-- Read through the server only: never expose session secrets or round answers.
create index game_sessions_leaderboard_idx
  on public.game_sessions (difficulty, owner_id)
  where current_round = 5 and owner_id is not null;

create function public.player_leaderboard(
  p_difficulty text default 'all',
  p_search text default '',
  p_page integer default 1,
  p_limit integer default 25
) returns jsonb
language sql stable security invoker set search_path = '' as $$
  with completed as (
    select s.id, s.owner_id, sum((r.result->>'score')::integer) as score
    from public.game_sessions s
    join public.game_rounds r on r.session_id = s.id
    where s.current_round = 5 and s.owner_id is not null
      and (p_difficulty = 'all' or s.difficulty = p_difficulty)
    group by s.id, s.owner_id
    having count(*) = 5 and count(r.result) = 5
  ), players as (
    select p.id as player_id, p.display_name,
      max(c.score) as best_score, avg(c.score) as average_score,
      count(*) as games_played
    from completed c join public.profiles p on p.id = c.owner_id
    group by p.id, p.display_name
  ), ranked as (
    select row_number() over (
      order by best_score desc, average_score desc, games_played desc, player_id
    ) as rank, player_id, display_name, best_score,
      round(average_score)::integer as average_score, games_played
    from players
  ), matched as (
    select * from ranked
    where strpos(lower(display_name), lower(left(trim(coalesce(p_search, '')), 64))) > 0
  ), settings as (
    select greatest(1, least(coalesce(p_limit, 25), 100)) as page_size
  ), counts as (
    select (select count(*) from matched) as matching_players,
      greatest(1, ceil((select count(*) from matched)::numeric / settings.page_size)::integer) as pages
    from settings
  ), pagination as (
    select *, greatest(1, least(coalesce(p_page, 1), pages)) as page
    from counts cross join settings
  ), entries as (
    select * from matched order by rank
    limit (select page_size from pagination)
    offset (select (page - 1) * page_size from pagination)
  )
  select jsonb_build_object(
    'entries', coalesce((select jsonb_agg(to_jsonb(e) order by rank) from entries e), '[]'::jsonb),
    'leaders', coalesce((select jsonb_agg(to_jsonb(r) order by rank) from
      (select * from ranked order by rank limit 3) r), '[]'::jsonb),
    'total_players', (select count(*) from ranked),
    'total_games', (select count(*) from completed),
    'matching_players', matching_players, 'page', page, 'pages', pages
  ) from pagination;
$$;

revoke all on function public.player_leaderboard(text, text, integer, integer) from public, anon, authenticated;
grant execute on function public.player_leaderboard(text, text, integer, integer) to service_role;