package LIMS::Local::ExcelHandler;

# ParseExcel_XLHTML speeds up Spreadsheet::ParseExcel; requires xlhtml package (apt-get install xlhtml)
# IO::All & .csv file *much* faster than ParseExcel_XLHTML
# Text::CSV::Simple - about 50% of speed of IO::All->getline, but handles native .csv files better

use strict;
use warnings;

use File::stat;
use Data::Dumper;
use Text::CSV::Simple;
use LIMS::Local::Config;
use Spreadsheet::ParseExcel::Simple;

# use Time::HiRes qw(gettimeofday tv_interval); my $t0 = [gettimeofday];
# use Spreadsheet::ParseExcel_XLHTML; # use Spreadsheet::ParseExcel::Simple; # too slow

my $cfg = LIMS::Local::Config->instance;
my $path_to_app_root = $cfg->{path_to_app_root}
    || die "Couldn't find path to application directory"; # warn $path_to_app_root;

my ($specialities, $locales); # for lookup hashref tables, used if lookup = clinician

#------------------------------------------------------------------------------
sub new {
    my $class = shift;
    my $self  = {};

    $self->{WORKBOOK}      = undef;
    $self->{LOCATION_TYPE} = undef;

    bless ($self, $class);

    return $self;
}

#------------------------------------------------------------------------------
# setter: receives target type (hospital, clinician, etc) as arg, sets target xls file for target type:
# getter & setter: returns xls filename
sub source {
    my $self = shift;

    if (@_) {
        $self->{LOCATION_TYPE} = shift;

        $self->{WORKBOOK} = $self->_get_file('filename')
            || die "Cannot find target xls file for location type: $self->{LOCATION_TYPE}";
    }
    else {
        return $self->{WORKBOOK};
    }
}

#------------------------------------------------------------------------------
sub filedata {
	my $self = shift;

    my $src_file = $self->source;
    my $path_to_file = $path_to_app_root . '/src/data/' . $src_file . '.csv'; # warn $path_to_file;
	my $filedate = DateTime->from_epoch( epoch => stat($path_to_file)->mtime );
	my $age_in_months = DateTime->now->subtract_datetime($filedate)->delta_months;

	return { filename => $src_file, age => $age_in_months };
}

#------------------------------------------------------------------------------
# parse source file for $terms:
sub parse {
    my $self = shift;
    my $term = shift;

    # my $matches = $self->_parse_excel($term); # very slow
    # my $matches = $self->_parse_excel_xlhtml($term); # faster than ParseExcel
    my $matches = $self->_parse_csv_file($term); # massively faster even than ParseExcel_XLHTML

    # return ref to array of hashrefs:
    return $matches;
}

#------------------------------------------------------------------------------
sub parse_xl_file {
	my ($self, $xl_file) = @_; # warn $xl_file;
    # use Spreadsheet::ParseExcel_XLHTML qw/-install/; # speeds up 4x

	-e $xl_file or die "file does not exist: $xl_file";

    my $xls = Spreadsheet::ParseExcel::Simple->read($xl_file) or die $!;

    my @worksheets = $xls->sheets;
    my $worksheet  = $worksheets[0];
	
	my @data = (); # create array of row arrayrefs:
    while ($worksheet->has_data) {
		push @data, [ $worksheet->next_row ]; # next_row() = array mode
    }
    return \@data;
}

#------------------------------------------------------------------------------
sub fetch_all {
	my $self = shift;

	my $data = $self->_read_file;

	return $data;
}

#------------------------------------------------------------------------------
sub fetch_cols {
    my $self = shift;
    my $args = shift;
    
    my $fields = $args->{fields}; # cols to return data from
    my $select = $args->{select}; # which field to select on eg 'practice_code'
    my $value  = $args->{value};  # value of field eg 'B12345'

    my $xls_file = $self->source;
    my $src_file = $path_to_app_root . '/src/data/' . $xls_file; # warn $src_file;

    my $parser = Text::CSV::Simple->new();
    
    # get field definitions arrayref (eg code name null addr1, etc):    
    my %index = do {
        my $fields = $self->_get_file('fields'); # warn Dumper $fields;
        map{ $fields->[$_], $_ } (0 .. scalar @$fields - 1); # array to hash
    }; # warn Dumper \%index;
    
    # get array positions for data fields:
    my @required = @index{@$fields}; # warn Dumper \@required;
    $parser->want_fields(@required);

    # get array position for select field:
    my $select_pos = $index{$select}; # warn Dumper $select_pos;
    
    # die OK here: "Each time we call a trigger we wrap it in an eval block. 
    # If the eval block catches an error we simply call 'next' on the loop."
    $parser->add_trigger( after_parse => sub {
        my ($self, $data) = @_; # warn $data->[14];
        die unless $data->[$select_pos] eq $value;
      });
    
    my @data = $parser->read_file($src_file . '.csv'); # warn Dumper \@data;
    return \@data;
}

