fix: batch N+1 queries in import duplicate check and watch event dismiss

apply_mapping: 2 batch queries instead of up to 2N per-row lookups
dismiss: single fetch + single update instead of 2N per-event queries

crates/adapters/postgres/src/lib.rs

@@ -388,6 +388,54 @@ impl MovieRepository for PostgresRepository {
         Ok(())
     }
 
+    async fn existing_external_ids(
+        &self,
+        ids: &[ExternalMetadataId],
+    ) -> Result<std::collections::HashSet<String>, DomainError> {
+        if ids.is_empty() {
+            return Ok(Default::default());
+        }
+        let vals: Vec<String> = ids.iter().map(|id| id.value().to_string()).collect();
+        let rows: Vec<(String,)> = sqlx::query_as(
+            "SELECT external_metadata_id FROM movies WHERE external_metadata_id = ANY($1)",
+        )
+        .bind(&vals)
+        .fetch_all(&self.pool)
+        .await
+        .map_err(Self::map_err)?;
+        Ok(rows.into_iter().map(|(id,)| id).collect())
+    }
+
+    async fn existing_title_year_pairs(
+        &self,
+        pairs: &[(MovieTitle, ReleaseYear)],
+    ) -> Result<std::collections::HashSet<(String, u16)>, DomainError> {
+        if pairs.is_empty() {
+            return Ok(Default::default());
+        }
+        let titles: Vec<&str> = pairs.iter().map(|(t, _)| t.value()).collect();
+        let years: Vec<i64> = pairs.iter().map(|(_, y)| y.value() as i64).collect();
+        use sqlx::Row;
+        let rows = sqlx::query(
+            "SELECT DISTINCT m.title, m.release_year FROM movies m \
+             INNER JOIN unnest($1::text[], $2::bigint[]) AS p(title, release_year) \
+             ON m.title = p.title AND m.release_year = p.release_year",
+        )
+        .bind(&titles)
+        .bind(&years)
+        .fetch_all(&self.pool)
+        .await
+        .map_err(Self::map_err)?;
+        Ok(rows
+            .into_iter()
+            .map(|r| {
+                let t: String = r.get("title");
+                let y: i64 = r.get("release_year");
+                (t, y as u16)
+            })
+            .collect())
+    }
+
     async fn list_movies(
         &self,
         page: &domain::models::collections::PageParams,

crates/adapters/postgres/src/watch_event.rs

@@ -115,6 +115,45 @@ impl WatchEventRepository for PostgresWatchEventRepository {
         row.as_ref().map(row_to_watch_event).transpose()
     }
 
+    async fn get_by_ids(&self, ids: &[WatchEventId]) -> Result<Vec<WatchEvent>, DomainError> {
+        if ids.is_empty() {
+            return Ok(vec![]);
+        }
+        let id_strs: Vec<String> = ids.iter().map(|id| id.value().to_string()).collect();
+        let rows = sqlx::query(
+            "SELECT id, user_id, movie_id, title, year, external_metadata_id, \
+                    source, \
+                    to_char(watched_at AT TIME ZONE 'UTC', 'YYYY-MM-DD HH24:MI:SS') AS watched_at, \
+                    status, \
+                    to_char(created_at AT TIME ZONE 'UTC', 'YYYY-MM-DD HH24:MI:SS') AS created_at \
+             FROM watch_events WHERE id = ANY($1)",
+        )
+        .bind(&id_strs)
+        .fetch_all(&self.pool)
+        .await
+        .map_err(map_err)?;
+        rows.iter().map(row_to_watch_event).collect()
+    }
+
+    async fn update_status_batch(
+        &self,
+        ids: &[WatchEventId],
+        status: WatchEventStatus,
+    ) -> Result<u64, DomainError> {
+        if ids.is_empty() {
+            return Ok(0);
+        }
+        let id_strs: Vec<String> = ids.iter().map(|id| id.value().to_string()).collect();
+        let status_str = status.to_string();
+        let result = sqlx::query("UPDATE watch_events SET status = $1 WHERE id = ANY($2)")
+            .bind(&status_str)
+            .bind(&id_strs)
+            .execute(&self.pool)
+            .await
+            .map_err(map_err)?;
+        Ok(result.rows_affected())
+    }
+
     async fn find_duplicate(
         &self,
         user_id: &UserId,

crates/adapters/sqlite/src/lib.rs

@@ -402,6 +402,57 @@ impl MovieRepository for SqliteMovieRepository {
         Ok(())
     }
 
