From 125142492aaca2f1ddb3df86fb1256e7f679a323 Mon Sep 17 00:00:00 2001
From: Diretnan Domnan <diretnandomnan@gmail.com>
Date: Wed, 25 Sep 2024 21:32:42 +0200
Subject: [PATCH] DROPPREDINDEX command parsing

---
 ahnlich/dsl/src/db.rs          | 51 ++++++++++++++++++++++++++++++++++
 ahnlich/dsl/src/syntax/db.pest |  7 +++--
 2 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/ahnlich/dsl/src/db.rs b/ahnlich/dsl/src/db.rs
index 1f464f3a..f78439b1 100644
--- a/ahnlich/dsl/src/db.rs
+++ b/ahnlich/dsl/src/db.rs
@@ -47,6 +47,32 @@ pub fn parse_db_query(input: &str) -> Result<Vec<DBQuery>, DslError> {
                     predicates,
                 }
             }
+            Rule::drop_pred_index => {
+                let mut inner_pairs = statement.into_inner().peekable();
+                let mut if_exists = false;
+                if let Some(next_pair) = inner_pairs.peek() {
+                    if next_pair.as_rule() == Rule::if_exists {
+                        inner_pairs.next(); // Consume it if needed
+                        if_exists = true;
+                    }
+                };
+                let index_names_pair = inner_pairs
+                    .next()
+                    .ok_or(DslError::UnexpectedSpan((start_pos, end_pos)))?;
+                let store = inner_pairs
+                    .next()
+                    .ok_or(DslError::UnexpectedSpan((start_pos, end_pos)))?
+                    .as_str();
+                let predicates = index_names_pair
+                    .into_inner()
+                    .map(|index_pair| MetadataKey::new(index_pair.as_str().to_string()))
+                    .collect();
+                DBQuery::DropPredIndex {
+                    store: StoreName(store.to_string()),
+                    predicates,
+                    error_if_not_exists: !if_exists,
+                }
+            }
             Rule::drop_store => {
                 let mut inner_pairs = statement.into_inner();
                 let store = inner_pairs
@@ -165,4 +191,29 @@ mod tests {
             }]
         );
     }
+
+    #[test]
+    fn test_drop_pred_index_parse() {
+        let input = r#"DROPPREDINDEX (here, th2) in store2"#;
+        assert_eq!(
+            parse_db_query(input).expect("Could not parse query input"),
+            vec![DBQuery::DropPredIndex {
+                store: StoreName("store2".to_string()),
+                predicates: HashSet::from_iter([
+                    MetadataKey::new("here".to_string()),
+                    MetadataKey::new("th2".to_string()),
+                ]),
+                error_if_not_exists: true,
+            }]
+        );
+        let input = r#"DROPPREDINDEX IF EXISTS (off) in storememe"#;
+        assert_eq!(
+            parse_db_query(input).expect("Could not parse query input"),
+            vec![DBQuery::DropPredIndex {
+                store: StoreName("storememe".to_string()),
+                predicates: HashSet::from_iter([MetadataKey::new("off".to_string()),]),
+                error_if_not_exists: false,
+            }]
+        );
+    }
 }
diff --git a/ahnlich/dsl/src/syntax/db.pest b/ahnlich/dsl/src/syntax/db.pest
index 80a1de5c..84ae45ad 100644
--- a/ahnlich/dsl/src/syntax/db.pest
+++ b/ahnlich/dsl/src/syntax/db.pest
@@ -2,16 +2,17 @@ whitespace = _{ " " | "\t" }
 
 query = _{ statement ~ (";" ~ statement) * } // Matches multiple statements separated by ;
 
-statement = _{ ping | info_server | list_stores | list_clients | drop_store | create_pred_index | invalid_statement }
+statement = _{ ping | info_server | list_stores | list_clients | drop_store | create_pred_index | drop_pred_index | invalid_statement }
 
 ping = { whitespace* ~ ^"ping" ~ whitespace* }
 info_server = { whitespace* ~ ^"infoserver" ~ whitespace* }
 list_stores = { whitespace* ~ ^"liststores" ~ whitespace* }
 list_clients = { whitespace* ~ ^"listclients" ~ whitespace* }
 drop_store = { whitespace* ~ ^"dropstore" ~ whitespace* ~ store_name ~ (if_exists | invalid_statement)? }
-create_pred_index = { whitespace* ~ ^"createpredindex" ~ whitespace* ~ "(" ~ index_names ~ ")" ~ whitespace* ~ ^"in" ~whitespace* ~ store_name }
+create_pred_index = { whitespace* ~ ^"createpredindex" ~ whitespace* ~ "(" ~ index_names ~ ")" ~ whitespace* ~ ^"in" ~ whitespace* ~ store_name }
+drop_pred_index = { whitespace* ~ ^"droppredindex" ~ whitespace* ~ (if_exists)? ~ "(" ~ index_names ~ ")" ~ whitespace* ~ ^"in" ~whitespace* ~ store_name }
 
-if_exists = { whitespace* ~ ^"if" ~ whitespace* ~ "exists" ~ whitespace* }
+if_exists = { whitespace* ~ ^"if" ~ whitespace* ~ ^"exists" ~ whitespace* }
 
 // stores and predicates can be alphanumeric
 store_name = { (ASCII_ALPHANUMERIC | "_" | "-")+ }