#!/usr/bin/perl
use strict;
use warnings;

use 5.010;

use YAML::Any;
use Template;
use RT::Client::REST;
use RT::Client::REST::Ticket;
use RT::Client::REST::User;

use DateTime;

my $config = RTI::Config->new();

#print Dump $config; exit;

my $invoiceid = 1;    # $state->{lastinvoice} + 1;

my $startdate;
my @invoices;
foreach my $cust ( @{ $config->get('customers') } ) {

    # my $state = RTI::State->new($cust);
    # $invoice{state} = $state;
    my $lastinvdate;  # = $state->{lastinvoicedte}; XXX Needs to be a DateTime
                      #$lastinvdate = DateTime->now->subtract( months => 2 )
                      #    ->set( hour => 0, minute => 0, second => 0 );

    my %invoice = (
        from  => $config->get('from'),
        info  => $config->get('info'),
        to    => $cust->{address},
        rates => $cust->{rates},
        match => $cust->{match},
    );

    if ( $cust->{base_rate} ) {
        my $day  = $cust->{day}       || 1;
        my $freq = $cust->{frequency} || 1;

        my $day_method;
        my $per;
        given ( $cust->{per} ) {
            when ('week')  { $per = 'weeks';  $day_method = 'dow' }
            when ('month') { $per = 'months'; $day_method = 'day' }
            default { die "Unknown per [$cust->{per}]\n" }
        }

        my $lastbill
            = DateTime->now->set( hour => 0, minute => 0, second => 0 );
        while ( $lastbill->$day_method != $day ) {
            $lastbill->subtract( days => 1 );
        }

        my $date
            = $lastinvdate
            ? $lastinvdate->clone->add( days => 1 )
            : $lastbill->clone->subtract( $per => $freq );

        my $title
            = $freq == 1
            ? ucfirst( $cust->{per} . 'ly' )
            : $freq . ' ' . ucfirst( $cust->{per} );
        $title .= ' Retainer';

        my %project = ( title => $title, fees => [], );

        while ( $date < $lastbill ) {
            my $start = $date->clone;

            $date->add( $per => $freq );
            $date = $lastbill->clone if $date > $lastbill;
            if ( my $diff = $date->$day_method - $day ) {
                $date->subtract( days => $diff );
            }

            my $end = $date->clone;

            $end->subtract( seconds => 1 );

            $startdate = $start->clone if !$startdate || $startdate > $start;
            $invoice{start} ||= $start->clone;
            $invoice{end} = $end->clone;
            my %hours = (
                start => $start->clone,
                end   => $end->clone,
                hours => { %{ $cust->{hours} } },
            );

            push @{ $invoice{hours} }, \%hours;
            push @{ $project{fees} },
                {
                count    => 1,
                rate     => $cust->{base_rate},
                contents => $start->ymd . ' to ' . $end->ymd,
                };

        }

        if ( @{ $project{fees} } ) {
            push @{ $invoice{projects} }, \%project;
        }
    }
    else {
        $invoice{end} = DateTime->now;
        push @{ $invoice{hours} },
            { end => DateTime->now, hours => $cust->{hours} };
    }

    next unless $invoice{end};
    push @invoices, \%invoice;
}

#print Dump \@invoices; exit;

my $rt_conf = $config->get('rt');
my $rt      = RT::Client::REST->new(
    server  => $rt_conf->{server},
    timeout => $rt_conf->{timeout},
);
$rt->login(
    username => $rt_conf->{user},
    password => $rt_conf->{pass},
);
my $tickets = RT::Client::REST::Ticket->new( rt => $rt );
my $users = RT::Client::REST::User->new( rt => $rt );

my @limits = map +{
    attribute  => 'status',
    operator   => '=',
    value      => $_,
    aggregator => 'or',
    },

    # XXX This should be a config option
    qw/ open stalled resolved /;

if ($startdate) {
    push @limits,
        {
        attribute => 'last_updated',
        operator  => '>=',
        value     => $startdate->ymd,
        };
}

my $results = $tickets->search(
    limits  => \@limits,
    orderby => 'id',
);

my $count = $results->count;
print "There are $count results that matched your query\n";

my $iterator = $results->get_iterator;
while ( my $ticket = &$iterator ) {
    my $invoice = find_invoice_for_ticket( \@invoices, $ticket );

    if ( !$invoice ) {
        say "No invoice found for ticket " . $ticket->id;

