package alui

import (
	"errors"

	"github.com/spf13/afero"
	"opslag.de/schobers/allg5"
	"opslag.de/schobers/fs/vfs"
	"opslag.de/schobers/geom"
)

type Application struct {
	disp *allg5.Display
	eq   *allg5.EventQueue
	dirs map[string]vfs.CopyDir
}

func NewApplication(size geom.Point, dispOptions allg5.NewDisplayOptions) (*Application, error) {
	var init = allg5.InitAll
	init.Audio = false
	err := allg5.Init(init)
	if err != nil {
		return nil, err
	}

	app := &Application{}

	disp, err := allg5.NewDisplay(size.X, size.Y, dispOptions)
	if err != nil {
		return nil, err
	}
	app.disp = disp

	eq, err := allg5.NewEventQueue()
	if err != nil {
		app.Destroy()
		return nil, err
	}
	app.eq = eq

	eq.RegisterDisplay(disp)
	eq.RegisterKeyboard()
	eq.RegisterMouse()

	return app, nil
}

func (a *Application) Destroy() {
	a.disp.Destroy()
	a.eq.Destroy()
	if a.dirs != nil {
		for _, dir := range a.dirs {
			dir.Destroy()
		}
	}
}

func (a *Application) AddDir(path string, backup afero.Fs) (vfs.CopyDir, error) {
	fs := vfs.NewOsFsFallback(path, backup)
	copy, err := vfs.NewCopyDir(fs)
	if err != nil {
		return nil, err
	}
	if a.dirs == nil {
		a.dirs = map[string]vfs.CopyDir{}
	}
	a.dirs[path] = copy
	return copy, nil
}

func (a *Application) UseFile(dir, name string, use func(string) error) error {
	if a.dirs == nil {
		return errors.New(`no directories available`)
	}
	resources, ok := a.dirs[dir]
	if !ok {
		return errors.New(`direct not found`)
	}
	path, err := resources.Retrieve(name)
	if err != nil {
		return err
	}
	return use(path)
}

func (a *Application) Run(main Control, init func(*UI) error) error {
	disp := a.disp
	eq := a.eq

	ui := NewUI(disp, main)
	defer ui.Destroy()
	err := init(ui)
	if err != nil {
		return err
	}

	ctx := ui.Context()
	for {
		allg5.ClearToColor(ctx.Palette.Background)
		ui.Render()
		disp.Flip()

		if ctx.quit {
			return nil
		}

		e := eq.Get()
		for e != nil {
			switch e := e.(type) {
			case *allg5.DisplayCloseEvent:
				return nil
			case *allg5.KeyCharEvent:
				if e.KeyCode == allg5.KeyF4 && e.Modifiers&allg5.KeyModAlt != 0 {
					return nil
				}
			}
			ui.Handle(e)
			if ctx.quit {
				return nil
			}
			e = eq.Get()
		}
	}
}