insights-correlations (#22)

Reviewed-on: #22

crates/adapters/postgres/src/insights.rs

@@ -0,0 +1,81 @@
+use std::collections::HashMap;
+
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError, models::insights::WatchRow, ports::InsightsQuery, value_objects::UserId,
+};
+use sqlx::{PgPool, Row};
+
+use adapter_common::{parse_datetime, parse_uuid};
+
+use crate::wrapup::fetch_genres_pg;
+
+/// Postgres twin of `SqliteInsightsQuery` — same shape, `$n` binds, and the
+/// same thin "rows in, rows out" contract (ADR-0010).
+pub struct PostgresInsightsQuery {
+    pool: PgPool,
+}
+
+impl PostgresInsightsQuery {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl InsightsQuery for PostgresInsightsQuery {
+    async fn get_watch_rows(&self, user_id: &UserId) -> Result<Vec<WatchRow>, DomainError> {
+        let rows = sqlx::query(
+            "SELECT movie_id, rating, \
+                    to_char(watched_at AT TIME ZONE 'UTC', 'YYYY-MM-DD HH24:MI:SS') AS watched_at, \
+                    watch_medium \
+             FROM reviews \
+             WHERE user_id = $1 AND remote_actor_url IS NULL \
+             ORDER BY watched_at ASC",
+        )
+        .bind(user_id.value().to_string())
+        .fetch_all(&self.pool)
+        .await
+        .map_err(adapter_common::map_sqlx_error)?;
+
+        let mut movie_ids: Vec<String> = Vec::new();
+        let mut seen = std::collections::HashSet::new();
+        for row in &rows {
+            let mid: String = row
+                .try_get("movie_id")
+                .map_err(adapter_common::map_sqlx_error)?;
+            if seen.insert(mid.clone()) {
+                movie_ids.push(mid);
+            }
+        }
+
+        let genres_map: HashMap<String, Vec<String>> =
+            fetch_genres_pg(&self.pool, &movie_ids).await?;
+
+        let mut result = Vec::with_capacity(rows.len());
+        for row in &rows {
+            let movie_id: String = row
+                .try_get("movie_id")
+                .map_err(adapter_common::map_sqlx_error)?;
+            let rating: i64 = row
+                .try_get("rating")
+                .map_err(adapter_common::map_sqlx_error)?;
+            let watched_at: String = row
+                .try_get("watched_at")
+                .map_err(adapter_common::map_sqlx_error)?;
+            let watch_medium: Option<String> = row
+                .try_get("watch_medium")
+                .map_err(adapter_common::map_sqlx_error)?;
+
+            result.push(WatchRow {
+                movie_id: parse_uuid(&movie_id)?,
+                rating: rating as u8,
+                watched_at: parse_datetime(&watched_at)?,
+                watch_medium,
+                genres: genres_map.get(&movie_id).cloned().unwrap_or_default(),
+            });
+        }
+
+        Ok(result)
+    }
+}