package shared

import (
	"context"
	"sync"

	"gioui.org/app"
	"gioui.org/io/event"
	"gioui.org/widget/material"
	"github.com/rs/zerolog/log"
)

type GlobalState struct {
	Window *app.Window
	Theme  *material.Theme
	state  WindowState
}

func Run(ctx context.Context, window *app.Window, initialState WindowState) error {
	// Set up global data first
	state := GlobalState{}
	theme := material.NewTheme()
	theme.Bg = BackgroundColor
	theme.Fg = TextColor
	state.Theme = theme
	state.Window = window
	state.state = initialState
	// Then start showing the window and polling for events
	// Though technically, I don't think window.Event will cause the window to display yet
	// since what should it display? It doesn't have anything to display. So first display happens at event.Frame
	eventChan := make(chan event.Event)
	go func() {
		for {
			eventChan <- window.Event()
			if ctx.Err() != nil {
				return
			}
		}
	}()
	for {
		select {
		case <-ctx.Done():
			log.Info().Msg("Context cancelled, preparing shutdown")
			// Force one update for polling goroutine to exit
			state.Window.Invalidate()
			// Then keep awaiting more events. Since quit is just another event
			// and the event channel is unbuffered, at least one more event has to be read for the poller to exit
		case e := <-eventChan:
			// Let the current view handle the event, then update accordingly
			newState := state.state.Run(&state, e)
			if newState.NextState != nil {
				state.state = newState.NextState
			}
			if newState.ExitCode != nil {
				log.Info().Msg("Received shutdown request from window")
				wg := sync.WaitGroup{}
				wg.Add(1)
				go state.state.Exit(&state, &wg)
				wg.Wait()
				log.Info().Msg("Shutdown of window complete")
				return nil
			}
		}
	}
}