package Mojo::Client;

use strict;
use warnings;

use base 'Mojo::Base';

use Carp 'croak';
use Mojo::Asset::File;
use Mojo::Asset::Memory;
use Mojo::ByteStream 'b';
use Mojo::Content::MultiPart;
use Mojo::Content::Single;
use Mojo::CookieJar;
use Mojo::IOLoop;
use Mojo::Log;
use Mojo::Parameters;
use Mojo::Server::Daemon;
use Mojo::Transaction::HTTP;
use Mojo::Transaction::WebSocket;
use Mojo::URL;
use Scalar::Util 'weaken';

# Debug
use constant DEBUG => $ENV{MOJO_CLIENT_DEBUG} || 0;

# You can't let a single bad experience scare you away from drugs.
__PACKAGE__->attr(
    [qw/app http_proxy https_proxy tls_ca_file tls_verify_cb tx/]);
__PACKAGE__->attr(cookie_jar => sub { Mojo::CookieJar->new });
__PACKAGE__->attr(ioloop     => sub { Mojo::IOLoop->new });
__PACKAGE__->attr(keep_alive_timeout         => 15);
__PACKAGE__->attr(log                        => sub { Mojo::Log->new });
__PACKAGE__->attr(max_keep_alive_connections => 5);
__PACKAGE__->attr(max_redirects     => sub { $ENV{MOJO_MAX_REDIRECTS} || 0 });
__PACKAGE__->attr(websocket_timeout => 300);

# Singleton
our $CLIENT;

# Make sure we leave a clean ioloop behind
sub DESTROY {
    my $self = shift;

    # Loop
    return unless my $loop = $self->ioloop;

    # Cleanup active connections
    my $cs = $self->{_cs} || {};
    $loop->drop($_) for keys %$cs;

    # Cleanup keep alive connections
    my $cache = $self->{_cache} || [];
    for my $cached (@$cache) {
        $loop->drop($cached->[1]);
    }
}

# Homer, it's easy to criticize.
# Fun, too.
sub async {
    my $self = shift;

    # Already async or async not possible
    return $self if $self->{_is_async};

    # Create async client
    unless ($self->{_async}) {

        # Clone and cache async client
        my $clone = $self->{_async} = $self->clone;
        $clone->{_is_async} = 1;

        # Make async client use the global ioloop if available
        my $singleton = Mojo::IOLoop->singleton;
        $clone->ioloop($singleton->is_running ? $singleton : $self->ioloop);

        # Inherit test server
        $clone->{_server} = $self->{_server};
        $clone->{_port}   = $self->{_port};
    }

    return $self->{_async};
}

# Ah, alcohol and night-swimming. It's a winning combination.
sub build_form_tx {
    my $self = shift;

    # URL
    my $url = shift;

    # Callback
    my $cb = pop @_ if ref $_[-1] && ref $_[-1] eq 'CODE';

    # Encoding
    my $encoding = shift;

    # Form
    my $form = ref $encoding ? $encoding : shift;
    $encoding = undef if ref $encoding;

    # Parameters
    my $params = Mojo::Parameters->new;
    $params->charset($encoding) if defined $encoding;
    my $multipart;
    for my $name (sort keys %$form) {

        # Array
        if (ref $form->{$name} eq 'ARRAY') {
            $params->append($name, $_) for @{$form->{$name}};
        }

        # Hash
        elsif (ref $form->{$name} eq 'HASH') {
            my $hash = $form->{$name};

            # Enforce "multipart/form-data"
            $multipart = 1;

            # File
            if (my $file = $hash->{file}) {

                # Upgrade
                $file = $hash->{file} = Mojo::Asset::File->new(path => $file)
                  unless ref $file;

                # Filename
                $hash->{filename} ||= $file->path if $file->can('path');
            }

            # Memory
            elsif (defined(my $content = delete $hash->{content})) {
                $hash->{file} = Mojo::Asset::Memory->new->add_chunk($content);
            }

            # Content-Type
            $hash->{'Content-Type'} ||= 'application/octet-stream';

            # Append
            push @{$params->params}, $name, $hash;
        }

        # Single value
        else { $params->append($name, $form->{$name}) }
    }

    # New transaction
    my $tx = $self->build_tx(POST => $url);

    # Request
    my $req = $tx->req;

    # Headers
    my $headers = $req->headers;
    $headers->from_hash(ref $_[0] eq 'HASH' ? $_[0] : {@_});

    # Multipart
    $headers->content_type('multipart/form-data') if $multipart;
    my $type = $headers->content_type || '';
    if ($type eq 'multipart/form-data') {

        # Formdata
        my $form = $params->to_hash;

        # Parts
        my @parts;
        foreach my $name (sort keys %$form) {

            # Part
            my $part = Mojo::Content::Single->new;

            # Headers
            my $h = $part->headers;

            # Form
            my $f = $form->{$name};

            # File
            my $filename;
            if (ref $f eq 'HASH') {

                # Filename
                $filename = delete $f->{filename} || $name;
                $filename = b($filename);
                $filename->encode($encoding) if $encoding;
                $filename =
                  $filename->url_escape($Mojo::URL::PARAM)->to_string;