        # XXX should construct a "new" invoice to pop onto the list
        next;
    }

    my %project = (
        id     => $ticket->id,
        queue  => $ticket->queue,
        owner  => $ticket->owner,
        title  => $ticket->subject,
        detail => 'Ticket: '
            . $ticket->id
            . ' Queue: '
            . $ticket->queue
            . ' Requestors: '
            . join( ', ', $ticket->requestors ),
        fees     => [],
        expenses => [],
    );

    #foreach my $r ($ticket->requestors) {
    #    $users->id( $r );
    #    $users->retrieve;
    #    print Dump $users;
    #}

    my $txns = $ticket->transactions( type => [qw(Comment Correspond)] );
    my $txn_i = $txns->get_iterator;
    while ( my $txn = $txn_i->() ) {
        next unless $txn->time_taken;

        my ( $date, $time ) = split ' ', $txn->created;
        my ( $year, $month,  $day )    = split '-', $date;
        my ( $hour, $minute, $second ) = split ':', $time;

        my $txn_date = DateTime->new(
            year   => $year,
            month  => $month,
            day    => $day,
            hour   => $hour,
            minute => $minute,
            second => $second,
        );

        next if $invoice->{start} && $invoice->{start} > $txn_date;
        next if $invoice->{end} < $txn_date;

        my $fee = make_fee( $ticket, $txn, $invoice->{rates} );
        push @{ $project{fees} }, $fee;

        my $hours = hours_for_date( $invoice, $txn_date );

        my $h_type
            = exists $hours->{ $fee->{type} }
            ? $fee->{type}
            : 'default';

        next unless exists $hours->{$h_type} && $hours->{$h_type} > 0;

        my $discount_time = 0;
        if ( $hours->{$h_type} > $fee->{count} ) {
            $hours->{$h_type} -= $fee->{count};
            $discount_time = $fee->{count};
        }
        else {
            $discount_time = $hours->{$h_type};
            $hours->{$h_type} = 0;
        }

        if ($discount_time) {
            $invoice->{discount}{amount} += $discount_time * $fee->{rate};
            $invoice->{discount}{hours}{$h_type} += $discount_time;

            $h_type = '' if $h_type eq 'default';
            $fee->{detail} = "$discount_time $h_type Hours Discounted";
        }

        #print Dump $txn; exit;
    }

    next unless @{ $project{fees} } || @{ $project{expenses} };
    print " Added ticket $project{id}\n";
    push @{ $invoice->{projects} }, \%project;
}

foreach my $invoice (@invoices) {
    next unless $invoice->{projects} && @{ $invoice->{projects} };

    foreach my $project ( @{ $invoice->{projects} } ) {
        print "$project->{title}\n";
        my $subtotal = 0;
        foreach my $fee ( @{ $project->{fees} } ) {
            my $amount = round( $fee->{count} * $fee->{rate} );
            print "  $amount (" . ( $fee->{count} * $fee->{rate} ) . ")\n";
            $subtotal += $amount;
        }
        foreach my $expense ( @{ $project->{expenses} } ) {
            $subtotal += round( $expense->{amount} );
        }
        $project->{total} = $subtotal;
        $invoice->{total} += $subtotal;
        print " Subtotal $subtotal\n";
    }

    if ( $invoice->{discount} ) {
        my $c = "Included Hours\n";
        if ( $invoice->{discount}{hours} ) {
            foreach my $t ( keys %{ $invoice->{discount}{hours} } ) {
                $c .= "\n$invoice->{discount}{hours}{$t} $t hour";
                $c .= 's' if $invoice->{discount}{hours}{$t} != 1;
                $c .= "\n";
            }
        }
        $invoice->{discount}{contents} = $c;
        $invoice->{total} -= round( $invoice->{discount}{amount} );
    }

    if ( $invoice->{past_due} ) {
        $invoice->{total_due} = $invoice->{total} + $invoice->{past_due};
    }

    foreach my $key (qw/ start end /) {
        if ( exists $invoice->{$key} ) {
            $invoice->{$key} = $invoice->{$key}->strftime('%B %d, %Y');
        }
    }

