package snakesimulator

import (
	context "context"
	fmt "fmt"
	math "math"
	"math/rand"
	"net"
	"sort"
	"time"

	"gonum.org/v1/gonum/mat"

	genetic "../genetic"
	neuralnetwork "../neuralnetwork"
	grpc "google.golang.org/grpc"
)

type SnakeSimulator struct {
	field            *Field
	snake            *Snake
	stats            *Stats
	speed            uint32
	fieldUpdateQueue chan bool
	snakeUpdateQueue chan bool
	statsUpdateQueue chan bool
	speedQueue       chan uint32
}

func NewSnakeSimulator() (s *SnakeSimulator) {
	s = &SnakeSimulator{
		field: &Field{
			Food:   &Point{},
			Width:  40,
			Height: 40,
		},
		snake: &Snake{
			Points: []*Point{
				&Point{X: 20, Y: 20},
				&Point{X: 21, Y: 20},
				&Point{X: 22, Y: 20},
			},
		},
		stats:            &Stats{},
		fieldUpdateQueue: make(chan bool, 2),
		snakeUpdateQueue: make(chan bool, 2),
		statsUpdateQueue: make(chan bool, 2),
		speedQueue:       make(chan uint32, 1),
		speed:            10,
	}
	return
}

func (s *SnakeSimulator) Verify(population *genetic.Population) (fitnesses []*genetic.IndividalFitness) {
	s.stats.Generation++
	s.statsUpdateQueue <- true
	s.field.GenerateNextFood()
	s.fieldUpdateQueue <- true

	fitnesses = make([]*genetic.IndividalFitness, len(population.Networks))
	for index, inidividual := range population.Networks {
		s.stats.Individual = uint32(index)
		s.statsUpdateQueue <- true

		s.runSnake(inidividual, false)
		fitnesses[index] = &genetic.IndividalFitness{
			Fitness: float64(len(s.snake.Points)-2) * float64(s.stats.Move),
			// Fitness: float64(s.stats.Move),
			Index: index,
		}
	}

	//This is duplication of crossbreedPopulation functionality.
	sort.Slice(fitnesses, func(i, j int) bool {
		return fitnesses[i].Fitness > fitnesses[j].Fitness //Descent order best will be on top, worst in the bottom
	})

	//Best snake showtime!
	prevSpeed := s.speed
	s.speed = 2
	s.runSnake(population.Networks[fitnesses[0].Index], false)
	s.speed = prevSpeed
	return
}

func (s *SnakeSimulator) runSnake(inidividual *neuralnetwork.NeuralNetwork, randomStart bool) {
	if randomStart {
		rand.Seed(time.Now().UnixNano())
		switch rand.Uint32() % 4 {
		case 1:
			s.snake = &Snake{
				Points: []*Point{
					&Point{X: 20, Y: 20},
					&Point{X: 21, Y: 20},
					&Point{X: 22, Y: 20},
				},
			}
		case 2:
			s.snake = &Snake{
				Points: []*Point{
					&Point{X: 22, Y: 20},
					&Point{X: 21, Y: 20},
					&Point{X: 20, Y: 20},
				},
			}
		case 3:
			s.snake = &Snake{
				Points: []*Point{
					&Point{X: 20, Y: 20},
					&Point{X: 20, Y: 21},
					&Point{X: 20, Y: 22},
				},
			}
		default:
			s.snake = &Snake{
				Points: []*Point{
					&Point{X: 20, Y: 22},
					&Point{X: 20, Y: 21},
					&Point{X: 20, Y: 20},
				},
			}
		}
	} else {
		s.snake = &Snake{
			Points: []*Point{
				&Point{X: 19, Y: 20},
				&Point{X: 20, Y: 20},
				&Point{X: 21, Y: 20},
			},
		}
	}

	i := 0
	s.stats.Move = 0
	for i < 300 {
		if s.speed > 0 {
			s.statsUpdateQueue <- true
		}

