###########################################################################
#
# ImageConverter - helper plugin that does image conversion using ImageMagick
#
# A component of the Greenstone digital library software
# from the New Zealand Digital Library Project at the 
# University of Waikato, New Zealand.
#
# Copyright (C) 2008 New Zealand Digital Library Project
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
###########################################################################
package ImageConverter;

use BaseMediaConverter;


use strict;
no strict 'refs'; # allow filehandles to be variables and viceversa

use gsprintf 'gsprintf';

BEGIN {
    @ImageConverter::ISA = ('BaseMediaConverter');
}

my $arguments = [
      { 'name' => "create_thumbnail",
	'desc' => "{ImageConverter.create_thumbnail}",
	'type' => "enum",
	'list' => [{'name' => "true", 'desc' => "{common.true}"},
		   {'name' => "false", 'desc' => "{common.false}"}],
	'deft' => "true",
	'reqd' => "no" },
      { 'name' => "thumbnailsize",
	'desc' => "{ImageConverter.thumbnailsize}",
	'type' => "int",
	'deft' => "100",
	'range' => "1,",
	'reqd' => "no" },
      { 'name' => "thumbnailtype",
	'desc' => "{ImageConverter.thumbnailtype}",
	'type' => "string",
	'deft' => "gif",
	'reqd' => "no" },
      { 'name' => "noscaleup",
	'desc' => "{ImageConverter.noscaleup}",
	'type' => "flag",
	'reqd' => "no" },
      { 'name' => "create_screenview",
	'desc' => "{ImageConverter.create_screenview}",
	'type' => "enum",
	'list' => [{'name' => "true", 'desc' => "{common.true}"},
		   {'name' => "false", 'desc' => "{common.false}"}],
	'deft' => "true",
	'reqd' => "no" },
      { 'name' => "screenviewsize",
	'desc' => "{ImageConverter.screenviewsize}",
	'type' => "int",
	'deft' => "500",
	'range' => "1,",
	'reqd' => "no" },
      { 'name' => "screenviewtype",
	'desc' => "{ImageConverter.screenviewtype}",
	'type' => "string",
	'deft' => "jpg",
	'reqd' => "no" },
      { 'name' => "converttotype",
	'desc' => "{ImageConverter.converttotype}",
	'type' => "string",
	'deft' => "",
	'reqd' => "no" },
      { 'name' => "minimumsize",
	'desc' => "{ImageConverter.minimumsize}",
	'type' => "int",
	'deft' => "100",
	'range' => "1,",
	'reqd' => "no" }
		 ];

my $options = { 'name' => "ImageConverter",
		'desc' => "{ImageConverter.desc}",
		'abstract' => "yes",
		'inherits' => "yes",
		'args' => $arguments };

sub new {
    my ($class) = shift (@_);
    my ($pluginlist,$inputargs,$hashArgOptLists) = @_;
    push(@$pluginlist, $class);

    push(@{$hashArgOptLists->{"ArgList"}},@{$arguments});
    push(@{$hashArgOptLists->{"OptList"}},$options);

    my $self = new BaseMediaConverter($pluginlist, $inputargs, $hashArgOptLists, 1);


    return bless $self, $class;

}

# needs to be called after BasePlugin init, so that outhandle is set up.
sub init {
    my $self = shift(@_);

    $self->{'tmp_file_paths'} = ();

    # Check that ImageMagick is installed and available on the path 
    my $image_conversion_available = 1;
    my $no_image_conversion_reason = "";
    # None of this works very well on Windows 95/98...
    if ($ENV{'GSDLOS'} eq "windows" && !Win32::IsWinNT()) {
	$image_conversion_available = 0;
	$no_image_conversion_reason = "win95notsupported";
    } else {
	my $result = `identify -help 2>&1`;
	my $return_value = $?;
	if ( ($ENV{'GSDLOS'} eq "windows" && $return_value == 256) || $return_value == -1) {  # Linux and Windows return different values for "program not found"
	    $image_conversion_available = 0;
	    $no_image_conversion_reason = "imagemagicknotinstalled";
	}
    }
    $self->{'image_conversion_available'} = $image_conversion_available;
    $self->{'no_image_conversion_reason'} = $no_image_conversion_reason;

    if ($self->{'image_conversion_available'} == 0) {
	my $outhandle = $self->{'outhandle'};
	&gsprintf($outhandle, "ImageConverter: {ImageConverter.noconversionavailable} ({ImageConverter.".$self->{'no_image_conversion_reason'}."})\n");
    }
       
