WITH get_files AS (
    SELECT
        type,
        country
    FROM files
    WHERE title IS NOT NULL
)
INSERT INTO history_person_file (
    name,
    document_type,
    age
)
SELECT
    p.name,
    f.type,
    p.age
FROM person p
LEFT JOIN get_files f
ON p.country = f.country
ON conflict (name) do nothing;

with num_docs as (
 select type, country, 
        row_number() over (partition by country 
                               order by title) as rn
   from files
  where title is not null
), num_person as (
 select name, age, country,
        row_number() over (partition by country
                               order by name) as rn
   from person
)
select p.country, p.name, d.country, d.type, d.age
  from num_docs d
       full join num_person p 
         on (p.country, p.rn) = (d.country, d.rn);

    WITH RankedPersons AS (
    SELECT
        p.name,
        p.age,
        p.country,
        ROW_NUMBER() OVER (PARTITION BY p.country ORDER BY f.title IS NULL) AS 
    row_num
    FROM person p
    LEFT JOIN files f ON p.country = f.country AND f.title IS NOT NULL
    ),
    NextAvailableFile AS (
    SELECT
        f.type,
        f.country
    FROM files f
    LEFT JOIN RankedPersons p ON f.country = p.country AND p.row_num = 1
    WHERE p.row_num IS NULL
    LIMIT 1
    )
    INSERT INTO person_file (name, document_type, age)
    SELECT
    p.name,
    COALESCE(naf.type, 'default_document_type'),
    p.age
    FROM RankedPersons p
    LEFT JOIN NextAvailableFile naf ON p.country = naf.country
    WHERE p.row_num = 1
    ON CONFLICT (name) DO NOTHING;