#! perl

# The international bank script. There are five commands one can
# give the banker in-game:
# - help, will show the usage information
# - deposit, can deposit a certain amount of a given currency unit
# - withdraw, can give out a certain amount of a given currency unit
#      provided, the bank account has this amount of money
# - exchange, will exchange between royalties and platinum coins
# - balance, simply shows how much money one has on his/her account.
#
# TODO:
# - Comment more steps
# - Implement exchange()

# The units are being used in each sub so they are declared globally.
my %unit = (
   silver   => 1,
   gold     => 10,
   platina  => 50,
   royalty  => 5000,
); 

# Subroutine just to calculate exchange rates.
sub calc_exchange_rate {
   my ($value, $from_cur, $to_cur) = @_;

   $value * $unit{$from_cur} / $unit{$to_cur}
}

sub amount_str {
   my $amount = shift;

   my $royalties = calc_exchange_rate $amount, "silver", "royalty";
   my $platinum  = calc_exchange_rate $royalties - (int $royalties), "royalty", "platina";
   my $gold      = calc_exchange_rate $platinum - (int $platinum), "platina", "gold";
   my $silver    = calc_exchange_rate $gold - (int $gold), "gold", "silver";

      (int $royalties) . " royalties, "
    . (int $platinum) . " platinum, "
    . (int $gold) . " gold and about "
    . (int $silver) ." silver coins.";

}

# Calculates and returns how much money someone has starting with the
# highest value currency going down. Think of it like having the date
# and time in the format of 2006-05-19 03:21:31 UTC instead of 1148001691
# seconds since 1970-01-01 00:00:00 UTC.
sub balance {
   my ($who, $is_wiz) = @_;
   my $balance = $who->{bank_balance};

   unless ($is_wiz) {
      return "Sorry, you have no balance."
         unless $balance >= 1;
   } else {
      return $who->name." has no balance."
         unless $balance >= 1;
   }

   my $account_info = amount_str ($balance);

   return "You have $account_info"
      unless $is_wiz;

   return $who->name." has $account_info";
}

sub transaction {
   my ($who, $action, $amount, $currency) = @_;
   my $pay = $amount * $unit{$currency};

   return "We don't trade in that currency."
      unless exists $unit{$currency};

   return "You can not $action fractions."
      unless $amount =~ /^\d+$/;

   # First check for possible overflow and user stupidity
   if ($amount > 2**31) {
      return "Sorry, we do not handle that kind of money for one ".$action.".";
   } elsif ($amount == 0) {
      return "You can not ".$action." nothing.";
   } elsif ($amount < 0) {
      return "You can not ".$action." negative values.";
   }

   # Here we handle the transactions 
   if ($action eq "deposit") {
      if ($who->pay_amount ($pay)) {
         $who->{bank_balance} += $pay;
         return "$amount $currency received.";
      } else {
         return "You don't have enough money with you.";
      }
   } elsif ($action eq "withdraw") {
      if ($pay <= $who->{bank_balance}) {
         my $paid = $who->pay_player_arch (
            $currency eq 'royalty' ? 'royalty' : $currency . "coin",
            $amount
         );
         if ($paid) {
            $who->{bank_balance} -= $pay;
         } else {
            $amount = 0;
         }
         return "Withdrew $amount $currency";
      } else {
         return "You don't have that much money on your bank account.";
      }
   }
}

sub help {
   my ($command) = @_;

   if ($command eq "") {
      return "You can:
      deposit <amount> <currency>
      withdraw <amount> <currency>
      balance
      exchange <amount> <direction>
      help <topic>";
   } elsif ($command eq "deposit") {
      return "You can deposit some of the money you don't currently use in our bank. To do this, ask me to:
      deposit <amount> <currency>\nSee help exchange for our currencies.";
   } elsif ($command eq "withdraw") {
      return "To get the money you stored in our system back, just say:
      withdraw <amount> <currency>";
   } elsif ($command eq "balance") {
      return "I can tell you how much money you are saving in our bank, just ask me about your balance.";
   } elsif ($command eq "exchange") {
      return "We exchange between royalties and platina coins at a very low price. To change from platina to royalties, say:
      exchange <amount> platina royalty\nTo change from royalties to platina, say:
      exchange <amount> royalty platina\nWe currently only exchange between these two currencies. If you want to know more about exchange rates, ask me:
      help exchange rates\nThanks for using our bank.";
   } elsif ($command eq "exchange rates") {
      my @units = sort { $unit{$b} <=> $unit{$a} } keys %unit;
      my $exchange_rates = "Here is a list of exchange rates:\n";

      for my $from_cur_nr (0 .. $#units) {
         for my $to_cur_nr ($from_cur_nr+1 .. $#units) {
            $exchange_rates = $exchange_rates."One $units[$from_cur_nr] is ".calc_exchange_rate(1, $units[$from_cur_nr], $units[$to_cur_nr])." $units[$to_cur_nr]\n";
         }
      }
      return $exchange_rates."This may change a bit with the stock markets but don't expect it to be much.";
   }
}

cf::register_script_function "bank::command" => sub {
   my ($who, $msg, $npc) = @_;

   my ($cmd, $arguments) = split /\s+/, $msg, 2;
   my ($amount, $currency) = split /\s+/, $arguments, 2;
   my $service_charge = 5;
   my @units = sort keys %unit;
   my $units = join ", ", @units;
   my $fees = - ($service_charge / 100) + 1;

   # Have some aliases for currencies
   if ($currency eq "platinum") {
      $currency = "platina";
   } elsif ($currency eq "royalties") {
      $currency = "royalty";
   }

   if ($cmd eq "balance") {
      if ($who->flag (cf::FLAG_WIZ)) {
         if (my $player = cf::player::find $arguments) {
            $who->reply ($npc, balance $player->ob, 1);
         }
      } else {
         $who->reply ($npc, balance $who, 0);
      }

   } elsif ($cmd eq "balance" and !$arguments) {
      $who->reply ($npc, "Balance of whom?");

   } elsif ($cmd eq "deposit" and $currency) {
      $who->reply ($npc, transaction $who, "deposit", $amount, $currency);
      $who->reply ($npc, balance $who);
      
   } elsif ($cmd eq "deposit" and $amount and $currency eq "") {
      $who->reply ($npc, "deposit $amount of what: $units");

   } elsif ($cmd eq "deposit" and $amount eq "" and $currency eq "") {
      $who->reply ($npc, "How much do you want to deposit?");

   } elsif ($cmd eq "withdraw" and $currency) {
      $who->reply ($npc, transaction $who, "withdraw", $amount, $currency);
      $who->reply ($npc, balance $who);

   } elsif ($cmd eq "withdraw" and $amount and $currency eq "") {
      $who->reply ($npc, "Withdraw $amount of what: $units");

   } elsif ($cmd eq "withdraw" and $amount eq "" and $currency eq "") {
      $who->reply ($npc, "How much do you want to withdraw?");

   } elsif ($cmd eq "exchange") {
      $who->reply ($npc, "This function is not yet implemented. Ask me again later.");

   } elsif ($cmd eq "help" or $cmd eq "yes" and $arguments eq "") {
      $who->reply ($npc, help $arguments);

   } elsif ($cmd eq "help" or $cmd eq "yes" and $arguments ne "") {
      $who->reply ($npc, help);

   } else {
      $who->reply ($npc, "Do you need help?");
   }
}