package main

import (
	"fmt"
	"log"
	"math/rand"
	"relay/game"
	"relay/gfx"
	"time"

	"github.com/faiface/pixel"
	"github.com/faiface/pixel/pixelgl"
)

func run() error {
	cfg := pixelgl.WindowConfig{
		Title:  "Relay",
		Bounds: pixel.R(0, 0, 2400, 512),
		VSync:  true,
	}

	w, err := pixelgl.NewWindow(cfg)
	if err != nil {
		return err
	}

	rand.Seed(time.Now().UnixNano())

	s := game.NewState()

	rs := gfx.RenderState{
		Frames: 15,
	}
	sb, err := gfx.NewSpriteBank()
	if err != nil {
		return err
	}
	sOld := s
	turn := 1

	cmdC := make(chan []game.Command)
	go func() { cmdC <- game.PollCommands(s) }()

	stateCA := make(chan game.State)
	stateCB := make(chan game.State)

	go renderLoop(w, rs, s, sOld, stateCA, sb)

	for !w.Closed() {
		switch {
		case w.Pressed(pixelgl.KeyQ):
			return nil
		case w.Pressed(pixelgl.KeySpace):
			cmds := <-cmdC
			s = game.UpdateState(s, sOld, cmds)
			turn++
			if s.GameOver {
				s = game.NewState()
				sOld = s
				turn = 1
			}
			go func() {
				s := <-stateCB
				cmdC <- game.PollCommands(s)
			}()
			stateCA <- s
			stateCB <- s
		}

		w.UpdateInput()
	}
	return nil
}

func pixelRun() {
	if err := run(); err != nil {
		log.Fatal(err)
	}
}

func main() {
	pixelgl.Run(pixelRun)
}

func renderLoop(w *pixelgl.Window, rs gfx.RenderState, s game.State, sOld game.State, stateC <-chan game.State, sb *gfx.SpriteBank) {
	var (
		frames = 0
		second = time.Tick(time.Second)
	)

	for !w.Closed() {
		if rs.Frame == rs.Frames {
			select {
			case ss := <-stateC:
				sOld = s
				s = ss
				rs.Frame = 0
			default:
			}
		}

		rs = gfx.Render(rs, sOld, s, w, *sb)
		w.Update()
		frames++

		select {
		case <-second:
			w.SetTitle(fmt.Sprintf("%s | FPS: %d", "Relay", frames))
			frames = 0
		default:
		}
	}
}