import type { DatabaseSync } from "node:sqlite";

// Idempotent: safe to run against a fresh db (already created from schema.sql
// with these columns/tables) or an existing one that predates them.
export function up(db: DatabaseSync): void {
  const commentCols = db.prepare(`PRAGMA table_info(comments);`).all() as {
    name: string;
  }[];
  if (!commentCols.some((c) => c.name === "like_count")) {
    db.exec(
      `ALTER TABLE comments ADD COLUMN like_count INTEGER NOT NULL DEFAULT 0;`,
    );
  }

  db.exec(`CREATE TABLE IF NOT EXISTS comment_likes (
    comment_id TEXT NOT NULL,
    user_id    TEXT NOT NULL,
    created_at TEXT NOT NULL,
    PRIMARY KEY (comment_id, user_id),
    FOREIGN KEY (comment_id) REFERENCES comments(id) ON DELETE CASCADE,
    FOREIGN KEY (user_id)    REFERENCES users(id)    ON DELETE CASCADE
  );`);

  db.exec(
    `CREATE INDEX IF NOT EXISTS idx_comment_likes_user ON comment_likes(user_id);`,
  );
}