Changed sqlite FTS to use a trigram tokenizer

priv/repo/migrations/20240523183003_change_media_items_search_index_tokenizer.exs

@@ -0,0 +1,60 @@
+defmodule Pinchflat.Repo.Migrations.ChangeMediaItemsSearchIndexTokenizer do
+  use Ecto.Migration
+
+  def up do
+    # These all need to run as part of separate `execute` blocks. Do NOT ask me why.
+    execute "DROP TRIGGER media_items_search_index_insert;"
+    execute "DROP TRIGGER media_items_search_index_update;"
+    execute "DROP TRIGGER media_items_search_index_delete;"
+    execute "DROP TABLE media_items_search_index;"
+
+    execute """
+      CREATE VIRTUAL TABLE media_items_search_index USING fts5(
+        title,
+        description,
+        tokenize=trigram
+      );
+    """
+
+    execute """
+      CREATE TRIGGER media_items_search_index_insert AFTER INSERT ON media_items BEGIN
+        INSERT INTO media_items_search_index(
+          rowid,
+          title,
+          description
+        )
+        VALUES(
+          new.id,
+          new.title,
+          new.description
+        );
+      END;
+    """
+
+    execute """
+      CREATE TRIGGER media_items_search_index_update AFTER UPDATE ON media_items BEGIN
+        UPDATE media_items_search_index SET
+          title = new.title,
+          description = new.description
+        WHERE
+          rowid = old.id;
+      END;
+    """
+
+    execute """
+      CREATE TRIGGER media_items_search_index_delete AFTER DELETE ON media_items BEGIN
+        DELETE FROM media_items_search_index WHERE rowid = old.id;
+      END;
+    """
+
+    # Fully re-index the media_items table
+    execute """
+      INSERT INTO media_items_search_index(rowid, title, description)
+      SELECT id, title, description FROM media_items;
+    """
+  end
+
+  def down do
+    execute "DROP TABLE media_items_search_index;"
+  end
+end