                # Asset
                $part->asset(delete $f->{file});

                # Headers
                $h->from_hash($f);
            }

            # Fields
            else {

                # Values
                my $chunk = join ',', ref $f ? @$f : ($f);
                $chunk = b($chunk)->encode($encoding)->to_string if $encoding;
                $part->asset->add_chunk($chunk);

                # Content-Type
                my $type = 'text/plain';
                $type .= qq/;charset=$encoding/ if $encoding;
                $h->content_type($type);
            }

            # Content-Disposition
            my $escaped = b($name);
            $escaped->encode($encoding) if $encoding;
            $escaped = $escaped->url_escape($Mojo::URL::PARAM)->to_string;
            my $disposition = qq/form-data; name="$escaped"/;
            $disposition .= qq/; filename="$filename"/ if $filename;
            $h->content_disposition($disposition);

            push @parts, $part;
        }

        # Multipart content
        my $content = Mojo::Content::MultiPart->new;
        $headers->content_type('multipart/form-data');
        $content->headers($headers);
        $content->parts(\@parts);

        # Add content to transaction
        $req->content($content);
    }

    # Urlencoded
    else {
        $headers->content_type('application/x-www-form-urlencoded');
        $req->body($params->to_string);
    }

    return $tx unless wantarray;
    return $tx, $cb;
}

sub build_tx {
    my $self = shift;

    # New transaction
    my $tx = Mojo::Transaction::HTTP->new;

    # Request
    my $req = $tx->req;

    # Method
    $req->method(shift);

    # URL
    my $url = shift;
    $url = "http://$url" unless $url =~ /^\/|\:\/\//;
    $req->url->parse($url);

    # Callback
    my $cb = pop @_ if ref $_[-1] && ref $_[-1] eq 'CODE';

    # Body
    $req->body(pop @_)
      if @_ & 1 == 1 && ref $_[0] ne 'HASH' || ref $_[-2] eq 'HASH';

    # Headers
    $req->headers->from_hash(ref $_[0] eq 'HASH' ? $_[0] : {@_});

    return $tx unless wantarray;
    return $tx, $cb;
}

sub build_websocket_tx {
    my $self = shift;

    # New WebSocket
    my ($tx, $cb) = $self->build_tx(GET => @_);

    # Request
    my $req = $tx->req;

    # URL
    my $url = $req->url;

    # Scheme
    my $abs = $url->to_abs;
    if (my $scheme = $abs->scheme) {
        $scheme = $scheme eq 'wss' ? 'https' : 'http';
        $req->url($abs->scheme($scheme));
    }

    # Handshake
    Mojo::Transaction::WebSocket->new(handshake => $tx)->client_handshake;

    return $tx unless wantarray;
    return $tx, $cb;
}

sub clone {
    my $self = shift;

    # Clone
    my $clone = $self->new;
    $clone->app($self->app);
    $clone->log($self->log);
    $clone->cookie_jar($self->cookie_jar);
    $clone->keep_alive_timeout($self->keep_alive_timeout);
    $clone->max_keep_alive_connections($self->max_keep_alive_connections);
    $clone->max_redirects($self->max_redirects);
    $clone->tls_ca_file($self->tls_ca_file);
    $clone->tls_verify_cb($self->tls_verify_cb);
    $clone->websocket_timeout($self->websocket_timeout);

    return $clone;
}

# The only thing I asked you to do for this party was put on clothes,
# and you didn't do it.
sub delete {
    my $self = shift;
    return $self->_tx_queue_or_process($self->build_tx('DELETE', @_));
}

sub detect_proxy {
    my $self = shift;
    $self->http_proxy($ENV{HTTP_PROXY}   || $ENV{http_proxy});
    $self->https_proxy($ENV{HTTPS_PROXY} || $ENV{https_proxy});
    return $self;
}

sub finish {
    my $self = shift;

    # Transaction
    my $tx = $self->tx;

    # WebSocket
    croak 'Transaction is not a WebSocket' unless $tx->is_websocket;

    # Finish
    $tx->finish;
}

sub finished {
    my $self = shift;

    # Transaction
    my $tx = $self->tx;

    # WebSocket
    croak 'Transaction is not a WebSocket' unless $tx->is_websocket;

    # Callback
    my $cb = shift;

    # Weaken
    weaken $self;
    weaken $tx;

    # Connection finished
    $tx->finished(sub { shift; local $self->{tx} = $tx; $self->$cb(@_) });
}

# "What are you lookin' at?" - the innocent words of a drunken child.
sub get {
    my $self = shift;
    return $self->_tx_queue_or_process($self->build_tx('GET', @_));
}

sub head {
    my $self = shift;
    return $self->_tx_queue_or_process($self->build_tx('HEAD', @_));
}

sub post {
    my $self = shift;
    return $self->_tx_queue_or_process($self->build_tx('POST', @_));
}

sub post_form {
    my $self = shift;
    return $self->_tx_queue_or_process($self->build_form_tx(@_));
}

# Olive oil? Asparagus? If your mother wasn't so fancy,
# we could just shop at the gas station like normal people.
sub process {
    my $self = shift;

    # Queue
    $self->queue(@_) if @_;
    my $queue = delete $self->{_queue} || [];

    # Process sync subrequests in new client
    if (!$self->{_is_async} && $self->{_processing}) {
        my $clone = $self->clone;
        $clone->queue(@$_) for @$queue;
        return $clone->process;
    }

