"""
Python Backend API to chat with private data  

08/14/2023
D.M. Theekshana Samaradiwakara
"""

import os
import time

from dotenv import load_dotenv

from langchain.chains import RetrievalQA
from langchain.callbacks.streaming_stdout import StreamingStdOutCallbackHandler

from langchain.llms import GPT4All
from langchain.llms import HuggingFaceHub
from langchain.chat_models import ChatOpenAI
from langchain.chat_models import ChatAnyscale

# from langchain.retrievers.self_query.base import SelfQueryRetriever
# from langchain.chains.query_constructor.base import AttributeInfo

# from chromaDb import load_store
from faissDb import load_FAISS_store

from langchain.agents import ZeroShotAgent, Tool, AgentExecutor

from langchain.prompts import PromptTemplate
from langchain.chains import LLMChain, ConversationalRetrievalChain
from conversationBufferWindowMemory import ConversationBufferWindowMemory
from langchain.memory import ReadOnlySharedMemory

load_dotenv()

#gpt4 all model
gpt4all_model_path = os.environ.get('GPT4ALL_MODEL_PATH')
model_n_ctx = os.environ.get('MODEL_N_CTX')
model_n_batch = int(os.environ.get('MODEL_N_BATCH',8))
target_source_chunks = int(os.environ.get('TARGET_SOURCE_CHUNKS',4))

openai_api_key = os.environ.get('OPENAI_API_KEY')
anyscale_api_key = os.environ.get('ANYSCALE_ENDPOINT_TOKEN')

verbose = os.environ.get('VERBOSE')

# activate/deactivate the streaming StdOut callback for LLMs
callbacks = [StreamingStdOutCallbackHandler()]

memory = ConversationBufferWindowMemory(
            memory_key="chat_history",
            input_key="question",
            return_messages=True,
            k=3
        )

readonlymemory = ReadOnlySharedMemory(memory=memory)

class Singleton:
   __instance = None
   @staticmethod 
   def getInstance():
      """ Static access method. """
      if Singleton.__instance == None:
         Singleton()
      return Singleton.__instance
   def __init__(self):
      """ Virtually private constructor. """
      if Singleton.__instance != None:
         raise Exception("This class is a singleton!")
      else:
         Singleton.__instance = QAPipeline()

def get_local_LLAMA2():
    import torch
    from transformers import AutoTokenizer, AutoModelForCausalLM

    tokenizer = AutoTokenizer.from_pretrained("NousResearch/Llama-2-13b-chat-hf",
                                        # use_auth_token=True,
                                        )

    model = AutoModelForCausalLM.from_pretrained("NousResearch/Llama-2-13b-chat-hf",
                                            device_map='auto',
                                            torch_dtype=torch.float16,
                                            use_auth_token=True,
                                        #  load_in_8bit=True,
                                        #  load_in_4bit=True
                                        )
    from transformers import pipeline

    pipe = pipeline("text-generation",
                    model=model,
                    tokenizer= tokenizer,
                    torch_dtype=torch.bfloat16,
                    device_map="auto",
                    max_new_tokens = 512,
                    do_sample=True,
                    top_k=30,
                    num_return_sequences=1,
                    eos_token_id=tokenizer.eos_token_id
                    )
    
    from langchain import HuggingFacePipeline
    LLAMA2 = HuggingFacePipeline(pipeline = pipe, model_kwargs = {'temperature':0})
    print(f"\n\n> torch.cuda.is_available(): {torch.cuda.is_available()}")
    print("\n\n> local LLAMA2 loaded")
    return LLAMA2

class QAPipeline:

    def __init__(self):

        print("\n\n> Initializing QAPipeline:")
        self.llm_name = None
        self.llm = None

        self.dataset_name = None
        self.vectorstore = None

        self.qa_chain = None
        self.agent = None


    def run(self,query, model, dataset):

        if (self.llm_name != model) or (self.dataset_name != dataset) or (self.qa_chain == None):
            self.set_model(model)
            self.set_vectorstore(dataset)
            self.set_qa_chain()

        # Get the answer from the chain
        start = time.time()
        res = self.qa_chain(query)
        # answer, docs = res['result'],res['source_documents']
        end = time.time()

