use v5.10;
use strict;
use warnings;

use Test2::V0 0.000148; # is_refcount

use Future;

my $__dummy; # to defeat non-closure optimsation

{
   my $f1 = Future->new;

   my $cb;
   my $called = 0;
   my $fseq = $f1->followed_by( $cb = sub {
      $called++;
      ref_is( $_[0], $f1, 'followed_by block passed $f1' );
      return $_[0];
   } );

   ok( defined $fseq, '$fseq defined' );
   isa_ok( $fseq, [ "Future" ], '$fseq' );

   is_oneref( $fseq, '$fseq has refcount 1 initially' );
   # Two refs; one in lexical $f1, one in $fseq's cancellation closure
   is_refcount( $f1, 2, '$f1 has refcount 2 initially' );
   # We're looking for *at least* two refs; PP has 2, XS has 3
   # TODO: This'll be a lot nicer with https://github.com/Test-More/Test2-Suite/issues/259
   ok( refcount( $cb ) > 1, '$cb has refcount > 1 captured by followed_by callback' );

   is( $called, 0, '$called before $f1 done' );

   $f1->done( results => "here" );

   is( $called, 1, '$called after $f1 done' );

   ok( $fseq->is_ready, '$fseq is done after $f1 done' );
   is( [ $fseq->result ], [ results => "here" ], '$fseq->result returns results' );

   is_oneref( $fseq, '$fseq has refcount 1 before EOF' );
   is_oneref( $f1, '$f1 has refcount 1 before EOF' );
   is_oneref( $cb, '$cb has refcount 1 before EOF' );
}

{
   my $f1 = Future->new;

   my $called = 0;
   my $fseq = $f1->followed_by( sub {
      $called++;
      ref_is( $_[0], $f1, 'followed_by block passed $f1' );
      return $_[0];
   } );

   ok( defined $fseq, '$fseq defined' );
   isa_ok( $fseq, [ "Future" ], '$fseq' );

   is_oneref( $fseq, '$fseq has refcount 1 initially' );

   is( $called, 0, '$called before $f1 done' );

   $f1->fail( "failure\n" );

   is( $called, 1, '$called after $f1 failed' );

   ok( $fseq->is_ready, '$fseq is ready after $f1 failed' );
   is( [ $fseq->failure ], [ "failure\n" ], '$fseq->failure returns failure' );

   is_oneref( $fseq, '$fseq has refcount 1 before EOF' );
}

# code dies
{
   my $f1 = Future->new;

   my $fseq = $f1->followed_by( sub {
      die "It fails\n";
   } );

   ok( lives { $f1->done }, 'exception not propagated from code call' );

   ok( $fseq->is_ready, '$fseq is ready after code exception' );
   is( scalar $fseq->failure, "It fails\n", '$fseq->failure after code exception' );
}

# Cancellation
{
   my $f1 = Future->new;

   my $fseq = $f1->followed_by(
      sub { die "followed_by of cancelled future should not be invoked" }
   );

   $fseq->cancel;

   ok( $f1->is_cancelled, '$f1 cancelled by $fseq->cancel' );

   $f1 = Future->new;
   my $f2 = Future->new;

   $fseq = $f1->followed_by( sub { $f2 } );

   $f1->done;
   $fseq->cancel;

   ok( $f2->is_cancelled, '$f2 cancelled by $fseq->cancel' );

   $f1 = Future->done;
   $f2 = Future->new;

   $fseq = $f1->followed_by( sub { $f2 } );

   $fseq->cancel;

   ok( $f2->is_cancelled, '$f2 cancelled by $fseq->cancel on $f1 immediate' );
}

# immediately done
{
   my $f1 = Future->done;

   my $cb;
   my $called = 0;
   my $fseq = $f1->followed_by(
      $cb = sub { $called++; return $_[0] }
   );

   is( $called, 1, 'followed_by block invoked immediately for already-done' );
   is_oneref( $cb, '$cb has refcount 1 before EOF' );
}

# immediately done
{
   my $f1 = Future->fail("Failure\n");

   my $called = 0;
   my $fseq = $f1->followed_by(
      sub { $called++; return $_[0] }
   );

   is( $called, 1, 'followed_by block invoked immediately for already-failed' );
}

# immediately code dies
{
   my $f1 = Future->done;

   my $fseq;

   ok( lives {
      $fseq = $f1->followed_by( sub {
         die "It fails\n";
      } );
   }, 'exception not propagated from ->followed_by on immediate' );

   ok( $fseq->is_ready, '$fseq is ready after code exception on immediate' );
   is( scalar $fseq->failure, "It fails\n", '$fseq->failure after code exception on immediate' );
}

# Non-future return is upgraded
{
   my $f1 = Future->new;

   my $fseq = $f1->followed_by( sub { "result" } );
   my $fseq2 = $f1->followed_by( sub { Future->done } );

   ok( lives { $f1->done },
       '->done with non-future return from ->followed_by does not die' );

   is( scalar $fseq->result, "result",
       'non-future return from ->followed_by is upgraded' );

   ok( $fseq2->is_ready, '$fseq2 is ready after failure of $fseq' );

   my $fseq3;
   ok( lives { $fseq3 = $f1->followed_by( sub { "result" } ) },
      'non-future return from ->followed_by on immediate does not die' );

   is( scalar $fseq3->result, "result",
       'non-future return from ->followed_by on immediate is upgraded' );
}

# Void context raises a warning
{
   my $warnings;
   local $SIG{__WARN__} = sub { $warnings .= $_[0]; };

   Future->done->followed_by(
      sub { Future->new }
   );

   like( $warnings,
         qr/^Calling ->followed_by in void context at /,
         'Warning in void context' );
}

done_testing;