    # Add async transactions from queue
    else { $self->_tx_start(@$_) for @$queue }

    # Process sync requests
    if (!$self->{_is_async} && $self->{_processing}) {

        # Start loop
        my $loop = $self->ioloop;
        $loop->start;

        # Cleanup
        $loop->one_tick(0);
    }

    return $self;
}

sub put {
    my $self = shift;
    $self->_tx_queue_or_process($self->build_tx('PUT', @_));
}

# And I gave that man directions, even though I didn't know the way,
# because that's the kind of guy I am this week.
sub queue {
    my $self = shift;

    # Callback
    my $cb = pop @_ if ref $_[-1] && ref $_[-1] eq 'CODE';

    # Queue transactions
    my $queue = $self->{_queue} ||= [];
    push @$queue, [$_, $cb] for @_;

    return $self;
}

sub receive_message {
    my $self = shift;

    # Transaction
    my $tx = $self->tx;

    # WebSocket
    croak 'Transaction is not a WebSocket' unless $tx->is_websocket;

    # Callback
    my $cb = shift;

    # Weaken
    weaken $self;
    weaken $tx;

    # Receive
    $tx->receive_message(
        sub { shift; local $self->{tx} = $tx; $self->$cb(@_) });

    return $self;
}

sub req { shift->tx->req(@_) }
sub res { shift->tx->res(@_) }

sub singleton { $CLIENT ||= shift->new(@_) }

# Wow, Barney. You brought a whole beer keg.
# Yeah... where do I fill it up?
sub send_message {
    my $self = shift;

    # Transaction
    my $tx = $self->tx;

    # WebSocket
    croak 'Transaction is not a WebSocket' unless $tx->is_websocket;

    # Send
    $tx->send_message(@_);

    return $self;
}

# It's like my dad always said: eventually, everybody gets shot.
sub test_server {
    my $self = shift;

    # Server
    unless ($self->{_port}) {
        my $server = $self->{_server} =
          Mojo::Server::Daemon->new(ioloop => $self->ioloop, silent => 1);
        my $port = $self->{_port} = $self->ioloop->generate_port;
        die "Couldn't find a free TCP port for testing.\n" unless $port;
        $server->listen("http://*:$port");
        $server->prepare_ioloop;
    }

    # Application
    my $server = $self->{_server};
    delete $server->{app};
    my $app = $self->app;
    ref $app ? $server->app($app) : $server->app_class($app);
    $self->log($server->app->log);

    return $self->{_port};
}

# Are we there yet?
# No
# Are we there yet?
# No
# Are we there yet?
# No
# ...Where are we going?
sub websocket {
    my $self = shift;
    $self->queue($self->build_websocket_tx(@_));
}

sub _cache {
    my ($self, $name, $id) = @_;

    # Cache
    my $cache = $self->{_cache} ||= [];

    # Enqueue
    if ($id) {

        # Limit keep alive connections
        my $max = $self->max_keep_alive_connections;
        while (@$cache > $max) {
            my $cached = shift @$cache;
            $self->_drop($cached->[1]);
        }

        # Add to cache
        push @$cache, [$name, $id] if $max;

        return $self;
    }

    # Dequeue
    my $result;
    my @cache;
    for my $cached (@$cache) {

        # Search for name or id
        $result = $cached->[1] and next
          if $cached->[1] eq $name || $cached->[0] eq $name;

        # Cache again
        push @cache, $cached;
    }
    $self->{_cache} = \@cache;

    return $result;
}

# Where on my badge does it say anything about protecting people?
# Uh, second word, chief.
sub _connect {
    my ($self, $tx, $cb) = @_;

    # Check for specific connection id
    my $id = $tx->connection;

    # Loop
    my $loop = $self->ioloop;

    # Info
    my ($scheme, $address, $port) = $self->_tx_info($tx);

    # Keep alive connection
    $id ||= $self->_cache("$scheme:$address:$port");
    if ($id && !ref $id) {

        # Debug
        warn "KEEP ALIVE CONNECTION ($scheme:$address:$port)\n" if DEBUG;

        # Add new connection
        $self->{_cs}->{$id} = {cb => $cb, tx => $tx};

        # Kept alive
        $tx->kept_alive(1);

        # Connected
        $self->_connected($id);
    }

    # New connection
    else {

        # TLS/WebSocket proxy
        unless (($tx->req->method || '') eq 'CONNECT') {

            # CONNECT request to proxy required
            return if $self->_connect_proxy($tx, $cb);
        }

        # Debug
        warn "NEW CONNECTION ($scheme:$address:$port)\n" if DEBUG;

        # Weaken
        weaken $self;

        # Connect
        $id = $loop->connect(
            address => $address,
            port    => $port,
            socket  => $id,
            tls     => $scheme eq 'https' ? 1 : 0,
            tls_ca_file => $self->tls_ca_file || $ENV{MOJO_CA_FILE},
            tls_verify_cb => $self->tls_verify_cb,
            connect_cb    => sub { $self->_connected($_[1]) },
            error_cb      => sub { $self->_error(@_) },
            hup_cb        => sub { $self->_hup(@_) },
            read_cb       => sub { $self->_read(@_) }
        );

