package hirondelle.fish.exercise.fileupload;

import hirondelle.web4j.action.ActionTemplateShowAndApply;
import hirondelle.web4j.model.AppException;
import hirondelle.web4j.model.ModelCtorException;
import hirondelle.web4j.request.RequestParser;
import hirondelle.web4j.action.ResponsePage;
import hirondelle.web4j.request.RequestParameter;
import hirondelle.fish.util.TemplatedPage;
import hirondelle.web4j.util.Util;
import hirondelle.web4j.model.ModelFromRequest;
import java.io.*;
import java.util.logging.*;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.fileupload.FileItem;
import hirondelle.web4j.security.SafeText;

/**
 Overwrite the image used on the home page.
 
 <P>This is an example of uploading a file, validating it, and saving it to the file system.
 
 <P>See {@link hirondelle.fish.exercise.fileupload.Image} for details regarding validation.
*/
public final class ImageUploadAction extends ActionTemplateShowAndApply {

  /** Constructor */
  public ImageUploadAction(RequestParser aRequestParser){
    super(FORWARD, REDIRECT, aRequestParser);
  }
  
  /** This 'regular' param will have its value checked by <tt>ApplicationFirewallImpl</tt> in the usual way.  */
  public static final RequestParameter DESCRIPTION = RequestParameter.withLengthCheck("Description");
  /** This file upload param will not have its <em>value</em> checked as would a regular param. */
  public static final RequestParameter IMAGE_FILE = RequestParameter.forFileUpload("ImageFile");

  /** Show a blank form.  */
  @Override protected void show() throws AppException {
    //empty 
  }
  
  /**Ensure user input can create an {@link Image} object.  */
  @Override protected void validateUserInput() throws AppException {
    extractFileUploadFields();
    try {
      ModelFromRequest builder = new ModelFromRequest(getRequestParser());
      fImage = builder.build(
        Image.class, DESCRIPTION, 
        SafeText.from(fFileItem.getName()), 
        SafeText.from(fFileItem.getContentType()), 
        fFileItem.getSize()
      );
    }
    catch(ModelCtorException ex){
      addError(ex);
    }
  }
  
  /** If user input is valid, overwrite the image file used on the home page.  */
  @Override protected void apply() throws AppException {
    overwriteImageFile(fImage);
    addMessage("New Home Page image has been overwritten.");
  }
  
  // PRIVATE //
  private FileItem fFileItem;
  private Image fImage;
  private static final String IMAGE_FILE_SAVE_AS = "/images/FishAndChips.jpg";
  private static final ResponsePage FORWARD = TemplatedPage.get("Upload", "view.jsp", ImageUploadAction.class);
  private static final ResponsePage REDIRECT =  new ResponsePage("ImageUploadAction.show");
  private static final Logger fLogger = Util.getLogger(ImageUploadAction.class);
  
  private void extractFileUploadFields(){
    HttpServletRequest request = getRequestParser().getRequest();
    SafeText description = getParam(DESCRIPTION);
    
    //note a cast is needed here to get the file-related data
    FileUploadWrapper wrappedRequest = (FileUploadWrapper)request;
    fFileItem = wrappedRequest.getFileItem(IMAGE_FILE.getName());
    fLogger.fine("Extracted Description: " + description);
    fLogger.fine("Extracted File Name: " + fFileItem.getName());
    fLogger.fine("Extracted File Content Type: " + fFileItem.getContentType());
    fLogger.fine("Extracted File Size : " + fFileItem.getSize());
  }

  private void overwriteImageFile(Image aImage) throws AppException {
    String imageFilePath = getExistingSession().getServletContext().getRealPath(IMAGE_FILE_SAVE_AS);
    File file = new File(imageFilePath);
    try {
      fFileItem.write(file);
    }
    catch(Exception ex){
      throw new AppException("Cannot save file.", ex);
    }
  }
}