From 8f5b149386da524a1b0eac4078a3704362b99db6 Mon Sep 17 00:00:00 2001
From: Adam Reichold <adam.reichold@t-online.de>
Date: Thu, 1 Feb 2024 14:18:38 +0100
Subject: [PATCH] Add field_boosts and fuzzy_fields optional parameters to
 Index::parse_query to expose this QueryParser functionality.

---
 src/index.rs | 38 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/src/index.rs b/src/index.rs
index 4636d24e6..5195a117b 100644
--- a/src/index.rs
+++ b/src/index.rs
@@ -1,5 +1,7 @@
 #![allow(clippy::new_ret_no_self)]
 
+use std::collections::HashMap;
+
 use pyo3::{exceptions, prelude::*, types::PyAny};
 
 use crate::{
@@ -358,14 +360,26 @@ impl Index {
     ///
     /// Args:
     ///     query: the query, following the tantivy query language.
+    ///
     ///     default_fields_names (List[Field]): A list of fields used to search if no
     ///         field is specified in the query.
     ///
-    #[pyo3(signature = (query, default_field_names = None))]
+    ///     field_boosts: A dictionary keyed on field names which provides default boosts
+    ///         for the query constructed by this method.
+    ///
+    ///     fuzzy_fields: A dictionary keyed on field names which provides (prefix, distance, transpose_cost_one)
+    ///         triples making queries constructed by this method fuzzy against the given fields
+    ///         and using the given parameters.
+    ///         `prefix` determines if terms which prefixes of the given term match the query.
+    ///         `distance` determines the maximum Levenshtein distance between terms matching the query and the given term.
+    ///         `transpose_cost_one` determines if transpositions of neighbouring characters are counted only once against the Levenshtein distance.
+    #[pyo3(signature = (query, default_field_names = None, field_boosts = HashMap::new(), fuzzy_fields = HashMap::new()))]
     pub fn parse_query(
         &self,
         query: &str,
         default_field_names: Option<Vec<String>>,
+        field_boosts: HashMap<String, tv::Score>,
+        fuzzy_fields: HashMap<String, (bool, u8, bool)>,
     ) -> PyResult<Query> {
         let mut default_fields = vec![];
         let schema = self.index.schema();
@@ -394,8 +408,28 @@ impl Index {
                 }
             }
         }
-        let parser =
+        let mut parser =
             tv::query::QueryParser::for_index(&self.index, default_fields);
+
+        for (field_name, boost) in field_boosts {
+            let field = schema.get_field(&field_name).map_err(|_err| {
+                exceptions::PyValueError::new_err(format!(
+                    "Field `{field_name}` is not defined in the schema."
+                ))
+            })?;
+            parser.set_field_boost(field, boost);
+        }
+
+        for (field_name, (prefix, distance, transpose_cost_one)) in fuzzy_fields
+        {
+            let field = schema.get_field(&field_name).map_err(|_err| {
+                exceptions::PyValueError::new_err(format!(
+                    "Field `{field_name}` is not defined in the schema."
+                ))
+            })?;
+            parser.set_field_fuzzy(field, prefix, distance, transpose_cost_one);
+        }
+
         let query = parser.parse_query(query).map_err(to_pyerr)?;
 
         Ok(Query { inner: query })