        # Error
        unless (defined $id) {
            $tx->req->error("Couldn't connect.");
            $self->_tx_finish($tx, $cb);
            return;
        }

        # Add new connection
        $self->{_cs}->{$id} = {cb => $cb, tx => $tx};
    }

    return $id;
}

# Hey, Weener Boy... where do you think you're going?
sub _connect_proxy {
    my ($self, $old, $cb) = @_;

    # Request
    my $req = $old->req;

    # URL
    my $url = $req->url;

    # Proxy
    return unless my $proxy = $req->proxy;

    # WebSocket and/or HTTPS
    return
      unless ($req->headers->upgrade || '') eq 'WebSocket'
      || ($url->scheme || '') eq 'https';

    # CONNECT request
    my $new = $self->build_tx(CONNECT => $url->clone);
    $new->req->proxy($proxy);

    # Start CONNECT request
    $self->_tx_start(
        $new => sub {
            my ($self, $tx) = @_;

            # CONNECT failed
            unless (($tx->res->code || '') eq '200') {
                $old->req->error('Proxy connection failed.');
                $self->_tx_finish($old, $cb);
                return;
            }

            # TLS upgrade
            if ($tx->req->url->scheme eq 'https') {

                # Connection from keep alive cache
                return unless my $oid = $tx->connection;

                # Start TLS
                my $nid = $self->ioloop->start_tls(
                    $oid,
                    tls_ca_file => $self->tls_ca_file || $ENV{MOJO_CA_FILE},
                    tls_verify_cb => $self->tls_verify_cb
                );

                # Cleanup
                $old->req->proxy(undef);
                delete $self->{_cs}->{$oid};
                $tx->connection($nid);
            }

            # Share connection
            $old->connection($tx->connection);

            # Start real transaction
            $self->_tx_start($old, $cb);
        }
    );

    return 1;
}

# I don't mind being called a liar when I'm lying, or about to lie,
# or just finished lying, but NOT WHEN I'M TELLING THE TRUTH.
sub _connected {
    my ($self, $id) = @_;

    # Loop
    my $loop = $self->ioloop;

    # Transaction
    my $tx = $self->{_cs}->{$id}->{tx};

    # Connection
    $tx->connection($id);

    # Store connection information in transaction
    my $local = $loop->local_info($id);
    $tx->local_address($local->{address});
    $tx->local_port($local->{port});
    my $remote = $loop->remote_info($id);
    $tx->remote_address($remote->{address});
    $tx->remote_port($remote->{port});

    # Keep alive timeout
    $loop->connection_timeout($id => $self->keep_alive_timeout);

    # Write
    $self->_write($id);
}

# Mrs. Simpson, bathroom is not for customers.
# Please use the crack house across the street.
sub _drop {
    my ($self, $id) = @_;

    # Keep alive
    my $tx = $self->{_cs}->{$id}->{tx};
    if ($tx && $tx->keep_alive && !$tx->error) {

        # Don't keep CONNECTed connections alive
        my $method = $tx->req->method || '';
        my $code   = $tx->res->code   || '';
        unless ($method eq 'CONNECT' && $code eq '200') {

            # Keep connection alive
            $self->_cache(join(':', $self->_tx_info($tx)), $id);
        }
    }

    # Connection close
    else {
        $self->_cache($id);
        $self->ioloop->drop($id);
    }

    # Drop connection
    delete $self->{_cs}->{$id};
}

sub _error {
    my ($self, $loop, $id, $error) = @_;

    # Transaction
    if (my $tx = $self->{_cs}->{$id}->{tx}) { $tx->res->error($error) }

    # Log
    $self->log->error($error);

    # Finished
    $self->_handle($id);
}

# No children have ever meddled with the Republican Party and lived to tell
# about it.
sub _handle {
    my ($self, $id) = @_;

    # Connection
    my $c = $self->{_cs}->{$id};

    # Old transaction
    my $old = $c->{tx};

    # WebSocket
    if ($old && $old->is_websocket) {

        # Finish transaction
        $old->client_close;

        # Counter
        $self->{_processing} -= 1;

        # Cleanup
        delete $self->{_cs}->{$id};
        $self->_drop($id);
    }

    # Upgrade connection to WebSocket
    elsif ($old && (my $new = $self->_upgrade($id))) {

        # Finish
        $self->_tx_finish($new, $c->{cb});

        # Leftovers
        $new->client_read($old->res->leftovers);
    }

    # Normal connection
    else {

        # Cleanup
        $self->_drop($id);

        # Idle connection
        return unless $old;

        # Extract cookies
        if (my $jar = $self->cookie_jar) { $jar->extract($old) }

        # Counter
        $self->{_processing} -= 1;

        # Redirect or callback
        $self->_tx_finish($new || $old, $c->{cb})
          unless $self->_redirect($c, $old);
    }

    # Cleanup
    $self->ioloop->stop if !$self->{_is_async} && !$self->{_processing};
}

sub _hup { shift->_handle(pop) }

# Have you ever seen that Blue Man Group? Total ripoff of the Smurfs.
# And the Smurfs, well, they SUCK.
sub _read {
    my ($self, $loop, $id, $chunk) = @_;

