// common/src/search.rs

use tantivy::schema::*;
use tantivy::tokenizer::*;
use tantivy::Index;

/// Creates a hybrid Slovak search schema with optimized prefix fields.
pub fn create_search_schema() -> Schema {
    let mut schema_builder = Schema::builder();

    schema_builder.add_u64_field("pg_id", INDEXED | STORED);

    // FIELD 1: For prefixes (1-4 chars).
    let short_prefix_indexing = TextFieldIndexing::default()
        .set_tokenizer("slovak_prefix_edge")
        .set_index_option(IndexRecordOption::WithFreqsAndPositions);
    let short_prefix_options = TextOptions::default()
        .set_indexing_options(short_prefix_indexing)
        .set_stored();
    schema_builder.add_text_field("prefix_edge", short_prefix_options);

    // FIELD 2: For the full word.
    let full_word_indexing = TextFieldIndexing::default()
        .set_tokenizer("slovak_prefix_full")
        .set_index_option(IndexRecordOption::WithFreqsAndPositions);
    let full_word_options = TextOptions::default()
        .set_indexing_options(full_word_indexing)
        .set_stored();
    schema_builder.add_text_field("prefix_full", full_word_options);

    // NGRAM FIELD: For substring matching.
    let ngram_field_indexing = TextFieldIndexing::default()
        .set_tokenizer("slovak_ngram")
        .set_index_option(IndexRecordOption::WithFreqsAndPositions);
    let ngram_options = TextOptions::default()
        .set_indexing_options(ngram_field_indexing)
        .set_stored();
    schema_builder.add_text_field("text_ngram", ngram_options);

    schema_builder.build()
}

/// Registers all necessary Slovak tokenizers with the index.
///
/// This must be called by ANY process that opens the index
/// to ensure the tokenizers are loaded into memory.
pub fn register_slovak_tokenizers(index: &Index) -> tantivy::Result<()> {
    let tokenizer_manager = index.tokenizers();

    // TOKENIZER for `prefix_edge`: Edge N-gram (1-4 chars)
    let edge_tokenizer =
        TextAnalyzer::builder(NgramTokenizer::new(1, 4, true)?)
            .filter(RemoveLongFilter::limit(40))
            .filter(LowerCaser)
            .filter(AsciiFoldingFilter)
            .build();
    tokenizer_manager.register("slovak_prefix_edge", edge_tokenizer);

    // TOKENIZER for `prefix_full`: Simple word tokenizer
    let full_tokenizer =
        TextAnalyzer::builder(SimpleTokenizer::default())
            .filter(RemoveLongFilter::limit(40))
            .filter(LowerCaser)
            .filter(AsciiFoldingFilter)
            .build();
    tokenizer_manager.register("slovak_prefix_full", full_tokenizer);

    // NGRAM TOKENIZER: For substring matching.
    let ngram_tokenizer =
        TextAnalyzer::builder(NgramTokenizer::new(3, 3, false)?)
            .filter(RemoveLongFilter::limit(40))
            .filter(LowerCaser)
            .filter(AsciiFoldingFilter)
            .build();
    tokenizer_manager.register("slovak_ngram", ngram_tokenizer);

    Ok(())
}