use std::collections::HashSet;

use big_s::S;
use milli::update::Settings;
use milli::{RankingRule, Search, SearchResult, TermsMatchingStrategy};
use RankingRule::*;

use crate::search::{self, EXTERNAL_DOCUMENTS_IDS};

macro_rules! test_distinct {
    ($func:ident, $distinct:ident, $exhaustive:ident, $limit:expr, $offset:expr, $criteria:expr, $n_res:expr) => {
        #[test]
        fn $func() {
            let criteria = $criteria;
            let index = search::setup_search_index_with_criteria(&criteria);

            // update distinct attribute
            let mut wtxn = index.write_txn().unwrap();
            let config = milli::update::IndexerConfig::default();
            let mut builder = Settings::new(&mut wtxn, &index, &config);
            builder.set_distinct_field(S(stringify!($distinct)));
            builder.execute(|_| (), || false).unwrap();
            wtxn.commit().unwrap();

            let rtxn = index.read_txn().unwrap();

            let mut search = Search::new(&rtxn, &index);
            search.query(search::TEST_QUERY);
            search.limit($limit);
            search.offset($offset);
            search.exhaustive_number_hits($exhaustive);

            search.terms_matching_strategy(TermsMatchingStrategy::default());

            let SearchResult { documents_ids, candidates, .. } = search.execute().unwrap();

            assert_eq!(candidates.len(), $n_res);

            let mut distinct_values = HashSet::new();
            let expected_external_ids: Vec<_> =
                search::expected_order(&criteria, TermsMatchingStrategy::default(), &[])
                    .into_iter()
                    .filter_map(|d| {
                        if distinct_values.contains(&d.$distinct) {
                            None
                        } else {
                            distinct_values.insert(d.$distinct.to_owned());
                            Some(d.id)
                        }
                    })
                    .skip($offset)
                    .take($limit)
                    .collect();

            let documents_ids = search::internal_to_external_ids(&index, &documents_ids);
            assert_eq!(documents_ids, expected_external_ids);
        }
    };
}

test_distinct!(
    exhaustive_distinct_string_default_criteria,
    tag,
    true,
    1,
    0,
    vec![Words, Typo, Proximity, Attribute, Exactness],
    3
);
test_distinct!(
    exhaustive_distinct_number_default_criteria,
    asc_desc_rank,
    true,
    1,
    0,
    vec![Words, Typo, Proximity, Attribute, Exactness],
    7
);
test_distinct!(
    exhaustive_distinct_number_weird_order_criteria,
    asc_desc_rank,
    true,
    0,
    0,
    vec![Desc(S("attribute_rank")), Desc(S("exactness_rank")), Exactness, Typo],
    7
);

test_distinct!(
    distinct_string_default_criteria,
    tag,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words, Typo, Proximity, Attribute, Exactness],
    3
);
test_distinct!(
    distinct_number_default_criteria,
    asc_desc_rank,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words, Typo, Proximity, Attribute, Exactness],
    7
);
test_distinct!(
    distinct_string_criterion_words,
    tag,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words],
    3
);
test_distinct!(
    distinct_number_criterion_words,
    asc_desc_rank,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words],
    7
);
test_distinct!(
    distinct_string_criterion_words_typo,
    tag,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words, Typo],
    3
);
test_distinct!(
    distinct_number_criterion_words_typo,
    asc_desc_rank,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words, Typo],
    7
);
test_distinct!(
    distinct_string_criterion_words_proximity,
    tag,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words, Proximity],
    3
);
test_distinct!(
    distinct_number_criterion_words_proximity,
    asc_desc_rank,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words, Proximity],
    7
);
test_distinct!(
    distinct_string_criterion_words_attribute,
    tag,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words, Attribute],
    3
);
test_distinct!(
    distinct_number_criterion_words_attribute,
    asc_desc_rank,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words, Attribute],
    7
);
test_distinct!(
    distinct_string_criterion_words_exactness,
    tag,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words, Exactness],
    3
);
test_distinct!(
    distinct_number_criterion_words_exactness,
    asc_desc_rank,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    0,
    vec![Words, Exactness],
    7
);
test_distinct!(
    // testing: https://github.com/meilisearch/meilisearch/issues/4078
    distinct_string_limit_and_offset,
    tag,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    1,
    vec![],
    2
);
test_distinct!(
    // testing: https://github.com/meilisearch/meilisearch/issues/4078
    exhaustive_distinct_string_limit_and_offset,
    tag,
    true,
    1,
    2,
    vec![],
    1
);
test_distinct!(
    // testing: https://github.com/meilisearch/meilisearch/issues/4078
    distinct_number_limit_and_offset,
    asc_desc_rank,
    false,
    EXTERNAL_DOCUMENTS_IDS.len(),
    2,
    vec![],
    5
);
test_distinct!(
    // testing: https://github.com/meilisearch/meilisearch/issues/4078
    exhaustive_distinct_number_limit_and_offset,
    asc_desc_rank,
    true,
    2,
    4,
    vec![],
    3
);