package Mojolicious::Plugin::DefaultHelpers;
use Mojo::Base 'Mojolicious::Plugin';

use Mojo::Asset::File;
use Mojo::ByteStream;
use Mojo::Collection;
use Mojo::Exception;
use Mojo::IOLoop;
use Mojo::Promise;
use Mojo::Util qw(dumper hmac_sha1_sum steady_time);
use Time::HiRes qw(gettimeofday tv_interval);
use Scalar::Util qw(blessed weaken);

sub register {
  my ($self, $app) = @_;

  # Controller alias helpers
  for my $name (qw(app param stash session url_for)) {
    $app->helper($name => sub { shift->$name(@_) });
  }

  # Stash key shortcuts (should not generate log messages)
  for my $name (qw(extends layout title)) {
    $app->helper($name => sub { shift->stash($name, @_) });
  }

  $app->helper(accepts => sub { $_[0]->app->renderer->accepts(@_) });
  $app->helper(b       => sub { shift; Mojo::ByteStream->new(@_) });
  $app->helper(c       => sub { shift; Mojo::Collection->new(@_) });
  $app->helper(config  => sub { shift->app->config(@_) });

  $app->helper(content      => sub { _content(0, 0, @_) });
  $app->helper(content_for  => sub { _content(1, 0, @_) });
  $app->helper(content_with => sub { _content(0, 1, @_) });

  $app->helper($_ => $self->can("_$_"))
    for qw(csrf_token current_route flash inactivity_timeout is_fresh), qw(redirect_to respond_to url_with validation);

  $app->helper(dumper  => sub { shift; dumper @_ });
  $app->helper(include => sub { shift->render_to_string(@_) });

  $app->helper(log => \&_log);

  $app->helper('proxy.get_p'   => sub { _proxy_method_p('GET',  @_) });
  $app->helper('proxy.post_p'  => sub { _proxy_method_p('POST', @_) });
  $app->helper('proxy.start_p' => \&_proxy_start_p);

  $app->helper("reply.$_" => $self->can("_$_")) for qw(asset file static);

  $app->helper('reply.exception' => sub { _development('exception', @_) });
  $app->helper('reply.not_found' => sub { _development('not_found', @_) });

  $app->helper('timing.begin'         => \&_timing_begin);
  $app->helper('timing.elapsed'       => \&_timing_elapsed);
  $app->helper('timing.rps'           => \&_timing_rps);
  $app->helper('timing.server_timing' => \&_timing_server_timing);

  $app->helper(ua => sub { shift->app->ua });
}

sub _asset {
  my $c = shift;
  $c->app->static->serve_asset($c, @_);
  $c->rendered;
}

sub _block { ref $_[0] eq 'CODE' ? $_[0]() : $_[0] }

sub _content {
  my ($append, $replace, $c, $name, $content) = @_;
  $name ||= 'content';

  my $hash = $c->stash->{'mojo.content'} //= {};
  if (defined $content) {
    if   ($append)  { $hash->{$name} .= _block($content) }
    if   ($replace) { $hash->{$name} = _block($content) }
    else            { $hash->{$name} //= _block($content) }
  }

  return Mojo::ByteStream->new($hash->{$name} // '');
}

sub _csrf_token { $_[0]->session->{csrf_token} ||= hmac_sha1_sum($$ . steady_time . rand, $_[0]->app->secrets->[0]) }

sub _current_route {
  return '' unless my $route = shift->match->endpoint;
  return @_ ? $route->name eq shift : $route->name;
}

sub _development {
  my ($page, $c, $e) = @_;

  $c->helpers->log->error(($e = _is_e($e) ? $e : Mojo::Exception->new($e))->inspect) if $page eq 'exception';

  # Filtered stash snapshot
  my $stash = $c->stash;
  %{$stash->{snapshot} = {}} = map { $_ => $stash->{$_} } grep { !/^mojo\./ and defined $stash->{$_} } keys %$stash;
  $stash->{exception} = $page eq 'exception' ? $e : undef;