    # Debug
    warn "< $chunk\n" if DEBUG;

    # Connection
    return unless my $c = $self->{_cs}->{$id};

    # Transaction
    if (my $tx = $c->{tx}) {

        # Read
        $tx->client_read($chunk);

        # Finish
        if ($tx->is_done) { $self->_handle($id) }

        # Writing
        elsif ($c->{tx}->is_writing) { $self->_write($id) }

        return;
    }

    # Corrupted connection
    $self->_drop($id);
}

sub _redirect {
    my ($self, $c, $old) = @_;

    # Response
    my $res = $old->res;

    # Code
    return unless $res->is_status_class('300');
    return if $res->code == 305;

    # Location
    return unless my $location = $res->headers->location;

    # Method
    my $method = $old->req->method;
    $method = 'GET' unless $method =~ /^GET|HEAD$/i;

    # Max redirects
    my $r = $c->{redirects} || 0;
    my $max = $self->max_redirects;
    return unless $r < $max;

    # New transaction
    my $new = Mojo::Transaction::HTTP->new;
    my $req = $new->req;
    $req->method($method);
    $req->url->parse($location);
    $new->previous($old);

    # Start redirected request
    my $nid = $self->_tx_start($new, $c->{cb});

    # Create new connection
    $self->{_cs}->{$nid}->{redirects} = $r + 1;

    # Redirecting
    return 1;
}

# Oh, I'm in no condition to drive. Wait a minute.
# I don't have to listen to myself. I'm drunk.
sub _tx_finish {
    my ($self, $tx, $cb) = @_;

    # Response
    my $res = $tx->res;

    # 400/500
    $res->error($res->message, $res->code)
      if $res->is_status_class(400) || $res->is_status_class(500);

    # Callback
    return unless $cb;
    local $self->{tx} = $tx;
    $self->$cb($tx);
}

sub _tx_info {
    my ($self, $tx) = @_;

    # Request
    my $req = $tx->req;

    # URL
    my $url = $req->url;

    # Info
    my $scheme = $url->scheme || 'http';
    my $host   = $url->ihost;
    my $port   = $url->port;

    # Proxy info
    if (my $proxy = $req->proxy) {
        $scheme = $proxy->scheme;
        $host   = $proxy->ihost;
        $port   = $proxy->port;
    }

    # Default port
    $port ||= $scheme eq 'https' ? 443 : 80;

    return ($scheme, $host, $port);
}

sub _tx_queue_or_process {
    my ($self, $tx, $cb) = @_;

    # Quick process
    $self->process($tx, sub { $tx = $_[1] }) and return $tx
      if !$cb && !$self->{_is_async};

    # Queue transaction with callback
    $self->queue($tx, $cb);
}

# It's greeat! We can do *anything* now that Science has invented Magic.
sub _tx_start {
    my ($self, $tx, $cb) = @_;

    # Embedded server
    if ($self->app) {
        my $req = $tx->req;
        my $url = $req->url->to_abs;

        # Relative
        unless ($url->host) {
            $url->scheme('http');
            $url->host('localhost');
            $url->port($self->test_server);
            $req->url($url);
        }
    }

    # Request
    my $req = $tx->req;

    # Scheme
    my $scheme = $req->url->scheme || '';

    # Detect proxy
    $self->detect_proxy if $ENV{MOJO_PROXY};

    # HTTP proxy
    if (my $proxy = $self->http_proxy) {
        $req->proxy($proxy) if !$req->proxy && $scheme eq 'http';
    }

    # HTTPS proxy
    if (my $proxy = $self->https_proxy) {
        $req->proxy($proxy) if !$req->proxy && $scheme eq 'https';
    }

    # Make sure WebSocket requests have an origin header
    my $headers = $req->headers;
    $headers->origin($req->url)
      if $headers->upgrade && !$headers->origin;

    # We identify ourself
    $headers->user_agent('Mojolicious (Perl)') unless $headers->user_agent;

    # Inject cookies
    if (my $jar = $self->cookie_jar) { $jar->inject($tx) }

    # Connect
    return unless my $id = $self->_connect($tx, $cb);

    # Weaken
    weaken $self;

    # Resume callback
    $tx->resume_cb(sub { $self->_write($id) });

    # Counter
    $self->{_processing} ||= 0;
    $self->{_processing} += 1;

    return $id;
}

# Once the government approves something, it's no longer immoral!
sub _upgrade {
    my ($self, $id) = @_;

    # Connection
    my $c = $self->{_cs}->{$id};

    # Last transaction
    my $old = $c->{tx};

    # Request
    my $req = $old->req;

    # Headers
    my $headers = $req->headers;

    # No upgrade request
    return unless $headers->upgrade;

    # Response
    my $res = $old->res;

    # Handshake failed
    return unless ($res->code || '') eq '101';

    # Upgrade to WebSocket transaction
    my $new = Mojo::Transaction::WebSocket->new(handshake => $old);
    $new->kept_alive($old->kept_alive);

    # WebSocket challenge
    $res->error('WebSocket challenge failed.') and return
      unless $new->client_challenge;
    $c->{tx} = $new;

