use v6.e.PREVIEW;

#| Post database
unit module DB;

use Pandoc;
use JSON::Class:auth<zef:vrurg>;

use DB::Post;
use DB::BlogMeta;
use DB::MarkdownPost;

#| A plain markdown post
class IdrisPost does Post is json {
    #| Marker for disambiguation between post types in json representation, the
    #| cheaty way
    has Bool:D $.idris = True;

    method title(--> Str:D) {
        markdown-title($!source)
    }
}

class Posts is json(:dictionary(:keyof(Int:D), MarkdownPost:D, IdrisPost:D)) {}

subset PostTypes where MarkdownPost:D | IdrisPost:D;

#| The top level posts database
class PostDB is json(:pretty) {
   #| The metadat for the blog
   has BlogMeta:D $.meta is required;
   #| A mapping from post ids to posts
   has %.posts is Posts;

   method TWEAK() {
       %!posts := Posts.new unless %!posts;
   }

   #| Get the next unused post ID
   method next-post-id(--> Int) {
       if %!posts.elems > 0 {
           %!posts.keys.max + 1
       } else {
           0
       }
   }

   #| Insert a new post to the DB, returning its id
   method insert-post(PostTypes $post --> Int) {
       my $id = self.next-post-id;
       %!posts{$id} = $post;
       $id
   }
}