#!/usr/bin/env perl
use v5.10;
use strict;
use warnings;

our $VERSION = '1.0';

use Data::Dumper;
use FS::cust_main_county;
use FS::Log;
use FS::Record qw( qsearch qsearchs );
use FS::UID qw( adminsuidsetup );
use Getopt::Long;
use Pod::Usage;

# Begin transaction
local $FS::UID::AutoCommit = 0;

my(
  $dbh,
  $freeside_user,
  $opt_check,
  $opt_fix_usf,
  @opt_merge,
  $opt_merge_all,
  @opt_set_source_null,
);

GetOptions(
  'check'             => \$opt_check,
  'fix-usf'           => \$opt_fix_usf,
  'merge=s'           => \@opt_merge,
  'merge-all'         => \$opt_merge_all,
  'set-source-null=s' => \@opt_set_source_null,
);
@opt_merge = split(',',join(',',@opt_merge));
@opt_set_source_null = split(',',join(',',@opt_set_source_null));


# say Dumper({
#   check => $opt_check,
#   merge => \@opt_merge,
#   set_source_numm => \@opt_set_source_null,
# });

validate_opts();

$dbh = adminsuidsetup( $freeside_user )
  or die "Bad  username: $freeside_user\n";

my $log = FS::Log->new('freeside-wa-tax-table-resolve');

if ( $opt_check ) {
  check();
} elsif ( @opt_merge ) {
  merge();
} elsif ( @opt_set_source_null ) {
  set_source_null();
} elsif ( $opt_merge_all ) {
  merge_all();
} elsif ( $opt_fix_usf ) {
  fix_usf();
} else {
  error_and_help('No options selected');
}

# Commit transaction
$dbh->commit;
local $FS::UID::AutoCommit = 1;

exit;


sub set_source_null {
  my @cust_main_county;
  for my $taxnum ( @opt_set_source_null ) {
    my $row = qsearchs( cust_main_county => { taxnum => $taxnum } );
    if ( $row ) {
      push @cust_main_county, $row;
    } else {
      error_and_help("Invalid taxnum specified: $taxnum");
    }
  }

  say "=== Specified tax rows ===";
  print_taxnum($_) for @cust_main_county;

  confirm_to_continue("

    The source column will be set to NULL for each of the
    tax rows listed.  The tax row will no longer be managed
    by the washington state sales tax table update utilities.

    The listed taxes should be manually created taxes, that
    were never intended to be managed by the auto updater.

  ");

  for my $row ( @cust_main_county ) {

    $row->setfield( source => undef );
    my $error = $row->replace;

    if ( $error ) {
      $dbh->rollback;

      my $message = sprintf 'Error setting source=null taxnum %s: %s',
          $row->taxnum, $error;

      $log->error( $message );
      say $message;

      return;
    }

    my $message = sprintf 'Source column set to null for taxnum %s',
      $row->taxnum;

    $log->warn( $message );
    say $message;
  }
}

sub merge {
  my $source = qsearchs( cust_main_county => { taxnum => $opt_merge[0] });
  my $target = qsearchs( cust_main_county => { taxnum => $opt_merge[1] });

  error_and_help("Invalid source taxnum: $opt_merge[0]")
    unless $source;
  error_and_help("Invalid target taxnum: $opt_merge[1]")
    unless $target;

  local $| = 1; # disable output buffering

  say '==== source row ====';
  print_taxnum( $source );

  say '==== target row ====';
  print_taxnum( $target );

  confirm_to_continue("
  
    The source tax will be merged into the target tax.
    All references to the source tax on customer invoices
    will be replaced with references to the target tax.
    The source tax will be removed from the tax tables.

  ");

  merge_into( $source, $target );
}

sub merge_into {
  my ( $source, $target ) = @_;

  local $@;
  eval { $source->_merge_into( $target, { identical_record_check => 0 } ) };
  if ( $@ ) {
    $dbh->rollback;
  
    my $message = sprintf 'Failed to merge wa sales tax %s into %s: %s',
        $source->taxnum, $target->taxnum, $@;

    say $message;
    $log->error( $message );

  } else {
    my $message = sprintf 'Merged wa sales tax %s into %s for district %s',
        $source->taxnum, $target->taxnum, $source->district;

    say $message;
    $log->warn( $message );
  }
}

sub merge_all {
  my @dupes = FS::cust_main_county->find_wa_tax_dupes;

  unless ( @dupes ) {
    say 'No duplicate tax rows detected for WA sales tax districts';
    return;
  }

  confirm_to_continue(sprintf "

    %s blocking duplicate rows detected

    Duplicate rows will be merged using FS::cust_main_county::_merge_into()

    Rows are considered duplicates when they:
    - Share the same tax class
    - Share the same district
    - Contain 'wa_sales' in the source column

  ", scalar @dupes);

  # Sort dupes into buckets to be merged, by taxclass and district
  # $to_merge{taxclass}->{district} = [ @rows_to_merge ]
  my %to_merge;
  for my $row ( @dupes ) {
    my $taxclass = $row->taxclass || 'none';
    $to_merge{$taxclass} ||= {};
    $to_merge{$taxclass}->{$row->district} ||= [];
    push @{ $to_merge{$taxclass}->{$row->district} }, $row;
  }

  # Merge the duplicates
  for my $taxclass ( keys %to_merge ) {
    for my $district ( keys %{ $to_merge{$taxclass} }) {

      # Keep the first row in the list as the target.
      # Merge the remaining rows into the target
      my $rows = $to_merge{$taxclass}->{$district};
      my $target = shift @$rows;

      while ( @$rows ) {
        merge_into( shift(@$rows), $target );
      }
    }
  }

  say "

