from typing import Optional, Union, Sequence, Iterator, TextIO, Any
import time
import warnings
import re
from netmiko.no_enable import NoEnable
from netmiko.base_connection import DELAY_FACTOR_DEPR_SIMPLE_MSG
from netmiko.cisco_base_connection import CiscoSSHConnection


class VyOSSSH(NoEnable, CiscoSSHConnection):
    """Implement methods for interacting with VyOS network devices."""

    def session_preparation(self) -> None:
        """Prepare the session after the connection has been established."""
        self._test_channel_read()
        self.set_base_prompt()
        self.set_terminal_width(command="set terminal width 512", pattern="terminal")
        self.disable_paging(command="set terminal length 0")
        # Clear the read buffer
        time.sleep(0.3 * self.global_delay_factor)
        self.clear_buffer()

    def check_config_mode(
        self, check_string: str = "#", pattern: str = "", force_regex: bool = False
    ) -> bool:
        """Checks if the device is in configuration mode"""
        return super().check_config_mode(check_string=check_string, pattern=pattern)

    def config_mode(
        self,
        config_command: str = "configure",
        pattern: str = r"\[edit\]",
        re_flags: int = 0,
    ) -> str:
        return super().config_mode(
            config_command=config_command, pattern=pattern, re_flags=re_flags
        )

    def exit_config_mode(
        self, exit_config: str = "exit", pattern: str = r"exit"
    ) -> str:
        """Exit configuration mode"""
        output = ""
        if self.check_config_mode():
            output = self._send_command_timing_str(
                exit_config, strip_prompt=False, strip_command=False
            )
            if "Cannot exit: configuration modified" in output:
                output += self._send_command_timing_str(
                    "exit discard", strip_prompt=False, strip_command=False
                )
            if self.check_config_mode():
                raise ValueError("Failed to exit configuration mode")
        return output

    def commit(
        self,
        comment: str = "",
        read_timeout: float = 120.0,
        delay_factor: Optional[float] = None,
    ) -> str:
        """
        Commit the candidate configuration.

        Commit the entered configuration. Raise an error and return the failure
        if the commit fails.

        default:
           command_string = commit
        comment:
           command_string = commit comment <comment>

        delay_factor: Deprecated in Netmiko 4.x. Will be eliminated in Netmiko 5.

        """

        if delay_factor is not None:
            warnings.warn(DELAY_FACTOR_DEPR_SIMPLE_MSG, DeprecationWarning)

        error_marker = ["Failed to generate committed config", "Commit failed"]
        command_string = "commit"

        if comment:
            command_string += f' comment "{comment}"'

        output = self.config_mode()
        output += self._send_command_str(
            command_string,
            strip_prompt=False,
            strip_command=False,
            read_timeout=read_timeout,
        )

        if any(x in output for x in error_marker):
            raise ValueError(f"Commit failed with following errors:\n\n{output}")
        return output

    def set_base_prompt(
        self,
        pri_prompt_terminator: str = "$",
        alt_prompt_terminator: str = "#",
        delay_factor: float = 1.0,
        pattern: Optional[str] = None,
    ) -> str:
        """Sets self.base_prompt: used as delimiter for stripping of trailing prompt in output."""

        # VyOS can have a third terminator; switch to a pattern solution
        if pattern is None:
            pri_term = re.escape(pri_prompt_terminator)
            alt_term = re.escape(alt_prompt_terminator)
            third_terminator = re.escape(">")
            pattern = rf"({pri_term}|{alt_term}|{third_terminator})"

        prompt = super().set_base_prompt(
            pri_prompt_terminator=pri_prompt_terminator,
            alt_prompt_terminator=alt_prompt_terminator,
            delay_factor=delay_factor,
            pattern=pattern,
        )
        # Set prompt to user@hostname (remove two additional characters)
        self.base_prompt = prompt[:-2].strip()
        return self.base_prompt

    def send_config_set(
        self,
        config_commands: Union[str, Sequence[str], Iterator[str], TextIO, None] = None,
        exit_config_mode: bool = False,
        **kwargs: Any,
    ) -> str:
        """Remain in configuration mode."""
        return super().send_config_set(
            config_commands=config_commands, exit_config_mode=exit_config_mode, **kwargs
        )

    def save_config(
        self, cmd: str = "save", confirm: bool = False, confirm_response: str = ""
    ) -> str:
        """Saves Config."""
        output = self.config_mode()
        output += super().save_config(
            cmd=cmd, confirm=confirm, confirm_response=confirm_response
        )
        output += self.exit_config_mode()
        if "Done" not in output:
            raise ValueError(f"Save failed with following errors:\n\n{output}")
        return output