tantivy-py/src/query.rs

use crate::{make_term, Schema};
use pyo3::{exceptions, prelude::*, types::PyAny, types::PyString, types::PyTuple};
use tantivy as tv;

/// Custom Tuple struct to represent a pair of Occur and Query
/// for the BooleanQuery
struct OccurQueryPair(Occur, Query);

impl <'source> FromPyObject<'source> for OccurQueryPair {
    fn extract(ob: &'source PyAny) -> PyResult<Self> {
        let tuple = ob.downcast::<PyTuple>()?;
        let occur = tuple.get_item(0)?.extract()?;
        let query = tuple.get_item(1)?.extract()?;

        Ok(OccurQueryPair(occur, query))
    }
}


/// Tantivy's Occur
#[pyclass(frozen, module = "tantivy.tantivy")]
#[derive(Clone)]
pub enum Occur {
    Must,
    Should,
    MustNot,
}

impl From<Occur> for tv::query::Occur {
    fn from(occur: Occur) -> tv::query::Occur {
        match occur {
            Occur::Must => tv::query::Occur::Must,
            Occur::Should => tv::query::Occur::Should,
            Occur::MustNot => tv::query::Occur::MustNot,
        }
    }
}

/// Tantivy's Query
#[pyclass(frozen, module = "tantivy.tantivy")]
pub(crate) struct Query {
    pub(crate) inner: Box<dyn tv::query::Query>,
}

impl Clone for Query {
    fn clone(&self) -> Self {
        Query {
            inner: self.inner.box_clone(),
        }
    }
}

impl Query {
    pub(crate) fn get(&self) -> &dyn tv::query::Query {
        &self.inner
    }
}

#[pymethods]
impl Query {
    fn __repr__(&self) -> PyResult<String> {
        Ok(format!("Query({:?})", self.get()))
    }

    /// Construct a Tantivy's TermQuery
    #[staticmethod]
    #[pyo3(signature = (schema, field_name, field_value, index_option = "position"))]
    pub(crate) fn term_query(
        schema: &Schema,
        field_name: &str,
        field_value: &PyAny,
        index_option: &str,
    ) -> PyResult<Query> {
        let term = make_term(&schema.inner, field_name, field_value)?;
        let index_option = match index_option {
            "position" => tv::schema::IndexRecordOption::WithFreqsAndPositions,
            "freq" => tv::schema::IndexRecordOption::WithFreqs,
            "basic" => tv::schema::IndexRecordOption::Basic,
            _ => return Err(exceptions::PyValueError::new_err(
                "Invalid index option, valid choices are: 'basic', 'freq' and 'position'"
            ))
        };
        let inner = tv::query::TermQuery::new(term, index_option);
        Ok(Query {
            inner: Box::new(inner),
        })
    }

    /// Construct a Tantivy's AllQuery
    #[staticmethod]
    pub(crate) fn all_query() -> PyResult<Query> {
        let inner = tv::query::AllQuery {};
        Ok(Query {
            inner: Box::new(inner),
        })
    }

    /// Construct a Tantivy's FuzzyTermQuery
    ///
    /// # Arguments
    ///
    /// * `schema` - Schema of the target index.
    /// * `field_name` - Field name to be searched.
    /// * `text` - String representation of the query term.
    /// * `distance` - (Optional) Edit distance you are going to alow. When not specified, the default is 1.
    /// * `transposition_cost_one` - (Optional) If true, a transposition (swapping) cost will be 1; otherwise it will be 2. When not specified, the default is true.
    /// * `prefix` - (Optional) If true, prefix levenshtein distance is applied. When not specified, the default is false.
    #[staticmethod]
    #[pyo3(signature = (schema, field_name, text, distance = 1, transposition_cost_one = true, prefix = false))]
    pub(crate) fn fuzzy_term_query(
        schema: &Schema,
        field_name: &str,
        text: &PyString,
        distance: u8,
        transposition_cost_one: bool,
        prefix: bool,
    ) -> PyResult<Query> {
        let term = make_term(&schema.inner, field_name, &text)?;
        let inner = if prefix {
            tv::query::FuzzyTermQuery::new_prefix(
                term,
                distance,
                transposition_cost_one,
            )
        } else {
            tv::query::FuzzyTermQuery::new(
                term,
                distance,
                transposition_cost_one,
            )
        };
        Ok(Query {
            inner: Box::new(inner),
        })
    }

    #[staticmethod]
    #[pyo3(signature = (subqueries))]
    pub(crate) fn boolean_query(
        subqueries: Vec<(Occur, Query)>
    ) -> PyResult<Query> {
        let dyn_subqueries = subqueries
            .into_iter()
            .map(|(occur, query)| (occur.into(), query.inner.box_clone()))
            .collect::<Vec<_>>();
        
        let inner = tv::query::BooleanQuery::from(dyn_subqueries);

        Ok(Query {
            inner: Box::new(inner),
        })
    }
}