feat(api): series, season and episode endpoints (#81)

crates/arr-db/src/policy.rs

@@ -27,13 +27,13 @@ pub enum PolicyError {
     },
 }
 
-/// The effective policy for one movie, plus the root it is attached to.
+/// The effective policy for one title, plus the root it is attached to.
 ///
 /// The root's `kind` and `audience` are the Transmission label and the
 /// on-disk layout (§7.1, §7.4), and they only exist together with the policy,
 /// so they are returned together.
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub struct MoviePolicy {
+pub struct TitlePolicy {
     pub policy: Policy,
     /// Per-title relaxations and tightenings of the root policy (§5.1).
     pub overrides: TitleOverrides,
@@ -45,6 +45,9 @@ pub struct MoviePolicy {
     pub root_path: String,
 }
 
+/// What [`Db::movie_policy`] returned before episodes needed the same shape.
+pub type MoviePolicy = TitlePolicy;
+
 /// The raw policy columns, as the `policies` table stores them (§5.5, §10).
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct PolicyColumns {
@@ -139,7 +142,7 @@ impl Db {
     ///
     /// If the query fails, or a policy column does not hold the JSON its
     /// migration promises.
-    pub async fn movie_policy(&self, movie_id: i64) -> Result<Option<MoviePolicy>, PolicyError> {
+    pub async fn movie_policy(&self, movie_id: i64) -> Result<Option<TitlePolicy>, PolicyError> {
         let row = sqlx::query!(
             r#"
             SELECT   m.overrides       AS "overrides!: String",
@@ -184,7 +187,82 @@ impl Db {
         }
         .to_policy()?;
 
-        Ok(Some(MoviePolicy {
+        Ok(Some(TitlePolicy {
+            policy,
+            overrides: TitleOverrides {
+                only_4k: overrides.only_4k,
+                allow_english_audio: overrides.allow_english_audio,
+            },
+            root_id: row.root_id,
+            root_kind: row.root_kind,
+            root_audience: row.root_audience,
+            root_path: row.root_path,
+        }))
+    }
+
+    /// The policy attached to an episode's series root, with that series'
+    /// overrides.
+    ///
+    /// Overrides sit on the series (§5.1): an episode is a leaf carrying
+    /// intent, never its own policy.
+    ///
+    /// `None` when the episode does not exist.
+    ///
+    /// # Errors
+    ///
+    /// If the query fails, or a policy column does not hold the JSON its
+    /// migration promises.
+    pub async fn episode_policy(
+        &self,
+        episode_id: i64,
+    ) -> Result<Option<TitlePolicy>, PolicyError> {
+        let row = sqlx::query!(
+            r#"
+            SELECT   s.overrides       AS "overrides!: String",
+                     r.id              AS "root_id!: i64",
+                     r.kind            AS "root_kind!: String",
+                     r.audience        AS "root_audience!: String",
+                     r.path            AS "root_path!: String",
+                     p.id              AS "policy_id!: i64",
+                     p.name            AS "policy_name!: String",
+                     p.required_audio  AS "required_audio!: String",
+                     p.dub_blacklist   AS "dub_blacklist!: String",
+                     p.hdr_rules       AS "hdr_rules!: String",
+                     p.size_bands      AS "size_bands!: String",
+                     p.resolution_pref AS "resolution_pref!: String",
+                     p.source_weights  AS "source_weights!: String",
+                     p.score_weights   AS "score_weights!: String"
+            FROM     episodes e
+            JOIN     seasons se  ON se.id = e.season_id
+            JOIN     series s    ON s.id = se.series_id
+            JOIN     roots r     ON r.id = s.root_id
+            JOIN     policies p  ON p.id = r.policy_id
+            WHERE    e.id = ?
+            "#,
+            episode_id
+        )
+        .fetch_optional(self.pool())
+        .await?;
+
+        let Some(row) = row else {
+            return Ok(None);
+        };
+
+        let overrides: OverridesJson = json("overrides", &row.overrides)?;
+        let policy = PolicyColumns {
+            id: row.policy_id,
+            name: row.policy_name,
+            required_audio: row.required_audio,
+            dub_blacklist: row.dub_blacklist,
+            hdr_rules: row.hdr_rules,
+            size_bands: row.size_bands,
+            resolution_pref: row.resolution_pref,
+            source_weights: row.source_weights,
+            score_weights: row.score_weights,
+        }
+        .to_policy()?;
+
+        Ok(Some(TitlePolicy {
             policy,
             overrides: TitleOverrides {
                 only_4k: overrides.only_4k,