    $invoice->{id}   = $invoiceid;
    $invoice->{file} = 'invoice_' . $invoiceid . '.pdf';

    print "Created Invoice\n";
    print Dump $invoice;

    my $tt = Template->new;
    $tt->process( 'invoice.tex.tt', $invoice, $invoice->{file} )
        or die $tt->error . "\n";

    print "Generated $invoice->{file}\n";

    $invoiceid++;
}

# XXX Save State

sub round {
    my ($amount) = @_;

    #$amount =~ s/\.\d\d\K.*$//;
    #return $amount;
    return sprintf "%.02f", $amount;
}

sub find_invoice_for_ticket {
    my ( $invoices, $ticket ) = @_;

INVOICE: foreach my $i ( @{$invoices} ) {
        next INVOICE unless $i->{match};
        foreach my $m ( @{ $i->{match} } ) {
            my $type = $m->{type};
            my $thing = join ' ', $ticket->$type;

            if ( $m->{$type} ) {
                my $match = lc $m->{$type};
                next INVOICE unless lc($thing) ~~ $match;
            }
            elsif ( $m->{regex} ) {
                next INVOICE unless $thing ~~ /\Q$m->{regex}\E/;
            }
            else {
                warn "Invalid match!";
                next INVOICE;
            }
        }
        return $i;
    }
}

sub make_fee {
    my ( $ticket, $txn, $rates ) = @_;

    my $work_time = sprintf "%.03f", $txn->time_taken / 60;
    my $work_type = $txn->cf('WorkType');
    my $work_rate = $rates->{$work_type} || $rates->{default} || 0;

    my %fee = (
        id       => $txn->id,
        contents => $txn->created . ' ('
            . $txn->id . ')' . "\n\n"
            . ( $txn->data || $ticket->subject ),
        count => $work_time,
        rate  => $work_rate,
        type  => $work_type,
    );

    if ( $work_type && $work_type ne 'Normal' ) {
        $fee{detail} = $work_type . ' rate';
    }

    return \%fee;
}

sub hours_for_date {
    my ( $invoice, $date ) = @_;

    my $hours = {};
    if ( $invoice->{hours} ) {
        foreach my $h ( @{ $invoice->{hours} } ) {
            next if $h->{start} && $h->{start} > $date;
            next if $h->{end} < $date;

            $hours = $h->{hours};
            last;
        }
    }
    return $hours;
}

package RTI::Config;
use strict;
use warnings;

use 5.010;

use YAML::Any qw/ LoadFile /;

sub new {
    my ( $class, $args ) = @_;

    my $self = { file => '', };
    bless $self, $class;
    my $file = $args->{file} || $self->_find_config;
    $self->read_config($file);

    return $self;
}

sub _find_config {
    my ($self) = @_;

    # XXX This needs to be better
    foreach my $file (qw/ rt_invoice.conf rt_invoice.cfg .rt_invoicerc /) {
        foreach my $dir ( '.', $ENV{HOME} . '/.rt_invoice', $ENV{HOME} ) {
            my $path = join '/', $dir, $file;
            return $path if -e $path;
        }
    }
    return;
}

sub read_config {
    my ( $self, $file ) = @_;

    $file ||= $self->{file};
    die "$file: no such file\n" unless -e $file;

    my $c = LoadFile($file) or die "Unable to load $file\n";

    $c->{customers} ||= [];
    if ( $c->{default} ) {
        foreach my $cust ( @{ $c->{customers} } ) {
            foreach my $k ( keys %{ $c->{default} } ) {
                $cust->{$k} //= $c->{default}->{$k};
            }
        }
    }

    $self->{_config} = $c;
    $self->{file}    = $file;
}

sub get {
    my ( $self, $key ) = @_;

    # XXX This should deep copy? not a reference would be good
    return $self->{_config}->{$key};
}

package RTI::State;
use strict;
use warnings;

use 5.010;

use YAML::Any qw/ LoadFile DumpFile /;

sub new {
    my ( $class, $args ) = @_;

    my $self = { file => '', };
    bless $self, $class;
    my $file = $args->{file} || $self->_find_config;
    $self->read_config($file);

    return $self;
}