Introduce the criteria update setting

src/criterion.rs

@@ -1,5 +1,7 @@
-use crate::FieldId;
+use crate::{FieldsIdsMap, FieldId};
 
+use anyhow::{Context, bail};
+use regex::Regex;
 use serde::{Serialize, Deserialize};
 
 #[derive(Debug, Serialize, Deserialize, Copy, Clone, PartialEq, Eq)]
@@ -24,6 +26,38 @@ pub enum Criterion {
     Desc(FieldId),
 }
 
+impl Criterion {
+    pub fn from_str(fields_ids_map: &mut FieldsIdsMap, txt: &str) -> anyhow::Result<Criterion> {
+        match txt {
+            "typo" => Ok(Criterion::Typo),
+            "words" => Ok(Criterion::Words),
+            "proximity" => Ok(Criterion::Proximity),
+            "attribute" => Ok(Criterion::Attribute),
+            "wordsposition" => Ok(Criterion::WordsPosition),
+            "exactness" => Ok(Criterion::Exactness),
+            text => {
+                let re = Regex::new(r#"(asc|desc)\(([\w_-]+)\)"#)?;
+                let caps = re.captures(text).with_context(|| format!("unknown criterion name: {}", text))?;
+                let order = caps.get(1).unwrap().as_str();
+                let field_name = caps.get(2).unwrap().as_str();
+                let field_id = fields_ids_map.insert(field_name).context("field id limit reached")?;
+                match order {
+                    "asc" => Ok(Criterion::Asc(field_id)),
+                    "desc" => Ok(Criterion::Desc(field_id)),
+                    otherwise => bail!("unknown criterion name: {}", otherwise),
+                }
+            },
+        }
+    }
+
+    pub fn field_id(&self) -> Option<FieldId> {
+        match *self {
+            Criterion::Asc(fid) | Criterion::Desc(fid) => Some(fid),
+            _ => None,
+        }
+    }
+}
+
 pub fn default_criteria() -> Vec<Criterion> {
     vec![
         Criterion::Typo,