import collections
import random
import time
from typing import Literal

import interface
import requests
from loguru import logger


class TokenBuffer:
    def __init__(self, stop_sequences: list[str]) -> None:
        self.stop_sequences = stop_sequences
        self.longest_stop_len = max((len(stop) for stop in stop_sequences), default=0)
        self.tokens = collections.deque()
        self.token_lens = collections.deque()
        self.total_len = 0

    def add(self, token: interface.Token):
        self.tokens.append(token)
        self.token_lens.append(len(token))
        self.total_len += len(token)
        while True:
            if not self.tokens:
                break
            head_len = self.token_lens[0]
            if self.total_len - head_len >= self.longest_stop_len:
                token = self.tokens.popleft()
                self.token_lens.popleft()
                self.total_len -= head_len
                yield token
            else:
                break

    def finish(self, reason: Literal["length", "eos_token", "stop_sequence"]):
        if reason == "stop_sequence":
            end_sequence = ""
            while self.tokens:
                end_sequence = self.tokens.pop().text + end_sequence
                if end_sequence in self.stop_sequences:
                    break
            yield from self.tokens
        else:
            yield from self.tokens


def wait_for_inference_server(inference_server_url: str, timeout: int = 600):
    health_url = f"{inference_server_url}/health"
    time_limit = time.time() + timeout
    while True:
        try:
            response = requests.get(health_url)
            response.raise_for_status()
        except (requests.HTTPError, requests.ConnectionError):
            if time.time() > time_limit:
                raise
            sleep_duration = random.uniform(0, 10)
            logger.warning(f"Inference server not ready. Retrying in {sleep_duration:.2f} seconds")
            time.sleep(sleep_duration)
        else:
            logger.info("Inference server is ready")
            break