mod db_cache;
mod graph_based_ranking_rule;
mod interner;
mod logger;
mod query_graph;
mod query_term;
mod ranking_rule_graph;

mod ranking_rules;
mod resolve_query_graph;
// TODO: documentation + comments
mod small_bitmap;
// TODO: documentation + comments
mod sort;
// TODO: documentation + comments
mod words;

pub use logger::{DefaultSearchLogger, SearchLogger};

use std::collections::BTreeSet;

use charabia::Tokenize;
use db_cache::DatabaseCache;
use heed::RoTxn;
use query_graph::{QueryGraph, QueryNode};
pub use ranking_rules::{bucket_sort, RankingRule, RankingRuleOutput, RankingRuleQueryTrait};
use roaring::RoaringBitmap;

use self::interner::Interner;
use self::query_term::{Phrase, WordDerivations};
use self::resolve_query_graph::{resolve_query_graph, QueryTermDocIdsCache};
use crate::search::new::graph_based_ranking_rule::GraphBasedRankingRule;
use crate::search::new::query_term::located_query_terms_from_string;
use crate::search::new::ranking_rule_graph::{ProximityGraph, TypoGraph};
use crate::search::new::words::Words;
use crate::{Filter, Index, Result, TermsMatchingStrategy};

pub enum BitmapOrAllRef<'s> {
    Bitmap(&'s RoaringBitmap),
    All,
}

pub struct SearchContext<'search> {
    pub index: &'search Index,
    pub txn: &'search RoTxn<'search>,
    pub db_cache: DatabaseCache<'search>,
    pub word_interner: Interner<String>,
    pub phrase_interner: Interner<Phrase>,
    pub derivations_interner: Interner<WordDerivations>,
    pub query_term_docids: QueryTermDocIdsCache,
}
impl<'search> SearchContext<'search> {
    pub fn new(index: &'search Index, txn: &'search RoTxn<'search>) -> Self {
        Self {
            index,
            txn,
            db_cache: <_>::default(),
            word_interner: <_>::default(),
            phrase_interner: <_>::default(),
            derivations_interner: <_>::default(),
            query_term_docids: <_>::default(),
        }
    }
}

#[allow(clippy::too_many_arguments)]
fn resolve_maximally_reduced_query_graph<'search>(
    ctx: &mut SearchContext<'search>,
    universe: &RoaringBitmap,
    query_graph: &QueryGraph,
    matching_strategy: TermsMatchingStrategy,
    logger: &mut dyn SearchLogger<QueryGraph>,
) -> Result<RoaringBitmap> {
    let mut graph = query_graph.clone();
    let mut positions_to_remove = match matching_strategy {
        TermsMatchingStrategy::Last => {
            let mut all_positions = BTreeSet::new();
            for n in query_graph.nodes.iter() {
                match n {
                    QueryNode::Term(term) => {
                        all_positions.extend(term.positions.clone().into_iter());
                    }
                    QueryNode::Deleted | QueryNode::Start | QueryNode::End => {}
                }
            }
            all_positions.into_iter().collect()
        }
        TermsMatchingStrategy::All => vec![],
    };
    // don't remove the first term
    positions_to_remove.remove(0);
    loop {
        if positions_to_remove.is_empty() {
            break;
        } else {
            let position_to_remove = positions_to_remove.pop().unwrap();
            let _ = graph.remove_words_starting_at_position(position_to_remove);
        }
    }
    logger.query_for_universe(&graph);
    let docids = resolve_query_graph(ctx, &graph, universe)?;

    Ok(docids)
}

#[allow(clippy::too_many_arguments)]
pub fn execute_search<'search>(
    ctx: &mut SearchContext<'search>,
    query: &str,
    filters: Option<Filter>,
    from: usize,
    length: usize,
    logger: &mut dyn SearchLogger<QueryGraph>,
) -> Result<Vec<u32>> {
    assert!(!query.is_empty());
    let query_terms = located_query_terms_from_string(ctx, query.tokenize(), None)?;
    let graph = QueryGraph::from_query(ctx, query_terms)?;

    logger.initial_query(&graph);

    let universe = if let Some(filters) = filters {
        filters.evaluate(ctx.txn, ctx.index)?
    } else {
        ctx.index.documents_ids(ctx.txn)?
    };

    let universe = resolve_maximally_reduced_query_graph(
        ctx,
        &universe,
        &graph,
        TermsMatchingStrategy::Last,
        logger,
    )?;
    // TODO: create ranking rules here

