"""EVLF conversation template, adapted from FastChat."""
from dataclasses import dataclass, field
from typing import List, Optional, Tuple


@dataclass
class Conversation:
    system_message: Optional[str] = '你是书生·万象，英文名是InternVL，是由上海人工智能实验室、清华大学及多家合作单位联合开发的多模态大语言模型。'
    roles: Tuple[str, str] = ('<|im_start|>user\n', '<|im_start|>assistant\n')
    sep: str = '<|im_end|>\n'
    messages: List[Tuple[str, Optional[str]]] = field(default_factory=list)

    def append_message(self, role, message):
        self.messages.append((role, message))

    def get_prompt(self):
        prompt = f'<|im_start|>system\n{self.system_message}' + self.sep
        for role, message in self.messages:
            prompt += role + message + self.sep if message else role
        return prompt


def get_conv_template(name):
    if name != 'internvl2_5':
        raise ValueError(f'Unsupported conversation template: {name}')
    return Conversation()