package Trog::DataModule;

use strict;
use warnings;

use UUID::Tiny;
use List::Util;
use File::Copy;
use Mojo::File;
use Plack::MIME;

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

=head1 QUERY FORMAT

The $query_language and $query_help variables are presented to the user as to how to use the search box in the tCMS header.

=head1 POST STRUCTURE

Posts generally need to have the following:

    data: Brief description of content, or the content itself.
    content_type: What this content actually is.  Used to filter into the appropriate pages.
    href: Primary link.  This is the subject of a news post, or a link to the item itself.  Can be local or remote.
    local_href: Backup link.  Automatically created link to a static cache of the content.
    title: Title of the content.  Used as link name for the 'href' attribute.
    user: User was banned for this post
    id: Internal identifier in datastore for the post.
    tags: array ref of appropriate tags.
    created: timestamp of creation of this version of the post
    version: revision # of this post.

=head1 CONSTRUCTOR

=head2 new(Config::Simple $config)

Try not to do expensive things here.

=cut

sub new ($class, $config) {
    $config = $config->vars();
    return bless($config, $class);
}

#It is required that subclasses implement this
sub lang  ($self) { ... }
sub help  ($self) { ... }
sub read  ($self,$query={}) { ... }
sub write ($self) { ... }
sub count ($self) { ... }
sub tags  ($self) { ... }

=head1 METHODS

=head2 get(%request)

Queries the data model.  Should return the following:

    id   => Filter down to just the post by ID.  May be subsequently filtered by ACL, resulting in a 404 (which is good, as it does not disclose info).

    version => if id is passed, return the provided post version rather than the most recent one

    tags => ARRAYREF of tags, any one of which is required to give a result.  If none are passed, no filtering is performed.

    acls => ARRAYREF of acl tags, any one of which is required to give result. Filter applies after tags.  'admin' ACL being present skips this filter.

    page => Offset multiplier for pagination.

    limit => Offset for pagination.

    like => Search query, as might be passed in the search bar.

    author => filter by post author

If it is more efficient to filter within your data storage engine, you probably should override this method.
As implemented, this takes the data as a given and filters in post.

=cut

sub get ($self, %request) {

    my $posts = $self->read(\%request);
    return @$posts if $request{raw};

    my @filtered = $self->filter(\%request, @$posts);
    @filtered = $self->_fixup(@filtered);
    @filtered = $self->paginate(\%request,@filtered);
    return @filtered;
}

sub _fixup ($self, @filtered) {
    # urlencode spaces in filenames
    @filtered = map {
        my $subj = $_;
        foreach my $param (qw{href preview video_href audio_href local_href wallpaper}) {
            next unless exists $subj->{$param};
            $subj->{$param} =~ s/ /%20/g;
        }

        #XXX Add dynamic routing data for posts which don't have them (/posts/$id) and (/users/$user)
        my $is_user_page = grep { $_ eq 'about' } @{$subj->{tags}};
        if (!exists $subj->{local_href}) {
            $subj->{local_href} = "/posts/$subj->{id}";
            $subj->{local_href} = "/users/$subj->{user}" if $is_user_page;
        }
        if (!exists $subj->{callback}) {
            $subj->{callback} = "Trog::Routes::HTML::posts";
            $subj->{callback} = "Trog::Routes::HTML::users" if $is_user_page;
        }

        $subj->{method} = 'GET' unless exists($subj->{method});

        $subj
    } @filtered;

    return @filtered;
}

sub filter ($self, $query, @filtered) {
    $query->{acls} //= [];
    $query->{tags} //=[];
    $query->{exclude_tags} //= [];

    # If an ID is passed, just get that (and all it's prior versions)
    if ($query->{id}) {
        @filtered = grep { $_->{id} eq $query->{id} } @filtered;
        @filtered = _dedup_versions($query->{version}, @filtered);
        return @filtered;
    }

    # XXX aclname and id are essentially serving the same purpose, should unify
    if ($query->{aclname}) {
        @filtered = grep { ($_->{aclname} || '') eq $query->{aclname} } @filtered;
        @filtered = _dedup_versions($query->{version}, @filtered);
        return @filtered;
    }

    @filtered = _dedup_versions(undef, @filtered);

    #Filter out posts which are too old
    #Coerce older into numeric
    $query->{older} =~ s/[^0-9]//g if $query->{older};
    @filtered = grep { $_->{created} < $query->{older} } @filtered if $query->{older};