#------------------------------------------------------------------------------
# uses Text::CSV::Simple - faster than ParseExcel, but slower than direct read
# (IO::All->getline); but speed boost using add_trigger() in _read_file()
sub _parse_csv_file {
    my $self = shift;
    my $term = shift;

	my $src_file = $self->source;
    my $data = $self->_read_file($term);
	my $fields = $self->_get_file('fields');

    if ($src_file eq 'econcur') {
        $specialities = $self->_get_specialities;
        $locales = $self->_get_locales;
    }

    my @matches; # for results

    ROW: foreach my $row (@$data) { # warn Dumper $row; next;
        # next ROW unless grep { $row->{$_} =~ /$term/i } keys %$row; - using add_trigger() now
        if ($src_file eq 'econcur') {
            $self->_manipulate_clinician_data($row);
        }

        my $display = join ', ', map $row->{$_},
            grep $row->{$_}, # if field contains entry
                grep $_ !~ /^(code|null)$/, # skip code field & nulls
                    @$fields;

        push @matches, {
            code    => $row->{code},
            display => $display,
        };
    } # timings($t0);

    return \@matches;
}

#------------------------------------------------------------------------------
=begin # fastest method - reads csv file directly:
sub parse_csv_file {
    my $self = shift;
    my $term = shift;

    my $xls_file = $self->source;

    my $path_to_file = $path_to_app_root . '/src/data/' . $xls_file;

    my $io = io($path_to_file . '.csv');

    my @matches; # for results
    # get field definitions hashref (eg CODE => 0, NAME => 1, etc):
    my $FIELD = $self->_get_file('fields');
    # get array of required field positions (eg 0, 1, 4, 5, etc):
    my @field_positions = grep $_, @{$FIELD}{ qw(NAME CODE2 ADDR1 ADDR2 ADDR3 ADDR4 PCODE) };

    use Time::HiRes qw(gettimeofday tv_interval);
    my $t0 = [gettimeofday];

    {    # localise to switch off warnings:
        no warnings 'uninitialized'; # for regex on potentially empty fields

#       timings($t0);
        ROW : while ( my $line = $io->getline ) { # TODO: doesn't work if row contains comma within field
            # split line on comma:
            my @cells = split ',', $line; # warn Dumper @cells; next;
            # get national code, or skip line:
            my $code_cell = $cells[$FIELD->{CODE}] || next ROW; # warn Dumper $code_cell; next;
            # get rest of required fields (if defined) into array:
            my @data_cells = grep $_, @cells[@field_positions]; # warn Dumper \@data_cells; next;

            # look for matches in all collected fields, or skip line:
            next ROW unless grep { $_ =~ /$term/i } (@data_cells, $code_cell);

            push @matches, {
                code    => $code_cell,
                display => join ', ', @data_cells,
            };
        }
       timings($t0);
    }

    return \@matches;
}
=cut

#------------------------------------------------------------------------------
=begin # use the Spreadsheet::ParseExcel_XLHTML method - several times faster than Spreadsheet::ParseExcel:
sub _parse_excel_xhtml {
    my $self = shift;
    my $term = shift;

    my $xls_file = $self->source;

    my $path_to_file = $path_to_app_root . '/src/data/' . $xls_file;

    my $excel = new Spreadsheet::ParseExcel_XLHTML;

    my $workbook  = $excel->Parse($path_to_file . '.xls');
    my $worksheet = $workbook->Worksheet(0);

    my ( $row_min, $row_max ) = $worksheet->row_range();

    my @matches; # results array
    my $FIELD_FOR = $self->_get_file('fields'); # hashref

    ROW : for my $row ( $row_min .. $row_max ) {
        my $code_cell = $worksheet->get_cell( $row, $FIELD_FOR->{CODE} );
        next ROW unless $code_cell; # next ROW unless length $code > 3; need parent code for appropriate matching

        my @location_cells;
        CELL : for my $col ( @{$FIELD_FOR}{ qw(NAME CODE2 ADDR1 ADDR2 ADDR3 ADDR4 PCODE) } ) {
            my $cell = $worksheet->get_cell( $row, $col );
            next CELL unless $cell;
            push @location_cells, $cell;
        }

        next ROW unless grep $_->value =~ /$term/i, (@location_cells, $code_cell);

        push @matches, {
            code    => $code_cell->value,
            display => join ', ', map { $_->value } @location_cells,
        };
    }

    return \@matches;
}
=cut

#------------------------------------------------------------------------------
=begin # uses Spreadsheet::ParseExcel::Simple - much slower than Spreadsheet::ParseExcel_XLHTML
sub _parse_excel {
    my $self = shift;
    my $term = shift;

    my $xls_file = $self->source_file;

    my $path_to_file = $path_to_app_root . '/src/data/' . $xls_file;

    my $xls = Spreadsheet::ParseExcel::Simple->read($path_to_file . '.xls');

    my @worksheets = $xls->sheets;
    my $worksheet  = $worksheets[0];

    my $FIELD_FOR = $self->_get_file('fields');

    my @matches; # results array

    while ($worksheet->has_data) {
        my @data = $worksheet->next_row; # warn Dumper \@data;

