feat(db): align movie state with canonical MediaState (#85)

crates/arr-db/migrations/0007_movie_state_canonical.sql

@@ -0,0 +1,73 @@
+-- #73. movies.state used missing|grabbed|imported, predating arr-core's
+-- canonical MediaState vocabulary (missing|downloading|available) that
+-- series/episodes (0005) already follow.
+--
+-- SQLite can't ALTER a CHECK constraint, so this rebuilds the table -- which
+-- means dropping the old copy. `movie_releases` references it with
+-- ON DELETE CASCADE, so the drop would take its rows down too; stash them
+-- first and restore them once the new `movies` exists with the same ids.
+
+CREATE TABLE movie_releases_backup AS SELECT * FROM movie_releases;
+
+CREATE TABLE movies_new (
+    id                INTEGER PRIMARY KEY,
+    tmdb_id           INTEGER NOT NULL UNIQUE,
+    title             TEXT NOT NULL,
+    year              INTEGER,
+    original_language TEXT,
+    root_id           INTEGER NOT NULL REFERENCES roots (id),
+    wanted            INTEGER NOT NULL DEFAULT 1 CHECK (wanted IN (0, 1)),
+    overrides         TEXT NOT NULL DEFAULT '{}' CHECK (json_valid(overrides)),
+    state             TEXT NOT NULL DEFAULT 'missing'
+                      CHECK (state IN ('missing', 'downloading', 'available')),
+    blocked           INTEGER NOT NULL DEFAULT 0 CHECK (blocked IN (0, 1)),
+    search_attempts   INTEGER NOT NULL DEFAULT 0,
+    last_searched_at  TEXT,
+    created_at        TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+    updated_at        TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+) STRICT;
+
+INSERT INTO movies_new (
+    id, tmdb_id, title, year, original_language, root_id, wanted, overrides,
+    state, blocked, search_attempts, last_searched_at, created_at, updated_at
+)
+SELECT
+    id, tmdb_id, title, year, original_language, root_id, wanted, overrides,
+    CASE state
+        WHEN 'grabbed'  THEN 'downloading'
+        WHEN 'imported' THEN 'available'
+        ELSE state
+    END,
+    blocked, search_attempts, last_searched_at, created_at, updated_at
+FROM movies;
+
+DROP TABLE movies;
+
+ALTER TABLE movies_new RENAME TO movies;
+
+CREATE INDEX movies_pending_search
+    ON movies (last_searched_at)
+    WHERE wanted = 1 AND blocked = 0;
+
+CREATE INDEX movies_state ON movies (state);
+CREATE INDEX movies_root ON movies (root_id);
+
+-- Dropping `movies` drops the triggers defined on it too (0005); recreate
+-- the movie-root invariant they enforced.
+CREATE TRIGGER movies_require_movie_root
+BEFORE INSERT ON movies
+WHEN EXISTS (SELECT 1 FROM roots WHERE id = NEW.root_id AND kind != 'movie')
+BEGIN
+    SELECT RAISE(ABORT, 'movies require a movie root');
+END;
+
+CREATE TRIGGER movies_require_movie_root_on_update
+BEFORE UPDATE OF root_id ON movies
+WHEN EXISTS (SELECT 1 FROM roots WHERE id = NEW.root_id AND kind != 'movie')
+BEGIN
+    SELECT RAISE(ABORT, 'movies require a movie root');
+END;
+
+INSERT INTO movie_releases SELECT * FROM movie_releases_backup;
+
+DROP TABLE movie_releases_backup;