var customCssUrls = require('gulp-custom-css-urls');
var gulp = require('gulp');
var path = require('path');
gulp.task('cssDemo',function(){
  return gulp.src('assets/**/*.css')
    .pipe(customCssUrls({
      /** 
       * static filepath relative absolute filepath's physical position. 
       * eg: 
       * image path inline css is '/images/demo.png', 
       * image absoulte filepath is '/Users/Navy/Desktop/code/demo/assets/images/demo.png', 
       * the process(process.cwd()) path is '/Users/Navy/Desktop/code/demo', 
       * so the image path relative website root path is 'assets/'
      */
      staticfile_relative_website_rootpath: 'assets/', 
      outputImage: true, // output images file , default to false
      outputImage_path: './.gulp_dist_output_images', // default to './.gulp_dist_output_images'
      modify: function (imageRelativePath, cssFilePath, imageRelativeWebsiteRootPath, imgInfo) {
        // modify image url before prepend or append
        // the imgInfo param is object, {hash: 3503865059, width: 1782, height: 530, orgin_filename: 'custom.png'}
        return path.join(imageRelativeWebsiteRootPath, path.basename(imageRelativePath)); //let the relative path become an absolute path
      },
      prepend: '', // prepend string before image url
      append: '', // append string after image url
      processPath: process.cwd() // custom process path , default to process.cwd()
    }))
    .pipe(gulp.dest('tmp/'));
});
gulp.task('jadeDemo',function() {
  return gulp.src('views/test.jade')
    .pipe(customCssUrls({
      staticfile_relative_website_rootpath: staticfile_relative_website_rootpath,
      modify: function (imageRelativePath, cssFilePath, imageRelativeWebsiteRootPath, imgInfo) {
        imageRelativePath.should.equal('example_1968_920.1373564769.png');
        imageRelativeWebsiteRootPath.should.equal('/images');
        imgInfo.should.have.properties({hash: 1373564769, width: 1968, height: 920, orgin_filename: 'example.png' });
        return path.join(imageRelativeWebsiteRootPath, imageRelativePath);
      },
      outputImage: true,
      ext: 'jade',
      outputImage_path: './.test_dist_img'
    }))
});

//rollback template content
gulp.task('returnToOrigin', function() {
  return gulp.src('views/forcemodify.html')
    .pipe(customCssUrls({
      forceModify: function (imageUrl, filePath) {
        var qiniu_host = 'https://demo.com';
        var ext = path.extname(imagesUrl);
        if (!ext) {
        return imagesUrl;
        }
        return imagesUrl.replace(ext, '').replace(qiniu_host, '').replace(/_\d{1,}_\d{1,}\.\d{1,}$/, '') + ext;
      },
      ext: 'html'
    }))
    .pipe(gulp.dest('views/'))
});
gulp.task('default',['cssDemo']);
gulp.task('jade',['jadeDemo']);
gulp.task('originTemplateContent',['returnToOrigin']);