  # Render with fallbacks
  my $app     = $c->app;
  my $mode    = $app->mode;
  my $options = {
    format   => $stash->{format} || $app->renderer->default_format,
    handler  => undef,
    status   => $page eq 'exception' ? 500 : 404,
    template => "$page.$mode"
  };
  my $bundled = 'mojo/' . ($mode eq 'development' ? 'debug' : $page);
  return $c if _fallbacks($c, $options, $page, $bundled);
  _fallbacks($c, {%$options, format => 'html'}, $page, $bundled);
  return $c;
}


sub _fallbacks {
  my ($c, $options, $template, $bundled) = @_;

  # Mode specific template
  return 1 if $c->render_maybe(%$options);

  # Normal template
  return 1 if $c->render_maybe(%$options, template => $template);

  # Inline template
  my $stash = $c->stash;
  return undef unless $options->{format} eq 'html';
  delete @$stash{qw(extends layout)};
  return $c->render_maybe($bundled, %$options, handler => 'ep');
}

sub _file { _asset(shift, Mojo::Asset::File->new(path => shift)) }

sub _flash {
  my $c = shift;

  # Check old flash
  my $session = $c->session;
  return $session->{flash} ? $session->{flash}{$_[0]} : undef if @_ == 1 && !ref $_[0];

  # Initialize new flash and merge values
  my $values = ref $_[0] ? $_[0] : {@_};
  @{$session->{new_flash} //= {}}{keys %$values} = values %$values;

  return $c;
}

sub _inactivity_timeout {
  my ($c, $timeout) = @_;
  my $stream = Mojo::IOLoop->stream($c->tx->connection // '');
  $stream->timeout($timeout) if $stream;
  return $c;
}

sub _is_e { blessed $_[0] && $_[0]->isa('Mojo::Exception') }

sub _is_fresh {
  my ($c, %options) = @_;
  return $c->app->static->is_fresh($c, \%options);
}

sub _log { $_[0]->stash->{'mojo.log'} ||= $_[0]->app->log->context('[' . $_[0]->req->request_id . ']') }

sub _proxy_method_p {
  my ($method, $c) = (shift, shift);
  return _proxy_start_p($c, $c->ua->build_tx($method, @_));
}

sub _proxy_start_p {
  my ($c, $source_tx) = @_;
  my $tx = $c->render_later->tx;

  my $promise = Mojo::Promise->new;
  $source_tx->res->content->auto_upgrade(0)->auto_decompress(0)->once(
    body => sub {
      my $source_content = shift;

      my $source_res = $source_tx->res;
      my $res        = $tx->res;
      my $content    = $res->content;
      $res->code($source_res->code)->message($source_res->message);
      my $headers = $source_res->headers->clone->dehop;
      $content->headers($headers);
      $promise->resolve;

      my $source_stream = Mojo::IOLoop->stream($source_tx->connection);
      return unless my $stream = Mojo::IOLoop->stream($tx->connection);

      my $write = $source_content->is_chunked ? 'write_chunk' : 'write';
      $source_content->unsubscribe('read')->on(
        read => sub {
          my $data = pop;
          $content->$write(length $data ? $data : ()) and $tx->resume;

          # Throttle transparently when backpressure rises
          return if $stream->can_write;
          $source_stream->stop;
          $stream->once(drain => sub { $source_stream->start });
        }
      );

      # Unknown length (fall back to connection close)
      $source_res->once(finish => sub { $content->$write('') and $tx->resume })
        unless length($headers->content_length // '');
    }
  );
  weaken $source_tx;
  $source_tx->once(finish => sub { $promise->reject(_tx_error(@_)) });

  $c->ua->start_p($source_tx)->catch(sub { });

  return $promise;
}

sub _redirect_to {
  my $c = shift;

  # Don't override 3xx status
  my $res = $c->res;
  $res->headers->location($c->url_for(@_));
  return $c->rendered($res->is_redirect ? () : 302);
}

sub _respond_to {
  my ($c, $args) = (shift, ref $_[0] ? $_[0] : {@_});

  # Find target
  my $target;
  my $renderer = $c->app->renderer;
  my @formats  = @{$renderer->accepts($c)};
  for my $format (@formats ? @formats : ($renderer->default_format)) {
    next unless $target = $args->{$format};
    $c->stash->{format} = $format;
    last;
  }

  # Fallback
  unless ($target) {
    return $c->rendered(204) unless $target = $args->{any};
    delete $c->stash->{format};
  }