    logger.initial_universe(&universe);

    let words = &mut Words::new(TermsMatchingStrategy::Last);
    // let sort = &mut Sort::new(index, txn, "release_date".to_owned(), true)?;
    let proximity = &mut GraphBasedRankingRule::<ProximityGraph>::new("proximity".to_owned());
    let typo = &mut GraphBasedRankingRule::<TypoGraph>::new("typo".to_owned());
    // TODO: ranking rules given as argument
    let ranking_rules: Vec<&mut dyn RankingRule<'search, QueryGraph>> =
        vec![words, typo, proximity /*sort*/];

    bucket_sort(ctx, ranking_rules, &graph, &universe, from, length, logger)
}

#[cfg(test)]
mod tests {
    // use crate::allocator::ALLOC;
    use std::fs::File;
    use std::io::{BufRead, BufReader, Cursor, Seek};
    use std::time::Instant;

    use big_s::S;
    use heed::EnvOpenOptions;
    use maplit::hashset;

    use crate::documents::{DocumentsBatchBuilder, DocumentsBatchReader};
    // use crate::search::new::logger::detailed::DetailedSearchLogger;
    use crate::search::new::logger::DefaultSearchLogger;
    use crate::search::new::{execute_search, SearchContext};
    use crate::update::{IndexDocuments, IndexDocumentsConfig, IndexerConfig, Settings};
    use crate::{Criterion, Index, Object, Search, TermsMatchingStrategy};

    #[test]
    fn search_wiki_new() {
        let mut options = EnvOpenOptions::new();
        options.map_size(100 * 1024 * 1024 * 1024); // 100 GB

        let index = Index::new(options, "data_wiki").unwrap();
        let txn = index.read_txn().unwrap();

        println!("nbr docids: {}", index.documents_ids(&txn).unwrap().len());

        // loop {
        let start = Instant::now();

        let mut logger = crate::search::new::logger::detailed::DetailedSearchLogger::new("log");
        let mut ctx = SearchContext::new(&index, &txn);
        let results = execute_search(
            &mut ctx,
            "zero config",
            None,
            0,
            20,
            // &mut DefaultSearchLogger,
            &mut logger,
        )
        .unwrap();

        logger.write_d2_description(&mut ctx);

        let elapsed = start.elapsed();
        println!("{}us", elapsed.as_micros());

        let _documents = index
            .documents(&txn, results.iter().copied())
            .unwrap()
            .into_iter()
            .map(|(id, obkv)| {
                let mut object = serde_json::Map::default();
                for (fid, fid_name) in index.fields_ids_map(&txn).unwrap().iter() {
                    let value = obkv.get(fid).unwrap();
                    let value: serde_json::Value = serde_json::from_slice(value).unwrap();
                    object.insert(fid_name.to_owned(), value);
                }
                (id, serde_json::to_string_pretty(&object).unwrap())
            })
            .collect::<Vec<_>>();

        println!("{}us: {:?}", elapsed.as_micros(), results);
        // }
        // for (id, _document) in documents {
        //     println!("{id}:");
        //     // println!("{document}");
        // }
    }

    #[test]
    fn search_wiki_old() {
        let mut options = EnvOpenOptions::new();
        options.map_size(100 * 1024 * 1024 * 1024); // 100 GB

        let index = Index::new(options, "data_wiki").unwrap();

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

        let rr = index.criteria(&txn).unwrap();
        println!("{rr:?}");

        let start = Instant::now();

        let mut s = Search::new(&txn, &index);
        s.query("which a the releases from poison by the government");
        s.terms_matching_strategy(TermsMatchingStrategy::Last);
        s.criterion_implementation_strategy(crate::CriterionImplementationStrategy::OnlySetBased);
        let docs = s.execute().unwrap();

        let elapsed = start.elapsed();

        let documents = index
            .documents(&txn, docs.documents_ids.iter().copied())
            .unwrap()
            .into_iter()
            .map(|(id, obkv)| {
                let mut object = serde_json::Map::default();
                for (fid, fid_name) in index.fields_ids_map(&txn).unwrap().iter() {
                    let value = obkv.get(fid).unwrap();
                    let value: serde_json::Value = serde_json::from_slice(value).unwrap();
                    object.insert(fid_name.to_owned(), value);
                }
                (id, serde_json::to_string_pretty(&object).unwrap())
            })
            .collect::<Vec<_>>();

        println!("{}us: {:?}", elapsed.as_micros(), docs.documents_ids);
        for (id, _document) in documents {
            println!("{id}:");
            // println!("{document}");
        }
    }
    #[test]
    fn search_movies_new() {
        let mut options = EnvOpenOptions::new();
        options.map_size(100 * 1024 * 1024 * 1024); // 100 GB

        let index = Index::new(options, "data_movies").unwrap();
        let txn = index.read_txn().unwrap();