        # Print the result
        print("\n\n> Question:")
        print(query)
        print(f"\n> Answer (took {round(end - start, 2)} s.):")
        print( res)

        return res
    
    def run_agent(self,query, model, dataset):

        try:

            if (self.llm_name != model) or (self.dataset_name != dataset) or (self.agent == None):
                self.set_model(model)
                self.set_vectorstore(dataset)
                self.set_qa_chain_with_agent()

            # Get the answer from the chain
            start = time.time()
            res = self.agent(query)
            # answer, docs = res['result'],res['source_documents']
            end = time.time()

            # Print the result
            print("\n\n> Question:")
            print(query)
            print(f"\n> Answer (took {round(end - start, 2)} s.):")
            print( res)

            return res["output"]
    
        except Exception as e:
        # logger.error(f"Answer retrieval failed with {e}")
            print(f"> QAPipeline run_agent Error : {e}")#, icon=":books:")
            return 


    def set_model(self,model_type):
        if model_type != self.llm_name:
            match model_type:
                case "gpt4all":
                    # self.llm = GPT4All(model=gpt4all_model_path, n_ctx=model_n_ctx, backend='gptj', n_batch=model_n_batch, callbacks=callbacks, verbose=verbose)
                    self.llm = GPT4All(model=gpt4all_model_path, max_tokens=model_n_ctx, backend='gptj', n_batch=model_n_batch, callbacks=callbacks, verbose=verbose)
                    # self.llm = HuggingFaceHub(repo_id="nomic-ai/gpt4all-j", model_kwargs={"temperature":0.001, "max_length":1024})
                case "google/flan-t5-xxl":
                    self.llm = HuggingFaceHub(repo_id="google/flan-t5-xxl", model_kwargs={"temperature":0.001, "max_length":1024})
                case "tiiuae/falcon-7b-instruct":
                    self.llm = HuggingFaceHub(repo_id=model_type, model_kwargs={"temperature":0.001, "max_length":1024})
                case "openai":
                    self.llm = ChatOpenAI(model_name="gpt-3.5-turbo", temperature=0)
                case "Deci/DeciLM-6b-instruct":
                    self.llm = ChatOpenAI(model_name="Deci/DeciLM-6b-instruct", temperature=0)
                case "Deci/DeciLM-6b":
                    self.llm = ChatOpenAI(model_name="Deci/DeciLM-6b", temperature=0)
                case "local/LLAMA2":
                    self.llm = get_local_LLAMA2()
                case "anyscale/Llama-2-13b-chat-hf":
                    self.llm = ChatAnyscale(anyscale_api_key=anyscale_api_key,temperature=0, model_name='meta-llama/Llama-2-13b-chat-hf', streaming=False)
                case "anyscale/Llama-2-70b-chat-hf":
                    self.llm = ChatAnyscale(anyscale_api_key=anyscale_api_key,temperature=0, model_name='meta-llama/Llama-2-70b-chat-hf', streaming=False)
                case _default:
                    # raise exception if model_type is not supported
                    raise Exception(f"Model type {model_type} is not supported. Please choose a valid one")
                 
            self.llm_name = model_type
    


    def set_vectorstore(self, dataset):
        if dataset != self.dataset_name:
            # self.vectorstore = load_store(dataset)
            self.vectorstore = load_FAISS_store()
            print("\n\n> vectorstore loaded:")
            self.dataset_name = dataset
    
    def set_qa_chain(self):
    
        self.qa_chain = RetrievalQA.from_chain_type(
            llm=self.llm,
            chain_type="stuff",
            retriever = self.vectorstore.as_retriever(), 
            # retriever = self.vectorstore.as_retriever(search_kwargs={"k": target_source_chunks}
            return_source_documents= True
        )


    def set_qa_chain_with_agent(self):

        try:

            # Define a custom prompt
            general_qa_template = (
                """[INST]<<SYS>> You are the AI of company boardpac which provide services to company board members related to banking and financial sector. You should only continue the conversation and reply to users questions like welcomes, greetings and goodbyes.
                If you dont know the answer say you dont know, dont try to makeup answers. Answer should be short and simple as possible. Start the answer with code word Boardpac AI (chat): <</SYS>>
                Conversation: {chat_history}
                Question: {question} [/INST]"""
            )

            general_qa_chain_prompt = PromptTemplate(input_variables=["question", "chat_history"], template=general_qa_template)
            
            general_qa_chain = LLMChain(
                llm=self.llm, 
                prompt=general_qa_chain_prompt,
                verbose=True,
                memory=readonlymemory,  # use the read-only memory to prevent the tool from modifying the memory
            )

            general_qa_chain_tool = Tool(
                    name="general qa",
                    func= general_qa_chain.run,
                    description='''use this when only you need to answer questions like welcomes, greetings and goodbyes. 
                    Input should be a fully formed question.''',
                    return_direct=True,
                    
