#!/usr/binenv perl
BEGIN{ $DB::signal=0; }
use strict;
use warnings;
use Fcntl;

use Digest::SHA1 qw();
use IO::File;
use Text::CSV;
use File::Spec qw();
use File::Basename qw();
use File::Path qw();
use File::stat;
use Memoize;
memoize( 'generate_tempname' );

use constant VERBOSE => 1;

use feature ':5.10';

use HTTP::Request::Common qw(GET POST HEAD);

sub POE::Kernel::ASSERT_DEFAULT () { 1 }
use POE qw(Component::Client::HTTP) # Component::Client::Keepalive);


#my $pool = POE::Component::Client::Keepalive->new( max_per_host => 4, timeout => 1800, keep_alive => 180 );
POE::Component::Client::HTTP->spawn(
	Alias               => 'dmua'
	, Streaming         => 4096
#	, ConnectionManager => $pool
	, FollowRedirects   => 2
	, Agent             => 'Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.3) Gecko/2008101315 Ubuntu/8.10 (intrepid) Firefox/3.0.3'
	, From              => 'evan@dealermade.com'
);

POE::Session->create(
	inline_states => {
		_start                => \&client_start
		, _stop               => \&client_stop
		, got_response        => \&client_got_response
		, transfer_complete   => \&finalize_transfer
	}
);

$poe_kernel->run();

### Event handlers begin here.
sub client_start {
	my ($kernel, $heap) = @_[KERNEL, HEAP];

	## $poe_kernel->sig(INT => "_stop");
	
	my $fh = IO::File->new( 'dealermade_pictures.csv', 'r' );
	my $header = $fh->getline;
	my $csv = Text::CSV->new;

	while ( my $line = $fh->getline ) {
		$csv->parse( $line );
		my ( $picid, $url, $lot, $is_primary ) = $csv->fields;

		my $temp = generate_tempname( $url );

		if ( -e $temp && -f $temp && -s $temp ) {
			$kernel->post( dmua => request => got_response => HEAD( $url ) );
		}
		else {
			$kernel->post( dmua => request => got_response => GET( $url, Accept => 'image/*' ) );
		}
	}

}

sub client_stop {
	my $heap = $_[HEAP];
}

sub client_got_response {
	my ($heap, $req, $res, $data ) = ( $_[HEAP], $_[ARG0]->[0], @{$_[ARG1]} );

	my $uri  = $req->uri;
	my $temp = generate_tempname( $uri );
	
	given ( $req->method ) {
		
		when ( 'HEAD' ) {
			if ( -e $temp && -f $temp ) {
				my $stat = stat( $temp );
				my $badSize = $res->content_length && $stat->size != $res->content_length;
				my $badDate = $stat->mtime - $res->fresh_until > 0;
				## My slow sledge hammer
				## use DateTime qw();
				## my $badDate = DateTime->from_epoch( epoch => $stat->mtime )
				## 	->subtract_datetime( DateTime->from_epoch( epoch => $res->fresh_until ) )
				## 	->is_positive
				## ;
				if ( VERBOSE ) {
					if ( $badDate || $badSize ) {
						say "Posting to the kernel a request to redownload $uri";
						say "\tBAD SIZE detected, our file is ". $stat->size ." and it should be ". $res->content_length
							if $badSize
						;
						say "\tBAD DATE detected -- file has since been modified" if $badDate;
					}
					else {
						say "Skipping $uri -- all is current";
					}
				}
				
				$poe_kernel->post( dmua => request => got_response => GET( $uri, Accept => 'image/*' ) )
					if $badSize || $badDate
				;

			}
			else {
				warn "HEAD requested on non-cached file $temp\n";
			}

		}

		when ( 'GET' ) {

			my $this = $_[HEAP]->{uri}{$uri};
			my $fh   = $this->{fh};

			if ( !defined($res->code) || $res->code != '200' ) {
				say $res->code . " was received from request to $uri";
				if ( $res->code == 500 ) {
					use XXX; YYY [ $req, $res, $_[HEAP]->{connection} ];
					$DB::signal=1;
				}
				return;
			}

			## If we've never encoutered a response from this request.
			unless ( $fh ) {
				if ( VERBOSE ) {
					say "Started download of $uri : " . $res->code;
					say "\tDestination temp name:\t$temp";
				}

				## If the file exists simply unlink it and start over.
				## This is here so we can refresh the data behind the url
				if ( -e $temp && -f $temp ) {
					say "\tUnlinking preexiting uri first" if VERBOSE;
					unlink ( $temp );
				}

				## Else we might have to create the path to it.
				else {
					my $path = File::Basename::dirname( $temp );
					unless ( -d $path and -e $path ) {
						File::Path::mkpath( $path );
						say "\tCreating path:\t$path";
					}
				}

				sysopen ( $fh , $temp , O_WRONLY|O_CREAT );
				binmode($fh); ## win32 not required in linux
			
				$this = { fh => $fh, temp => $temp, uri => $uri };
				$_[HEAP]->{uri}{$uri} = $this;
			}

			##
			## If we have data send it to our file handle
			##
			if ( defined $data ) {
				print $fh $data;
			}
			##
			## If we have no more data hard link to store and remove
			##
			else {
				close $fh;
	
				my $stor = generate_storename( $uri );
				
				say "Linking $temp to $stor" if VERBOSE;
				
				my $path = File::Basename::dirname( $stor );
				File::Path::mkpath( $path ) unless -e $path && -d $path;
				CORE::link( $temp, $stor ) unless -e $stor ;

				delete $heap->{uri}{$this->{uri}};
			}

		}

	}

}

sub generate_tempname {
	my $uri = shift;
	my $sha1 = Digest::SHA1::sha1_hex( $uri );
	my ( $f1, $f2, $file ) = unpack ( 'A2A2A*', $sha1 );
	$uri =~ /.*([.].*?)$/;
	my $ext = $1;
	File::Spec->catfile( qw/out temp/, $f1, $f2, $file . $ext||'.jpg' );
}

sub generate_storename {
	my $uri = shift;
	my $tempname = generate_tempname($uri);
	my $io = IO::File->new( $tempname, 'r' );
	my $sha1 = Digest::SHA1->new;
	$sha1->addfile($io);
	$io->close;
	my ( $f1, $f2, $file ) = unpack ( 'A2A2A*', $sha1->hexdigest );
	$uri =~ /.*([.].*?)$/;
	my $ext = $1;
	#File::Spec->catfile( qw/out store/, $sha1->hexdigest . $ext );
	File::Spec->catfile( qw/out store/, $f1, $f2, $file . $ext||'.jpg' );
}