CREATE TABLE IF NOT EXISTS achievements (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name VARCHAR(255) NOT NULL,
    description TEXT NOT NULL,
    icon_url VARCHAR(512),
    created_at TIMESTAMP NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMP NOT NULL DEFAULT NOW()
);

CREATE TABLE IF NOT EXISTS user_achievements (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    achievement_id UUID NOT NULL REFERENCES achievements(id) ON DELETE CASCADE,
    received_at TIMESTAMP NOT NULL DEFAULT NOW(),
    UNIQUE(user_id, achievement_id)
);

CREATE INDEX IF NOT EXISTS idx_user_achievements_user_id ON user_achievements(user_id);
CREATE INDEX IF NOT EXISTS idx_user_achievements_achievement_id ON user_achievements(achievement_id);