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-- Biblioteca pública de materiais de estudo.
create table if not exists public.study_materials (
  id uuid primary key default gen_random_uuid(),
  owner_id uuid not null default auth.uid() references auth.users(id) on delete cascade,
  subject_index integer not null check (subject_index between 0 and 3),
  topic_index integer not null check (topic_index >= 0),
  kind text not null check (kind in ('Aula','Simulado','Resumo','PDF','Link','Outro')),
  title text not null check (char_length(title) between 1 and 120),
  description text not null default '' check (char_length(description) <= 500),
  url text check (url is null or url ~ '^https?://'),
  created_at timestamptz not null default now()
);
create index if not exists study_materials_topic_idx on public.study_materials (subject_index, topic_index, created_at desc);
alter table public.study_materials enable row level security;
grant select on table public.study_materials to anon, authenticated;
grant insert, update, delete on table public.study_materials to authenticated;
drop policy if exists "Public can read study materials" on public.study_materials;
create policy "Public can read study materials" on public.study_materials for select to anon, authenticated using (true);
drop policy if exists "Signed-in users can publish study materials" on public.study_materials;
create policy "Signed-in users can publish study materials" on public.study_materials for insert to authenticated with check (auth.uid() = owner_id);
drop policy if exists "Authors can update their study materials" on public.study_materials;
create policy "Authors can update their study materials" on public.study_materials for update to authenticated using (auth.uid() = owner_id) with check (auth.uid() = owner_id);
drop policy if exists "Authors can delete their study materials" on public.study_materials;
create policy "Authors can delete their study materials" on public.study_materials for delete to authenticated using (auth.uid() = owner_id);