import wikipedia

def search_wiki(query, lang='en'):
    wikipedia.set_lang(lang)
    topics = wikipedia.search(query)
    if not topics:
        return "No topics found."
    topics = topics[:5]
    return [{"topic": topic, "summary": wikipedia.summary(topic)} for topic in topics]

def summary_wiki(query, lang='en'):
    wikipedia.set_lang(lang)
    return wikipedia.summary(query)

def page_wiki(query, lang='en'):
    wikipedia.set_lang(lang)
    return wikipedia.page(query).content

def random_wiki(lang='en'):
    wikipedia.set_lang(lang)
    return wikipedia.page(wikipedia.random()).content