package main

import (
	"errors"
	"fmt"
	"github.com/nfnt/resize"
	"image"
	"image/color"
	"image/draw"
	"image/jpeg"
	"os"
)

type ImageBasicInformation struct {
	length int
	width int
	pixelPerL int
	pixelPerW int
	quality int
}


func CreateBackground(information ImageBasicInformation,filePath string,barrierPath string) (*image.NRGBA,error) {
	imgFile, err := os.Create(filePath)
	if err!=nil {
		return nil,err
	}
	defer imgFile.Close()
	barrFile, err := os.Open(barrierPath)
	if err!=nil {
		return nil,err
	}
	defer barrFile.Close()
	barr, _, err := image.Decode(barrFile)
	if err != nil {
		return nil,err
	}


	maxL:=information.length
	maxW:=information.width
	ppL:=information.pixelPerL
	ppW:=information.pixelPerW
	pixelForL:=maxL*ppL
	pixelForW:=maxW*ppW

	newImg := image.NewNRGBA(image.Rect(0, 0, pixelForL, pixelForW)) //创建一个新RGBA图像
	for i := 0; i < pixelForL; i++ {
		for j := 0; j < pixelForW; j++ {
			newImg.SetNRGBA(i,j,color.NRGBA{
				R: 255,
				G: 255,
				B: 255,
				A: 255,
			})
		}
	}
	barrResized := resize.Resize(uint(information.pixelPerL), uint(information.pixelPerW), barr, resize.Lanczos3)
	for i:=0;i<maxL;i++ {
		draw.Draw(newImg,newImg.Bounds(),barrResized,image.Pt(-1*i*ppL,0),draw.Over)
		fmt.Println("a")
		draw.Draw(newImg,newImg.Bounds(),barrResized,image.Pt(-1*i*ppL,-1*(maxW-1)*ppW),draw.Over)
		fmt.Println("b")
	}
	for i:=1;i<maxW-1;i++ {
		draw.Draw(newImg,newImg.Bounds(),barrResized,image.Pt(0,-1*i*ppW),draw.Over)
		fmt.Println("c")
		draw.Draw(newImg,newImg.Bounds(),barrResized,image.Pt(-1*(maxL-1)*ppL,-1*i*ppL),draw.Over)
		fmt.Println("d")
	}
	err=jpeg.Encode(imgFile, newImg, &jpeg.Options{information.quality})
	if err!=nil {
		return nil,err
	}
	return newImg,nil
}

func OpenImageAndGetData(path string,information ImageBasicInformation) (*image.Image,error) {
	imgFile, err := os.Open(path)
	if err!=nil {
		return nil,err
	}
	defer imgFile.Close()
	img, _, err := image.Decode(imgFile)
	if err != nil {
		return nil,err
	}
	imgResized := resize.Resize(uint(information.pixelPerL), uint(information.pixelPerW), img, resize.Lanczos3)
	return &imgResized,err
}

func RenderCandyAndSnake(filePath string,candy *Candy,snake *Snake,background *image.NRGBA,candyData *image.Image,snakeData *image.Image,information *ImageBasicInformation) error {
	ppL:=information.pixelPerL
	ppW:=information.pixelPerW
	draw.Draw(background,background.Bounds(),*candyData,image.Pt(-1*candy.Abscissa*ppL,-1*candy.Ordinate*ppW),draw.Over)
	for i := 0; i < len(snake.SnakeLine)-1; i++ {
		if snake.SnakeLine[i].Direction == Up {
			j := snake.SnakeLine[i].Abscissa
			for k := snake.SnakeLine[i+1].Ordinate; k < snake.SnakeLine[i].Ordinate+1; k++ {
				draw.Draw(background,background.Bounds(),*snakeData,image.Pt(-1*j*ppL,-1*k*ppW),draw.Over)
			}
		}
		if snake.SnakeLine[i].Direction==Right {
			j:=snake.SnakeLine[i].Ordinate
			for k:=snake.SnakeLine[i].Abscissa;k<snake.SnakeLine[i+1].Abscissa+1;k++ {
				draw.Draw(background,background.Bounds(),*snakeData,image.Pt(-1*k*ppL,-1*j*ppW),draw.Over)
			}
		}
		if snake.SnakeLine[i].Direction==Down {
			j:=snake.SnakeLine[i].Abscissa
			for k:=snake.SnakeLine[i].Ordinate;k<snake.SnakeLine[i+1].Ordinate+1;k++ {
				draw.Draw(background,background.Bounds(),*snakeData,image.Pt(-1*j*ppL,-1*k*ppW),draw.Over)
			}
		}
		if snake.SnakeLine[i].Direction==Left {
			j:=snake.SnakeLine[i].Ordinate
			for k:=snake.SnakeLine[i+1].Abscissa;k<snake.SnakeLine[i].Abscissa+1;k++ {
				draw.Draw(background,background.Bounds(),*snakeData,image.Pt(-1*k*ppL,-1*j*ppW),draw.Over)
			}
		}
		if snake.SnakeLine[i].Direction==End {
			return errors.New("蛇末提前到来")
		}
	}
	imgFile, err := os.Create(filePath)
	if err!=nil {
		return err
	}
	defer imgFile.Close()
	err=jpeg.Encode(imgFile, background, &jpeg.Options{information.quality})

	if err!=nil {
		return err
	}
	return nil
}