+    async fn existing_external_ids(
+        &self,
+        ids: &[ExternalMetadataId],
+    ) -> Result<std::collections::HashSet<String>, DomainError> {
+        if ids.is_empty() {
+            return Ok(Default::default());
+        }
+        let placeholders: Vec<&str> = ids.iter().map(|_| "?").collect();
+        let sql = format!(
+            "SELECT external_metadata_id FROM movies WHERE external_metadata_id IN ({})",
+            placeholders.join(",")
+        );
+        let mut q = sqlx::query_scalar::<_, String>(&sql);
+        for id in ids {
+            q = q.bind(id.value().to_string());
+        }
+        let rows = q.fetch_all(&self.pool).await.map_err(Self::map_err)?;
+        Ok(rows.into_iter().collect())
+    }
+
+    async fn existing_title_year_pairs(
+        &self,
+        pairs: &[(MovieTitle, ReleaseYear)],
+    ) -> Result<std::collections::HashSet<(String, u16)>, DomainError> {
+        if pairs.is_empty() {
+            return Ok(Default::default());
+        }
+        let conditions: Vec<String> = pairs
+            .iter()
+            .map(|_| "(title = ? AND release_year = ?)".to_string())
+            .collect();
+        let sql = format!(
+            "SELECT DISTINCT title, release_year FROM movies WHERE {}",
+            conditions.join(" OR ")
+        );
+        use sqlx::Row;
+        let mut q = sqlx::query(&sql);
+        for (t, y) in pairs {
+            q = q.bind(t.value().to_string()).bind(y.value() as i64);
+        }
+        let rows = q.fetch_all(&self.pool).await.map_err(Self::map_err)?;
+        Ok(rows
+            .into_iter()
+            .map(|r| {
+                let t: String = r.get("title");
+                let y: i64 = r.get("release_year");
+                (t, y as u16)
+            })
+            .collect())
+    }
+
     async fn list_movies(
         &self,
         page: &domain::models::collections::PageParams,

crates/adapters/sqlite/src/watch_event.rs

@@ -122,6 +122,46 @@ impl WatchEventRepository for SqliteWatchEventRepository {
         row.as_ref().map(row_to_watch_event).transpose()
     }
 
+    async fn get_by_ids(&self, ids: &[WatchEventId]) -> Result<Vec<WatchEvent>, DomainError> {
+        if ids.is_empty() {
+            return Ok(vec![]);
+        }
+        let placeholders: Vec<&str> = ids.iter().map(|_| "?").collect();
+        let sql = format!(
+            "SELECT id, user_id, movie_id, title, year, external_metadata_id, \
+                    source, watched_at, status, created_at \
+             FROM watch_events WHERE id IN ({})",
+            placeholders.join(",")
+        );
+        let mut q = sqlx::query(&sql);
+        for id in ids {
+            q = q.bind(id.value().to_string());
+        }
+        let rows = q.fetch_all(&self.pool).await.map_err(map_err)?;
+        rows.iter().map(row_to_watch_event).collect()
+    }
+
+    async fn update_status_batch(
+        &self,
+        ids: &[WatchEventId],
+        status: WatchEventStatus,
+    ) -> Result<u64, DomainError> {
+        if ids.is_empty() {
+            return Ok(0);
+        }
+        let placeholders: Vec<&str> = ids.iter().map(|_| "?").collect();
+        let sql = format!(
+            "UPDATE watch_events SET status = ? WHERE id IN ({})",
+            placeholders.join(",")
+        );
+        let mut q = sqlx::query(&sql).bind(status.to_string());
+        for id in ids {
+            q = q.bind(id.value().to_string());
+        }
+        let result = q.execute(&self.pool).await.map_err(map_err)?;
+        Ok(result.rows_affected())
+    }
+
     async fn find_duplicate(
         &self,
         user_id: &UserId,