// warning this code is messy and terrible
package launcher

import (
	"fmt"
	"os"
	"os/exec"

	"github.com/spf13/cobra"

	"github.com/charmbracelet/bubbles/key"
	"github.com/charmbracelet/bubbles/list"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
)

// ===============
// lipgloss styles
var appStyle = lipgloss.NewStyle().Margin(1, 2)

var titleStyle = lipgloss.NewStyle().
	Foreground(lipgloss.Color("0")).
	Background(lipgloss.Color("5")).
	Padding(0, 1)

var categoryTitleStyle = lipgloss.NewStyle().
	Foreground(lipgloss.Color("0")).
	Background(lipgloss.Color("4")).
	Padding(0, 1)

// ============
// data structs
type Category struct {
	title    string
	desc     string
	programs []list.Item
}

func (c Category) Title() string       { return c.title }
func (c Category) Description() string { return c.desc }
func (c Category) FilterValue() string { return c.title }

type Program struct {
	title string
	desc  string
	exec  string
}

func (p Program) Title() string       { return p.title }
func (p Program) Description() string { return p.desc }
func (p Program) FilterValue() string { return p.title }

// ======================
// bubbletea model struct
type model struct {
	categoriesList   list.Model
	categoriesKeys   *categoriesKeyMap
	programsList     list.Model
	programsKeys     *programsKeyMap
	selectedCategory bool
	shouldExec       string
}

// =============
// list keybinds
type categoriesKeyMap struct {
	selectKey key.Binding
}

func newCategoriesKeyMap() *categoriesKeyMap {
	return &categoriesKeyMap{
		selectKey: key.NewBinding(
			key.WithKeys("enter"),
			key.WithHelp("enter", "select"),
		),
	}
}

type programsKeyMap struct {
	exec key.Binding
	back key.Binding
}

func newProgramsKeyMap() *programsKeyMap {
	return &programsKeyMap{
		exec: key.NewBinding(
			key.WithKeys("enter"),
			key.WithHelp("enter", "exec"),
		),
		back: key.NewBinding(
			key.WithKeys("b"),
			key.WithHelp("b", "back"),
		),
	}
}

// =======================
// bubbletea model methods
func (m model) Init() tea.Cmd {
	return nil
}

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	var cmds []tea.Cmd

	switch msg := msg.(type) {
	case tea.KeyMsg:
		if msg.String() == "ctrl+c" {
			return m, tea.Quit
		}
		if !m.selectedCategory {
			switch {
			case key.Matches(msg, m.categoriesKeys.selectKey):
				var cat = m.categoriesList.SelectedItem().(Category)
				m.programsList.SetItems(cat.programs)
				m.programsList.Title = cat.title
				m.selectedCategory = true
			}
		} else {
			switch {
			case key.Matches(msg, m.programsKeys.back):
				m.selectedCategory = false
			case key.Matches(msg, m.programsKeys.exec):
				var prog = m.programsList.SelectedItem().(Program)
				m.shouldExec = prog.exec
				return m, tea.Quit
			}
		}
	case tea.WindowSizeMsg:
		h, v := appStyle.GetFrameSize()
		m.categoriesList.SetSize(msg.Width-h, msg.Height-v)
		m.programsList.SetSize(msg.Width-h, msg.Height-v)
	}

	var cmd tea.Cmd
	if m.selectedCategory {
		m.programsList, cmd = m.programsList.Update(msg)
	} else {
		m.categoriesList, cmd = m.categoriesList.Update(msg)
	}
	cmds = append(cmds, cmd)
	return m, tea.Batch(cmds...)
}

func (m model) View() string {
	if m.selectedCategory {
		return appStyle.Render(m.programsList.View())
	} else {
		return appStyle.Render(m.categoriesList.View())
	}
}

// ============
// run launcher
func Run(cmd *cobra.Command, args []string) error {
	// =========
	// init data

