# File: Commands.pm
#
# Author: pragma_
#
# Purpose: Registers commands. Invokes commands with user capability
# validation.

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

package PBot::Commands;

use warnings;
use strict;

use feature 'unicode_strings';

use base 'PBot::Registerable';

use Carp ();
use PBot::HashObject;
use Time::Duration qw/duration/;

sub new {
  Carp::croak("Options to " . __FILE__ . " should be key/value pairs, not hash reference") if ref($_[1]) eq 'HASH';
  my ($class, %conf) = @_;
  my $self = bless {}, $class;
  $self->initialize(%conf);
  return $self;
}

sub initialize {
  my ($self, %conf) = @_;
  $self->SUPER::initialize(%conf);
  $self->{pbot} = $conf{pbot} // Carp::croak("Missing pbot reference to " . __FILE__);

  $self->{metadata} = PBot::HashObject->new(pbot => $self->{pbot}, name => 'Commands', filename => $conf{filename});
  $self->load_metadata;

  $self->register(sub { $self->cmdset(@_)     },  "cmdset",    1);
  $self->register(sub { $self->cmdunset(@_)   },  "cmdunset",  1);
  $self->register(sub { $self->help(@_)       },  "help",      0);
  $self->register(sub { $self->uptime(@_)     },  "uptime",    0);
  $self->register(sub { $self->in_channel(@_) },  "in",        1);
}

sub register {
  my ($self, $subref, $name, $requires_cap) = @_;

  if (not defined $subref or not defined $name) {
    Carp::croak("Missing parameters to Commands::register");
  }

  my $ref = $self->SUPER::register($subref);
  $ref->{name} = lc $name;
  $ref->{requires_cap} = $requires_cap // 0;

  if (not $self->{metadata}->exists($name)) {
    $self->{metadata}->add($name, { requires_cap => $requires_cap, help => '' }, 1);
  } else {
    if (not defined $self->get_meta($name, 'requires_cap')) {
      $self->{metadata}->set($name, 'requires_cap', $requires_cap, 1);
    }
  }

  # add can-cmd capability
  $self->{pbot}->{capabilities}->add("can-$name", undef, 1);

  return $ref;
}

sub unregister {
  my ($self, $name) = @_;
  Carp::croak("Missing name parameter to Commands::unregister") if not defined $name;
  $name = lc $name;
  @{ $self->{handlers} } = grep { $_->{name} ne $name } @{ $self->{handlers} };
}

sub exists {
  my ($self, $keyword) = @_;
  $keyword = lc $keyword;
  foreach my $ref (@{ $self->{handlers} }) {
    return 1 if $ref->{name} eq $keyword;
  }
  return 0;
}

sub interpreter {
  my ($self, $stuff) = @_;
  my $result;

  if ($self->{pbot}->{registry}->get_value('general', 'debugcontext')) {
    use Data::Dumper;
    $Data::Dumper::Sortkeys  = 1;
    $self->{pbot}->{logger}->log("Commands::interpreter\n");
    $self->{pbot}->{logger}->log(Dumper $stuff);
  }

  my $keyword = lc $stuff->{keyword};
  my $from = $stuff->{from};

  my ($cmd_channel) = $stuff->{arguments} =~ m/\B(#[^ ]+)/; # assume command is invoked in regards to first channel-like argument
  $cmd_channel = $from if not defined $cmd_channel;         # otherwise command is invoked in regards to the channel the user is in
  my $user = $self->{pbot}->{users}->loggedin($cmd_channel, "$stuff->{nick}!$stuff->{user}\@$stuff->{host}");

  my $cap_override;
  if (exists $stuff->{'cap-override'}) {
    $self->{pbot}->{logger}->log("Override cap to $stuff->{'cap-override'}\n");
    $cap_override = $stuff->{'cap-override'};
  }

  foreach my $ref (@{ $self->{handlers} }) {
    if ($ref->{name} eq $keyword) {
      my $requires_cap = $self->get_meta($keyword, 'requires_cap') // $ref->{requires_cap};
      if ($requires_cap) {
        if (defined $cap_override) {
          if (not $self->{pbot}->{capabilities}->has($cap_override, "can-$keyword")) {
            return "/msg $stuff->{nick} The $keyword command requires the can-$keyword capability, which cap-override $cap_override does not have.";
          }
        } else {
          if (not defined $user) {
            return "/msg $stuff->{nick} You must be logged into your user account to use $keyword.";
          }

          if (not $self->{pbot}->{capabilities}->userhas($user, "can-$keyword")) {
            return "/msg $stuff->{nick} The $keyword command requires the can-$keyword capability, which your user account does not have.";
          }
        }
      }

