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

# SPDX-FileCopyrightText: 2021 Pragmatic Software <pragma78@gmail.com>
# SPDX-License-Identifier: MIT

package PBot::Core::Commands;
use parent 'PBot::Core::Class';

use PBot::Imports;
use PBot::Core::Utils::LoadModules qw/load_modules/;

sub initialize {
    my ($self, %conf) = @_;

    # registered commands hashtable
    $self->{commands} = {};

    # command metadata stored as a HashObject
    $self->{metadata} = PBot::Core::Storage::HashObject->new(
        pbot     => $self->{pbot},
        name     => 'Command metadata',
        filename => $conf{filename},
    );

    $self->{metadata}->load;
}

# load commands in PBot::Core::Commands directory
sub load_commands {
    my ($self) = @_;
    $self->{pbot}->{logger}->log("Loading commands:\n");
    load_modules($self, 'PBot::Core::Commands');
}

# named-parameters interface to register()
sub add {
    my ($self, %args) = @_;

    # expected parameters
    my @valid = qw(subref name requires_cap help);

    # check for unexpected parameters
    my @invalid;
    foreach my $key (keys %args) {
        if (not grep { $_ eq $key } @valid) {
            push @invalid, $key;
        }
    }

    # die if any unexpected parameters were passed
    if (@invalid) {
        $self->{pbot}->{logger}->log("Commands: error: invalid arguments provided to add(): @invalid\n");
        die "Commands: error: invalid arguments provided to add(): @invalid";
    }

    # register command
    $self->register(
        $args{subref},
        $args{name},
        $args{requires_cap},
        $args{help},
    );
}

# alias to unregister() for consistency
sub remove {
    my $self = shift @_;
    $self->unregister(@_);
}

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

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

    $name = lc $name;
    $requires_cap //= 0;
    $help //= '';

    if (exists $self->{commands}->{$name}) {
        $self->{pbot}->{logger}->log("Commands: warning: overwriting existing command $name\n");
    }

    # register command
    $self->{commands}->{$name} = {
        requires_cap => $requires_cap,
        subref       => $subref,
    };

    # update command metadata
    if (not $self->{metadata}->exists($name)) {
        # create new metadata
        $self->{metadata}->add($name, { requires_cap => $requires_cap, help => $help }, 1);
    } else {
        # metadata already exists
        # we update data unless it's already set so the metadata file can be edited manually.

        # update requires_cap unless it's already set.
        if (not defined $self->get_meta($name, 'requires_cap')) {
            $self->{metadata}->set($name, 'requires_cap', $requires_cap, 1);
        }

        # update help text unless it's already set.
        if (not $self->get_meta($name, 'help')) {
            $self->{metadata}->set($name, 'help', $help, 1);
        }
    }

    # add can-<command> capability to PBot capabilities if required
    if ($requires_cap) {
        $self->{pbot}->{capabilities}->add("can-$name", undef, 1);
    }
}

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

sub exists {
    my ($self, $name) = @_;
    return exists $self->{commands}->{lc $name};
}

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

sub get_meta {
    my ($self, $command, $key) = @_;
    return $self->{metadata}->get_data($command, $key);
}

# main entry point for PBot::Core::Interpreter to interpret a registered bot command
# see also PBot::Core::Factoids::Interpreter for factoid commands
sub interpreter {
    my ($self, $context) = @_;

    # debug flag to trace $context location and contents
    if ($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 $context);
    }

    # some convenient aliases
    my $keyword = lc $context->{keyword};
    my $from    = $context->{from};

    # alias to the command
    my $command = $self->{commands}->{$keyword};

    # bail early if the command doesn't exist
    return undef if not defined $command;

    # set the channel the command is in reference to
    my ($cmd_channel) = $context->{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

    $context->{channel} = $cmd_channel;

    # get the user's bot account
    my $user = $self->{pbot}->{users}->find_user($cmd_channel, $context->{hostmask});

    # check for a capability override
    my $cap_override;

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

    # does this command require capabilities
    my $requires_cap = $self->get_meta($keyword, 'requires_cap') // $command->{requires_cap};

    # validate can-command capability
    if ($requires_cap) {
        if (defined $cap_override) {
            if (not $self->{pbot}->{capabilities}->has($cap_override, "can-$keyword")) {
                return "/msg $context->{nick} The $keyword command requires the can-$keyword capability, which cap-override $cap_override does not have.";
            }
        } else {
            if (not defined $user) {
                my ($found_chan, $found_mask) = $self->{pbot}->{users}->find_user_account($cmd_channel, $context->{hostmask}, 1);

                if (not defined $found_chan) {
                    return "/msg $context->{nick} You must have a user account to use $keyword. You may use the `my` command to create a personal user account. See `help my`.";
                } else {
                    return "/msg $context->{nick} You must have a user account in $cmd_channel to use $keyword. (You have an account in $found_chan.)";
                }
            } elsif (not $user->{loggedin}) {
                return "/msg $context->{nick} You must be logged into your user account to use $keyword.";
            }

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

    if ($self->get_meta($keyword, 'preserve_whitespace')) {
        $context->{preserve_whitespace} = 1;
    }

    # tell PBot::Core::Interpreter to prepend caller's nick to output
    if ($self->get_meta($keyword, 'add_nick')) {
        $context->{add_nick} = 1;
    }

    unless ($context->{'dont-replace-pronouns'}) {
        $context->{arguments} = $self->{pbot}->{factoids}->{variables}->expand_factoid_vars($context, $context->{arguments});
        $context->{arglist}   = $self->{pbot}->{interpreter}->make_args($context->{arguments});
    }

    # execute this command as a backgrounded process?
    if ($self->get_meta($keyword, 'background-process')) {
        # set timeout to command metadata value
        my $timeout = $self->get_meta($keyword, 'process-timeout');

        # otherwise set timeout to default value
        $timeout //= $self->{pbot}->{registry}->get_value('processmanager', 'default_timeout');

        # execute command in background
        $self->{pbot}->{process_manager}->execute_process(
            $context,
            sub { $context->{result} = $command->{subref}->($context) },
            $timeout,
        );

        # return no output since it will be handled by process manager
        return '';
    } else {
        # execute this command normally
        my $result = $command->{subref}->($context);

        # disregard undesired command output if command is embedded
        return undef if $context->{embedded} and $result =~ m/(?:usage:|no results)/i;

        # return command output
        return $result;
    }
}

1;