-- 020: User messages/notifications (user-service / notification-service)
CREATE TABLE IF NOT EXISTS messages (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    title VARCHAR(200) NOT NULL,
    content TEXT NOT NULL,
    type VARCHAR(30) NOT NULL DEFAULT 'system' CHECK (type IN (
        'system', 'trade', 'coupon', 'wallet', 'kyc', 'compliance', 'promotion'
    )),
    is_read BOOLEAN NOT NULL DEFAULT false,
    reference_type VARCHAR(30),
    reference_id UUID,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

CREATE INDEX idx_messages_user_id ON messages(user_id);
CREATE INDEX idx_messages_is_read ON messages(is_read);
CREATE INDEX idx_messages_type ON messages(type);
CREATE INDEX idx_messages_created_at ON messages(created_at DESC);