        # skip regional entries eg RR8, RAE, etc
        next unless length $data[ $FIELD_FOR->{CODE} ] > 3; # warn Dumper $data[ $FIELD_FOR->{CODE} ];

        next unless grep $data[ $FIELD_FOR->{$_} ] =~ /$term/i, qw(NAME ADDR CITY);
            # warn Dumper join ', ', @data[ @$FIELD_FOR{ qw(NAME ADDR CITY PCODE) } ];

        push @matches, {
            code    => $data[ $FIELD_FOR->{CODE} ],
            display => join ', ', @data[ @$FIELD_FOR{ qw(NAME ADDR1 CITY PCODE) } ],
        };
    }

    # return ref to array of hashrefs:
    return \@matches;
}
=cut

#------------------------------------------------------------------------------
sub _get_file {
    my $self = shift;
    my $attr = shift || die 'attribute arg required';

    my $location_type = $self->{LOCATION_TYPE}
        or die 'Cannot get location type'; # warn 'LOCATION TYPE:'.$location_type;

    my %xls_file_for = ( # NB: "Fields named 'null' vanish into the ether".
        hospital => {
            filename => 'etrust',
            fields => [ qw( code name null null addr1 null null addr4 null post_code ) ],
        },

        prison   => {
            filename => 'eprison',
            fields => [ qw( code name null null addr1 addr2 addr3 addr4 null post_code ) ],
        },
        GP => {
            filename => 'egpcur',
            fields => [ qw( code name null null addr1 addr2 addr3 addr4 null post_code null
                null null null practice_code) ],
        },
        practice => {
            filename => 'epraccur',
            fields => [ qw( code name null null addr1 addr2 addr3 addr4 null post_code ) ],
        },
        independant => {
            filename => 'ephpsite',
            fields => [ qw( code name null null addr1 addr2 addr3 addr4 null post_code ) ],
        },
        clinician => {
            filename => 'econcur',
            fields => [ qw( null code name init sex speciality_code null org_code ) ],
        },		
    );

    return $xls_file_for{$location_type}{$attr};
}

#------------------------------------------------------------------------------
sub _read_file {
	my $self = shift;
    my $term = shift; # optional term to search for 

    my $xls_file = $self->source;
    my $path_to_file = $path_to_app_root . '/src/data/' . $xls_file;

    # get field definitions arrayref (eg code name null addr1, etc):
    my $fields = $self->_get_file('fields'); # warn Dumper $fields; 
    
    my $parser = Text::CSV::Simple->new();
    $parser->field_map(@$fields);

    if ($term) { # warn Dumper $term;
        # get array positions of @$fields non-null vals:
        my @indexes = grep { $fields->[$_] ne 'null' } (0 .. @$fields -1); # warn @indexes;
        # this is faster than collecting all rows & discarding all not matching $term
        $parser->add_trigger( after_parse => sub {
            my ($self, $data) = @_; # warn Dumper $data;
            die unless grep $data->[$_] =~ /$term/i, @indexes; # 'die' is OK - see docs
          });
    }
    my @data = $parser->read_file($path_to_file . '.csv'); # timings($t0);

	return \@data;
}

#------------------------------------------------------------------------------
sub _get_locales {
    my $self = shift;

    my $file = $path_to_app_root . '/src/data/etr.csv';

    my $parser = Text::CSV::Simple->new();
    $parser->want_fields(0,1);

    my @data = $parser->read_file($file);

    my %locales;

    foreach my $row (@data) { # warn Dumper $row; next;
        my ($code,$name) = @$row;
        $locales{$code} = $name;
    }

    return \%locales;
}

#------------------------------------------------------------------------------
sub _get_specialities {
    my $self = shift;

    my $file = $path_to_app_root . '/src/data/specialities.csv';

    my $parser = Text::CSV::Simple->new();
    $parser->want_fields(0,1);

    my @data = $parser->read_file($file);

    my %specialities;

    foreach my $row (@data) { # warn Dumper $row; next;
        my ($code,$name) = @$row;
        $specialities{$code} = uc $name;
    }

    return \%specialities;
}

#------------------------------------------------------------------------------
sub _manipulate_clinician_data {
    my $self = shift;
    my $row  = shift;

    my $id = sprintf '%s %s [%s]', @{$row}{qw(name init sex)};
    map delete $row->{$_}, qw(name init sex);
    $row->{name} = $id;

    my $org_code = $row->{org_code};
    $row->{org_code} = $locales->{$org_code} || "UNKNOWN LOCATION [$org_code]";
    my $speciality_code = $row->{speciality_code};
    $row->{speciality_code} = $specialities->{$speciality_code} || "UNKNOWN SPECIALITY [$speciality_code]";
}

#------------------------------------------------------------------------------
sub timings {
#    my $t0 = shift;
#    warn sprintf "%.4f sec\n", tv_interval $t0, [gettimeofday];
}

1;