from __future__ import annotations

import typing

from .. import operator, entities, errors


@operator.operator_class(
    name='list', help='列出此会话中的所有历史对话', usage='!list\n!list <页码>'
)
class ListOperator(operator.CommandOperator):
    async def execute(
        self, context: entities.ExecuteContext
    ) -> typing.AsyncGenerator[entities.CommandReturn, None]:
        page = 0

        if len(context.crt_params) > 0:
            try:
                page = int(context.crt_params[0] - 1)
            except Exception:
                yield entities.CommandReturn(
                    error=errors.CommandOperationError('页码应为整数')
                )
                return

        record_per_page = 10

        content = ''

        index = 0

        using_conv_index = 0

        for conv in context.session.conversations[::-1]:
            time_str = conv.create_time.strftime('%Y-%m-%d %H:%M:%S')

            if conv == context.session.using_conversation:
                using_conv_index = index

            if index >= page * record_per_page and index < (page + 1) * record_per_page:
                content += f'{index} {time_str}: {conv.messages[0].readable_str() if len(conv.messages) > 0 else "无内容"}\n'
            index += 1

        if content == '':
            content = '无'
        else:
            if context.session.using_conversation is None:
                content += '\n当前处于新会话'
            else:
                content += f'\n当前会话: {using_conv_index} {context.session.using_conversation.create_time.strftime("%Y-%m-%d %H:%M:%S")}: {context.session.using_conversation.messages[0].readable_str() if len(context.session.using_conversation.messages) > 0 else "无内容"}'

        yield entities.CommandReturn(text=f'第 {page + 1} 页 (时间倒序):\n{content}')