package HTTP::Proxy;

use HTTP::Daemon;
use HTTP::Date qw(time2str);
use LWP::UserAgent;
use LWP::ConnCache;
use Fcntl ':flock';         # import LOCK_* constants
use IO::Select;
use Sys::Hostname;          # hostname()
use Carp;

use strict;
use vars qw( $VERSION $AUTOLOAD @METHODS
             @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS );

require Exporter;
@ISA    = qw(Exporter);
@EXPORT = ();               # no export by default
@EXPORT_OK = qw( ERROR NONE    PROXY  STATUS PROCESS SOCKET HEADERS FILTERS
                 DATA  CONNECT ENGINE ALL );
%EXPORT_TAGS = ( log => [@EXPORT_OK] );    # only one tag

$VERSION = '0.20';

my $CRLF = "\015\012";                     # "\r\n" is not portable

# standard filters
use HTTP::Proxy::HeaderFilter::standard;

# constants used for logging
use constant ERROR   => -1;    # always log
use constant NONE    => 0;     # never log
use constant PROXY   => 1;     # proxy information
use constant STATUS  => 2;     # HTTP status
use constant PROCESS => 4;     # sub-process life (and death)
use constant SOCKET  => 8;     # low-level connections
use constant HEADERS => 16;    # HTTP headers
use constant FILTERS => 32;    # Messages from filters
use constant DATA    => 64;    # Data received by the filters
use constant CONNECT => 128;   # Data transmitted by the CONNECT method
use constant ENGINE  => 256;   # Internal information from the Engine
use constant ALL     => 511;   # All of the above

# modules that need those constants to be defined
use HTTP::Proxy::Engine;
use HTTP::Proxy::FilterStack;

# Methods we can forward
my %METHODS;

# HTTP (RFC 2616)
$METHODS{http} = [qw( CONNECT DELETE GET HEAD OPTIONS POST PUT TRACE )];

# WebDAV (RFC 2518)
$METHODS{webdav} = [
    @{ $METHODS{http} },
    qw( COPY LOCK MKCOL MOVE PROPFIND PROPPATCH UNLOCK )
];

# Delta-V (RFC 3253)
$METHODS{deltav} = [
    @{ $METHODS{webdav} },
    qw( BASELINE-CONTROL CHECKIN CHECKOUT LABEL MERGE MKACTIVITY
        MKWORKSPACE REPORT UNCHECKOUT UPDATE VERSION-CONTROL ),
];

# the whole method list
@METHODS = HTTP::Proxy->known_methods();

# useful regexes (from RFC 2616 BNF grammar)
my %RX;
$RX{token}  = qr/[-!#\$%&'*+.0-9A-Z^_`a-z|~]+/;
$RX{mime}   = qr($RX{token}/$RX{token});
$RX{method} = '(?:' . join ( '|', @METHODS ) . ')';
$RX{method} = qr/$RX{method}/;

sub new {
    my $class  = shift;
    my %params = @_;

    # some defaults
    my %defaults = (
        agent    => undef,
        chunk    => 4096,
        daemon   => undef,
        host     => 'localhost',
        logfh    => *STDERR,
        logmask  => NONE,
        max_connections => 0,
        max_keep_alive_requests => 10,
        port     => 8080,
        stash    => {},
        timeout  => 60,
        via      => hostname() . " (HTTP::Proxy/$VERSION)",
        x_forwarded_for => 1,
    );

    # non modifiable defaults
    my $self = bless { conn => 0, loop => 1 }, $class;