            )

            # Define a custom prompt
            retrieval_qa_template = (
                """[INST]<<SYS>> You are the AI of company boardpac which provide services to company board members. Only answer questions related to Banking and Financial Services Sector like Banking & Financial regulations, legal framework, governance framework, compliance requirements as per Central Bank regulations.
                please answer the question based on the chat history and context information provided below related to central bank acts published in various years. The published year is mentioned as the  metadata 'year' of each source document.
                The content of a bank act of a past year can updated by a bank act from a latest year. Always try to answer with latest information and mention the year which information extracted.
                If you dont know the answer say you dont know, dont try to makeup answers. Answer should be short and simple as possible. Start the answer with code word Boardpac AI (QA): <</SYS>>
                Conversation: {chat_history}
                Context: {context}
                Question : {question} [/INST]"""
            )

            retrieval_qa_chain_prompt = PromptTemplate(
                input_variables=["question", "context", "chat_history"], 
                template=retrieval_qa_template
            )
            
            document_combine_prompt = PromptTemplate(
                input_variables=["source","year", "page","page_content"],
                template= 
                """<doc> source: {source}, year: {year}, page: {page}, page content: {page_content} </doc>"""
            )

            bank_regulations_qa = ConversationalRetrievalChain.from_llm(
                llm=self.llm,
                chain_type="stuff",
                retriever = self.vectorstore.as_retriever(),
                # retriever = self.vectorstore.as_retriever(
                #     search_type="mmr",
                #     search_kwargs={
                #         'k': 6, 
                #         # 'lambda_mult': 0.1, 
                #         'fetch_k': 50},
                #     # search_type="similarity_score_threshold",  
                #     # search_kwargs={"score_threshold": .5}  
                # ),
                return_source_documents= True,
                return_generated_question= True,
                get_chat_history=lambda h : h,
                combine_docs_chain_kwargs={
                    "prompt": retrieval_qa_chain_prompt,
                    "document_prompt": document_combine_prompt,
                },
                verbose=True,
                memory=readonlymemory,  # use the read-only memory to prevent the tool from modifying the memory
            )

            bank_regulations_qa_tool = Tool(
                name="bank regulations",
                func= lambda question: bank_regulations_qa({"question": question}),
                description='''Use this more  when you need to answer questions about Banking and Financial Services Sector like Banking & Financial regulations, legal framework, governance framework, compliance requirements as per Central Bank regulations. 
                Input should be a fully formed question.''',
                return_direct=True,
            )

            tools = [
                bank_regulations_qa_tool,
                general_qa_chain_tool
            ]

            prefix = """<<SYS>> You are the AI of company boardpac which provide services to company board members related to banking and financial sector. Have a conversation with the user, answering the following questions as best you can. You have access to the following tools:"""
            suffix = """Begin! "
            {agent_scratchpad} 
            <chat history>: {chat_history}
            <</SYS>>

            [INST]
            <Question>: {question}
            [/INST]"""

            agent_prompt = ZeroShotAgent.create_prompt(
                tools,
                prefix=prefix,
                suffix=suffix,
                input_variables=["question", "chat_history", "agent_scratchpad"],
            )

            llm_chain = LLMChain(llm=self.llm, prompt=agent_prompt)

            agent = ZeroShotAgent(
                llm_chain=llm_chain, 
                tools=tools, 
                verbose=True,
            )

            agent_chain = AgentExecutor.from_agent_and_tools(
                agent=agent, 
                tools=tools, 
                verbose=True,
                memory=memory,
                handle_parsing_errors=True,
            )

            self.agent = agent_chain

            print(f"\n> agent_chain created")

        except Exception as e:
            # logger.error(f"Answer retrieval failed with {e}")
            print(f"> QAPipeline set_qa_chain_with_agent Error : {e}")#, icon=":books:")
            return