import type { PoolClient } from 'pg';

/**
 * Upserts a player. A non-null name replaces the stored one only if it was observed at least as late as the
 * current name (late replays never revert a rename) and is recorded in name_history;
 * `seen` updates last_seen (only for events proving the player was online).
 */
export async function ensurePlayer(c: PoolClient, uuid: string, name: string | null, ts: number, seen: boolean): Promise<void> {
  await c.query(
    `INSERT INTO players(uuid, name, name_seen_at, first_seen, last_seen)
     VALUES ($1, $2, CASE WHEN $2::text IS NOT NULL THEN to_timestamp($3 / 1000.0) END,
             to_timestamp($3 / 1000.0), CASE WHEN $4 THEN to_timestamp($3 / 1000.0) END)
     ON CONFLICT (uuid) DO UPDATE SET
       name = CASE WHEN EXCLUDED.name IS NOT NULL AND (players.name_seen_at IS NULL OR EXCLUDED.name_seen_at >= players.name_seen_at)
                   THEN EXCLUDED.name ELSE players.name END,
       name_seen_at = CASE WHEN EXCLUDED.name IS NOT NULL AND (players.name_seen_at IS NULL OR EXCLUDED.name_seen_at >= players.name_seen_at)
                   THEN EXCLUDED.name_seen_at ELSE players.name_seen_at END,
       first_seen = LEAST(players.first_seen, EXCLUDED.first_seen),
       last_seen = CASE WHEN $4 THEN GREATEST(players.last_seen, EXCLUDED.last_seen) ELSE players.last_seen END`,
    [uuid, name, ts, seen],
  );
  if (name) {
    await c.query(
      `INSERT INTO name_history(uuid, name, seen_at) VALUES ($1, $2, to_timestamp($3 / 1000.0))
       ON CONFLICT (uuid, name) DO UPDATE SET seen_at = GREATEST(name_history.seen_at, EXCLUDED.seen_at)`,
      [uuid, name, ts],
    );
  }
}