        // let primary_key = index.primary_key(&txn).unwrap().unwrap();
        // let primary_key = index.fields_ids_map(&txn).unwrap().id(primary_key).unwrap();
        // loop {
        let start = Instant::now();

        let mut logger = crate::search::new::logger::detailed::DetailedSearchLogger::new("log");
        let mut ctx = SearchContext::new(&index, &txn);
        let results = execute_search(
            &mut ctx,
            "releases from poison by the government",
            None,
            0,
            20,
            // &mut DefaultSearchLogger,
            &mut logger,
        )
        .unwrap();

        logger.write_d2_description(&mut ctx);

        let elapsed = start.elapsed();

        // let ids = index
        //     .documents(&txn, results.iter().copied())
        //     .unwrap()
        //     .into_iter()
        //     .map(|x| {
        //         let obkv = &x.1;
        //         let id = obkv.get(primary_key).unwrap();
        //         let id: serde_json::Value = serde_json::from_slice(id).unwrap();
        //         id.as_str().unwrap().to_owned()
        //     })
        //     .collect::<Vec<_>>();

        println!("{}us: {results:?}", elapsed.as_micros());
        // println!("external ids: {ids:?}");
        // }
    }

    #[test]
    fn search_movies_old() {
        let mut options = EnvOpenOptions::new();
        options.map_size(100 * 1024 * 1024 * 1024); // 100 GB

        let index = Index::new(options, "data_movies").unwrap();

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

        let rr = index.criteria(&txn).unwrap();
        println!("{rr:?}");

        let primary_key = index.primary_key(&txn).unwrap().unwrap();
        let primary_key = index.fields_ids_map(&txn).unwrap().id(primary_key).unwrap();

        let start = Instant::now();

        let mut s = Search::new(&txn, &index);
        s.query("which a the releases from poison by the government");
        s.terms_matching_strategy(TermsMatchingStrategy::Last);
        s.criterion_implementation_strategy(crate::CriterionImplementationStrategy::OnlySetBased);
        let docs = s.execute().unwrap();

        let elapsed = start.elapsed();

        let ids = index
            .documents(&txn, docs.documents_ids.iter().copied())
            .unwrap()
            .into_iter()
            .map(|x| {
                let obkv = &x.1;
                let id = obkv.get(primary_key).unwrap();
                let id: serde_json::Value = serde_json::from_slice(id).unwrap();
                id.as_str().unwrap().to_owned()
            })
            .collect::<Vec<_>>();

        println!("{}us: {:?}", elapsed.as_micros(), docs.documents_ids);
        println!("external ids: {ids:?}");
    }

    #[test]
    fn _settings_movies() {
        let mut options = EnvOpenOptions::new();
        options.map_size(100 * 1024 * 1024 * 1024); // 100 GB

        let index = Index::new(options, "data_movies").unwrap();
        let mut wtxn = index.write_txn().unwrap();

        let config = IndexerConfig::default();
        let mut builder = Settings::new(&mut wtxn, &index, &config);

        builder.set_min_word_len_one_typo(5);
        builder.set_min_word_len_two_typos(100);
        builder.set_sortable_fields(hashset! { S("release_date") });
        builder.set_criteria(vec![
            Criterion::Words,
            Criterion::Typo,
            Criterion::Proximity,
            Criterion::Asc("release_date".to_owned()),
        ]);

        builder.execute(|_| (), || false).unwrap();
        wtxn.commit().unwrap();
    }