    # Upgrade connection timeout
    $self->ioloop->connection_timeout($id, $self->websocket_timeout);

    # Weaken
    weaken $self;

    # Resume callback
    $new->resume_cb(sub { $self->_write($id) });

    return $new;
}

# Oh well. At least we'll die doing what we love: inhaling molten rock.
sub _write {
    my ($self, $id) = @_;

    # Connection
    return unless my $c = $self->{_cs}->{$id};

    # Transaction
    return unless my $tx = $c->{tx};

    # Not writing
    return unless $tx->is_writing;

    # Chunk
    my $chunk = $c->{tx}->client_write;

    # Still writing
    my $cb;
    if ($tx->is_writing) {

        # Weaken
        weaken $self;

        $cb = sub { $self->_write($id) };
    }

    # Write
    $self->ioloop->write($id, $chunk, $cb);

    # Finish
    $self->_handle($id) if $tx->is_done;

    # Debug
    warn "> $chunk\n" if DEBUG;
}

1;
__END__

=head1 NAME

Mojo::Client - Async IO HTTP 1.1 And WebSocket Client

=head1 SYNOPSIS

    use Mojo::Client;
    my $client = Mojo::Client->new;

    # Grab the latest Mojolicious release :)
    my $latest = 'http://mojolicious.org/Mojolicious-latest.tar.gz';
    print $client->get($latest)->res->body;

    # Quick JSON request
    my $trends = 'http://search.twitter.com/trends.json';
    print $client->get($trends)->res->json->{trends}->[0]->{name};

    # Extract data from HTML and XML resources
    print $client->get('mojolicious.org')->res->dom->at('title')->text;

    # Scrape the latest headlines from a news site
    my $news = 'http://digg.com';
    $client->get($news)->res->dom->find("h3 > a.offsite")->each(sub {
        print shift->text . "\n";
    });

    # Form post with exception handling
    my $cpan   = 'http://search.cpan.org/search';
    my $search = {q => 'mojo'};
    my $tx     = $client->post_form($cpan => $search);
    if (my $res = $tx->success) { print $res->body }
    else {
        my ($message, $code) = $tx->error;
        print "Error: $message";
    }

    # Parallel requests
    my $callback = sub { print shift->res->body };
    $client->get('http://mojolicious.org' => $callback);
    $client->get('http://search.cpan.org' => $callback);
    $client->process;

    # Websocket request
    $client->websocket(
        'ws://websockets.org:8787' => sub {
            my $client = shift;
            $client->receive_message(
                sub {
                    my ($client, $message) = @_;
                    print "$message\n";
                    $client->finish;
                }
            );
            $client->send_message('hi there!');
        }
    )->process;

=head1 DESCRIPTION

L<Mojo::Client> is a full featured async io HTTP 1.1 and WebSocket client
with C<IPv6>, C<TLS>, C<epoll> and C<kqueue> support.

Optional modules L<IO::KQueue>, L<IO::Epoll>, L<IO::Socket::INET6> and
L<IO::Socket::SSL> are supported transparently and used if installed.

=head1 ATTRIBUTES

L<Mojo::Client> implements the following attributes.

=head2 C<app>

    my $app = $client->app;
    $client = $client->app(MyApp->new);

A Mojo application to associate this client with.
If set, local requests will be processed in this application.

=head2 C<cookie_jar>

    my $cookie_jar = $client->cookie_jar;
    $client        = $client->cookie_jar(Mojo::CookieJar->new);

Cookie jar to use for this clients requests, by default a L<Mojo::CookieJar>
object.

=head2 C<http_proxy>

    my $proxy = $client->http_proxy;
    $client   = $client->http_proxy('http://sri:secret@127.0.0.1:8080');

Proxy server to use for HTTP and WebSocket requests.

=head2 C<https_proxy>

    my $proxy = $client->https_proxy;
    $client   = $client->https_proxy('http://sri:secret@127.0.0.1:8080');

Proxy server to use for HTTPS and WebSocket requests.

=head2 C<ioloop>

    my $loop = $client->ioloop;
    $client  = $client->ioloop(Mojo::IOLoop->new);

Loop object to use for io operations, by default a L<Mojo::IOLoop> object
will be used.

=head2 C<keep_alive_timeout>

    my $keep_alive_timeout = $client->keep_alive_timeout;
    $client                = $client->keep_alive_timeout(15);

Timeout in seconds for keep alive between requests, defaults to C<15>.

=head2 C<log>

    my $log = $client->log;
    $client = $client->log(Mojo::Log->new);

A L<Mojo::Log> object used for logging, by default the application log will
be used.

=head2 C<max_keep_alive_connections>

    my $max_keep_alive_connections = $client->max_keep_alive_connections;
    $client                        = $client->max_keep_alive_connections(5);

Maximum number of keep alive connections that the client will retain before
it starts closing the oldest cached ones, defaults to C<5>.

=head2 C<max_redirects>

    my $max_redirects = $client->max_redirects;
    $client           = $client->max_redirects(3);

Maximum number of redirects the client will follow before it fails, defaults
to C<0>.

=head2 C<tls_ca_file>

    my $tls_ca_file = $client->tls_ca_file;
    $client         = $client->tls_ca_file('/etc/tls/cacerts.pem');

TLS certificate authority file to use, defaults to the C<MOJO_CA_FILE>
environment variable.
Note that L<IO::Socket::SSL> must be installed for HTTPS support.

