/**
 * Copyright (C) 2021, Tim Holloway
 *
 * Date written: Nov 26, 2021
 * Author: Tim Holloway <timh@mousetech.com>
 */
package com.mousetech.gourmetj.springweb;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.imageio.ImageIO;
import javax.imageio.stream.ImageInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.servlet.http.Part;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import com.mousetech.gourmetj.UserSession;
import com.mousetech.gourmetj.persistence.model.Recipe;
import com.mousetech.gourmetj.persistence.service.RecipeService;

/**
 * @author timh
 * @since Nov 26, 2021
 */
@Controller
@RequestMapping(path="/img")
public class PictureController {

	/* Logger */
	private static final Logger log =
			LoggerFactory.getLogger(PictureController.class);

	@Autowired
	private RecipeService recipeService;

	/**
	 * @return the recipeService
	 */
	public RecipeService getRecipeService() {
		return recipeService;
	}

	/**
	 * @param recipeService the recipeService to set
	 */
	public void setRecipeService(RecipeService recipeService) {
		this.recipeService = recipeService;
	}

	// ***
	/**
	 * Default image returned if a recipe has no actual image.
	 * It's thumbnail-sized, so does double duty.
	 */
	static byte[] BLANK_IMAGE;

	public PictureController() {
		init();
	}

	/**
	 * General setup. Constructs BLANK_IMAGE.
	 */
	private void init() {
		BufferedImage tbi = new BufferedImage(40, 40,
				BufferedImage.TYPE_INT_ARGB);
		Graphics2D ig2 = tbi.createGraphics();
		ig2.setBackground(Color.WHITE);
		ig2.clearRect(0, 0, 40, 40);

		try {
			ByteArrayOutputStream os =
					new ByteArrayOutputStream(946);
			ImageIO.write(tbi, "png", os);
			BLANK_IMAGE = os.toByteArray();
		} catch (IOException e) {
			log.error("Unable to create BLANK_IMAGE", e);
		}
	}

	// ==========================================
	@GetMapping(value = "/picture/{recipeId}")
	@PostMapping(value = "/picture/{recipeId}")
	public ResponseEntity<byte[]> bigPicture(
			@PathVariable long recipeId) {

		Recipe recipe = recipeService.findByPrimaryKey(recipeId);
		if (recipe != null) {
			HttpHeaders httpHeaders = new HttpHeaders();
			httpHeaders.set(HttpHeaders.CONTENT_TYPE,
				MediaType.IMAGE_PNG_VALUE);
			httpHeaders.set(HttpHeaders.CACHE_CONTROL,
				"no-cache");
			byte[] image = recipe.getImage();
			if (image == null) {
				image = BLANK_IMAGE;
			}
			return ResponseEntity.ok().headers(httpHeaders)
				.body(image);
		}

		// NotFound, need dummy picture!:
		return ResponseEntity.status(404).body(new byte[0]);
	}

	/**
	 * Dummy picture request. Made when recipeId is not yet
	 * assigned.
	 * 
	 * @param req The HttpServletRequest from Spring.
	 * @return Image response.
	 */
	@GetMapping(value = "/picture/")
	public ResponseEntity<byte[]> bigPicture(
			HttpServletRequest req) {

		final HttpSession httpSession = req.getSession(false);
		final UserSession userSession = (UserSession) httpSession
			.getAttribute("userSession");

		Recipe editRecipe = userSession.getRecipe();

		HttpHeaders httpHeaders = new HttpHeaders();
		httpHeaders.set(HttpHeaders.CONTENT_TYPE,
			MediaType.IMAGE_PNG_VALUE);
		httpHeaders.set(HttpHeaders.CACHE_CONTROL, "no-cache");
		byte[] image = null;
		if ( editRecipe != null ) {
			// Otherwise we are creating new recipe, pre-display
			image = editRecipe.getImage();
		}

		if (image == null) {
			image = BLANK_IMAGE;
		}
		return ResponseEntity.ok().headers(httpHeaders)
			.body(image);
	}