    # Filter posts not matching the passed tag(s), if any
    @filtered = grep {
        my $tags = $_->{tags};
        grep { my $t = $_; grep { $t eq $_ } @{$query->{tags}} } @$tags
    } @filtered if @{$query->{tags}};

    # Filter posts *matching* the passed exclude_tag(s), if any
    @filtered = grep {
        my $tags = $_->{tags};
        !grep { my $t = $_; grep { $t eq $_ } @{$query->{exclude_tags}} } @$tags
    } @filtered if @{$query->{exclude_tags}};

    # Filter posts without the proper ACLs
    @filtered = grep {
        my $tags = $_->{tags};
        grep { my $t = $_; grep { $t eq $_ } @{$query->{acls}} } @$tags
    } @filtered unless grep { $_ eq 'admin' } @{$query->{acls}};

    @filtered = grep { $_->{title} =~ m/\Q$query->{like}\E/i || $_->{data} =~ m/\Q$query->{like}\E/i } @filtered if $query->{like};

    @filtered = grep { $_->{user} eq $query->{author} } @filtered if $query->{author};

    return @filtered;
}

sub paginate ($self, $query, @filtered) {
    my $offset = int($query->{limit} // 25);
    $offset = @filtered < $offset ? @filtered : $offset;
    @filtered = splice(@filtered, ( int($query->{page}) -1) * $offset, $offset) if $query->{page} && $query->{limit};
    return @filtered;
}

sub _dedup_versions ($version=-1, @posts) {

    #ASSUMPTION made here - if we pass version this is direct ID query
    if (defined $version) {
        my $version_max = List::Util::max(map { $_->{version} } @posts);

        return map {
            $_->{version_max} //= $version_max;
            $_
        } grep { $_->{version} eq $version } @posts;
    }

    my @uniqids = List::Util::uniq(map { $_->{id} } @posts);
    my %posts_deduped;
    for my $id (@uniqids) {
        my @ofid = sort { $b->{version} <=> $a->{version} } grep { $_->{id} eq $id } @posts;
        my $version_max = List::Util::max(map { $_->{version } } @ofid);
        $posts_deduped{$id} = $ofid[0];
        $posts_deduped{$id}{version_max} = $version_max;
        # Show orig creation date, and original author.
        # XXX this doesn't show the mtime correctly for whatever reason, so I'm omitting it from the interface
        $posts_deduped{$id}{modified} = $ofid[0]{created};
        $posts_deduped{$id}{created}  = $ofid[-1]{created};
        $posts_deduped{$id}{author}   = $ofid[-1]{author};
    }
    my @deduped = @posts_deduped{@uniqids};

    return @deduped;
}

=head2 count() = INT $num

Returns the total number of posts.
Used to determine paginator parameters.

=cut

=head2 add(@posts) = BOOL $failed_or_not

Add the provided posts to the datastore.
If any post already exists with the same id, a new post with a version higher than it will be added.

Passes an array of new posts to add to the data store module's write() function.

You probably won't want to override this.

=cut

sub add ($self, @posts) {
    my @to_write;

    foreach my $post (@posts) {
        $post->{id} //= UUID::Tiny::create_uuid_as_string(UUID::Tiny::UUID_V1, UUID::Tiny::UUID_NS_DNS);
        $post->{aliases} //= [];
        $post->{aliases} = [$post->{aliases}] unless ref $post->{aliases} eq 'ARRAY';

        if ($post->{aclname}) {
            # Then this is a series
            $post->{local_href} //= "/$post->{aclname}";
            push(@{$post->{aliases}}, "/posts/$post->{id}", "/series/$post->{id}" );
        }

        $post->{callback}   //= 'Trog::Routes::HTML::posts';
        # If this is a user creation post, add in the /user/ route
        if ($post->{callback} eq 'Trog::Routes::HTML::users') {
            $post->{local_href} = "/users/$post->{user}";
        }

        $post->{local_href} //= "/posts/$post->{id}";
        $post->{method}     //= 'GET';
        $post->{created}    = time();
        my @existing_posts = $self->get( id => $post->{id} );
        if (@existing_posts) {
            my $existing_post = $existing_posts[0];
            $post->{version}  = $existing_post->{version};
            $post->{version}++;
        }
        $post->{version} //= 0;