	// TODO read this from a file instead
	categories := []list.Item{
		Category{
			title: "editors",
			desc:  "for all your programming needs",
			programs: []list.Item{
				Program{
					title: "helix (hx)",
					desc:  "next-generation modal editor",
					exec:  "hx",
				},
				Program{
					title: "micro",
					desc:  "modern batteries-included editor",
					exec:  "micro",
				},
				Program{
					title: "nano",
					desc:  "the easy option",
					exec:  "nano",
				},
				Program{
					title: "neovim (nvim)",
					desc:  "like vim, but neo",
					exec:  "nvim",
				},
				Program{
					title: "vim",
					desc:  "the one and only",
					exec:  "vim",
				},
			},
		},
		Category{
			title: "games",
			desc:  "terminal fun",
			programs: []list.Item{
				Program{
					title: "botany",
					desc:  "grow a plant in your terminal",
					exec:  "botany",
				},
				Program{
					title: "nethack",
					desc:  "80s console roguelike",
					exec:  "nethack",
				},
				Program{
					title: "nsnake",
					desc:  "ncurses snake game",
					exec:  "nsnake",
				},
			},
		},
		Category{
			title: "social",
			desc:  "email, irc, etc.",
			programs: []list.Item{
				Program{
					title: "irssi",
					desc:  "minimal irc client",
					exec:  "irssi",
				},
				Program{
					title: "mutt",
					desc:  "tui email client",
					exec:  "mutt",
				},
				Program{
					title: "weechat",
					desc:  "extendable, easy-to-use irc client",
					exec:  "weechat",
				},
			},
		},
		Category{
			title: "utilities",
			desc:  "misc commands",
			programs: []list.Item{
				Program{
					title: "chsh",
					desc:  "change your login shell",
					exec:  "chsh",
				},
				Program{
					title: "passwd",
					desc:  "change your password",
					exec:  "passwd",
				},
			},
		},
	}

	// =============================
	// create delegates and keybinds
	categoryDelegate := list.NewDefaultDelegate()
	categoryKeys := newCategoriesKeyMap()
	programDelegate := list.NewDefaultDelegate()
	programKeys := newProgramsKeyMap()

	// ===================
	// set delegate styles
	categoryDelegate.Styles.SelectedTitle = categoryDelegate.Styles.SelectedTitle.
		Foreground(lipgloss.Color("4")).BorderLeftForeground(lipgloss.Color("4"))
	categoryDelegate.Styles.SelectedDesc = categoryDelegate.Styles.SelectedTitle

	programDelegate.Styles.SelectedTitle = programDelegate.Styles.SelectedTitle.
		Foreground(lipgloss.Color("1")).BorderLeftForeground(lipgloss.Color("1"))
	programDelegate.Styles.SelectedDesc = programDelegate.Styles.SelectedTitle

	// ====================
	// define initial model
	initialModel := model{
		categoriesList:   list.New(categories, categoryDelegate, 0, 0),
		categoriesKeys:   categoryKeys,
		programsList:     list.New([]list.Item{}, programDelegate, 0, 0),
		programsKeys:     programKeys,
		selectedCategory: false,
	}

	// =================================
	// set initial model styles and keys
	initialModel.categoriesList.Title = "the cherry.town program directory"
	initialModel.categoriesList.Styles.Title = titleStyle
	initialModel.categoriesList.AdditionalShortHelpKeys = func() []key.Binding {
		return []key.Binding{
			categoryKeys.selectKey,
		}
	}
	initialModel.categoriesList.AdditionalFullHelpKeys = func() []key.Binding {
		return []key.Binding{
			categoryKeys.selectKey,
		}
	}

	initialModel.programsList.Styles.Title = categoryTitleStyle
	initialModel.programsList.AdditionalShortHelpKeys = func() []key.Binding {
		return []key.Binding{
			programKeys.exec,
			programKeys.back,
		}
	}
	initialModel.programsList.AdditionalFullHelpKeys = func() []key.Binding {
		return []key.Binding{
			programKeys.exec,
			programKeys.back,
		}
	}

	// =====================
	// run bubbletea program
	p := tea.NewProgram(initialModel)
	finalModel, err := p.Run()
	if err != nil {
		fmt.Println("error: ", err)
		os.Exit(1)
	}

	// ============
	// clear screen

	// TODO this feels hacky and should probably be replaced
	execCmd := exec.Command("clear")
	execCmd.Stdout = os.Stdout
	execCmd.Run()

	// ====================================
	// execute chosen command if one is set
	if finalModel, ok := finalModel.(model); ok && finalModel.shouldExec != "" {
		execCmd := exec.Command(finalModel.shouldExec)
		execCmd.Stdin = os.Stdin
		execCmd.Stdout = os.Stdout
		execCmd.Stderr = os.Stderr
		return execCmd.Run()
	}

	return nil
}