"""
ElkM1 message encode/decode.

Message format:
    LLMM<data>00CC, where:
    LL - length in ASCII hex
    MM - message code
    <data> - message contents; length varies by message code
    00 - constant two characters reserved (almost all messages)
    CC - checksum

The panel numbers zones, keypads, etc. in base 1. The interface of
this module refers to them using base 0. Conversion to base 1 is done
on sending and conversion to base 0 is done on receiving. So, base 0/1
conversion is encapsulated in this module.
"""

from __future__ import annotations

import datetime as dt
import re
import sys
import time
from collections import namedtuple
from collections.abc import Callable
from typing import Any, cast

from .const import (
    AlarmState,
    ArmedStatus,
    ArmLevel,
    ArmUpState,
    ChimeMode,
    ElkRPStatus,
    FunctionKeys,
    Max,
    SettingFormat,
    ThermostatFan,
    ThermostatMode,
    ThermostatSetting,
    ZoneAlarmState,
    ZoneLogicalStatus,
    ZonePhysicalStatus,
    ZoneType,
)

MessageEncode = namedtuple("MessageEncode", ["message", "response_command"])
MsgHandler = Callable[..., None]


def decode(msg: str) -> tuple[str, dict[str, Any]] | None:
    """Decode an Elk message by passing to appropriate decoder"""
    valid, error_msg = _is_valid_length_and_checksum(msg)
    if valid:
        cmd = msg[2:4]
        decoder = getattr(sys.modules[__name__], f"{cmd.lower()}_decode", None)
        if not decoder:
            return ("unknown", {"msg_code": cmd, "data": msg[4:-2]})
        try:
            decoded_msg = decoder(msg)
        except (IndexError, ValueError, AttributeError) as exc:
            raise ValueError("Cannot decode message") from exc
        return (cmd, decoded_msg)

    if not msg or msg.startswith("Username: ") or msg.startswith("Password: "):
        return None
    if "Login successful" in msg:
        return ("login", {"succeeded": True})
    if msg.startswith("Username/Password not found") or msg == "Disabled":
        return ("login", {"succeeded": False})
    raise ValueError(error_msg)


def _is_valid_length_and_checksum(msg: str) -> tuple[bool, str]:
    """Check packet length valid and that checksum is good."""
    try:
        if int(msg[:2], 16) != (len(msg) - 2):
            return (
                False,
                f"Incorrect message length, expected {msg[:2]}, got {len(msg) - 2:02X}. Msg {msg}",  # noqa: E501
            )
        checksum = int(msg[-2:], 16)
        for char in msg[:-2]:
            checksum += ord(char)
        if (checksum % 256) != 0:
            return False, f"Bad checksum. Msg: {msg}"
    except ValueError:
        return False, "Message invalid"

    return True, ""


def _chk_len(msg: str, msg_len: str) -> None:
    if msg[:2] != msg_len:
        raise ValueError(f"Expected msg len {msg_len}. Got msg {msg}")


def am_decode(msg: str) -> dict[str, list[bool]]:
    """AM: Alarm memory by area report."""
    _chk_len(msg, "0C")
    return {"alarm_memory": [x == "1" for x in msg[4 : 4 + Max.AREAS.value]]}


def as_decode(
    msg: str,
) -> dict[str, list[ArmedStatus] | list[ArmUpState] | list[AlarmState]]:
    """AS: Arming status report."""
    return {
        "armed_statuses": [ArmedStatus(x) for x in msg[4:12]],
        "arm_up_states": [ArmUpState(x) for x in msg[12:20]],
        "alarm_states": [AlarmState(x) for x in msg[20:28]],
    }


def az_decode(msg: str) -> dict[str, list[ZoneAlarmState]]:
    """AZ: Alarm by zone report."""
    _chk_len(msg, "D6")
    return {"alarm_status": [ZoneAlarmState(x) for x in msg[4 : 4 + Max.ZONES.value]]}


def _cr_one_custom_value_decode(index: int, part: str) -> dict[str, Any]:
    value = int(part[0:5])
    value_format = SettingFormat(int(part[5]))
    if value_format == SettingFormat.TIME_OF_DAY:
        ret: int | tuple[int, int] = ((value >> 8) & 0xFF, value & 0xFF)
    else:
        ret = value
    return {"index": index, "value": ret, "value_format": value_format}