        $post = _process($post);

        push @to_write, $post;
    }
    $self->write(\@to_write);

    #hup the parent to refresh the routing table IFF we aren't in an interactive session, such as migrate.pl
    if (!$ENV{NOHUP}) {
        my $parent = getppid;
        kill 'HUP', $parent;
    }

    return 0;
}

#XXX this level of post-processing seems gross, but may be unavoidable
# Not actually a subprocess, kek
sub _process ($post) {

    $post->{href}      = _handle_upload($post->{file}, $post->{id})             if $post->{file};
    $post->{preview}   = _handle_upload($post->{preview_file}, $post->{id})     if $post->{preview_file};
    $post->{wallpaper} = _handle_upload($post->{wallpaper_file}, $post->{id})   if $post->{wallpaper_file};
    $post->{preview}   = $post->{href} if $post->{app} && $post->{app} eq 'image';
    delete $post->{app};
    delete $post->{file};
    delete $post->{preview_file};
    delete $post->{wallpaper_file};

    delete $post->{scheme};
    delete $post->{route};
    delete $post->{domain};

    # Handle acls/tags
    $post->{tags} //= [];
    $post->{acls} //= [];
    @{$post->{tags}} = grep { my $subj = $_; !grep { $_ eq $subj} qw{public private unlisted} } @{$post->{tags}};
    push(@{$post->{tags}}, @{$post->{acls}}) if $post->{visibility} eq 'private';
    delete $post->{acls};
    push(@{$post->{tags}}, $post->{visibility});

    # Add the 'series' tag if we are in a series, restrict to relevant acl
    if ($post->{series}) {
        push(@{$post->{tags}}, 'series');
        push(@{$post->{tags}}, $post->{series});
    }

    #Filter adding the same acl twice
    @{$post->{tags}}    = List::Util::uniq(@{$post->{tags}});
    @{$post->{aliases}} = List::Util::uniq(@{$post->{aliases}});

    # Handle multimedia content types
    if ($post->{href}) {
        my $mf = Mojo::File->new("www/$post->{href}");
        my $ext = '.'.$mf->extname();
        $post->{content_type} = Plack::MIME->mime_type($ext) if $ext;
    }
    if ($post->{video_href}) {
        my $mf = Mojo::File->new("www/$post->{video_href}");
        my $ext = '.'.$mf->extname();
        $post->{video_content_type} = Plack::MIME->mime_type($ext) if $ext;
    }
    if ($post->{audio_href}) {
        my $mf = Mojo::File->new("www/$post->{audio_href}");
        my $ext = '.'.$mf->extname();
        $post->{audio_content_type} = Plack::MIME->mime_type($ext) if $ext;
    }
    $post->{content_type} ||= 'text/html';

    $post->{is_video}   = 1 if $post->{content_type} =~ m/^video\//;
    $post->{is_audio}   = 1 if $post->{content_type} =~ m/^audio\//;
    $post->{is_image}   = 1 if $post->{content_type} =~ m/^image\//;
    $post->{is_profile} = 1 if grep {$_ eq 'about' } @{$post->{tags}};

    return $post;
}

sub _handle_upload ($file, $uuid) {
    my $f = $file->{tempname};
    my $newname = "$uuid.$file->{filename}";
    File::Copy::move($f, "www/assets/$newname");
    return "/assets/$newname";
}

=head2 delete(@posts)

Delete the following posts.
Will remove all versions of said post.

You should override this, it is a stub here.

=cut

sub delete ($self) { die 'stub' }

=head2 routes() = HASH

Returns the routes to each post.
You should override this for performance reasons, as it's just a wrapper around get() by defualt.

=cut

sub routes($self) {
    my %routes = map { $_->{local_href} => { method => $_->{method}, callback => \&{$_->{callback}} } } ($self->get( limit => 0, acls => ['admin'] ));
    return %routes;
}

=head2 aliases() = HASH

Returns the aliases for each post, indexed by aliases.
You should override this for performance reasons, as it's just a wrapper around get() by defualt.

=cut

sub aliases($self) {
    my @posts = $self->get( limit => 0, acls => ['admin'] );
    my %aliases;
    foreach my $post (@posts) {
        @aliases{@{$post->{aliases}}} = $post->{local_href};
    }
    return %aliases;
}

1;