package gts

import (
	"fmt"
	"image"
	"os"
	"time"

	"github.com/diamondburned/cchat-gtk/internal/gts/throttler"
	"github.com/diamondburned/cchat-gtk/internal/log"
	"github.com/disintegration/imaging"
	"github.com/gotk3/gotk3/gdk"
	"github.com/gotk3/gotk3/glib"
	"github.com/gotk3/gotk3/gtk"
	"github.com/pkg/errors"
)

const AppID = "com.github.diamondburned.cchat-gtk"

var Args = append([]string{}, os.Args...)

var App struct {
	*gtk.Application
	Window *gtk.ApplicationWindow
	Header *gtk.HeaderBar

	Throttler *throttler.State
}

// Clipboard is initialized on init().
var Clipboard *gtk.Clipboard

// NewModalDialog returns a new modal dialog that's transient for the main
// window.
func NewModalDialog() (*gtk.Dialog, error) {
	d, err := gtk.DialogNew()
	if err != nil {
		return nil, err
	}
	d.SetModal(true)
	d.SetTransientFor(App.Window)
	App.Throttler.Connect(d)

	return d, nil
}

func NewEmptyModalDialog() (*gtk.Dialog, error) {
	d, err := NewModalDialog()
	if err != nil {
		return nil, err
	}

	b, err := d.GetContentArea()
	if err != nil {
		return nil, errors.Wrap(err, "Failed to get content area")
	}

	d.Remove(b)

	return d, nil
}

func AddAppAction(name string, call func()) {
	action := glib.SimpleActionNew(name, nil)
	action.Connect("activate", call)
	App.AddAction(action)
}

func init() {
	gtk.Init(&Args)
	App.Application, _ = gtk.ApplicationNew(AppID, 0)
	Clipboard, _ = gtk.ClipboardGet(gdk.SELECTION_CLIPBOARD)

	// Limit the TPS of the main loop on window unfocus.
	App.Throttler = throttler.Bind(App.Application)
}

// // AppMenuWidget returns the box that holds the app menu.
// func AppMenuWidget() (widget *gtk.Widget) {
// 	App.Header.For().Foreach(func(v interface{}) {
// 		// If we've already found the widget, then stop finding.
// 		if widget != nil {
// 			return
// 		}

// 		// Cast the interface to a widget.
// 		curr := v.(gtk.IWidget).ToWidget()

// 		log.Println("testing")

// 		// Check if the widget has a class named "left".
// 		if sctx, _ := curr.GetStyleContext(); sctx.HasClass("left") {
// 			log.Println("has class .left")
// 			widget = curr
// 		}
// 	})

// 	return
// }

type Window interface {
	Window() gtk.IWidget
	Header() gtk.IWidget
	Menu() *glib.MenuModel
	Icon() *gdk.Pixbuf
	Close()
}

func Main(wfn func() Window) {
	App.Application.Connect("activate", func() {
		// Load all CSS onto the default screen.
		loadProviders(getDefaultScreen())

		App.Header, _ = gtk.HeaderBarNew()
		// Right buttons only.
		App.Header.SetDecorationLayout(":minimize,close")
		App.Header.SetShowCloseButton(true)
		App.Header.SetProperty("spacing", 0)

		b, _ := gtk.BoxNew(gtk.ORIENTATION_HORIZONTAL, 0)
		App.Header.SetCustomTitle(b)

		App.Window, _ = gtk.ApplicationWindowNew(App.Application)
		App.Window.SetDefaultSize(1000, 500)
		App.Window.SetTitlebar(App.Header)

		// Execute the function later, because we need it to run after
		// initialization.
		w := wfn()
		App.Application.SetAppMenu(w.Menu())

		App.Window.SetIcon(w.Icon())
		App.Window.Add(w.Window())
		App.Window.Show()

		App.Header.Add(w.Header())
		App.Header.Show()

		// Connect extra actions.
		AddAppAction("quit", App.Window.Destroy)

		// Connect the destructor.
		App.Window.Connect("destroy", func() {
			// Hide the application window.
			App.Window.Hide()

