gem "langchainrb"

bundle install

export OPENAI_API_KEY="your-api-key"

Langchain::LLM::OpenAI.configure do |config|
  config.api_key = ENV["OPENAI_API_KEY"]
end

require "langchain"

llm = Langchain::LLM::OpenAI.new

response = llm.chat(
  messages: [
    {role: "user", content: "Who created the Ruby programming language?"}
  ]
)

puts response.message.content  
# => "Ruby was created by Yukihiro Matsumoto (Matz) in the mid-1990s."

embedding = llm.embed(text: "Ruby is elegant and expressive.")
another_embedding = llm.embed(text: "The Ruby language prioritizes developer happiness.")

similarity = embedding.cosine_similarity(another_embedding)

puts "Similarity score: #{similarity}" # => ~0.92 (rất gần nhau)

loader = Langchain::Loader.new("https://guides.rubyonrails.org/getting_started.html")
documents = loader.load

splitter = Langchain::Chunker::RecursiveText.new(documents, chunk_size: 500)
chunks = splitter.chunks

vector_store = []

chunks.each do |chunk|
  embedding = llm.embed(text: chunk.text)
  vector_store << { embedding: embedding, text: chunk.text }
end

question = "What is Rails?"
question_embedding = llm.embed(text: question)

closest = vector_store.max_by do |entry|
  question_embedding.cosine_similarity(entry[:embedding])
end

answer = llm.chat(
  messages: [
    {role: "system", content: "Answer based on the context: #{closest[:text]}"},
    {role: "user", content: question}
  ]
)

puts answer.message.content
# => "Rails is a web application framework written in Ruby..."

puts "Happy coding, Matz would approve! 🚀"