		//Read speed from client
		select {
		case newSpeed := <-s.speedQueue:
			fmt.Printf("Apply new speed: %v\n", newSpeed)
			if newSpeed < 10 {
				if newSpeed > 0 {
					s.speed = newSpeed
				} else {
					s.speed = 0
				}
			}
		default:
		}
		i++
		if s.speed > 0 {
			s.snakeUpdateQueue <- true
		}
		direction, _ := inidividual.Predict(mat.NewDense(inidividual.Sizes[0], 1, s.GetHeadState()))
		newHead := s.snake.NewHead(Direction(direction + 1))

		if selfCollisionIndex := s.snake.SelfCollision(newHead); selfCollisionIndex > 0 {
			if selfCollisionIndex == 1 {
				switch Direction(direction + 1) {
				case Direction_Up:
					newHead = s.snake.NewHead(Direction_Down)
				case Direction_Down:
					newHead = s.snake.NewHead(Direction_Up)
				case Direction_Left:
					newHead = s.snake.NewHead(Direction_Right)
				default:
					newHead = s.snake.NewHead(Direction_Left)
				}
				// continue
			} else {
				fmt.Printf("Game over self collision\n")
				break
			}
		}

		if newHead.X == s.field.Food.X && newHead.Y == s.field.Food.Y {
			i = 0
			s.snake.Feed(newHead)
			s.field.GenerateNextFood()
			s.fieldUpdateQueue <- true
		} else if newHead.X >= s.field.Width || newHead.Y >= s.field.Height || newHead.X < 0 || newHead.Y < 0 {
			// fmt.Printf("Game over\n")
			// time.Sleep(1000 * time.Millisecond)
			break
		} else {
			s.snake.Move(newHead)
		}
		if s.speed > 0 {
			time.Sleep(100 / time.Duration(s.speed) * time.Millisecond)
		}
		s.stats.Move++
	}
}

func (s *SnakeSimulator) GetHeadState() []float64 {
	headX := float64(s.snake.Points[0].X)
	headY := float64(s.snake.Points[0].Y)
	tailX := float64(s.snake.Points[len(s.snake.Points)-1].X)
	tailY := float64(s.snake.Points[len(s.snake.Points)-1].Y)
	// prevX := float64(s.snake.Points[1].X)
	// prevY := float64(s.snake.Points[1].Y)
	foodX := float64(s.field.Food.X)
	foodY := float64(s.field.Food.Y)
	width := float64(s.field.Width)
	height := float64(s.field.Height)
	diag := float64(width) * math.Sqrt2

	lWall := headX
	rWall := (width - headX)
	tWall := headY
	bWall := (height - headY)

	lFood := float64(width)
	rFood := float64(width)
	tFood := float64(height)
	bFood := float64(height)
	if headX == foodX {
		tFood = headY - foodY
		if tFood < 0 {
			tFood = height
		} else {
			tFood = 0
		}
		bFood = foodY - headY
		if bFood < 0 {
			bFood = height
		} else {
			bFood = 0
		}
	}

	if headY == foodY {
		rFood = foodX - headX
		if rFood < 0 {
			rFood = width
		} else {
			rFood = 0
		}
		lFood = headX - foodX
		if lFood < 0 {
			lFood = width
		} else {
			lFood = 0
		}
	}

	tlFood := float64(diag)
	trFood := float64(diag)
	blFood := float64(diag)
	brFood := float64(diag)
	if math.Abs(foodY-headY) == math.Abs(foodX-headX) {
		if foodX > headX {
			if foodY > headY {
				trFood = 0 //math.Abs(foodX-headX) * math.Sqrt2
			} else {
				brFood = 0 //math.Abs(foodX-headX) * math.Sqrt2
			}
		} else {
			if foodY > headY {
				tlFood = 0 //math.Abs(foodX-headX) * math.Sqrt2
			} else {
				blFood = 0 //math.Abs(foodX-headX) * math.Sqrt2
			}
		}
	}

	tlWall := float64(0)
	trWall := float64(0)
	blWall := float64(0)
	brWall := float64(0)
	if lWall > tWall {
		tlWall = float64(tWall) * math.Sqrt2
	} else {
		tlWall = float64(lWall) * math.Sqrt2
	}

	if rWall > tWall {
		trWall = float64(tWall) * math.Sqrt2
	} else {
		trWall = float64(rWall) * math.Sqrt2
	}

	if lWall > bWall {
		blWall = float64(bWall) * math.Sqrt2
	} else {
		blWall = float64(lWall) * math.Sqrt2
	}

	if rWall > bWall {
		blWall = float64(bWall) * math.Sqrt2
	} else {
		brWall = float64(rWall) * math.Sqrt2
	}

	if lWall > tWall {
		tlWall = float64(tWall) * math.Sqrt2
	} else {
		tlWall = float64(lWall) * math.Sqrt2
	}

	if rWall > tWall {
		trWall = float64(tWall) * math.Sqrt2
	} else {
		trWall = float64(rWall) * math.Sqrt2
	}

	if lWall > bWall {
		blWall = float64(bWall) * math.Sqrt2
	} else {
		blWall = float64(lWall) * math.Sqrt2
	}