      $stuff->{no_nickoverride} = 1;
      my $result = &{ $ref->{subref} }($stuff->{from}, $stuff->{nick}, $stuff->{user}, $stuff->{host}, $stuff->{arguments}, $stuff);
      return undef if $stuff->{referenced} and $result =~ m/(?:usage:|no results)/i;
      return $result;
    }
  }
  return undef;
}

sub set_meta {
  my ($self, $command, $key, $value, $save) = @_;
  $command = lc $command;
  return undef if not exists $self->{metadata}->{hash}->{$command};
  $self->{metadata}->{hash}->{$command}->{$key} = $value;
  $self->save_metadata if $save;
  return 1;
}

sub get_meta {
  my ($self, $command, $key) = @_;
  $command = lc $command;
  return undef if not exists $self->{metadata}->{hash}->{$command};
  return $self->{metadata}->{hash}->{$command}->{$key};
}

sub load_metadata {
  my ($self) = @_;
  $self->{metadata}->load;
}

sub save_metadata {
  my ($self) = @_;
  $self->{metadata}->save;
}

sub cmdset {
  my ($self, $from, $nick, $user, $host, $arguments, $stuff) = @_;
  my ($command, $key, $value) = $self->{pbot}->{interpreter}->split_args($stuff->{arglist}, 3);
  return "Usage: cmdset <command> [key [value]]" if not defined $command;
  return $self->{metadata}->set($command, $key, $value);
}

sub cmdunset {
  my ($self, $from, $nick, $user, $host, $arguments, $stuff) = @_;
  my ($command, $key) = $self->{pbot}->{interpreter}->split_args($stuff->{arglist}, 2);
  return "Usage: cmdunset <command> <key>" if not defined $command or not defined $key;
  return $self->{metadata}->unset($command, $key);
}

sub help {
  my ($self, $from, $nick, $user, $host, $arguments, $stuff) = @_;

  if (not length $arguments) {
    return "For general help, see <https://github.com/pragma-/pbot/tree/master/doc>. For help about a specific command or factoid, use `help <keyword> [channel]`.";
  }

  my $keyword = lc $self->{pbot}->{interpreter}->shift_arg($stuff->{arglist});

  # check built-in commands first
  if ($self->exists($keyword)) {
    if (exists $self->{metadata}->{hash}->{$keyword}) {
      my $name = $self->{metadata}->{hash}->{$keyword}->{_name};
      my $requires_cap = $self->{metadata}->{hash}->{$keyword}->{requires_cap};
      my $help = $self->{metadata}->{hash}->{$keyword}->{help};
      my $result = "/say $name: ";

      if ($requires_cap) {
        $result .= "[Requires can-$keyword] ";
      }

      if (not defined $help or not length $help) {
        $result .= "I have no help for this command yet.";
      } else {
        $result .= $help;
      }
      return $result;
    }
    return "$keyword is a built-in command, but I have no help for it yet.";
  }

  # then factoids
  my $channel_arg = $self->{pbot}->{interpreter}->shift_arg($stuff->{arglist});
  $channel_arg = $from if not defined $channel_arg or not length $channel_arg;
  $channel_arg = '.*' if $channel_arg !~ m/^#/;

  my @factoids = $self->{pbot}->{factoids}->find_factoid($channel_arg, $keyword, exact_trigger => 1);

  if (not @factoids or not $factoids[0]) {
    return "I don't know anything about $keyword.";
  }

  my ($channel, $trigger);

  if (@factoids > 1) {
    if (not grep { $_->[0] eq $channel_arg } @factoids) {
      return "/say $keyword found in multiple channels: " . (join ', ', sort map { $_->[0] eq '.*' ? 'global' : $_->[0] } @factoids) . "; use `help $keyword <channel>` to disambiguate.";
    } else {
      foreach my $factoid (@factoids) {
        if ($factoid->[0] eq $channel_arg) {
          ($channel, $trigger) = ($factoid->[0], $factoid->[1]);
          last;
        }
      }
    }
  } else {
    ($channel, $trigger) = ($factoids[0]->[0], $factoids[0]->[1]);
  }

  my $channel_name = $self->{pbot}->{factoids}->{factoids}->{hash}->{$channel}->{_name};
  my $trigger_name = $self->{pbot}->{factoids}->{factoids}->{hash}->{$channel}->{$trigger}->{_name};
  $channel_name = 'global channel' if $channel_name eq '.*';
  $trigger_name = "\"$trigger_name\"" if $trigger_name =~ / /;

  my $result = "/say ";
  $result .= "[$channel_name] " if $channel ne $from and $channel ne '.*';
  $result .= "$trigger_name: ";

  my $help = $self->{pbot}->{factoids}->{factoids}->{hash}->{$channel}->{$trigger}->{help};

  if (not defined $help or not length $help) {
    return "/say $trigger_name is a factoid for $channel_name, but I have no help for it yet.";
  }

  $result .= $help;
  return $result;
}

sub uptime {
  my ($self, $from, $nick, $user, $host, $arguments, $stuff) = @_;
  return localtime ($self->{pbot}->{startup_timestamp}) . " [" . duration (time - $self->{pbot}->{startup_timestamp}) . "]";
}

sub in_channel {
  my ($self, $from, $nick, $user, $host, $arguments, $stuff) = @_;

  my $usage = "Usage: in <channel> <command>";
  return $usage if not $arguments;

  my ($channel, $command) = $self->{pbot}->{interpreter}->split_args($stuff->{arglist}, 2, 0, 1);
  return $usage if not defined $channel or not defined $command;

  if (not $self->{pbot}->{nicklist}->is_present($channel, $nick)) {
    return "You must be present in $channel to do this.";
  }

  $stuff->{from} = $channel;
  $stuff->{command} = $command;
  return $self->{pbot}->{interpreter}->interpret($stuff);
}

1;