// Package ui contains the tview user interface.
package ui

import (
	"fmt"

	"github.com/gdamore/tcell/v2"
	"github.com/rivo/tview"
)

type view struct {
	key  rune
	name string
	body tview.Primitive
}

// App is the top-level arr-tui application.
type App struct {
	app    *tview.Application
	tabs   *tview.TextView
	pages  *tview.Pages
	status *tview.TextView
	views  []view
	active int
}

// New builds the application shell: a tab bar, one page per view and a status bar.
func New() *App {
	a := &App{
		app:    tview.NewApplication(),
		tabs:   tview.NewTextView().SetDynamicColors(true),
		pages:  tview.NewPages(),
		status: tview.NewTextView().SetDynamicColors(true),
	}

	a.views = []view{
		{'1', "Movies", placeholder("Movie search (M2)")},
		{'2', "Series", placeholder("Series search (M3)")},
		{'3', "Downloads", placeholder("Downloads (M4/M5)")},
		{'4', "Library", placeholder("Library (v0.2)")},
	}
	for i, v := range a.views {
		a.pages.AddPage(v.name, v.body, true, i == 0)
	}

	layout := tview.NewFlex().SetDirection(tview.FlexRow).
		AddItem(a.tabs, 1, 0, false).
		AddItem(a.pages, 0, 1, true).
		AddItem(a.status, 1, 0, false)

	a.app.SetRoot(layout, true).EnableMouse(false)
	a.app.SetInputCapture(a.handleKey)
	a.SetStatus("[gray]q quit · Tab / 1-4 switch view")
	a.switchTo(0)
	return a
}

// SetStatus replaces the status bar text. Safe to call only from the UI goroutine;
// use QueueUpdateDraw from other goroutines.
func (a *App) SetStatus(text string) {
	a.status.SetText(text)
}

// Run starts the event loop and blocks until the application quits.
func (a *App) Run() error {
	return a.app.Run()
}

func (a *App) handleKey(ev *tcell.EventKey) *tcell.EventKey {
	switch ev.Key() {
	case tcell.KeyCtrlC:
		a.app.Stop()
		return nil
	case tcell.KeyTab:
		a.switchTo((a.active + 1) % len(a.views))
		return nil
	case tcell.KeyBacktab:
		a.switchTo((a.active + len(a.views) - 1) % len(a.views))
		return nil
	case tcell.KeyRune:
		if ev.Rune() == 'q' {
			a.app.Stop()
			return nil
		}
		for i, v := range a.views {
			if ev.Rune() == v.key {
				a.switchTo(i)
				return nil
			}
		}
	}
	return ev
}

func (a *App) switchTo(i int) {
	a.active = i
	a.pages.SwitchToPage(a.views[i].name)
	a.renderTabs()
}

func (a *App) renderTabs() {
	var s string
	for i, v := range a.views {
		if i == a.active {
			s += fmt.Sprintf("[black:white] %c %s [-:-] ", v.key, v.name)
		} else {
			s += fmt.Sprintf("[gray] %c %s [-] ", v.key, v.name)
		}
	}
	a.tabs.SetText(s)
}

func placeholder(text string) tview.Primitive {
	return tview.NewTextView().SetText(text).SetTextAlign(tview.AlignCenter)
}