def cr_decode(msg: str) -> dict[str, Any]:
    """CR: Custom values"""
    if int(msg[4:6]) > 0:
        index = int(msg[4:6]) - 1
        return {"values": [_cr_one_custom_value_decode(index, msg[6:12])]}

    part = 6
    ret = []
    for i in range(Max.SETTINGS.value):
        ret.append(_cr_one_custom_value_decode(i, msg[part : part + 6]))
        part += 6
    return {"values": ret}


def cc_decode(msg: str) -> dict[str, Any]:
    """CC: Output status for single output."""
    return {"output": int(msg[4:7]) - 1, "output_status": msg[7] == "1"}


def cs_decode(msg: str) -> dict[str, Any]:
    """CS: Output status for all outputs."""
    output_status = [x == "1" for x in msg[4 : 4 + Max.OUTPUTS.value]]
    return {"output_status": output_status}


def cv_decode(msg: str) -> dict[str, Any]:
    """CV: Counter value."""
    return {"counter": int(msg[4:6]) - 1, "value": int(msg[6:11])}


def ee_decode(msg: str) -> dict[str, int | bool | ArmedStatus]:
    """EE: Entry/exit timer report."""
    return {
        "area": int(msg[4:5]) - 1,
        "is_exit": msg[5:6] == "0",
        "timer1": int(msg[6:9]),
        "timer2": int(msg[9:12]),
        "armed_status": ArmedStatus(msg[12:13]),
    }


def ic_decode(msg: str) -> dict[str, Any]:
    """IC: Send Valid Or Invalid User Code Format."""
    code = msg[4:16]
    if re.match(r"(0\d){6}", code):
        code = re.sub(r"0(\d)", r"\1", code)
    return {
        "code": code,
        "user": int(msg[16:19]) - 1,
        "keypad": int(msg[19:21]) - 1,
    }


def ie_decode(msg: str) -> dict[str, str]:
    """IE: Installer mode exited."""
    return {}


def ka_decode(msg: str) -> dict[str, Any]:
    """KA: Keypad areas for all keypads."""
    return {"keypad_areas": [ord(x) - 0x31 for x in msg[4 : 4 + Max.KEYPADS.value]]}


def kc_decode(msg: str) -> dict[str, Any]:
    """KC: Keypad key change."""
    return {"keypad": int(msg[4:6]) - 1, "key": int(msg[6:8])}


def kf_decode(msg: str) -> dict[str, Any]:
    """KF: Keypad function key press."""
    return {
        "keypad": int(msg[4:6]) - 1,
        "key": FunctionKeys(msg[6]),
        "chime_mode": [ChimeMode(int(x)) for x in msg[7:15]],
    }


def ld_decode(msg: str) -> dict[str, Any]:
    """LD: System Log Data Update."""
    area = int(msg[11]) - 1
    hour = int(msg[12:14])
    minute = int(msg[14:16])
    month = int(msg[16:18])
    day = int(msg[18:20])
    year = int(msg[24:26]) + 2000
    log_local_datetime = dt.datetime(year, month, day, hour, minute)
    log_local_time = time.mktime(log_local_datetime.timetuple())
    log_gm_timestruct = time.gmtime(log_local_time)

    log: dict[str, Any] = {}
    log["event"] = int(msg[4:8])
    log["number"] = int(msg[8:11])
    log["index"] = int(msg[20:23])
    log["timestamp"] = dt.datetime(*log_gm_timestruct[:6], tzinfo=dt.UTC).isoformat()

    return {"area": area, "log": log}


def lw_decode(msg: str) -> dict[str, Any]:
    """LW: temperatures from all keypads and zones 1-16."""
    keypad_temps = []
    zone_temps = []
    for i in range(16):
        keypad_temps.append(int(msg[4 + 3 * i : 7 + 3 * i]) - 40)
        zone_temps.append(int(msg[52 + 3 * i : 55 + 3 * i]) - 60)
    return {"keypad_temps": keypad_temps, "zone_temps": zone_temps}


def pc_decode(msg: str) -> dict[str, Any]:
    """PC: PLC (lighting) change."""
    housecode = msg[4:7]
    return {
        "housecode": housecode,
        "index": housecode_to_index(housecode),
        "light_level": int(msg[7:9]),
    }


def ps_decode(msg: str) -> dict[str, Any]:
    """PS: PLC (lighting) status."""
    return {
        "bank": ord(msg[4]) - 0x30,
        "statuses": [ord(x) - 0x30 for x in msg[5:69]],
    }