  # Dispatch
  ref $target eq 'CODE' ? $target->($c) : $c->render(%$target);

  return $c;
}

sub _static {
  my ($c, $file) = @_;
  return !!$c->rendered if $c->app->static->serve($c, $file);
  $c->helpers->log->debug(qq{Static file "$file" not found});
  return !$c->helpers->reply->not_found;
}

sub _timing_begin { shift->stash->{'mojo.timing'}{shift()} = [gettimeofday] }

sub _timing_elapsed {
  my ($c, $name) = @_;
  return undef unless my $started = $c->stash->{'mojo.timing'}{$name};
  return tv_interval($started, [gettimeofday()]);
}

sub _timing_rps { $_[1] == 0 ? undef : sprintf '%.3f', 1 / $_[1] }

sub _timing_server_timing {
  my ($c, $metric, $desc, $dur) = @_;
  my $value = $metric;
  $value .= qq{;desc="$desc"} if defined $desc;
  $value .= ";dur=$dur"       if defined $dur;
  $c->res->headers->append('Server-Timing' => $value);
}

sub _tx_error { (shift->error // {})->{message} // 'Unknown error' }

sub _url_with {
  my $c = shift;
  return $c->url_for(@_)->query($c->req->url->query->clone);
}

sub _validation {
  my $c = shift;

  my $stash = $c->stash;
  return $stash->{'mojo.validation'} if $stash->{'mojo.validation'};

  my $req    = $c->req;
  my $token  = $c->session->{csrf_token};
  my $header = $req->headers->header('X-CSRF-Token');
  my $hash   = $req->params->to_hash;
  $hash->{csrf_token} //= $header if $token && $header;
  $hash->{$_} = $req->every_upload($_) for map { $_->name } @{$req->uploads};
  my $v = $c->app->validator->validation->input($hash);
  return $stash->{'mojo.validation'} = $v->csrf_token($token);
}

1;

=encoding utf8

=head1 NAME

Mojolicious::Plugin::DefaultHelpers - Default helpers plugin

=head1 SYNOPSIS

  # Mojolicious
  $app->plugin('DefaultHelpers');

  # Mojolicious::Lite
  plugin 'DefaultHelpers';

=head1 DESCRIPTION

L<Mojolicious::Plugin::DefaultHelpers> is a collection of helpers for L<Mojolicious>.

This is a core plugin, that means it is always enabled and its code a good example for learning to build new plugins,
you're welcome to fork it.

See L<Mojolicious::Plugins/"PLUGINS"> for a list of plugins that are available by default.

=head1 HELPERS

L<Mojolicious::Plugin::DefaultHelpers> implements the following helpers.

=head2 accepts

  my $formats = $c->accepts;
  my $format  = $c->accepts('html', 'json', 'txt');

Select best possible representation for resource from C<format> C<GET>/C<POST> parameter, C<format> stash value or
C<Accept> request header with L<Mojolicious::Renderer/"accepts">, defaults to returning the first extension if no
preference could be detected.

  # Check if JSON is acceptable
  $c->render(json => {hello => 'world'}) if $c->accepts('json');

  # Check if JSON was specifically requested
  $c->render(json => {hello => 'world'}) if $c->accepts('', 'json');

  # Unsupported representation
  $c->render(data => '', status => 204)
    unless my $format = $c->accepts('html', 'json');

  # Detected representations to select from
  my @formats = @{$c->accepts};

=head2 app

  %= app->secrets->[0]

Alias for L<Mojolicious::Controller/"app">.

=head2 b

  %= b('Joel is a slug')->slugify

Turn string into a L<Mojo::ByteStream> object.

=head2 c

  %= c('a', 'b', 'c')->shuffle->join

Turn list into a L<Mojo::Collection> object.

=head2 config

  %= config 'something'

Alias for L<Mojolicious/"config">.

=head2 content

  %= content foo => begin
    test
  % end
  %= content bar => 'Hello World!'
  %= content 'foo'
  %= content 'bar'
  %= content

Store partial rendered content in a named buffer and retrieve it later, defaults to retrieving the named buffer
C<content>, which is used by the renderer for the C<layout> and C<extends> features. New content will be ignored if the
named buffer is already in use.

=head2 content_for

  % content_for foo => begin
    test
  % end
  %= content_for 'foo'

Same as L</"content">, but appends content to named buffers if they are already in use.

