-- Migration to add attachments and reactions
ALTER TABLE messages ADD COLUMN attachment_url VARCHAR(255) AFTER content;

CREATE TABLE IF NOT EXISTS message_reactions (
    id INT AUTO_INCREMENT PRIMARY KEY,
    message_id INT NOT NULL,
    user_id INT NOT NULL,
    emoji VARCHAR(50) NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    UNIQUE KEY (message_id, user_id, emoji),
    FOREIGN KEY (message_id) REFERENCES messages(id) ON DELETE CASCADE,
    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
);