package Future::HTTP;
use strict;
use Filter::signatures;
no warnings 'experimental::signatures';
use feature 'signatures';
 
our $VERSION = '0.12';
 
our @loops;
push @loops, (
    ['IO/Async.pm'    => 'Future::HTTP::NetAsync' ],
    ['Mojo/IOLoop.pm' => 'Future::HTTP::Mojo' ],
    ['AnyEvent.pm'    => 'Future::HTTP::AnyEvent'],
    ['AE.pm'          => 'Future::HTTP::AnyEvent'],
    # POE support would be nice
    # LWP::UserAgent support would be nice
 
    # A threaded backend would also be nice but likely brings in other
    # interesting problems. How will we load this? We have two prerequisites
    # now, threads.pm and HTTP::Tiny...
    #['threads.pm' => 'Future::HTTP::Tiny::threaded' ],
 
    ['HTTP/Tiny/Paranoid.pm' => 'Future::HTTP::Tiny::Paranoid'],
 
    # The fallback, will always catch due to loading Future::HTTP
    ['Future/HTTP.pm' => 'Future::HTTP::Tiny'],
);
our $implementation;
 
sub new($factoryclass, @args) {
    $implementation ||= $factoryclass->best_implementation();
 
    # return a new instance
    $implementation->new(@args);
}
 
sub best_implementation( $class, @candidates ) {
 
    if(! @candidates) {
        @candidates = @loops;
    };
 
    # Find the currently running/loaded event loop(s)
    #use Data::Dumper;
    #warn Dumper \%INC;
    #warn Dumper \@candidates;
    my @applicable_implementations = map {
        $_->[1]
    } grep {
        $INC{$_->[0]}
    } @candidates;
 
    # Check which one we can load:
    for my $impl (@applicable_implementations) {
        if( eval "require $impl; 1" ) {
            return $impl;
        };
    };
};