CREATE TYPE "public"."user_role" AS ENUM('admin', 'author');--> statement-breakpoint
CREATE TABLE "user_tags" (
	"user_id" integer NOT NULL,
	"tag_id" integer NOT NULL,
	CONSTRAINT "user_tags_user_id_tag_id_pk" PRIMARY KEY("user_id","tag_id")
);
--> statement-breakpoint
ALTER TABLE "posts" ADD COLUMN "author_id" integer;--> statement-breakpoint
ALTER TABLE "users" ADD COLUMN "role" "user_role" DEFAULT 'author' NOT NULL;--> statement-breakpoint
ALTER TABLE "user_tags" ADD CONSTRAINT "user_tags_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;--> statement-breakpoint
ALTER TABLE "user_tags" ADD CONSTRAINT "user_tags_tag_id_tags_id_fk" FOREIGN KEY ("tag_id") REFERENCES "public"."tags"("id") ON DELETE cascade ON UPDATE no action;--> statement-breakpoint
CREATE INDEX "user_tags_tag_id_idx" ON "user_tags" USING btree ("tag_id");--> statement-breakpoint
ALTER TABLE "posts" ADD CONSTRAINT "posts_author_id_users_id_fk" FOREIGN KEY ("author_id") REFERENCES "public"."users"("id") ON DELETE set null ON UPDATE no action;--> statement-breakpoint
-- Backfill: every account that existed before roles was the admin account,
-- and every existing post was written by it.
UPDATE "users" SET "role" = 'admin';--> statement-breakpoint
UPDATE "posts" SET "author_id" = (SELECT "id" FROM "users" WHERE "role" = 'admin' ORDER BY "id" LIMIT 1) WHERE "author_id" IS NULL;