-- 0004_perfil_maestros_avatares.sql
-- 3 bloques:
--  A) tabla prestamos.maestros (catalogo de tutores) + RLS
--  B) profiles.tutor_id + profiles.foto_path
--  C) bucket 'avatares' publico con RLS por carpeta = uid
-- + update de crear_solicitud: fallback a nombre del tutor si el
--   alumno deja p_maestro_responsable vacio.

begin;

-- ============================================================
-- A) Tabla de maestros (catalogo admin-managed)
-- ============================================================
create table if not exists prestamos.maestros (
  id serial primary key,
  nombre text not null unique,
  activo boolean not null default true,
  created_at timestamptz not null default now()
);

alter table prestamos.maestros enable row level security;

drop policy if exists maestros_read_all    on prestamos.maestros;
drop policy if exists maestros_admin_write on prestamos.maestros;

create policy maestros_read_all on prestamos.maestros
  for select to authenticated using (true);

create policy maestros_admin_write on prestamos.maestros
  for all to authenticated
  using (prestamos.is_admin())
  with check (prestamos.is_admin());

grant select, insert, update, delete on prestamos.maestros to authenticated, service_role;
grant usage, select on prestamos.maestros_id_seq to authenticated, service_role;

insert into prestamos.maestros (nombre) values
  ('Sin especificar')
on conflict (nombre) do nothing;

-- ============================================================
-- B) profiles: tutor_id + foto_path
-- ============================================================
alter table prestamos.profiles
  add column if not exists tutor_id int references prestamos.maestros(id) on delete set null,
  add column if not exists foto_path text;

-- policy profiles_update_self (definida en 0001) usa:
--   with check (id = auth.uid() and rol = (select rol from ...))
-- solo bloquea cambios al rol, permite editar matricula/semestre/tutor_id/foto_path.
-- No requiere cambios.

-- ============================================================
-- C) Bucket 'avatares' publico + policies por carpeta = uid
--    Path pattern esperado: '<uid>/<timestamp>.<ext>'
-- ============================================================
insert into storage.buckets (id, name, public)
values ('avatares', 'avatares', true)
on conflict (id) do update set public = true;

drop policy if exists "avatares_read_all"      on storage.objects;
drop policy if exists "avatares_owner_write"   on storage.objects;

create policy "avatares_read_all" on storage.objects
  for select to anon, authenticated
  using (bucket_id = 'avatares');

create policy "avatares_owner_write" on storage.objects
  for all to authenticated
  using (
    bucket_id = 'avatares'
    and (storage.foldername(name))[1] = auth.uid()::text
  )
  with check (
    bucket_id = 'avatares'
    and (storage.foldername(name))[1] = auth.uid()::text
  );

-- ============================================================
-- D) crear_solicitud: si p_maestro_responsable llega vacio,
--    autocompletar con el nombre del tutor guardado en profiles.
--    Si el usuario tampoco tiene tutor, sigue el raise
--    'maestro_responsable_requerido' original -> el checkout ya
--    guarda contra ese caso (perfil incompleto).
-- ============================================================
create or replace function prestamos.crear_solicitud(
  p_maestro_responsable text,
  p_notas text,
  p_items jsonb
) returns bigint
language plpgsql
security definer
set search_path = prestamos, pg_temp
as $$
declare
  v_alumno uuid := auth.uid();
  v_solicitud_id bigint;
  v_item jsonb;
  v_material_id int;
  v_cantidad int;
  v_descripcion text;
  v_disponible int;
  v_estado_mat text;
  v_trackeado boolean;
  v_unidad_id bigint;
  v_asignadas int;
  v_maestro text;
begin
  if v_alumno is null then
    raise exception 'no_autenticado';
  end if;

  v_maestro := nullif(trim(coalesce(p_maestro_responsable, '')), '');

  -- fallback al tutor del perfil si el alumno no escribio nada
  if v_maestro is null then
    select m.nombre into v_maestro
    from prestamos.profiles p
    join prestamos.maestros m on m.id = p.tutor_id
    where p.id = v_alumno;
  end if;

  if v_maestro is null then
    raise exception 'maestro_responsable_requerido';
  end if;

  if p_items is null or jsonb_typeof(p_items) <> 'array' or jsonb_array_length(p_items) = 0 then
    raise exception 'items_requeridos';
  end if;

  for v_material_id in
    select distinct (elem->>'material_id')::int
    from jsonb_array_elements(p_items) elem
    order by 1
  loop
    perform 1 from prestamos.materiales where id = v_material_id for update;
  end loop;

  insert into prestamos.solicitudes (alumno_id, estado, maestro_responsable, notas)
  values (v_alumno, 'pendiente', v_maestro, nullif(trim(coalesce(p_notas, '')), ''))
  returning id into v_solicitud_id;

  for v_item in select * from jsonb_array_elements(p_items)
  loop
    v_material_id := (v_item->>'material_id')::int;
    v_cantidad := (v_item->>'cantidad')::int;
    v_descripcion := nullif(trim(coalesce(v_item->>'descripcion', '')), '');

    if v_material_id is null or v_cantidad is null or v_cantidad <= 0 then
      raise exception 'item_invalido';
    end if;

    select cantidad_disponible, estado, trackeado_por_unidad
      into v_disponible, v_estado_mat, v_trackeado
    from prestamos.materiales where id = v_material_id;

    if v_estado_mat is null then
      raise exception 'material_no_existe: %', v_material_id;
    end if;
    if v_estado_mat <> 'disponible' then
      raise exception 'material_no_disponible: %', v_material_id;
    end if;
    if v_disponible < v_cantidad then
      raise exception 'stock_insuficiente: %', v_material_id;
    end if;

    if v_trackeado then
      v_asignadas := 0;
      while v_asignadas < v_cantidad loop
        select id into v_unidad_id
        from prestamos.material_unidades
        where material_id = v_material_id and estado = 'disponible'
        order by id
        for update skip locked
        limit 1;

        if v_unidad_id is null then
          raise exception 'sin_unidad_disponible: %', v_material_id;
        end if;

        insert into prestamos.solicitud_items
          (solicitud_id, material_id, cantidad, descripcion, material_unidad_id)
        values (v_solicitud_id, v_material_id, 1, v_descripcion, v_unidad_id);

        update prestamos.material_unidades
        set estado = 'prestado'
        where id = v_unidad_id;

        v_asignadas := v_asignadas + 1;
      end loop;
    else
      insert into prestamos.solicitud_items (solicitud_id, material_id, cantidad, descripcion)
      values (v_solicitud_id, v_material_id, v_cantidad, v_descripcion);
    end if;
  end loop;

  return v_solicitud_id;
end;
$$;

grant execute on function prestamos.crear_solicitud(text, text, jsonb) to authenticated;

commit;