#!/usr/bin/perl

# Copyright (c) 2020 Freda Bundchen

# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

use warnings;
use strict;

use Getopt::Std qw(getopts);

our ($opt_I);

my %date_formats = (
    'MM/DD/YYYY' => 's#(\d+)/(\d+)/(\d+)#$3$1$2#',
    'MM/DD/YY'   => 's#(\d+)/(\d+)/(\d+)#20$3$1$2#',
    'YYYY-MM-DD' => 's#(\d+)-(\d+)-(\d+)#$1$2$3#',
    'DD.MM.YY'   => 's#(\d+)\.(\d+)\.(\d+)#20$3$2$1#',
);

# === SUBROUTINES  =====================================================

sub usage () {
	printf STDERR "usage: %s -I accountname csvfilename\n", $0;
	exit 1;
}

# === MAIN PROGRAM =====================================================

getopts 'I:' or usage;
unless ($opt_I) {
	warn "The option -I is required.";
	usage;
}
my $account_name = $opt_I;

# Parse the configuration file.
my $fn = "import/" . $account_name . ".txt";
open my $in, '<', $fn or die "$fn: $!";
my ($cost_center_field, $csv_account, $date_field, $date_regex,
    $delim, $header, $quantity_field, $quote, @amount_fields,
    @compiled, @description_fields, @ignored);
while (<$in>) {
	chomp;
	s/\s+$//;
	next if /^(?:#|$)/;
	my $line = $_;
	if (s/^ACCOUNT\s+//) {
		$csv_account and die "duplicate ACCOUNT line: $_";
		/^(\d+)$/ or die "ACCOUNT parse error: $_";
		$csv_account = $1;
		next;
	}
	if (s/^AMOUNT\s+//) {
		@amount_fields and die "duplicate AMOUNT line: $_";
		push @amount_fields, $1 - 1 while s/(\d+)\s*//;
		$_ eq '' or die "trailing garbage: AMOUNT ... $_";
		next;
	}
	if (s/^COSTCENTER\s+//) {
		$cost_center_field and
		    die "duplicate COSTCENTER line: $_";
		/^(\d+)$/ or die "COSTCENTER parse error: $_";
		$cost_center_field = $1 - 1;
		next;
	}
	if (s/^DATE\s+//) {
		$date_field || $date_regex and
		    die "duplicate DATE line: $_";
		s/^(\d+)\s+(\S+)$//;
		$date_field = $1 or
		    die "DATE date_field parse error: $_";
		$date_field -= 1;
		$date_regex = $date_formats{$2}
		    or die "unknown date format: $2";
		next;
	}
	if (s/^DELIM\s+//) {
		$delim and die "duplicate DELIM line: $1";
		/^([^|\^\$\*\+\?\(\)\[\]\{\}\\])$/ or
		    die "DELIM parse error: $_";
		$delim = $1;
		next;
	}
	if (s/^DESCRIPTION\s+//) {
		@description_fields and die "duplicate DESCRIPTION line: $_";
		push @description_fields, $1 - 1 while s/(\d+)\s*//;
		$_ eq '' or die "trailing garbage: DESCRIPTION ... $_";
		next;
	}
	if (s/^HEADER\s+//) {
		$header and die "duplicate HEADER line: $1";
		$header = $_;
		next;
	}
	if (s/^IGNORE\s+//) {
		push @ignored, qr/$_/;
		next;
	}
	if (s/^QUANTITY\s+//) {
		$quantity_field and die "duplicate QUANTITY line: $1";
		/^(\d+)$/ or die "QUANTITY parse error: $_";
		$quantity_field = $1 - 1;
		next;
	}
	if (s/^QUOTE\s+//) {
		$quote and die "duplicate QUOTE line: $1";
		/^([^|\^\$\*\+\?\(\)\[\]\{\}\\])$/ or
		die "QUOTE parse error: $_";
		$quote = $1;
		next;
	}
	$delim or die "no DELIM line in $fn";
	s/^(.*)$delim\s+(\d+)\s+(\S+)// or
	    die "$fn import parse error: $line";
	push @compiled, {
		re => [map { qr/$_/ } split /$delim/, $1],
		ac => $2,
		id => $3,
	};
}
close $in;
$csv_account or die "no ACCOUNT line in $fn";

# Parse the CSV file from the bank.
if (@ARGV) {
	open STDIN, '<', $ARGV[0] or die "$ARGV[0]: $!";
}
LINE: while (<STDIN>) {
	chomp;
	s/\s*$//;
	next if (/^$/);
	foreach my $ignore (@ignored) {
		next LINE if /$ignore/;
	}
	my $line = $_;
	if ($header) {
		$line eq $header
		    or die "expected HEADER $header\nbut got $line";
		undef $header;
		next;
	}
	my $copy_line = $line;
	my @fields;
	if ($quote) {
		push @fields, $1 while $copy_line =~ s/$quote([^$quote]*)$quote$delim?//;
	} else {
		@fields = split /$delim/, $line;
	}
	my $matches = 0;
	my ($account, $booking);
	foreach my $selector (@compiled) {
		$matches = 1;
		for (my $i = 0; $i <= $#{$selector->{re}}; $i++) {
			next if $fields[$i] =~ $selector->{re}[$i];
			$matches = 0;
			last;
		}
		if ($matches) {
			$account = $selector->{ac};
			$booking = $selector->{id};
			last;
		}
	}
	$matches or die "unmatched CSV line: $line";
	my $date = $fields[$date_field] or
	    die "date parse error: $line";
	eval '$date =~ ' . $date_regex;
	foreach my $i (@amount_fields) {
		if (defined($fields[$i])) {
			$fields[$i] =~ s/,/./;
			$fields[$i] =~ s/\$//;
			$fields[$i] = "-$1" if $fields[$i] =~ /^\((\d+\.\d+)\)/;
		}
	}
	my $debit = $csv_account;
	my $credit = $account;
	my $amount = $fields[$amount_fields[-1]] || -$fields[$amount_fields[0]];
	if ($amount < 0) {
		$amount *= -1;
		$credit = $csv_account;
		$debit = $account;
	}
	$amount = sprintf "%.2f", $amount;
	my $description = join ' ', @fields[@description_fields];
	$date && $amount && $debit && $credit && $description
	    or die "import parse error: $line";
	$description =~ s/#//g;
	$description .= " [$fields[$cost_center_field]]"
	    if $cost_center_field;
	$description .= " quantity $fields[$quantity_field]"
	    if $quantity_field;
	print "$date $booking $debit $credit $amount $description\n";
}