  % content_for message => begin
    Hello
  % end
  % content_for message => begin
    world!
  % end
  %= content 'message'

=head2 content_with

  % content_with foo => begin
    test
  % end
  %= content_with 'foo'

Same as L</"content">, but replaces content of named buffers if they are already in use.

  % content message => begin
    world!
  % end
  % content_with message => begin
    Hello <%= content 'message' %>
  % end
  %= content 'message'

=head2 csrf_token

  %= csrf_token

Get CSRF token from L</"session">, and generate one if none exists.

=head2 current_route

  % if (current_route 'login') {
    Welcome to Mojolicious!
  % }
  %= current_route

Check or get name of current route.

=head2 dumper

  %= dumper {some => 'data'}

Dump a Perl data structure with L<Mojo::Util/"dumper">, very useful for debugging.

=head2 extends

  % extends 'blue';
  % extends 'blue', title => 'Blue!';

Set C<extends> stash value, all additional key/value pairs get merged into the L</"stash">.

=head2 flash

  my $foo = $c->flash('foo');
  $c      = $c->flash({foo => 'bar'});
  $c      = $c->flash(foo => 'bar');
  %= flash 'foo'

Data storage persistent only for the next request, stored in the L</"session">.

  # Show message after redirect
  $c->flash(message => 'User created successfully!');
  $c->redirect_to('show_user', id => 23);

=head2 inactivity_timeout

  $c = $c->inactivity_timeout(3600);

Use L<Mojo::IOLoop/"stream"> to find the current connection and increase timeout if possible.

  # Longer version
  Mojo::IOLoop->stream($c->tx->connection)->timeout(3600);

=head2 include

  %= include 'menubar'
  %= include 'menubar', format => 'txt'

Alias for L<Mojolicious::Controller/"render_to_string">.

=head2 is_fresh

  my $bool = $c->is_fresh;
  my $bool = $c->is_fresh(etag => 'abc');
  my $bool = $c->is_fresh(etag => 'W/"def"');
  my $bool = $c->is_fresh(last_modified => $epoch);

Check freshness of request by comparing the C<If-None-Match> and C<If-Modified-Since> request headers to the C<ETag>
and C<Last-Modified> response headers with L<Mojolicious::Static/"is_fresh">.

  # Add ETag/Last-Modified headers and check freshness before rendering
  $c->is_fresh(etag => 'abc', last_modified => 1424985708)
    ? $c->rendered(304)
    : $c->render(text => 'I ♥ Mojolicious!');

=head2 layout

  % layout 'green';
  % layout 'green', title => 'Green!';

Set C<layout> stash value, all additional key/value pairs get merged into the L</"stash">.

=head2 log

  my $log = $c->log;

Alternative to L<Mojolicious/"log"> that includes L<Mojo::Message::Request/"request_id"> with every log message.

  # Log message with context
  $c->log->debug('This is a log message with request id');

  # Pass logger with context to model
  my $log = $c->log;
  $c->some_model->create({foo => $foo}, $log);

=head2 param

  %= param 'foo'

Alias for L<Mojolicious::Controller/"param">.

=head2 proxy->get_p

  my $promise = $c->proxy->get_p('http://example.com' => {Accept => '*/*'});

Perform non-blocking C<GET> request and forward response as efficiently as possible, takes the same arguments as
L<Mojo::UserAgent/"get"> and returns a L<Mojo::Promise> object.

  # Forward with exception handling
  $c->proxy->get_p('http://mojolicious.org')->catch(sub ($err) {
    $c->log->debug("Proxy error: $err");
    $c->render(text => 'Something went wrong!', status => 400);
  });

=head2 proxy->post_p

  my $promise = $c->proxy->post_p('http://example.com' => {Accept => '*/*'});

Perform non-blocking C<POST> request and forward response as efficiently as possible, takes the same arguments as
L<Mojo::UserAgent/"post"> and returns a L<Mojo::Promise> object.

  # Forward with exception handling
  $c->proxy->post_p('example.com' => form => {test => 'pass'})->catch(sub ($err) {
    $c->log->debug("Proxy error: $err");
    $c->render(text => 'Something went wrong!', status => 400);
  });

=head2 proxy->start_p

  my $promise = $c->proxy->start_p(Mojo::Transaction::HTTP->new);

Perform non-blocking request for a custom L<Mojo::Transaction::HTTP> object and forward response as efficiently as
possible, returns a L<Mojo::Promise> object.