=head2 C<tls_verify_cb>

    my $tls_verify_cb = $client->tls_verify_cb;
    $client           = $client->tls_verify_cb(sub {...});

Callback to verify your TLS connection, by default the client will accept
most certificates.
Note that L<IO::Socket::SSL> must be installed for HTTPS support.

=head2 C<tx>

    $client->tx;

The last finished transaction, only available from callbacks.

=head2 C<websocket_timeout>

    my $websocket_timeout = $client->websocket_timeout;
    $client               = $client->websocket_timeout(300);

Timeout in seconds for WebSockets to be idle, defaults to C<300>.

=head1 METHODS

L<Mojo::Client> inherits all methods from L<Mojo::Base> and implements the
following new ones.

=head2 C<new>

    my $client = Mojo::Client->new;

Construct a new L<Mojo::Client> object.
Use C<singleton> if you want to share keep alive connections with other
clients.

=head2 C<async>

    my $async = $client->async;

Clone client instance and start using the global shared L<Mojo::IOLoop>
singleton if it is running.
Note that all cloned clients have their own keep alive connection queue, so
you can quickly run out of file descriptors with too many active clients.

=head2 C<build_form_tx>

    my $tx = $client->build_form_tx('http://kraih.com/foo' => {test => 123});
    my $tx = $client->build_form_tx(
        'http://kraih.com/foo',
        'UTF-8',
        {test => 123}
    );
    my $tx = $client->build_form_tx(
        'http://kraih.com/foo',
        {test => 123},
        {Expect => 'fun'}
    );
    my $tx = $client->build_form_tx(
        'http://kraih.com/foo',
        'UTF-8',
        {test => 123},
        {Expect => 'fun'}
    );
    my $tx = $client->build_form_tx(
        'http://kraih.com/foo',
        {file => {file => '/foo/bar.txt'}}
    );
    my $tx = $client->build_form_tx(
        'http://kraih.com/foo',
        {file => {content => 'lalala'}}
    );
    my $tx = $client->build_form_tx(
        'http://kraih.com/foo',
        {myzip => {file => $asset, filename => 'foo.zip'}}
    );

Versatile transaction builder for forms.

    my $tx = $client->build_form_tx('http://kraih.com/foo' => {test => 123});
    $tx->res->body(sub { print $_[1] });
    $client->process($tx);

=head2 C<build_tx>

    my $tx = $client->build_tx(GET => 'mojolicious.org');
    my $tx = $client->build_tx(POST => 'http://mojolicious.org');
    my $tx = $client->build_tx(
        GET => 'http://kraih.com' => {Connection => 'close'}
    );
    my $tx = $client->build_tx(
        POST => 'http://kraih.com' => {Connection => 'close'} => 'Hi!'
    );

Versatile general purpose transaction builder.

    # Streaming response
    my $tx = $client->build_tx(GET => 'http://mojolicious.org');
    $tx->res->body(sub { print $_[1] });
    $client->process($tx);

    # Custom socket
    my $tx = $client->build_tx(GET => 'http://mojolicious.org');
    $tx->connection($socket);
    $client->process($tx);

=head2 C<build_websocket_tx>

    my $tx = $client->build_websocket_tx('ws://localhost:3000');

WebSocket transaction builder.

=head2 C<clone>

    my $clone = $client->clone;

Clone client the instance.
Note that all cloned clients have their own keep alive connection queue, so
you can quickly run out of file descriptors with too many active clients.

=head2 C<delete>

    my $tx  = $client->delete('http://kraih.com');
    my $tx  = $client->delete('http://kraih.com' => {Connection => 'close'});
    my $tx  = $client->delete(
        'http://kraih.com' => {Connection => 'close'} => 'Hi!'
    );
    $client = $client->delete('http://kraih.com' => sub {...});
    $client = $client->delete(
        'http://kraih.com' => {Connection => 'close'} => sub {...}
    );
    $client = $client->delete(
        'http://kraih.com' => {Connection => 'close'} => 'Hi!' => sub {...}
    );

Send a HTTP C<DELETE> request.

=head2 C<detect_proxy>

    $client = $client->detect_proxy;

Check environment variables for proxy information.

=head2 C<finish>

    $client->finish;

Finish the WebSocket connection, only available from callbacks.

=head2 C<finished>

    $client->finished(sub {...});

Callback signaling that peer finished the WebSocket connection, only
available from callbacks.

    $client->finished(sub {
        my $client = shift;
    });

=head2 C<get>

    my $tx  = $client->get('http://kraih.com');
    my $tx  = $client->get('http://kraih.com' => {Connection => 'close'});
    my $tx  = $client->get(
        'http://kraih.com' => {Connection => 'close'} => 'Hi!'
    );
    $client = $client->get('http://kraih.com' => sub {...});
    $client = $client->get(
        'http://kraih.com' => {Connection => 'close'} => sub {...}
    );
    $client = $client->get(
        'http://kraih.com' => {Connection => 'close'} => 'Hi!' => sub {...}
    );

Send a HTTP C<GET> request.

