package Trog::Data::FlatFile;

use strict;
use warnings;

no warnings 'experimental';
use feature qw{signatures};

use Carp qw{confess};
use JSON::MaybeXS;
use File::Slurper;
use File::Copy;
use Mojo::File;

use lib 'lib';
use Trog::SQLite::TagIndex;

use parent qw{Trog::DataModule};

our $datastore = 'data/files';
sub lang { 'Perl Regex in Quotemeta' }
sub help { 'https://perldoc.perl.org/functions/quotemeta.html' }

=head1 Trog::Data::FlatFile

This data model has multiple drawbacks, but is "good enough" for most low-content and few editor applications.
You can only post once per second due to it storing each post as a file named after the timestamp.

=cut

our $parser = JSON::MaybeXS->new( utf8 => 1);

sub read ($self, $query={}) {
    $query->{limit} //= 25;

    #Optimize direct ID
    my @index;
    if ($query->{id}) {
        @index = ("$datastore/$query->{id}");
    } else {
        if (-f 'data/posts.db') {
            @index = map { "$datastore/$_" } Trog::SQLite::TagIndex::posts_for_tags(@{$query->{tags}})
        }
        @index = $self->_index() unless @index;
    }

    my @items;
    foreach my $item (@index) {
        next unless -f $item;
        my $slurped = eval { File::Slurper::read_text($item) };
        if (!$slurped) {
            print "Failed to Read $item:\n$@\n";
            next;
        }
        my $parsed  = eval { $parser->decode($slurped) };
        if (!$parsed) {
            # Try and read it in binary in case it was encoded incorrectly the first time
	    $slurped = eval { File::Slurper::read_binary($item) };
	    $parsed  = eval { $parser->decode($slurped) };
	    if (!$parsed) {
                print "JSON Decode error on $item:\n$@\n";
                next;
            }
        }

        #XXX this imposes an inefficiency in itself, get() will filter uselessly again here
        my @filtered = $query->{raw} ? @$parsed : $self->filter($query,@$parsed);

        push(@items,@filtered) if @filtered;
        next if $query->{limit} == 0; # 0 = unlimited
        last if scalar(@items) == $query->{limit};
    }

    return \@items;
}

sub _index ($self) {
    confess "Can't find datastore in $datastore !" unless -d $datastore;
    opendir(my $dh, $datastore) or confess;
    my @index = grep { -f } map { "$datastore/$_" } readdir $dh;
    closedir $dh;
    return sort { $b cmp $a } @index;
}

sub routes ($self) {
    return Trog::SQLite::TagIndex::routes();
}

sub aliases ($self) {
    return Trog::SQLite::TagIndex::aliases();
}

sub write($self,$data) {
    foreach my $post (@$data) {
        my $file = "$datastore/$post->{id}";
        my $update = [$post];
        if (-f $file) {
            my $slurped = File::Slurper::read_binary($file);
            my $parsed  = $parser->decode($slurped);

            $update = [(@$parsed, $post)];
        }

        mkdir $datastore;
        open(my $fh, '>', $file) or confess "Could not open $file";
        print $fh $parser->encode($update);
        close $fh;

        Trog::SQLite::TagIndex::add_post($post,$self);
    }
}

sub count ($self) {
    my @index = $self->_index();
    return scalar(@index);
}

sub delete($self, @posts) {
    foreach my $update (@posts) {
        unlink "$datastore/$update->{id}" or confess;
        Trog::SQLite::TagIndex::remove_post($update);
    }
    return 0;
}

sub tags($self) {
    return Trog::SQLite::TagIndex::tags();
}

1;