	@GetMapping(value = "/thumb/{recipeId}")
	public ResponseEntity<byte[]> thumbnail(
			@PathVariable long recipeId) {

		Recipe recipe = recipeService.findByPrimaryKey(recipeId);
		if (recipe != null) {
			HttpHeaders httpHeaders = new HttpHeaders();
			httpHeaders.set(HttpHeaders.CONTENT_TYPE,
				MediaType.IMAGE_PNG_VALUE);
			byte[] image = recipe.getThumb();
			// Empty thumbs have been seen with "H"!
			if (image == null || image.length < 2) {
				image = BLANK_IMAGE;
			}
			return ResponseEntity.ok().headers(httpHeaders)
				.body(image);
		}

		// NotFound, need dummy picture!:
		return ResponseEntity.status(404).body(new byte[0]);
	}

	/**
	 * Take imageFile input and store it as image for recipe.
	 * Generate thumnail
	 * 
	 * @param recipe    Recipe to store into.
	 * @param bs Info about uploaded data.
	 * 
	 *                  CalledFrom @see
	 *                  RecipeDetailBean#ajaxUploadImage(AjaxBehaviorEvent
	 *                  event)
	 */
	public static void importImage(Recipe recipe,
			byte[] bs) {
		try {
			byte[] bytes = null;

			InputStream istream =new ByteArrayInputStream(bs);
			ImageInputStream stream =
					ImageIO.createImageInputStream(istream);
			BufferedImage bi = ImageIO.read(stream);

			if ((bi.getWidth() > 512) || (bi.getWidth() > 512)) {
				bi = scaleImageSanely(bi);
			}

			ByteArrayOutputStream baos =
					new ByteArrayOutputStream();
			ImageIO.write(bi, "png", baos);
			bytes = baos.toByteArray();
			recipe.setImage(bytes);

			final int thumbHeight = 40;
			float ratio = ((float) bi.getHeight()) / thumbHeight;
			int thumbWidth = (int) (bi.getWidth() / ratio);

			BufferedImage resizedImg =
					new BufferedImage(thumbWidth, thumbHeight,
							BufferedImage.TRANSLUCENT);

			// Create a device-independent object to draw the
			// resized image
			Graphics2D g2 = resizedImg.createGraphics();

			g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
				RenderingHints.VALUE_INTERPOLATION_BILINEAR);

			// Finally draw the source image in the Graphics2D
			// with the desired size.
			g2.drawImage(bi, 0, 0, thumbWidth, thumbHeight,
				null);

			// Disposes of this graphics context and releases any
			// system resources that it is using
			g2.dispose();

			baos = new ByteArrayOutputStream();
			ImageIO.write(resizedImg, "png", baos);
			bytes = baos.toByteArray();
			recipe.setThumb(bytes);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	/**
	 * Reduce image so that width or height fit.
	 * 
	 * @param bi
	 * 
	 * @return
	 */
	private static BufferedImage scaleImageSanely(
			BufferedImage bi) {
		int w0 = bi.getWidth();
		int h0 = bi.getHeight();

		int w1 = w0;
		int h1 = h0;

		double ratio = 1.0;

		if (h0 > 512) {
			h1 = 512;
			ratio = ((double) h0) / ((double) h1);
			w1 = (int) (w0 / ratio);
		}
		if (w1 > 512) {
			w0 = w1;
			w1 = 512;
			ratio = ((double) w0) / ((double) w1);
			w1 = (int) (w0 / ratio);
		}

		BufferedImage resizedImg = new BufferedImage(w1, h1,
				BufferedImage.TRANSLUCENT);

		Graphics2D g2 = resizedImg.createGraphics();
		g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
			RenderingHints.VALUE_INTERPOLATION_BILINEAR);
		g2.drawImage(bi, 0, 0, w1, h1, null);
		g2.dispose();

		return resizedImg;
	}
}