ALTER TABLE chat_messages ADD COLUMN IF NOT EXISTS edited_at  TIMESTAMPTZ;
ALTER TABLE chat_messages ADD COLUMN IF NOT EXISTS deleted_at TIMESTAMPTZ;

CREATE TABLE IF NOT EXISTS chat_reactions (
  message_id UUID        NOT NULL REFERENCES chat_messages(id) ON DELETE CASCADE,
  user_id    UUID        NOT NULL REFERENCES users(id) ON DELETE CASCADE,
  emoji      VARCHAR(12) NOT NULL,
  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
  PRIMARY KEY (message_id, user_id, emoji)
);
CREATE INDEX IF NOT EXISTS idx_chat_reactions_message ON chat_reactions(message_id);