=head2 C<head>

    my $tx  = $client->head('http://kraih.com');
    my $tx  = $client->head('http://kraih.com' => {Connection => 'close'});
    my $tx  = $client->head(
        'http://kraih.com' => {Connection => 'close'} => 'Hi!'
    );
    $client = $client->head('http://kraih.com' => sub {...});
    $client = $client->head(
        'http://kraih.com' => {Connection => 'close'} => sub {...}
    );
    $client = $client->head(
        'http://kraih.com' => {Connection => 'close'} => 'Hi!' => sub {...}
    );

Send a HTTP C<HEAD> request.

=head2 C<post>

    my $tx  = $client->post('http://kraih.com');
    my $tx  = $client->post('http://kraih.com' => {Connection => 'close'});
    my $tx  = $client->post(
        'http://kraih.com' => {Connection => 'close'} => 'Hi!'
    );
    $client = $client->post('http://kraih.com' => sub {...});
    $client = $client->post(
        'http://kraih.com' => {Connection => 'close'} => sub {...}
    );
    $client = $client->post(
        'http://kraih.com',
        {Connection => 'close'},
        'message body',
        sub {...}
    );
    $client = $client->post(
        'http://kraih.com' => {Connection => 'close'} => 'Hi!' => sub {...}
    );

Send a HTTP C<POST> request.

=head2 C<post_form>

    my $tx  = $client->post_form('http://kraih.com/foo' => {test => 123});
    my $tx  = $client->post_form(
        'http://kraih.com/foo'
        'UTF-8',
        {test => 123}
    );
    my $tx  = $client->post_form(
        'http://kraih.com/foo',
        {test => 123},
        {Expect => 'fun'}
    );
    my $tx  = $client->post_form(
        'http://kraih.com/foo',
        'UTF-8',
        {test => 123},
        {Expect => 'fun'}
    );
    my $tx = $client->post_form(
        'http://kraih.com/foo',
        {file => {file => '/foo/bar.txt'}}
    );
    my $tx= $client->post_form(
        'http://kraih.com/foo',
        {file => {content => 'lalala'}}
    );
    my $tx = $client->post_form(
        'http://kraih.com/foo',
        {myzip => {file => $asset, filename => 'foo.zip'}}
    );
    $client = $client->post_form('/foo' => {test => 123}, sub {...});
    $client = $client->post_form(
        'http://kraih.com/foo',
        'UTF-8',
        {test => 123},
        sub {...}
    );
    $client = $client->post_form(
        'http://kraih.com/foo',
        {test => 123},
        {Expect => 'fun'},
        sub {...}
    );
    $client = $client->post_form(
        'http://kraih.com/foo',
        'UTF-8',
        {test => 123},
        {Expect => 'fun'},
        sub {...}
    );
    $client = $client->post_form(
        'http://kraih.com/foo',
        {file => {file => '/foo/bar.txt'}},
        sub {...}
    );
    $client = $client->post_form(
        'http://kraih.com/foo',
        {file => {content => 'lalala'}},
        sub {...}
    );
    $client = $client->post_form(
        'http://kraih.com/foo',
        {myzip => {file => $asset, filename => 'foo.zip'}},
        sub {...}
    );

Send a HTTP C<POST> request with form data.

=head2 C<process>

    $client = $client->process;
    $client = $client->process(@transactions);
    $client = $client->process(@transactions => sub {...});

Process all queued transactions.
Will be blocking unless you have a global shared ioloop and use the C<async>
method.

=head2 C<put>

    my $tx  = $client->put('http://kraih.com');
    my $tx  = $client->put('http://kraih.com' => {Connection => 'close'});
    my $tx  = $client->put(
        'http://kraih.com' => {Connection => 'close'} => 'Hi!'
    );
    $client = $client->put('http://kraih.com' => sub {...});
    $client = $client->put(
        'http://kraih.com' => {Connection => 'close'} => sub {...}
    );
    $client = $client->put(
        'http://kraih.com' => {Connection => 'close'} => 'Hi!' => sub {...}
    );

Send a HTTP C<PUT> request.

=head2 C<queue>

    $client = $client->queue(@transactions);
    $client = $client->queue(@transactions => sub {...});

Queue a list of transactions for processing.

=head2 C<receive_message>

    $client = $client->receive_message(sub {...});

Receive messages via WebSocket, only available from callbacks.

    $client->receive_message(sub {
        my ($client, $message) = @_;
    });

=head2 C<req>

    my $req = $client->req;

The request object of the last finished transaction, only available from
callbacks.

=head2 C<res>

    my $res = $client->res;

The response object of the last finished transaction, only available from
callbacks.

=head2 C<singleton>

    my $client = Mojo::Client->singleton;

The global client object, used to access a single shared client instance from
everywhere inside the process.

=head2 C<send_message>

    $client = $client->send_message('Hi there!');

Send a message via WebSocket, only available from callbacks.

=head2 C<test_server>

    my $port = $client->test_server;

Starts a test server for C<app> if neccessary and returns the port number.
Note that this method is EXPERIMENTAL and might change without warning!

=head2 C<websocket>

    $client = $client->websocket('ws://localhost:3000' => sub {...});
    $client = $client->websocket(
        'ws://localhost:3000' => {'User-Agent' => 'Agent 1.0'} => sub {...}
    );

Open a WebSocket connection with transparent handshake.

=head1 SEE ALSO

L<Mojolicious>, L<Mojolicious::Guides>, L<http://mojolicious.org>.

=cut