def rp_decode(msg: str) -> dict[str, ElkRPStatus]:
    """RP: Remote programming status."""
    return {"remote_programming_status": ElkRPStatus(int(msg[4:6]))}


def rr_decode(msg: str) -> dict[str, str]:
    """RR: Realtime clock."""
    return {"real_time_clock": msg[4:20]}


def sd_decode(msg: str) -> dict[str, Any]:
    """SD: Description text."""
    desc_ch1 = msg[9]
    show_on_keypad = ord(desc_ch1) >= 0x80
    if show_on_keypad:
        desc_ch1 = chr(ord(desc_ch1) & 0x7F)
    return {
        "desc_type": int(msg[4:6]),
        "unit": int(msg[6:9]) - 1,
        "desc": (desc_ch1 + msg[10:25]).rstrip(),
        "show_on_keypad": show_on_keypad,
    }


def ss_decode(msg: str) -> dict[str, str]:
    """SS: System status."""
    return {"system_trouble_status": msg[4:-2]}


def st_decode(msg: str) -> dict[str, int]:
    """ST: Temperature update."""
    group = int(msg[4:5])
    temperature = int(msg[7:10])
    if group == 0:
        temperature -= 60
    elif group == 1:
        temperature -= 40
    return {"group": group, "device": int(msg[5:7]) - 1, "temperature": temperature}


def tc_decode(msg: str) -> dict[str, int]:
    """TC: Task change."""
    return {"task": int(msg[4:7]) - 1}


def tr_decode(msg: str) -> dict[str, Any]:
    """TR: Thermostat data response."""
    _chk_len(msg, "13")
    return {
        "thermostat_index": int(msg[4:6]) - 1,
        "mode": ThermostatMode(int(msg[6])),
        "hold": msg[7] == "1",
        "fan": ThermostatFan(int(msg[8])),
        "current_temp": int(msg[9:11]),
        "heat_setpoint": int(msg[11:13]),
        "cool_setpoint": int(msg[13:15]),
        "humidity": int(msg[15:17]),
    }


def ua_decode(msg: str) -> dict[str, Any]:
    """UA: Valid User Code Areas."""
    return {
        "user_code": int(msg[4:10]),
        "valid_areas": int(msg[10:12], 16),
        "diagnostic": msg[12:20],
        "user_code_length": int(msg[20]),
        "user_code_type": int(msg[21]),
        "temperature_units": msg[22],
    }


def vn_decode(msg: str) -> dict[str, str]:
    """VN: Version information."""
    elkm1_version = f"{int(msg[4:6], 16)}.{int(msg[6:8], 16)}.{int(msg[8:10], 16)}"
    xep_version = f"{int(msg[10:12], 16)}.{int(msg[12:14], 16)}.{int(msg[14:16], 16)}"
    return {"elkm1_version": elkm1_version, "xep_version": xep_version}


def xk_decode(msg: str) -> dict[str, str]:
    """XK: Ethernet Test."""
    return {"real_time_clock": msg[4:20]}


def zb_decode(msg: str) -> dict[str, Any]:
    """ZB: Zone bypass report."""
    return {"zone_number": int(msg[4:7]) - 1, "zone_bypassed": msg[7] == "1"}


def zc_decode(
    msg: str,
) -> dict[str, int | tuple[ZoneLogicalStatus, ZonePhysicalStatus]]:
    """ZC: Zone Change."""
    _chk_len(msg, "0A")
    status = _status_decode(int(msg[7:8], 16))
    return {"zone_number": int(msg[4:7]) - 1, "zone_status": status}


def zd_decode(msg: str) -> dict[str, list[ZoneType]]:
    """ZD: Zone definitions."""
    _chk_len(msg, "D6")
    zone_definitions = [ZoneType(ord(x) - 0x30) for x in msg[4 : 4 + Max.ZONES.value]]
    return {"zone_definitions": zone_definitions}


def zp_decode(msg: str) -> dict[str, list[int]]:
    """ZP: Zone partitions."""
    zone_partitions = [ord(x) - 0x31 for x in msg[4 : 4 + Max.ZONES.value]]
    return {"zone_partitions": zone_partitions}


