#!/usr/bin/perl -w
use strict qw (vars);
use IO::Handle;
use POSIX;

our ($ship, %have, %price);

my $usage = <<END
usage:
  .../ypp-restock-rum [<prices>] [<ship> <stocks>]
where
 <prices> is three arguments: the prices for swill, grog and fine rum
 <ship> is a ship name or an amount of fine rum
 <stocks> are amounts on board for swill, grog and fine rum
END
;

sub main () {
    if (@ARGV==4) {
	($ship, $have{Swill}, $have{Grog}, $have{Fine}) = @ARGV;
	print_inputs();
	compute_restock_requirements();
    } elsif (@ARGV==3) {
	($price{Swill}, $price{Grog}, $price{Fine}) = @ARGV;
	print_inputs();
	compute_cheapest_rum();
    } elsif (@ARGV==7) {
	($price{Swill}, $price{Grog}, $price{Fine},
	 $ship,
	 $have{Swill}, $have{Grog}, $have{Fine}) = @ARGV;
	print_inputs();
	compute_cheapest_rum();
	compute_restock_requirements();
	compute_restock_cheapest_rum();
    } else {
	die $usage;
    }
}

our @rums= qw(Swill Grog Fine);
our %proof= qw(Swill  40
	       Grog   60
	       Fine  100);

our $ff = '%6.1f';

sub prvff ($$\%$) {
    my ($what, $format, $ary, $unit) = @_;
    printf("%-40s", "$what:");
    map {
	my $x= $ary->{$_};
	my $y= defined $x ? sprintf $format, $x : '   x';
	printf " %-10s", $y;
    } @rums;
    printf "  %s\n", $unit;
}

sub pr ($\%$) {
    my ($what, $ary, $unit) = @_;
    prvff($what, '%4d  ', %$ary, $unit);
}

sub prf ($\%$) {
    my ($what, $ary, $unit) = @_;
    prvff($what, $ff, %$ary, $unit);
}

sub pr1 ($$) {
    my ($k,$v) = @_;
    printf "%-20s %s\n", "$k:", $v;
}

our ($best_kind);

sub compute_cheapest_rum() {
    $best_kind= undef;
    my %norm_price;
    my $best_norm_price= 1e6;
    foreach $_ (@rums) {
	next unless defined $price{$_};
	$norm_price{$_} = $price{$_} * $proof{Fine} / $proof{$_};
	if ($norm_price{$_} <= $best_norm_price) {
	    $best_kind= $_;
	    $best_norm_price= $norm_price{$_};
	}
    };
    prf('normalised prices', %norm_price, 'poe/fine');
    if (defined $best_kind) {
	printf "best is %s\n\n", $best_kind;
    } else {
	die "no rum available ?\n";
    }
}

our $have_proof;

sub print_inputs () {
    printf("%40s",'');
    map { printf " %5s     ", $_ } @rums;
    print "\n\n";
    if (defined $price{Swill}) {
	map { $price{$_}= undef if $price{$_} eq 'x' } @rums;
	pr('prices', %price, 'poe ea.');
    }
    if (defined $have{Swill}) {
	$have_proof= 0;
	map { $have_proof += $have{$_} * $proof{$_} } @rums;
	pr('stock on board', %have, 'rum');
    }
}

our ($need_proof, %need, %buy);

sub compute_restock_requirements () {
    if ($ship =~ m/^\d+/) {
	$need{Fine} = $ship;
    } else {
	$ship =~ y/_/ /;
	open F, "/home/ian/private/puzzle-pirates" or die $!;
	my $this_ship= 0;
	my $the_ship;
	while (<F>) {
	    if (!m/\S/ || m/^\s*\#/) {
		$this_ship= 0;
		next;
	    }
	    if (!m/^\@/) {
		next;
	    }
	    if (m/^\@(( [A-Z][-a-z]+){2,})\s*$/) {
		$this_ship= (uc $1 eq uc " $ship" or
			     uc $+ eq uc " $ship");
		$the_ship= $1;
		next;
	    }
	    next unless $this_ship;
	    if (m/^\@\s+(\d+)\s+fine\s*/) {
		$need{Fine} = $1;
		last;
	    }
	}
	die $! if F->error;
	die "unknown ship $ship" unless defined $need{Fine};
	if (defined $ship) {
	    pr1("vessel",$the_ship);
	}
    }
    pr1('desired stock level', sprintf("%4d fine rum", $need{Fine}));
    $need_proof= $need{Fine} * $proof{Fine} - $have_proof;
    map {
	$buy{$_} = $need_proof / $proof{$_};
    } @rums;
    pr1("stock equivalent", sprintf "$ff fine rum", $have_proof / $proof{Fine});
    pr1("restock equivalent", sprintf "$ff fine rum", $need_proof / $proof{Fine});
    prf('would need', %buy, 'rum');
}

sub compute_restock_cheapest_rum() {
    my %bill;
    map {
	$bill{$_} = $buy{$_} * $price{$_} if defined $price{$_};
    } @rums;
    prf('nominal bill', %bill, 'poe');
    print "\n";
    if ($need_proof < 0) {
	printf "stocks are sufficient";
    } else {
	my $buy= ceil($buy{$best_kind});
	printf "buy %d %s at %d poe each for %d poe",
	    $buy, $best_kind, $price{$best_kind}, $buy * $price{$best_kind};
    }
    print "\n\n";
}

main();