ALTER TABLE calendar_item_chat_messages
ADD COLUMN IF NOT EXISTS edited_at TIMESTAMPTZ,
ADD COLUMN IF NOT EXISTS deleted_at TIMESTAMPTZ;

CREATE TABLE IF NOT EXISTS calendar_item_chat_attachments (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  chat_message_id UUID NOT NULL REFERENCES calendar_item_chat_messages(id) ON DELETE CASCADE,
  original_filename TEXT NOT NULL,
  stored_filename TEXT NOT NULL,
  mime_type TEXT NOT NULL,
  size_bytes BIGINT NOT NULL CHECK (size_bytes >= 0),
  storage_driver TEXT NOT NULL,
  storage_path TEXT NOT NULL,
  created_by UUID REFERENCES users(id) ON DELETE SET NULL,
  created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE INDEX IF NOT EXISTS idx_calendar_item_chat_attachments_message
  ON calendar_item_chat_attachments (chat_message_id, created_at);