def zs_decode(
    msg: str,
) -> dict[str, list[tuple[ZoneLogicalStatus, ZonePhysicalStatus]]]:
    """ZS: Zone statuses."""
    _chk_len(msg, "D6")
    status = [_status_decode(int(x, 16)) for x in msg[4 : 4 + Max.ZONES.value]]
    return {"zone_statuses": status}


def zv_decode(msg: str) -> dict[str, Any]:
    """ZV: Zone voltage."""
    return {"zone_number": int(msg[4:7]) - 1, "zone_voltage": int(msg[7:10]) / 10}


def housecode_to_index(housecode: str) -> int:
    """Convert a X10 housecode to a zero-based index"""
    match = re.search(r"^([A-P])(\d{1,2})$", housecode.upper())
    if match:
        house_index = int(match.group(2))
        if 1 <= house_index <= 16:
            return (ord(match.group(1)) - ord("A")) * 16 + house_index - 1
    raise ValueError(f"Invalid X10 housecode: {housecode}")


def index_to_housecode(index: int) -> str:
    """Convert a zero-based index to a X10 housecode."""
    if index < 0 or index > 255:
        raise ValueError
    quotient, remainder = divmod(index, 16)
    return f"{chr(ord('A') + quotient)}{remainder + 1:02}"


def get_elk_command(line: str) -> str:
    """Return the 2 character command in the message."""
    if len(line) < 4:
        return ""
    return line[2:4]


def _status_decode(status: int) -> tuple[ZoneLogicalStatus, ZonePhysicalStatus]:
    """Decode a 1 byte status into logical and physical statuses."""
    logical_status = ZoneLogicalStatus((status & 0b00001100) >> 2)
    physical_status = ZonePhysicalStatus(status & 0b00000011)
    return (logical_status, physical_status)


def al_encode(arm_mode: ArmLevel, area: int, user_code: int) -> MessageEncode:
    """al: Arm system. Note in 'al' the 'l' can vary"""
    return MessageEncode(f"0Da{arm_mode.value}{area + 1:1}{user_code:06}00", "AS")


def as_encode() -> MessageEncode:
    """as: Get area status."""
    return MessageEncode("06as00", "AS")


def az_encode() -> MessageEncode:
    """az: Get alarm by zone."""
    return MessageEncode("06az00", "AZ")


def cf_encode(output: int) -> MessageEncode:
    """cf: Turn off output."""
    return MessageEncode(f"09cf{output + 1:03}00", None)


def ct_encode(output: int) -> MessageEncode:
    """ct: Toggle output."""
    return MessageEncode(f"09ct{output + 1:03}00", None)


def cn_encode(output: int, seconds: int) -> MessageEncode:
    """cn: Turn on output."""
    return MessageEncode(f"0Ecn{output + 1:03}{seconds:05}00", None)


def cs_encode() -> MessageEncode:
    """cs: Get all output status."""
    return MessageEncode("06cs00", "CS")


def cp_encode() -> MessageEncode:
    """cp: Get ALL custom values."""
    return MessageEncode("06cp00", "CR")


def cr_encode(index: int) -> MessageEncode:
    """cr: Get a custom value."""
    return MessageEncode(f"08cr{index + 1:02}00", "CR")


def cw_encode(
    index: int, value: int | tuple[int, int], value_format: SettingFormat
) -> MessageEncode:
    """cw: Write a custom value."""
    if value_format == SettingFormat.TIME_OF_DAY:
        val = cast(tuple[int, int], value)
        enc = val[0] * 256 + val[1]
    else:
        enc = cast(int, value)
    return MessageEncode(f"0Dcw{index + 1:02}{enc:05}00", None)


def cv_encode(counter: int) -> MessageEncode:
    """cv: Get counter."""
    return MessageEncode(f"08cv{counter + 1:02}00", "CV")


def cx_encode(counter: int, value: int) -> MessageEncode:
    """cx: Change counter value."""
    return MessageEncode(f"0Dcx{counter + 1:02}{value:05}00", "CV")


def dm_encode(
    keypad_area: int, clear: int, beep: bool, timeout: int, line1: str, line2: str
) -> MessageEncode:
    """dm: Display message on keypad."""
    return MessageEncode(
        (
            f"2Edm{keypad_area + 1:1}{clear:1}{beep:1}"
            f"{timeout:05}{line1:^<16.16}{line2:^<16.16}00"
        ),
        None,
    )


def ka_encode() -> MessageEncode:
    """ka: Get keypad areas."""
    return MessageEncode("06ka00", "KA")


