import abc
import os
import time
import urllib
from queue import Queue
from threading import Thread
from typing import List, Optional

from langchain.chains.base import Chain

from app_modules.llm_loader import LLMLoader, TextIteratorStreamer
from app_modules.utils import remove_extra_spaces
from urllib.parse import urlparse, urlunparse, quote


class LLMInference(metaclass=abc.ABCMeta):
    llm_loader: LLMLoader
    chain: Chain

    def __init__(self, llm_loader):
        self.llm_loader = llm_loader
        self.chain = None

    @abc.abstractmethod
    def create_chain(self, inputs) -> Chain:
        pass

    def get_chain(self, inputs) -> Chain:
        if self.chain is None:
            self.chain = self.create_chain(inputs)

        return self.chain

    def run_chain(self, chain, inputs, callbacks: Optional[List] = []):
        return chain(inputs, callbacks)

    def call_chain(
        self,
        inputs,
        streaming_handler,
        q: Queue = None,
        testing: bool = False,
    ):
        print(inputs)
        if self.llm_loader.streamer.for_huggingface:
            self.llm_loader.lock.acquire()

        try:
            self.llm_loader.streamer.reset(q)

            chain = self.get_chain(inputs)
            result = (
                self._run_chain_with_streaming_handler(
                    chain, inputs, streaming_handler, testing
                )
                if streaming_handler is not None
                else self.run_chain(chain, inputs)
            )

            if "answer" in result:
                result["answer"] = remove_extra_spaces(result["answer"])

                source_path = os.environ.get("SOURCE_PATH")
                base_url = os.environ.get("PDF_FILE_BASE_URL")
                if base_url is not None and len(base_url) > 0:
                    documents = result["source_documents"]
                    for doc in documents:
                        source = doc.metadata["source"]
                        title = source.split("/")[-1]
                        doc.metadata["url"] = f"{base_url}{urllib.parse.quote(title)}"
                elif source_path is not None and len(source_path) > 0:
                    documents = result["source_documents"]
                    for doc in documents:
                        source = doc.metadata["source"]
                        url = source.replace(source_path, "https://")
                        url = url.replace(".html", "")
                        parsed_url = urlparse(url)

                        # Encode path, query, and fragment
                        encoded_path = quote(parsed_url.path)
                        encoded_query = quote(parsed_url.query)
                        encoded_fragment = quote(parsed_url.fragment)

                        # Construct the encoded URL
                        doc.metadata["url"] = urlunparse(
                            (
                                parsed_url.scheme,
                                parsed_url.netloc,
                                encoded_path,
                                parsed_url.params,
                                encoded_query,
                                encoded_fragment,
                            )
                        )

            return result
        finally:
            if self.llm_loader.streamer.for_huggingface:
                self.llm_loader.lock.release()

    def _execute_chain(self, chain, inputs, q, sh):
        q.put(self.run_chain(chain, inputs, callbacks=[sh]))

    def _run_chain_with_streaming_handler(
        self, chain, inputs, streaming_handler, testing
    ):
        que = Queue()

        t = Thread(
            target=self._execute_chain,
            args=(chain, inputs, que, streaming_handler),
        )
        t.start()

        if self.llm_loader.streamer.for_huggingface:
            count = (
                2
                if "chat_history" in inputs and len(inputs.get("chat_history")) > 0
                else 1
            )

            while count > 0:
                try:
                    for token in self.llm_loader.streamer:
                        if not testing:
                            streaming_handler.on_llm_new_token(token)

                    self.llm_loader.streamer.reset()
                    count -= 1
                except Exception:
                    if not testing:
                        print("nothing generated yet - retry in 0.5s")
                    time.sleep(0.5)

        t.join()
        return que.get()