    #[test]
    fn _index_movies() {
        let mut options = EnvOpenOptions::new();
        options.map_size(100 * 1024 * 1024 * 1024); // 100 GB

        let index = Index::new(options, "data_movies").unwrap();
        let mut wtxn = index.write_txn().unwrap();

        let primary_key = "id";
        let searchable_fields = vec!["title", "overview"];
        let filterable_fields = vec!["release_date", "genres"];

        let config = IndexerConfig::default();
        let mut builder = Settings::new(&mut wtxn, &index, &config);
        builder.set_primary_key(primary_key.to_owned());
        let searchable_fields = searchable_fields.iter().map(|s| s.to_string()).collect();
        builder.set_searchable_fields(searchable_fields);
        let filterable_fields = filterable_fields.iter().map(|s| s.to_string()).collect();
        builder.set_filterable_fields(filterable_fields);

        builder.set_min_word_len_one_typo(5);
        builder.set_min_word_len_two_typos(100);
        builder.set_criteria(vec![Criterion::Words, Criterion::Proximity]);
        builder.execute(|_| (), || false).unwrap();

        let config = IndexerConfig::default();
        let indexing_config = IndexDocumentsConfig::default();
        let builder =
            IndexDocuments::new(&mut wtxn, &index, &config, indexing_config, |_| (), || false)
                .unwrap();

        let documents = documents_from(
            "/Users/meilisearch/Documents/milli2/benchmarks/datasets/movies.json",
            "json",
        );
        let (builder, user_error) = builder.add_documents(documents).unwrap();
        user_error.unwrap();
        builder.execute().unwrap();
        wtxn.commit().unwrap();

        index.prepare_for_closing().wait();
    }
    #[test]
    fn _index_wiki() {
        let mut options = EnvOpenOptions::new();
        options.map_size(100 * 1024 * 1024 * 1024); // 100 GB

        let index = Index::new(options, "data_wiki").unwrap();
        let mut wtxn = index.write_txn().unwrap();

        // let primary_key = "id";
        let searchable_fields = vec!["body", "title", "url"];
        // let filterable_fields = vec![];
        let config = IndexerConfig::default();
        let mut builder = Settings::new(&mut wtxn, &index, &config);
        // builder.set_primary_key(primary_key.to_owned());
        let searchable_fields = searchable_fields.iter().map(|s| s.to_string()).collect();
        builder.set_searchable_fields(searchable_fields);
        // let filterable_fields = filterable_fields.iter().map(|s| s.to_string()).collect();
        // builder.set_filterable_fields(filterable_fields);

        // builder.set_min_word_len_one_typo(5);
        // builder.set_min_word_len_two_typos(100);
        builder.set_criteria(vec![Criterion::Words, Criterion::Typo, Criterion::Proximity]);
        builder.execute(|_| (), || false).unwrap();

        let config = IndexerConfig::default();
        let indexing_config =
            IndexDocumentsConfig { autogenerate_docids: true, ..Default::default() };
        let builder =
            IndexDocuments::new(&mut wtxn, &index, &config, indexing_config, |_| (), || false)
                .unwrap();

        let documents = documents_from(
            "/Users/meilisearch/Documents/milli2/benchmarks/datasets/smol-wiki-articles.csv",
            "csv",
        );
        let (builder, user_error) = builder.add_documents(documents).unwrap();
        user_error.unwrap();
        builder.execute().unwrap();
        wtxn.commit().unwrap();

        index.prepare_for_closing().wait();
    }

    fn documents_from(filename: &str, filetype: &str) -> DocumentsBatchReader<impl BufRead + Seek> {
        let reader = File::open(filename)
            .unwrap_or_else(|_| panic!("could not find the dataset in: {}", filename));
        let reader = BufReader::new(reader);
        let documents = match filetype {
            "csv" => documents_from_csv(reader).unwrap(),
            "json" => documents_from_json(reader).unwrap(),
            "jsonl" => documents_from_jsonl(reader).unwrap(),
            otherwise => panic!("invalid update format {:?}", otherwise),
        };
        DocumentsBatchReader::from_reader(Cursor::new(documents)).unwrap()
    }

    fn documents_from_jsonl(reader: impl BufRead) -> crate::Result<Vec<u8>> {
        let mut documents = DocumentsBatchBuilder::new(Vec::new());

        for result in serde_json::Deserializer::from_reader(reader).into_iter::<Object>() {
            let object = result.unwrap();
            documents.append_json_object(&object)?;
        }

        documents.into_inner().map_err(Into::into)
    }

    fn documents_from_json(reader: impl BufRead) -> crate::Result<Vec<u8>> {
        let mut documents = DocumentsBatchBuilder::new(Vec::new());

        documents.append_json_array(reader)?;

        documents.into_inner().map_err(Into::into)
    }

    fn documents_from_csv(reader: impl BufRead) -> crate::Result<Vec<u8>> {
        let csv = csv::Reader::from_reader(reader);

        let mut documents = DocumentsBatchBuilder::new(Vec::new());
        documents.append_csv(csv)?;

        documents.into_inner().map_err(Into::into)
    }
}