}
	

# convert image to new type if converttotype is set
# generate thumbnails if required
# generate screenview if required
# discover image metadata
# filename_no_path must be in utf8 and url-encoded
sub generate_images {
    my $self = shift(@_);
    my ($filename_full_path, $filename_no_path, $doc_obj, $section) = @_;

    # check image magick status
    return 0 if $self->{'image_conversion_available'} == 0;

    # check the filenames
    return 0 if ($filename_no_path eq "" || !-f $filename_full_path);

    if ($self->{'enable_cache'}) {
	$self->init_cache_for_file($filename_full_path);
    }

    my $verbosity = $self->{'verbosity'};
    my $outhandle = $self->{'outhandle'};

    # check the size of the image against minimum size if specified
    my $minimumsize = $self->{'minimumsize'};
    if (defined $minimumsize && (-s $filename_full_path < $minimumsize)) {
        print $outhandle "ImageConverter: \"$filename_full_path\" too small, skipping\n"
	    if ($verbosity > 1);
	return 0; # or is there a better return value??
    }
    
    my $filehead = $filename_no_path;
    $filehead =~ s/\.([^\.]*)$//; # filename with no extension
    my $assocfilemeta = "[assocfilepath]";
    if ($section ne $doc_obj->get_top_section()) {
	$assocfilemeta = "[parent(Top):assocfilepath]";
    }

    # The images that will get generated may contain percent signs in their src filenames
    # Encode those percent signs themselves so that urls to the imgs refer to them correctly 
    my $url_to_filehead = &unicode::filename_to_url($filehead);
    my $url_to_filename_no_path = &unicode::filename_to_url($filename_no_path);
    
    # Convert the image to a new type (if required).
    my $converttotype = $self->{'converttotype'};
    my $type = "unknown";

    if ($converttotype ne "" && $filename_full_path !~ m/$converttotype$/) {
	#    $doc_obj->add_utf8_metadata($section, "Image", $utf8_filename_meta);

	my ($result, $converted_filename_full_path)
	    = $self->convert($filename_full_path, $converttotype, "", "CONVERTTYPE");

	$type = $converttotype;
	$filename_full_path = $converted_filename_full_path;
	$filename_no_path = "$filehead.$type";
	$url_to_filename_no_path = "$url_to_filehead.$type";
    }

    # add Image metadata 
    $doc_obj->add_utf8_metadata($section, "Image", $url_to_filename_no_path); # url to generated image

    # here we overwrite the original with the potentially converted one
    $doc_obj->set_utf8_metadata_element($section, "Source", &unicode::url_decode($filename_no_path)); # displayname of generated image
    $doc_obj->set_utf8_metadata_element($section, "SourceFile", $url_to_filename_no_path); # displayname of generated image

    # use identify to get info about the (possibly converted) image
    my ($image_type, $image_width, $image_height, $image_size) 
	= &identify($filename_full_path, $outhandle, $verbosity);

    if ($image_type ne " ") {
	$type = $self->correct_mime_type($image_type);
    }

    #overwrite the ones added in BasePlugin
    $doc_obj->set_metadata_element ($section, "FileFormat", $type);
    $doc_obj->set_metadata_element ($section, "FileSize",   $image_size);

    $doc_obj->add_metadata ($section, "ImageType",   $image_type);
    $doc_obj->add_metadata ($section, "ImageWidth",  $image_width);
    $doc_obj->add_metadata ($section, "ImageHeight", $image_height);
    $doc_obj->add_metadata ($section, "ImageSize",   $image_size);

    if ((defined $self->{'MaxImageWidth'}) 
	&& ($image_width > $self->{'MaxImageWidth'})) {
	$self->{'MaxImageWidth'} = $image_width;
    }
    if ((defined $self->{'MaxImageHeight'})
	&& ($image_height > $self->{'MaxImageHeight'})) {
	$self->{'MaxImageHeight'} = $image_height;
    }


    $doc_obj->add_metadata ($section, "srclink", "<a href=\"_httpprefix_/collect/[collection]/index/assoc/$assocfilemeta/[Image]\">");
    $doc_obj->add_metadata ($section, "/srclink", "</a>");
    $doc_obj->add_metadata ($section, "srcicon", "<img src=\"_httpprefix_/collect/[collection]/index/assoc/$assocfilemeta/[Image]\" width=\"[ImageWidth]\" height=\"[ImageHeight]\">");