			// Let the main loop run once by queueing the stop loop afterwards.
			// This is to allow the main loop to properly hide the Gtk window
			// before trying to disconnect.
			ExecAsync(func() {
				// Stop the application loop.
				App.Application.Quit()
				// Finalize the application by running the closer.
				w.Close()
			})
		})
	})

	// Use a special function to run the application. Exit with the appropriate
	// exit code if necessary.
	if code := App.Run(Args); code > 0 {
		os.Exit(code)
	}
}

// Async runs fn asynchronously, then runs the function it returns in the Gtk
// main thread.
func Async(fn func() (func(), error)) {
	go func() {
		f, err := fn()
		if err != nil {
			log.Error(err)
		}

		// Attempt to run the callback if it's there.
		if f != nil {
			ExecAsync(f)
		}
	}()
}

// ExecAsync executes function asynchronously in the Gtk main thread.
func ExecAsync(fn func()) {
	glib.IdleAdd(fn)
}

// ExecSync executes the function asynchronously, but returns a channel that
// indicates when the job is done.
func ExecSync(fn func()) <-chan struct{} {
	var ch = make(chan struct{})

	glib.IdleAdd(func() {
		fn()
		close(ch)
	})

	return ch
}

// AfterFunc mimics time.AfterFunc's API but runs the callback inside the Gtk
// main loop.
func AfterFunc(d time.Duration, f func()) (stop func()) {
	h, err := glib.TimeoutAdd(
		uint(d.Milliseconds()),
		func() bool { f(); return true },
	)
	if err != nil {
		panic(err)
	}

	return func() { glib.SourceRemove(h) }
}

func EventIsRightClick(ev *gdk.Event) bool {
	keyev := gdk.EventButtonNewFromEvent(ev)
	return keyev.Type() == gdk.EVENT_BUTTON_PRESS && keyev.Button() == gdk.BUTTON_SECONDARY
}

func RenderPixbuf(img image.Image) *gdk.Pixbuf {
	var nrgba *image.NRGBA
	if n, ok := img.(*image.NRGBA); ok {
		nrgba = n
	} else {
		nrgba = imaging.Clone(img)
	}

	pix, err := gdk.PixbufNewFromData(
		nrgba.Pix, gdk.COLORSPACE_RGB,
		true, // NRGBA has alpha.
		8,    // 8-bit aka 1-byte per sample.
		nrgba.Rect.Dx(),
		nrgba.Rect.Dy(), // We already know the image size.
		nrgba.Stride,
	)

	if err != nil {
		panic(fmt.Sprintf("Failed to create pixbuf from *NRGBA: %v", err))
	}

	return pix
}

func SpawnUploader(dirpath string, callback func(absolutePaths []string)) {
	dialog, _ := gtk.FileChooserDialogNewWith2Buttons(
		"Upload File", App.Window,
		gtk.FILE_CHOOSER_ACTION_OPEN,
		"Cancel", gtk.RESPONSE_CANCEL,
		"Upload", gtk.RESPONSE_ACCEPT,
	)

	App.Throttler.Connect(dialog)
	BindPreviewer(dialog)

	if dirpath == "" {
		p, err := os.Getwd()
		if err != nil {
			p = glib.GetUserDataDir()
		}
		dirpath = p
	}

	dialog.SetLocalOnly(false)
	dialog.SetCurrentFolder(dirpath)
	dialog.SetSelectMultiple(true)

	defer dialog.Close()

	if res := dialog.Run(); res != gtk.RESPONSE_ACCEPT {
		return
	}

	names, _ := dialog.GetFilenames()
	callback(names)
}

// BindPreviewer binds the file chooser dialog with a previewer.
func BindPreviewer(fc *gtk.FileChooserDialog) {
	img, _ := gtk.ImageNew()

	fc.SetPreviewWidget(img)
	fc.Connect("update-preview",
		func(fc *gtk.FileChooserDialog, img *gtk.Image) {
			file := fc.GetPreviewFilename()

			b, err := gdk.PixbufNewFromFileAtScale(file, 256, 256, true)
			if err != nil {
				fc.SetPreviewWidgetActive(false)
				return
			}

			img.SetFromPixbuf(b)
			fc.SetPreviewWidgetActive(true)
		},
		img,
	)
}