package main

import (
	"fmt"
	"os"

	tea "github.com/charmbracelet/bubbletea"
)

const (
	BrowserSessions int = iota // Enumerating the sections
	Commands
)

type sessionOrCommand struct {
	displayString string
	commandString string
}

type Choices [][]sessionOrCommand

type SelectionSet map[int]struct{}

type model struct {
	activeSection int
	cursor        []int
	choices       Choices
	selected      []SelectionSet
}

var browserSelection SelectionSet
var commandSelection SelectionSet

func getBrowserSessions() []sessionOrCommand {
	// Placeholder
	return []sessionOrCommand{{
		displayString: "primary",
		commandString: "",
	}, {
		displayString: "breakfast",
		commandString: "",
	}}
}

func initialModel() model {
	browserSelection = make(SelectionSet)
	commandSelection = make(SelectionSet)
	return model{
		activeSection: BrowserSessions,
		cursor:        []int{0, 0},
		choices: Choices{
			getBrowserSessions(),
			[]sessionOrCommand{{
				displayString: "neomutt",
				commandString: "neomutt",
			}, {
				displayString: "bottom",
				commandString: "btm --group --battery --color gruvbox-light",
			}},
		},
		// An array maps which indicates which choices are selected. We're
		// using the map like a mathematical set. The keys refer to the
		// indexes of the `choices` slice, above.
		selected: []SelectionSet{browserSelection, commandSelection},
	}
}

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 "tab":
			if m.activeSection == BrowserSessions {
				m.activeSection = Commands
			} else {
				m.activeSection = BrowserSessions
			}
		case "up", "k":
			if m.cursor[m.activeSection] > 0 {
				m.cursor[m.activeSection]--
			}
		case "down", "j":
			if m.cursor[m.activeSection] < len(m.choices[m.activeSection])-1 {
				m.cursor[m.activeSection]++
			}
		case "enter", " ":
			_, ok := m.selected[m.activeSection][m.cursor[m.activeSection]]
			if ok {
				delete(m.selected[m.activeSection], m.cursor[m.activeSection])
			} else {
				m.selected[m.activeSection][m.cursor[m.activeSection]] = struct{}{}
			}
		}
	}

	return m, nil
}

func (m model) View() string {
	s := "What should we buy at the market?\n\n"

	for j := 0; j < 2; j++ {
		for i, choice := range m.choices[j] {
			cursor := " "
			if m.cursor[j] == i {
				cursor = ">"
			}

			checked := " "
			if _, ok := m.selected[j][i]; ok {
				checked = "x"
			}

			s += fmt.Sprintf("%s [%s] %s\n", cursor, checked, choice.displayString)
		}
		s += "\n\n"
	}

	// s += fmt.Sprintf("\n%+v", m.selected) // debug
	s += "\nPress q to quit.\n"

	return s
}

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)
	}
}