    # Add the image as an associated file
    $doc_obj->associate_file($filename_full_path, $filename_no_path, "image/$type", $section);

    if ($self->{'create_thumbnail'} eq "true") {
	$self->create_thumbnail($filename_full_path, $filehead, $doc_obj, $section, $assocfilemeta, $url_to_filehead);
    }
    if ($self->{'create_screenview'} eq "true") {
	$self->create_screenview($filename_full_path, $filehead, $doc_obj, $section, $assocfilemeta, $url_to_filehead, $image_width, $image_height);
    }
}

sub create_thumbnail {
    my $self = shift(@_);
    my ($original_file, $filehead, $doc_obj, $section, $assocfilemeta, $url_to_filehead) = @_;
    $url_to_filehead = $filehead unless defined $url_to_filehead; 

    my $thumbnailsize = $self->{'thumbnailsize'};
    my $thumbnailtype = $self->correct_mime_type($self->{'thumbnailtype'});

    # Generate the thumbnail with convert
    my ($result,$thumbnailfile) 
	= $self->convert($original_file, $thumbnailtype, "-geometry $thumbnailsize" . "x$thumbnailsize", "THUMB");
    
    # Add the thumbnail as an associated file ...
    if (-e "$thumbnailfile") { 
	$doc_obj->associate_file("$thumbnailfile", $filehead."_thumb.$thumbnailtype", 
				 "image/$thumbnailtype",$section); # name of generated image
	$doc_obj->add_metadata ($section, "ThumbType", $thumbnailtype);
	$doc_obj->add_utf8_metadata ($section, "Thumb", $url_to_filehead."_thumb.$thumbnailtype"); # url to generated image
	
	$doc_obj->add_metadata ($section, "thumbicon", "<img src=\"_httpprefix_/collect/[collection]/index/assoc/$assocfilemeta/[Thumb]\" width=[ThumbWidth] height=[ThumbHeight]>");
    
	
	# Extract Thumbnail metadata from convert output
	if ($result =~ m/[0-9]+x[0-9]+=>([0-9]+)x([0-9]+)/) {
	    $doc_obj->add_metadata ($section, "ThumbWidth", $1);
	    $doc_obj->add_metadata ($section, "ThumbHeight", $2);
	}
    } else {
	my $outhandle = $self->{'outhandle'};
	print $outhandle "Couldn't find thumbnail $thumbnailfile\n";

    }
}

sub create_screenview {
    
    my $self = shift(@_);
    my ($original_file, $filehead, $doc_obj, $section, $assocfilemeta, $url_to_filehead, $image_width, $image_height) = @_;
    $url_to_filehead = $filehead unless defined $url_to_filehead; 

    my $screenviewsize = $self->{'screenviewsize'};
    my $screenviewtype = $self->correct_mime_type($self->{'screenviewtype'});

    # Scale the image, unless the original image is smaller than the screenview size and -noscaleup is set
    my $scale_option = "-geometry $screenviewsize" . "x$screenviewsize";
    if ($self->{'noscaleup'} && $image_width < $screenviewsize && $image_height < $screenviewsize)
    {
	$scale_option = "";
    }
    
    # make the screenview image
    my ($result,$screenviewfilename) 
	= $self->convert($original_file, $screenviewtype, $scale_option, "SCREEN");    
    
    #add the screenview as an associated file ...
    if (-e "$screenviewfilename") { 
	$doc_obj->associate_file("$screenviewfilename", $filehead."_screen.$screenviewtype", "image/$screenviewtype",$section); # name of generated image
	$doc_obj->add_metadata ($section, "ScreenType", $screenviewtype);
	$doc_obj->add_utf8_metadata ($section, "Screen", $url_to_filehead."_screen.$screenviewtype"); # url to generated image
	
	$doc_obj->add_metadata ($section, "screenicon", "<img src=\"_httpprefix_/collect/[collection]/index/assoc/$assocfilemeta/[Screen]\" width=[ScreenWidth] height=[ScreenHeight]>");

	# get screenview dimensions, size and type
	if ($result =~ m/[0-9]+x[0-9]+=>([0-9]+)x([0-9]+)/) {
	    $doc_obj->add_metadata ($section, "ScreenWidth", $1);
	    $doc_obj->add_metadata ($section, "ScreenHeight", $2);
	} elsif ($result =~ m/([0-9]+)x([0-9]+)/) {
	    #if the image hasn't changed size, the previous regex doesn't match
	    $doc_obj->add_metadata ($section, "ScreenWidth", $1);
	    $doc_obj->add_metadata ($section, "ScreenHeight", $2);
	}
    } else {
	my $outhandle = $self->{'outhandle'};
	print $outhandle "Couldn't find screenview file $screenviewfilename\n";

