package Trog::DataModule;

use strict;
use warnings;

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

use Trog::Utils;
use Trog::Auth();

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 ) {

    my %user2display;

    # 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};

            #XXX I don't remember what this fixes, but it also breaks things.  URI::Escape usage instead is indicated.
            $subj->{$param} =~ s/ /%20/g;
        }

        $user2display{$subj->{user}} //= Trog::Auth::username2display( $subj->{user} );
        $subj->{display_name} = $user2display{$subj->{user}};

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

            #XXX this needs to be correctly populated in the form?
            if ($is_user_page) {
                my $display_name = $user2display{$subj->{user}};
                die "No display name for user!" unless $display_name;
                $subj->{local_href} = "/users/$display_name";
            }
        }
        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->{user_class}   = $user2display{$subj->{user}};
        $subj->{user_class}   =~ tr/ /_/;

        $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
    if ( $query->{older} ) {
        $query->{older} =~ s/[^0-9]//g;
        @filtered = grep { $_->{created} < $query->{older} } @filtered;
    }
    if ( $query->{newer} ) {
        $query->{newer} =~ s/[^0-9]//g;
        @filtered = grep { $_->{created} > $query->{newer} } @filtered;
    }

    # 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->{display_name}";
            $post->{title}      //= $post->{display_name};
        }

        $post->{local_href} //= "/posts/$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
    Trog::Utils::restart_parent();

    # Gorilla cache invalidation
    Path::Tiny::path('www/statics')->remove_tree;

    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;