ([]string, error) {
	fileInfos, err := ioutil.ReadDir(".")
	if err != nil {
		return nil, err
	}

	var filenames []string
	for _, fileInfo := range fileInfos {
		filenames = append(filenames, fileInfo.Name())
	}

	return filenames, nil
}

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

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.KeyMsg:
		switch msg.String() {
		case "ctrl+c", "q":
			return m, tea.Quit
		case "up", "k":
			if m.cursor > 0 {
				m.cursor--
			}
		case "down", "j":
			if m.cursor < len(m.manuals)-1 {
				m.cursor++
			}
		}
	}

	return m, nil
}

func (m model) View() string {
	ui := "File listing for current working directory\n\n"

	for i, choice := range m.manuals {
		cursor := " "
		if m.cursor == i {
			cursor = ">"
		}

		ui += fmt.Sprintf("%s %s\n", cursor, choice)
	}

	ui += "\nPress q to quit.\n"

	return ui
}

func main() {
	handleCliFlags()

	if helpFlag {
		fmt.Printf(help)
		os.Exit(0)
	}

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