def kf_encode(
    keypad: int, functionkey: FunctionKeys = FunctionKeys.FORCE_KF_SYNC
) -> MessageEncode:
    """kf: Function Key Press."""
    return MessageEncode(f"09kf{keypad + 1:02}{functionkey.value}00", "KF")


def lw_encode() -> MessageEncode:
    """lw: Get temperature data."""
    return MessageEncode("06lw00", "LW")


def pc_encode(
    index: int, function_code: int, extended_code: int, seconds: int
) -> MessageEncode:
    """pc: Control any PLC device."""
    return MessageEncode(
        f"11pc{index_to_housecode(index)}{function_code:02}{extended_code:02}{seconds:04}00",
        None,
    )


def pf_encode(index: int) -> MessageEncode:
    """pf: Turn off light."""
    return MessageEncode(f"09pf{index_to_housecode(index)}00", None)


def pn_encode(index: int) -> MessageEncode:
    """pn: Turn on light."""
    return MessageEncode(f"09pn{index_to_housecode(index)}00", None)


def ps_encode(bank: int) -> MessageEncode:
    """ps: Get lighting status."""
    return MessageEncode(f"07ps{bank:1}00", "PS")


def pt_encode(index: int) -> MessageEncode:
    """pt: Toggle light."""
    return MessageEncode(f"09pt{index_to_housecode(index)}00", None)


def sd_encode(desc_type: int, unit: int) -> MessageEncode:
    """sd: Get description."""
    return MessageEncode(f"0Bsd{desc_type:02}{unit + 1:03}00", "SD")


def sp_encode(phrase: int) -> MessageEncode:
    """sp: Speak phrase."""
    return MessageEncode(f"09sp{phrase:03}00", None)


def ss_encode() -> MessageEncode:
    """ss: Get system trouble status."""
    return MessageEncode("06ss00", "SS")


def sw_encode(word: int) -> MessageEncode:
    """sw: Speak word."""
    return MessageEncode(f"09sw{word:03}00", None)


def rw_encode(date_time: dt.datetime) -> MessageEncode:
    """rw: Write time given a datetime."""
    elk_weekday = (date_time.weekday() + 1) % 7 + 1
    time_str = date_time.strftime("%S%M%H.%d%m%y").replace(".", str(elk_weekday))
    return MessageEncode(f"13rw{time_str}00", None)


def tn_encode(task: int) -> MessageEncode:
    """tn: Activate task."""
    return MessageEncode(f"09tn{task + 1:03}00", None)


def tr_encode(thermostat: int) -> MessageEncode:
    """tr: Request thermostat data."""
    return MessageEncode(f"08tr{thermostat + 1:02}00", None)


def ts_encode(thermostat: int, value: int, element: ThermostatSetting) -> MessageEncode:
    """ts: Set thermostat data."""
    return MessageEncode(f"0Bts{thermostat + 1:02}{value:02}{element.value:1}00", None)


def ua_encode(user_code: int) -> MessageEncode:
    """ua: Requst valid user code areas"""
    return MessageEncode(f"0Cua{user_code:06}00", "UA")


def vn_encode() -> MessageEncode:
    """zd: Get panel software version information."""
    return MessageEncode("06vn00", "VN")


def zb_encode(zone: int, area: int, user_code: int) -> MessageEncode:
    """zb: Zone bypass. Zone < 0 unbypass all; Zone > Max bypass all."""
    if zone < 0:
        zone = 0
    elif zone > Max.ZONES.value:
        zone = 999
    else:
        zone += 1
    return MessageEncode(
        f"10zb{zone:03}{area + 1:1}{user_code:06}00",
        "ZB",
    )


def zd_encode() -> MessageEncode:
    """zd: Get zone definitions"""
    return MessageEncode("06zd00", "ZD")


def zp_encode() -> MessageEncode:
    """zp: Get zone partitions"""
    return MessageEncode("06zp00", "ZP")


def zs_encode() -> MessageEncode:
    """zs: Get zone statuses"""
    return MessageEncode("06zs00", "ZS")


def zt_encode(zone: int) -> MessageEncode:
    """zt: Trigger zone."""
    return MessageEncode(f"09zt{zone + 1:03}00", None)


def zv_encode(zone: int) -> MessageEncode:
    """zv: Get zone voltage"""
    return MessageEncode(f"09zv{zone + 1:03}00", "ZV")