    }

}



sub convert {
    my $self = shift(@_);
    my $source_file_path = shift(@_);
    my $target_file_type = shift(@_);
    my $convert_options  = shift(@_) || "";
    my $convert_id       = shift(@_) || "";

    my $outhandle = $self->{'outhandle'};
    my $verbosity = $self->{'verbosity'};

    my $source_file_no_path = &File::Basename::basename($source_file_path);

    # Determine the full name and path of the output file
    my $target_file_path;
    if ($self->{'enable_cache'}) {
	my $cached_image_dir = $self->{'cached_dir'};
	my $image_root = $self->{'cached_file_root'};
	$image_root .= "_$convert_id" if ($convert_id ne "");
	my $image_file = "$image_root.$target_file_type";
	$target_file_path = &util::filename_cat($cached_image_dir,$image_file);
    }
    else {
	$target_file_path = &util::get_tmp_filename($target_file_type);
	push(@{$self->{'tmp_file_paths'}}, $target_file_path);

	# Output filename used to be parsed from result line:
	#   my ($ofilename) = ($result =~ m/=>(.*\.$target_file_type)/);
	# by the function that called 'convert'
	# but this is no longer needed, as output filename is now
	# explicitly passed back
    }

    # Generate and run the convert command
    my $convert_command = "convert -interlace plane -verbose $convert_options \"$source_file_path\" \"$target_file_path\"";

    my $print_info = { 'message_prefix' => $convert_id,
		       'message' => "Converting image $source_file_no_path to: $convert_id $target_file_type" };
 
    my ($regenerated,$result,$had_error) 
	= $self->autorun_general_cmd($convert_command,$target_file_path,$print_info);

    return ($result,$target_file_path);
}


# Discover the characteristics of an image file with the ImageMagick
# "identify" command.

sub identify { 
    my ($image, $outhandle, $verbosity) = @_;

    # Use the ImageMagick "identify" command to get the file specs
    my $command = "identify \"$image\" 2>&1";
    print $outhandle "$command\n" if ($verbosity > 2);
    my $result = '';
    $result = `$command`;
    print $outhandle "$result\n" if ($verbosity > 3);

    # Read the type, width, and height
    my $type =   'unknown';
    my $width =  'unknown';
    my $height = 'unknown';

    my $image_safe = quotemeta $image;
    if ($result =~ /^$image_safe (\w+) (\d+)x(\d+)/) {
	$type = $1;
	$width = $2;
	$height = $3;
    }

    # Read the size
    my $size = "unknown";
    if ($result =~ m/^.* ([0-9]+)b/) {
	$size = $1;
    }
    elsif ($result =~ m/^.* ([0-9]+)(\.([0-9]+))?kb?/) {
	$size = 1024 * $1;
	if (defined($2)) {
	    $size = $size + (1024 * $2);
	    # Truncate size (it isn't going to be very accurate anyway)
	    $size = int($size);
	}
    }
    elsif ($result =~ m/^.* (([0-9]+)(\.([0-9]+))?e\+([0-9]+))(kb|b)?/) {
	# Deals with file sizes on Linux of type "3.4e+02kb" where e+02 is 1*10^2.
	# 3.4e+02 therefore evaluates to 3.4 x 1 x 10^2 = 340kb.
	# Programming languages including Perl know how that 3.4e+02 is a number,
	# so we don't need to do any calculations.
	$size = $1*1; # turn the string into a number by multiplying it by 1
	       #if we did $size = $1; $size would be merely the string "3.4e+02"
	$size = int($size); # truncate size
    }
    print $outhandle "file: $image:\t $type, $width, $height, $size\n" 
	if ($verbosity > 2);

    # Return the specs
    return ($type, $width, $height, $size);
}

sub clean_up_temporary_files {
    my $self = shift(@_);

    foreach my $tmp_file_path (@{$self->{'tmp_file_paths'}}) {
	if (-e $tmp_file_path) {
	    &util::rm($tmp_file_path);
	}
    }
   
}

# image/jpg is not a valid mime-type, it ought to be image/jpeg. 
# Sometimes JPEG is passed in also, want to keep things lowercase just in case.
sub correct_mime_type {
    my $self = shift(@_);
    my ($file_extension) = @_;
    
    $file_extension = lc($file_extension);
    $file_extension =~ s/jpg/jpeg/s; 

    return $file_extension;
}

1;