# SPDX-FileCopyrightText: 2020 The Magma Authors.
# SPDX-FileCopyrightText: 2022 Open Networking Foundation <support@opennetworking.org>
#
# SPDX-License-Identifier: BSD-3-Clause

from enum import Enum
from typing import Optional


class DuplexMode(Enum):
    FDD = 1
    TDD = 2


class LTEBandInfo:
    """ Class for holding information related to LTE band.
        Takes advantage of the following properties of LTE EARFCN assignment:
            - EARFCN spacing within a band is always 0.1MHz
            - 1:1 mapping between EARFCNDL and EARFCNUL (for FDD)
    """

    def __init__(
        self, duplex_mode, earfcndl, start_freq_dl_mhz,
        start_earfcnul=None, start_freq_ul_mhz=None,
    ):
        """
        Inputs:
        - Duplex mode - type = DuplexMode
        - earfcndl - List/generator of integer EARFCNDLs in band, from lowest to
                     highest
        - start_freq_dl_mhz - Frequency of lowest numbered EARFCNDL in band
                            (MHz)
        - start_earfcnul - Lowest numbered EARFCNUL in band
                            (or None if band is TDD)
        - start_freq_ul_mhz - Frequency of lowest numbered EARFCNUL in band
                              (MHz) (or None if band is TDD)
        """
        # Validate inputs
        assert type(earfcndl) == list or type(earfcndl) == range
        assert type(start_freq_dl_mhz) == int
        assert type(duplex_mode) == DuplexMode
        if duplex_mode == DuplexMode.FDD:
            assert type(start_earfcnul) == int
            assert type(start_freq_ul_mhz) == int
        else:
            assert start_earfcnul is None
            assert start_freq_ul_mhz is None

        # DuplexMode.TDD or DuplexMode.FDD
        self.duplex_mode = duplex_mode
        # Array of EARFCNDL values
        self.earfcndl = earfcndl
        # Array of DL frequencies in MHz, one per EARFCNDL
        self.freq_mhz_dl = [
            start_freq_dl_mhz + 0.1 * (earfcn - earfcndl[0])
            for earfcn in earfcndl
        ]

        if duplex_mode == DuplexMode.FDD:
            # Array of EARFCNUL values that map to EARFCNDL
            self.earfcnul = range(
                start_earfcnul,
                start_earfcnul + len(earfcndl),
            )
            # Array of UL frequencies in MHz, one per EARFCNUL
            self.freq_mhz_ul = [
                start_freq_ul_mhz + 0.1 * (
                    earfcn -
                    self.earfcnul[0]
                ) for earfcn in self.earfcnul
            ]
        else:
            self.earfcnul = None
            self.freq_mhz_ul = None


# See, for example, http://niviuk.free.fr/lte_band.php for LTE band info
LTE_BAND_INFO = {
    # FDD bands
    # duplex_mode, EARFCNDL, start_freq_dl, start_EARCNUL, start_freq_ul
    1: LTEBandInfo(DuplexMode.FDD, range(0, 600), 2110, 18000, 1920),
    2: LTEBandInfo(DuplexMode.FDD, range(600, 1200), 1930, 18600, 1850),
    3: LTEBandInfo(DuplexMode.FDD, range(1200, 1950), 1805, 19200, 1710),
    4: LTEBandInfo(DuplexMode.FDD, range(1950, 2400), 2110, 19950, 1710),
    5: LTEBandInfo(DuplexMode.FDD, range(2400, 2649), 869, 20400, 824),
    28: LTEBandInfo(DuplexMode.FDD, range(9210, 9660), 758, 27210, 703),
    # TDD bands
    # duplex_mode, EARFCNDL, start_freq_dl
    33: LTEBandInfo(DuplexMode.TDD, range(36000, 36199), 1900),
    34: LTEBandInfo(DuplexMode.TDD, range(36200, 36349), 2010),
    35: LTEBandInfo(DuplexMode.TDD, range(36350, 36949), 1850),
    36: LTEBandInfo(DuplexMode.TDD, range(36950, 37549), 1930),
    37: LTEBandInfo(DuplexMode.TDD, range(37550, 37750), 1910),
    38: LTEBandInfo(DuplexMode.TDD, range(37750, 38250), 2570),
    39: LTEBandInfo(DuplexMode.TDD, range(38250, 38650), 1880),
    40: LTEBandInfo(DuplexMode.TDD, range(38650, 39650), 2300),
    41: LTEBandInfo(DuplexMode.TDD, range(39650, 41590), 2496),
    42: LTEBandInfo(DuplexMode.TDD, range(41590, 43590), 3400),
    43: LTEBandInfo(DuplexMode.TDD, range(43590, 45590), 3600),
    44: LTEBandInfo(DuplexMode.TDD, range(45590, 46589), 703),
    45: LTEBandInfo(DuplexMode.TDD, range(46590, 46789), 1447),
    46: LTEBandInfo(DuplexMode.TDD, range(46790, 54539), 5150),
    47: LTEBandInfo(DuplexMode.TDD, range(54540, 55239), 5855),
    48: LTEBandInfo(DuplexMode.TDD, range(55240, 56740), 3550),
    49: LTEBandInfo(DuplexMode.TDD, range(56740, 58239), 3550),
    50: LTEBandInfo(DuplexMode.TDD, range(58240, 59089), 1432),
    51: LTEBandInfo(DuplexMode.TDD, range(59090, 59139), 1427),
    52: LTEBandInfo(DuplexMode.TDD, range(59140, 60139), 3300),
    # For the band #53 start_freq_dl is float value which require some changes
    # in the code
    # 53: LTEBandInfo(DuplexMode.TDD, range(60140, 60254), 2483.5),

}
# TODO - add remaining FDD LTE bands


def map_earfcndl_to_duplex_mode(earfcndl: int) -> Optional[DuplexMode]:
    """
    Returns None if we do not support the EARFCNDL
    """
    for band in LTE_BAND_INFO.keys():
        if earfcndl in LTE_BAND_INFO[band].earfcndl:
            return LTE_BAND_INFO[band].duplex_mode
    return None


def map_earfcndl_to_band_earfcnul_mode(earfcndl):
    """ Inputs:
            - EARFCNDL (integer)
        Outputs:
            - Band (integer)
            - Mode (DuplexMode)
            - EARFCNUL (integer - or None if TDD)
    """
    for band in LTE_BAND_INFO.keys():
        if earfcndl in LTE_BAND_INFO[band].earfcndl:
            if LTE_BAND_INFO[band].duplex_mode == DuplexMode.FDD:
                index = LTE_BAND_INFO[band].earfcndl.index(earfcndl)
                earfcnul = LTE_BAND_INFO[band].earfcnul[index]
            else:
                earfcnul = None

            return band, LTE_BAND_INFO[band].duplex_mode, earfcnul

    raise ValueError('EARFCNDL %d not found in LTE band info' % earfcndl)