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Initial implementation of brmbar v3 - brmbar v1 emulator brmbar-cli.pl

Browse source 
Uses PostgreSQL to store accounts and transactions, and Perl + Moose
for the implementation.

The schema is somewhat complicated, but brmburo-compatible; accounting
design by TMA.
This commit is contained in:
Petr Baudis 2012-08-29 03:52:30 +02:00
parent 540167bfb5
commit 945ee705c3
7 changed files with 521 additions and 0 deletions
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126
brmbar3/BrmBar/Currency.pm Normal file
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package BrmBar::Currency;
use strict;
use warnings;
use v5.10;
use utf8;
use encoding::warnings;
use open qw(:encoding(UTF-8));
use Moose;
use Carp;
has 'db' => (is => 'ro', isa => 'DBI::db', required => 1);
has 'id' => (is => 'ro', isa => 'Int');
has 'name' => (is => 'ro', isa => 'Str');
# Default wallet currency
sub default {
my ($class, %opts) = @_;
return $class->load(db => $opts{db}, name => 'Kč');
}
# Constructor for existing currency
sub load {
my ($class, %opts) = @_;
defined $opts{db} or croak "db parameter missing";
if (defined $opts{id}) {
my $q = $opts{db}->prepare('SELECT name FROM currencies WHERE id = ?');
$q->execute($opts{id});
($opts{name}) = $q->fetchrow_array();
} elsif (defined $opts{name}) {
my $q = $opts{db}->prepare('SELECT id FROM currencies WHERE name = ?');
$q->execute($opts{name});
($opts{id}) = $q->fetchrow_array();
}
my $self = $class->new(%opts);
return $self;
}
# Constructor for new currency
sub create {
my ($class, %opts) = @_;
defined $opts{db} or croak "db parameter missing";
defined $opts{name} or croak "name parameter missing";
my $q = $opts{db}->prepare('INSERT INTO currencies (name) VALUES (?) RETURNING id');
$q->execute($opts{name});
($opts{id}) = $q->fetchrow_array();
my $self = $class->new(%opts);
return $self;
}
# Set exchange rate against $other (BrmBar::Currency):
# $buy is the price of $self in means of $other when buying it (into brmbar)
# $sell is the price of $self in means of $other when selling it (from brmbar)
sub set_rate {
my ($self, $other, $buy, $sell) = @_;
my $qs = $self->db()->prepare("SELECT rate FROM exchange_rates WHERE target = ? AND source = ?");
my $qu = $self->db()->prepare("UPDATE exchange_rates SET rate = ?, rate_dir = ? WHERE target = ? AND source = ?");
my $qi = $self->db()->prepare("INSERT INTO exchange_rates (target, source, rate, rate_dir) VALUES (?, ?, ?, ?)");
$qs->execute($self->id(), $other->id());
if ($qs->fetchrow_array) {
$qu->execute($buy, 'target_to_source');
} else {
$qi->execute($self->id(), $other->id(), $buy, 'target_to_source');
}
$qs->execute($other->id(), $self->id());
if ($qs->fetchrow_array) {
$qu->execute($sell, 'source_to_target');
} else {
$qi->execute($other->id(), $self->id(), $sell, 'source_to_target');
}
}
# Return ($buy, $sell) rates of $self in relation to $other (BrmBar::Currency):
# $buy is the price of $self in means of $other when buying it (into brmbar)
# $sell is the price of $self in means of $other when selling it (from brmbar)
sub rates {
my ($self, $other) = @_;
my $qs = $self->db()->prepare("SELECT rate, rate_dir FROM exchange_rates WHERE target = ? AND source = ?");
$qs->execute($self->id(), $other->id());
my ($buy_rate, $buy_rate_dir) = $qs->fetchrow_array;
defined $buy_rate or croak "unknown conversion ".$other->name()." to ".$self->name();
my $buy = $buy_rate_dir eq 'target_to_source' ? $buy_rate : 1/$buy_rate;
$qs->execute($other->id(), $self->id());
my ($sell_rate, $sell_rate_dir) = $qs->fetchrow_array;
defined $sell_rate or croak "unknown conversion ".$self->name()." to ".$other->name();
my $sell = $sell_rate_dir eq 'source_to_target' ? $sell_rate : 1/$sell_rate;
return ($buy, $sell);
};
sub convert {
my ($self, $amount, $target) = @_;
my $q = $self->db()->prepare("SELECT rate, rate_dir FROM exchange_rates WHERE target = ? AND source = ? AND valid_since <= NOW() ORDER BY valid_since ASC LIMIT 1");
$q->execute($target->id(), $self->id());
my ($rate, $rate_dir) = $q->fetchrow_array();
defined $rate or croak "unknown conversion ".$self->name()." to ".$target->name();
return $rate_dir eq 'source_to_target' ? $amount * $rate : $amount / $rate;
}
sub str {
my ($self, $amount) = @_;
return $amount . ' ' . $self->name();
}
1;