"""Custom Netmiko driver for the ALL-SG8316M (sw1) -- Telnet-only, IOS-like but
non-standard CLI (no `terminal length`, `--More--` paging, `end` from
config-vlan skips straight to the top level). No stock Netmiko/NAPALM driver
matches this device.

NOT YET WIRED IN: this module is imported nowhere yet. The `claudecode`
Telnet account on sw1 is currently rejected ("Incorrect User Name!!", found
2026-07-16) so this driver is unverified against the real device. Once
working credentials exist, activate it from nautobot_config.py:

    import importlib
    import allnet_sg8316m_driver  # noqa: F401 (registers itself on import)

and add to PLUGINS_CONFIG["nautobot_plugin_nornir"]["dispatcher_mapping"]:

    "allnet_sg8316m": "allnet_sg8316m_driver.GoldenConfigAllnetSg8316m"

(dispatcher class still needs writing once the connection class below is
confirmed to log in cleanly -- see project_nautobot_allnet_cudy_scope_20260716
memory for the full status and the two netmiko gotchas that cost the most
time: device_type must contain the literal substring "_telnet" for Netmiko to
pick the Telnet transport at all (BaseConnection.__init__ checks this by
string, not by class hierarchy), and `netmiko.ssh_dispatcher` at package level
is the dispatcher *function*, not the submodule -- reach CLASS_MAPPER via
`importlib.import_module("netmiko.ssh_dispatcher")`.
"""

import importlib
import time

from netmiko.cisco_base_connection import CiscoBaseConnection

_nm_dispatch = importlib.import_module("netmiko.ssh_dispatcher")


class AllnetSg8316mTelnet(CiscoBaseConnection):
    def session_preparation(self):
        self._test_channel_read(pattern=r"[>#]")
        self.set_base_prompt()
        self.ansi_escape_codes = True

    def disable_paging(self, *args, **kwargs):
        # No config knob for this on this firmware; paging is handled
        # per-command in send_command_paged() below instead.
        return ""

    def telnet_login(
        self,
        pri_prompt_terminator=r"#\s*$",
        alt_prompt_terminator=r">\s*$",
        username_pattern=r"Username",
        pwd_pattern=r"Password",
        delay_factor=1,
        max_loops=20,
    ):
        return super().telnet_login(
            pri_prompt_terminator=pri_prompt_terminator,
            alt_prompt_terminator=alt_prompt_terminator,
            username_pattern=username_pattern,
            pwd_pattern=pwd_pattern,
            delay_factor=delay_factor,
            max_loops=max_loops,
        )

    def send_command_paged(self, command_string, max_pages=200, delay=0.3):
        """sg8316m paginates with '--More--' and has no length-0 setting;
        page through by sending a space each time it appears."""
        self.write_channel(command_string + self.RETURN)
        time.sleep(delay)
        output = ""
        for _ in range(max_pages):
            chunk = self.read_channel()
            output += chunk
            if "--More--" in chunk:
                self.write_channel(" ")
                time.sleep(delay)
                continue
            if any(p in chunk for p in ["sw1#", "sw1>"]) and "--More--" not in chunk:
                break
            if chunk == "":
                time.sleep(delay)
        return output.replace("--More--", "")


# Registered under the "_telnet" suffix required by Netmiko's own transport
# selection (see module docstring) -- registration is safe/inert on its own,
# nothing calls ConnectHandler(device_type="allnet_sg8316m_telnet") yet.
_nm_dispatch.CLASS_MAPPER["allnet_sg8316m_telnet"] = AllnetSg8316mTelnet
_nm_dispatch.platforms = list(_nm_dispatch.CLASS_MAPPER.keys())