    Merge operations completed

    Please run freeside-wa-tax-table-update.  This will update
    the merged district rows with correct county and city names

  ";

}

sub fix_usf {
  confirm_to_continue("

    Search for duplicate districts within the tax tables with
    - duplicate district column values
    - source = NULL
    - district = NOT NULL
    - taxclass = USF
    - tax > 17

    Merge these rows into a single USF row for each tax district

  ");

  my @rows = qsearch( cust_main_county => {
    taxclass => 'USF',
    source   => undef,
    state    => 'WA',
    country  => 'US',
    tax      => { op => '>',  value => 17 },
    district => { op => '!=', value => undef },
  });

  my %to_merge;
  for my $row (@rows) {
    $to_merge{$row->district} ||= [];
    push @{ $to_merge{$row->district} }, $row;
  }

  for my $dist_rows ( values %to_merge ) {
    my $target = shift @$dist_rows;
    while ( @$dist_rows ) {
      merge_into( shift(@$dist_rows), $target );
    }
  }

  say "

    USF clean up completed

    Please run freeside-wa-tax-table-update.  This will update
    the merged district rows with correct county and city names

  ";
}

sub validate_opts {

  $freeside_user = shift @ARGV
    or error_and_help('freeside_user parameter required');

  if ( @opt_merge ) {
    error_and_help(( '--merge requires a comma separated list of two taxnums'))
      unless scalar(@opt_merge) == 2
          && $opt_merge[0] =~ /^\d+$/
          && $opt_merge[1] =~ /^\d+$/;
  }

  for my $taxnum ( @opt_set_source_null ) {
    if ( $taxnum =~ /\D/ ) {
      error_and_help( "Invalid taxnum ($taxnum)" );
    }
  }
}

sub check {
  my @dupes = FS::cust_main_county->find_wa_tax_dupes;

  unless ( @dupes ) {
    say 'No duplicate tax rows detected for WA sales tax districts';
    return;
  }

  say sprintf '=== Detected %s duplicate tax rows ===', scalar @dupes;

  print_taxnum($_) for sort { $a->district <=> $b->district } @dupes;

  $log->error(
    sprintf 'Detected %s duplicate wa sales tax rows: %s',
      scalar( @dupes ),
      join( ',', map{ $_->taxnum } @dupes )
  );

  say "

    Rows are considered duplicates when they:
    - Share the same tax class
    - Share the same district
    - Contain 'wa_sales' in the source column

  ";
}

sub print_taxnum {
  my $taxnum = shift;
  die unless ref $taxnum;

  say 'taxnum: '.$taxnum->taxnum;
  say join "\n" => (
    map { sprintf('  %s:%s', $_, $taxnum->$_ ) }
    qw/district city county state tax taxname taxclass source/
  );
  print "\n";
}

sub confirm_to_continue {
  say shift;
  print "Confirm: [y/N]: ";
  my $yn = <STDIN>;
  chomp $yn;
  if ( lc $yn ne 'y' ) {
    say "\nAborted\n";
    exit;
  }
}

sub error_and_help {
  pod2usage({
    -message => sprintf( "\n\nError:\n\t%s\n\n", shift ),
    -exitval => 2,
    verbose => 1,
  });
  exit;
}

__END__

=head1 name

freeside-wa-tax-table-resolve

=head1 SYNOPSIS

  freeside-wa-tax-table-resolve --help
  freeside-wa-tax-table-resolve --check [freeside_user]
  freeside-wa-tax-table-resolve --merge 123,234 [freeside_user]
  freeside-wa-tax-table-resolve --set-source-null 1337,6553 [freeside_user]
  freeside-wa-tax-table-resolve --merge-all [freeside_user]
  freeside-wa-tax-table-resolve --fix-usf [freeside_user]

=head1 OPTIONS

=over 4

=item B<--help>

Display help and exit

=item B<--check>

Display info on any taxnums considered blocking duplicates

=item B<--merge> [source-taxnum],[target-taxnum]

Update all records referring to [source-taxnum], so they now
refer to [target-taxnum].  [source-taxnum] is deleted.

Used to merge duplicate taxnums

=item B<--set-source-null> [taxnum],[taxnum],...

Update all records for the given taxnums, by setting the
I<source> column to NULL.

Used for manually entered tax entries, incorrectly labelled
as created and managed for Washington State Sales Taxes

=item B<--merge-all>

Automatically merge all blocking duplicate taxnums.

If after reviewing all blocking duplicate taxnum rows with --check,
if all duplicate rows are safe to merge, this option will merge them all.

=item B<--fix-usf>

Fix routine for a particular USF issue

Search for duplicate districts within the tax tables with

  - duplicate district column values
  - source = NULL
  - district = NOT NULL
  - taxclass = USF
  - tax > 17

Merge these rows into a single USF row for each tax district

=back

=head1 DESCRIPTION

Tool to resolve tax table issues for customer using Washington state
sales tax districts.

If Freeside detects duplicate rows within the wa sales tax tables,
tax table updates are blocked, and a log message directs the
sysadmin to this tool.

Duplicate rows may be manually entered taxes, not related
to WA sales tax.  Or duplicate rows may have been manually entered
into freeside for other tax purposes.

Use --check to display which tax entries were detected as dupes.

For each tax entry, decide if it is a duplicate wa sales tax entry,
or some other manually entered tax.

if the row is a duplicate, merge the duplicates with the --merge
option of this script

If the row is a manually entered tax, not for WA state sales taxes,
keep the tax but remove the flag incorrectly labeling it as WA state
sales taxes with the --set-source-null option of this script

Once --check no longer returns problematic tax entries, the
wa state tax tables will be able to complete their automatic
tax rate updates

=cut