  # Forward with exception handling
  my $tx = $c->ua->build_tx(GET => 'http://mojolicious.org');
  $c->proxy->start_p($tx)->catch(sub ($err) {
    $c->log->debug("Proxy error: $err");
    $c->render(text => 'Something went wrong!', status => 400);
  });

  # Forward with custom request and response headers
  my $headers = $c->req->headers->clone->dehop;
  $headers->header('X-Proxy' => 'Mojo');
  my $tx = $c->ua->build_tx(GET => 'http://example.com' => $headers->to_hash);
  $c->proxy->start_p($tx);
  $tx->res->content->once(body => sub ($content) { $c->res->headers->header('X-Proxy' => 'Mojo') });

=head2 redirect_to

  $c = $c->redirect_to('named', foo => 'bar');
  $c = $c->redirect_to('named', {foo => 'bar'});
  $c = $c->redirect_to('/index.html');
  $c = $c->redirect_to('http://example.com/index.html');

Prepare a C<302> (if the status code is not already C<3xx>) redirect response with C<Location> header, takes the same
arguments as L</"url_for">.

  # Moved Permanently
  $c->res->code(301);
  $c->redirect_to('some_route');

  # Temporary Redirect
  $c->res->code(307);
  $c->redirect_to('some_route');

=head2 reply->asset

  $c->reply->asset(Mojo::Asset::File->new);

Reply with a L<Mojo::Asset::File> or L<Mojo::Asset::Memory> object using L<Mojolicious::Static/"serve_asset">, and
perform content negotiation with C<Range>, C<If-Modified-Since> and C<If-None-Match> headers.

  # Serve asset with custom modification time
  my $asset = Mojo::Asset::Memory->new;
  $asset->add_chunk('Hello World!')->mtime(784111777);
  $c->res->headers->content_type('text/plain');
  $c->reply->asset($asset);

  # Serve static file if it exists
  if (my $asset = $c->app->static->file('images/logo.png')) {
    $c->res->headers->content_type('image/png');
    $c->reply->asset($asset);
  }

=head2 reply->exception

  $c = $c->reply->exception('Oops!');
  $c = $c->reply->exception(Mojo::Exception->new);

Render the exception template C<exception.$mode.$format.*> or C<exception.$format.*> and set the response status code
to C<500>. Also sets the stash values C<exception> to a L<Mojo::Exception> object and C<snapshot> to a copy of the
L</"stash"> for use in the templates.

=head2 reply->file

  $c->reply->file('/etc/passwd');

Reply with a static file from an absolute path anywhere on the file system using L<Mojolicious/"static">.

  # Longer version
  $c->reply->asset(Mojo::Asset::File->new(path => '/etc/passwd'));

  # Serve file from an absolute path with a custom content type
  $c->res->headers->content_type('application/myapp');
  $c->reply->file('/home/sri/foo.txt');

  # Serve file from a secret application directory
  $c->reply->file($c->app->home->child('secret', 'file.txt'));

=head2 reply->not_found

  $c = $c->reply->not_found;

Render the not found template C<not_found.$mode.$format.*> or C<not_found.$format.*> and set the response status code
to C<404>. Also sets the stash value C<snapshot> to a copy of the L</"stash"> for use in the templates.

=head2 reply->static

  my $bool = $c->reply->static('images/logo.png');
  my $bool = $c->reply->static('../lib/MyApp.pm');

Reply with a static file using L<Mojolicious/"static">, usually from the C<public> directories or C<DATA> sections of
your application. Note that this helper uses a relative path, but does not protect from traversing to parent
directories.

  # Serve file from a relative path with a custom content type
  $c->res->headers->content_type('application/myapp');
  $c->reply->static('foo.txt');

=head2 respond_to

  $c = $c->respond_to(
    json => {json => {message => 'Welcome!'}},
    html => {template => 'welcome'},
    any  => sub {...}
  );

Automatically select best possible representation for resource from C<format> C<GET>/C<POST> parameter, C<format> stash
value or C<Accept> request header, defaults to L<Mojolicious::Renderer/"default_format"> or rendering an empty C<204>
response. Each representation can be handled with a callback or a hash reference containing arguments to be passed to
L<Mojolicious::Controller/"render">.