	if rWall > bWall {
		blWall = float64(bWall) * math.Sqrt2
	} else {
		brWall = float64(rWall) * math.Sqrt2
	}

	tTail := float64(0)
	bTail := float64(0)
	if headX == tailX {
		tTail = (headY - tailY)
		if tTail < 0 {
			tTail = height
		} else {
			tTail = 0
		}
		bTail = (tailY - headY)
		if bTail < 0 {
			bTail = height
		} else {
			bTail = 0
		}
	}

	lTail := float64(0)
	rTail := float64(0)
	if headY == tailY {
		lTail = (headX - tailX)
		if lTail < 0 {
			tTail = width
		} else {
			tTail = 0
		}
		rTail = (tailX - headX)
		if lTail < 0 {
			tTail = width
		} else {
			tTail = 0
		}
	}

	tlTail := float64(0)
	trTail := float64(0)
	blTail := float64(0)
	brTail := float64(0)
	if math.Abs(headY-tailY) == math.Abs(headX-tailX) {
		if tailY > headY {
			if tailX > headX {
				trTail = diag //math.Abs(tailX-headX) * math.Sqrt2
			} else {
				tlTail = diag //math.Abs(tailX-headX) * math.Sqrt2
			}
		} else {
			if tailX > headX {
				brTail = diag //math.Abs(tailX-headX) * math.Sqrt2
			} else {
				blTail = diag //math.Abs(tailX-headX) * math.Sqrt2
			}
		}
	}

	return []float64{
		lWall / width,
		rWall / width,
		tWall / height,
		bWall / height,
		(1.0 - lFood/width),
		(1.0 - rFood/width),
		(1.0 - tFood/height),
		(1.0 - bFood/height),
		tlWall / diag,
		trWall / diag,
		blWall / diag,
		brWall / diag,
		(1.0 - tlFood/diag),
		(1.0 - trFood/diag),
		(1.0 - blFood/diag),
		(1.0 - brFood/diag),
		tTail / height,
		bTail / height,
		lTail / width,
		rTail / width,
		tlTail / diag,
		trTail / diag,
		blTail / diag,
		brTail / diag,
	}
}

func (s *SnakeSimulator) StartServer() {
	go func() {
		grpcServer := grpc.NewServer()
		RegisterSnakeSimulatorServer(grpcServer, s)
		lis, err := net.Listen("tcp", "localhost:65002")
		if err != nil {
			fmt.Printf("Failed to listen: %v\n", err)
		}

		fmt.Printf("Listen SnakeSimulator localhost:65002\n")
		if err := grpcServer.Serve(lis); err != nil {
			fmt.Printf("Failed to serve: %v\n", err)
		}
	}()
}

// func (s *SnakeSimulator) Run() {
// 	s.field.GenerateNextFood()
// 	for true {
// 		direction := rand.Int31()%4 + 1
// 		newHead := s.snake.NewHead(Direction(direction))
// 		if newHead.X == s.field.Food.X && newHead.Y == s.field.Food.Y {
// 			s.snake.Feed(newHead)
// 			s.field.GenerateNextFood()

// 		} else if newHead.X > s.field.Width || newHead.Y > s.field.Height {
// 			fmt.Printf("Game over\n")
// 			break
// 		} else if selfCollisionIndex := s.snake.SelfCollision(newHead); selfCollisionIndex > 0 {
// 			if selfCollisionIndex == 1 {
// 				fmt.Printf("Step backward, skip\n")
// 				continue
// 			}
// 			fmt.Printf("Game over self collision\n")
// 			break
// 		} else {
// 			s.snake.Move(newHead)
// 		}
// 		s.snakeUpdateQueue <- true
// 		time.Sleep(50 * time.Millisecond)
// 	}
// }

func (s *SnakeSimulator) Field(_ *None, srv SnakeSimulator_FieldServer) error {
	ctx := srv.Context()
	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		default:
		}
		srv.Send(s.field)
		<-s.fieldUpdateQueue
	}
}

func (s *SnakeSimulator) Snake(_ *None, srv SnakeSimulator_SnakeServer) error {
	ctx := srv.Context()
	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		default:
		}
		srv.Send(s.snake)
		<-s.snakeUpdateQueue
	}
}

func (s *SnakeSimulator) Stats(_ *None, srv SnakeSimulator_StatsServer) error {
	ctx := srv.Context()
	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		default:
		}
		srv.Send(s.stats)
		<-s.statsUpdateQueue
	}
}

func (s *SnakeSimulator) SetSpeed(ctx context.Context, speed *Speed) (*None, error) {
	s.speedQueue <- speed.Speed
	return &None{}, nil
}