""" System related utilities for PagerMaid to integrate into the system. """

from platform import node
from getpass import getuser
from os import geteuid
from requests import head
from requests.exceptions import MissingSchema, InvalidURL, ConnectionError
from pagermaid import log
from pagermaid.listener import listener
from pagermaid.utils import attach_log, execute


@listener(outgoing=True, command="sh",
          description="在 Telegram 上执行 Shell 命令。",
          parameters="<命令>")
async def sh(context):
    """ Use the command-line from Telegram. """
    user = getuser()
    command = context.arguments
    hostname = node()
    if context.is_channel and not context.is_group:
        await context.edit("`出错了呜呜呜 ~ 当前配置禁止在频道中执行 Shell 命令。`")
        return

    if not command:
        await context.edit("`出错了呜呜呜 ~ 无效的参数。`")
        return

    if geteuid() == 0:
        await context.edit(
            f"`{user}`@{hostname} ~"
            f"\n> `#` {command}"
        )
    else:
        await context.edit(
            f"`{user}`@{hostname} ~"
            f"\n> `$` {command}"
        )

    result = await execute(command)

    if result:
        if len(result) > 4096:
            await attach_log(result, context.chat_id, "output.log", context.id)
            return

        if geteuid() == 0:
            await context.edit(
                f"`{user}`@{hostname} ~"
                f"\n> `#` {command}"
                f"\n`{result}`"
            )
        else:
            await context.edit(
                f"`{user}`@{hostname} ~"
                f"\n> `$` {command}"
                f"\n`{result}`"
            )
    else:
        return
    await log(f"在 Shell 中执行命令 `{command}`")


@listener(outgoing=True, command="restart", diagnostics=False,
          description="使 PagerMaid 重新启动")
async def restart(context):
    """ To re-execute PagerMaid. """
    if not context.text[0].isalpha():
        await context.edit("尝试重新启动系统。")
        await log("PagerMaid-Modify 重新启动。")
        await context.client.disconnect()


@listener(outgoing=True, command="trace",
          description="跟踪 URL 的重定向。",
          parameters="<url>")
async def trace(context):
    """ Trace URL redirects. """
    url = context.arguments
    reply = await context.get_reply_message()
    if reply:
        url = reply.text
    if url:
        if url.startswith("https://") or url.startswith("http://"):
            pass
        else:
            url = "https://" + url
        await context.edit("跟踪重定向中 . . .")
        result = str("")
        for url in url_tracer(url):
            count = 0
            if result:
                result += " ↴\n" + url
            else:
                result = url
            if count == 128:
                result += "\n\n出错了呜呜呜 ~ 超过128次重定向，正在中止!"
                break
        if result:
            if len(result) > 4096:
                await context.edit("输出超出限制，正在附加文件。")
                await attach_log(result, context.chat_id, "output.log", context.id)
                return
            await context.edit(
                "重定向:\n"
                f"{result}"
            )
            await log(f"Traced redirects of {context.arguments}.")
        else:
            await context.edit(
                "出错了呜呜呜 ~ 发出HTTP请求时出了点问题。"
            )
    else:
        await context.edit("无效的参数。")


@listener(outgoing=True, command="contact",
          description="向 Kat 发送消息。",
          parameters="<message>")
async def contact(context):
    """ Sends a message to Kat. """
    await context.edit("`对话已打开，请单击 `[here](tg://user?id=503691334)` 进入.`",
                       parse_mode="markdown")
    message = "Hi, I would like to report something about PagerMaid."
    if context.arguments:
        message = context.arguments
    await context.client.send_message(
        503691334,
        message
    )


def url_tracer(url):
    """ Method to trace URL redirects. """
    while True:
        yield url
        try:
            response = head(url)
        except MissingSchema:
            break
        except InvalidURL:
            break
        except ConnectionError:
            break
        if 300 < response.status_code < 400:
            url = response.headers['location']
        else:
            break