  # Everything else than "json" and "xml" gets a 204 response
  $c->respond_to(
    json => sub { $c->render(json => {just => 'works'}) },
    xml  => {text => '<just>works</just>'},
    any  => {data => '', status => 204}
  );

For more advanced negotiation logic you can also use L</"accepts">.

=head2 session

  %= session 'foo'

Alias for L<Mojolicious::Controller/"session">.

=head2 stash

  %= stash 'foo'
  % stash foo => 'bar';

Alias for L<Mojolicious::Controller/"stash">.

  %= stash('name') // 'Somebody'

=head2 timing->begin

  $c->timing->begin('foo');

Create named timestamp for L<"timing-E<gt>elapsed">.

=head2 timing->elapsed

  my $elapsed = $c->timing->elapsed('foo');

Return fractional amount of time in seconds since named timstamp has been created with L</"timing-E<gt>begin"> or
C<undef> if no such timestamp exists.

  # Log timing information
  $c->timing->begin('database_stuff');
  ...
  my $elapsed = $c->timing->elapsed('database_stuff');
  $c->app->log->debug("Database stuff took $elapsed seconds");

=head2 timing->rps

  my $rps = $c->timing->rps('0.001');

Return fractional number of requests that could be performed in one second if every singe one took the given amount of
time in seconds or C<undef> if the number is too low.

  # Log more timing information
  $c->timing->begin('web_stuff');
  ...
  my $elapsed = $c->timing->elapsed('web_stuff');
  my $rps     = $c->timing->rps($elapsed);
  $c->app->log->debug("Web stuff took $elapsed seconds ($rps per second)");

=head2 timing->server_timing

  $c->timing->server_timing('metric');
  $c->timing->server_timing('metric', 'Some Description');
  $c->timing->server_timing('metric', 'Some Description', '0.001');

Create C<Server-Timing> header with optional description and duration.

  # "Server-Timing: miss"
  $c->timing->server_timing('miss');

  # "Server-Timing: dc;desc=atl"
  $c->timing->server_timing('dc', 'atl');

  # "Server-Timing: db;desc=Database;dur=0.0001"
  $c->timing->begin('database_stuff');
  ...
  my $elapsed = $c->timing->elapsed('database_stuff');
  $c->timing->server_timing('db', 'Database', $elapsed);

  # "Server-Timing: miss, dc;desc=atl"
  $c->timing->server_timing('miss');
  $c->timing->server_timing('dc', 'atl');

=head2 title

  %= title
  % title 'Welcome!';
  % title 'Welcome!', foo => 'bar';

Get or set C<title> stash value, all additional key/value pairs get merged into the L</"stash">.

=head2 ua

  %= ua->get('mojolicious.org')->result->dom->at('title')->text

Alias for L<Mojolicious/"ua">.

=head2 url_for

  %= url_for 'named', controller => 'bar', action => 'baz'

Alias for L<Mojolicious::Controller/"url_for">.

  %= url_for('/index.html')->query(foo => 'bar')

=head2 url_with

  %= url_with 'named', controller => 'bar', action => 'baz'

Does the same as L</"url_for">, but inherits query parameters from the current request.

  %= url_with->query({page => 2})

=head2 validation

  my $v = $c->validation;

Get L<Mojolicious::Validator::Validation> object for current request to validate file uploads as well as C<GET> and
C<POST> parameters extracted from the query string and C<application/x-www-form-urlencoded> or C<multipart/form-data>
message body. Parts of the request body need to be loaded into memory to parse C<POST> parameters, so you have to make
sure it is not excessively large. There's a 16MiB limit for requests by default.

  # Validate GET/POST parameter
  my $v = $c->validation;
  $v->required('title', 'trim')->size(3, 50);
  my $title = $v->param('title');

  # Validate file upload
  my $v = $c->validation;
  $v->required('tarball')->upload->size(1, 1048576);
  my $tarball = $v->param('tarball');

=head1 METHODS

L<Mojolicious::Plugin::DefaultHelpers> inherits all methods from L<Mojolicious::Plugin> and implements the following
new ones.

=head2 register

  $plugin->register(Mojolicious->new);

Register helpers in L<Mojolicious> application.

=head1 SEE ALSO

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

=cut
