import logging
from argparse import ArgumentParser
from ctypes import c_byte, c_char, c_uint64, sizeof, Structure

import numpy


FOLDER_MOD = 100000
FILE_MOD = 1000
FILE_EXTENSION = ".bin"
MODULE_X_SIZE = 1024
MODULE_Y_SIZE = 512
BYTES_PER_PIXEL = 2
MODULE_N_PIXELS = MODULE_X_SIZE * MODULE_Y_SIZE
MODULE_N_BYTES = MODULE_N_PIXELS * BYTES_PER_PIXEL


_logger = logging.getLogger(__name__)



class BufferBinaryFormat(Structure):
    _pack_ = 1
    _fields_ = [
        ("FORMAT_MARKER",  c_char),
        ("pulse_id",       c_uint64),
        ("frame_index",    c_uint64),
        ("daq_rec",        c_uint64),
        ("n_recv_packets", c_uint64),
        ("module_id",      c_uint64),
        ("data",           c_byte * MODULE_N_BYTES)
    ]



class BinaryBufferReader:

    def __init__(self, root_folder, n_modules):
        self.root_folder = root_folder
        self.n_modules = n_modules


    def read_pulse_id(self, pulse_id):
        index_in_file = get_file_frame_index(pulse_id)
        n_bytes_offset = int(index_in_file * sizeof(BufferBinaryFormat))
        n_bytes_to_read = sizeof(BufferBinaryFormat)

        metadata = {
            "pulse_id": 0,
            "frame_index": 0,
            "daq_rec": 0,
            "is_good_frame": True
        }

        shape = [self.n_modules * MODULE_N_BYTES]
        data = numpy.zeros(shape=shape, dtype="byte")

        metadata_init = False

        for i_module in range(self.n_modules):
            device_name = f"M{i_module:02}"

            filename = get_filename(self.root_folder, device_name, pulse_id)

            with open(filename, "rb") as input_file:
                input_file.seek(n_bytes_offset)
                input_data = input_file.read(n_bytes_to_read)
                frame_buffer = BufferBinaryFormat.from_buffer_copy(input_data)

            output_prefix = f"[pulse_id {pulse_id} module {i_module}] "

            if frame_buffer.FORMAT_MARKER == b"\xBE":
                is_good_frame = (frame_buffer.n_recv_packets == 128)

                if is_good_frame:
                    if not metadata_init:
                        metadata["pulse_id"]    = frame_buffer.pulse_id
                        metadata["frame_index"] = frame_buffer.frame_index
                        metadata["daq_rec"]     = frame_buffer.daq_rec

                        metadata_init = True

                    if metadata["is_good_frame"]:
                        md_pulse_id = metadata["pulse_id"]
                        if md_pulse_id != frame_buffer.pulse_id:
                            _logger.debug(f"{output_prefix} Mismatch pulse_id {md_pulse_id}")
                            metadata["is_good_frame"] = False

                        md_frame_index = metadata["frame_index"]
                        if md_frame_index != frame_buffer.frame_index:
                            _logger.debug(f"{output_prefix} Mismatch frame_index {md_frame_index}")
                            metadata["is_good_frame"] = False

                        md_daq_rec = metadata["daq_rec"]
                        if md_daq_rec != frame_buffer.daq_rec:
                            _logger.debug(f"{output_prefix} Mismatch daq_rec {md_daq_rec}")
                            metadata["is_good_frame"] = False

                else:
                    n_lost_packets = 128 - frame_buffer.n_recv_packets
                    _logger.debug(f"{output_prefix} n_lost_packets {n_lost_packets}")
                    metadata["is_good_frame"] = False

                start_byte_image = MODULE_N_BYTES * i_module
                stop_byte_image = start_byte_image + MODULE_N_BYTES

                frame_data = numpy.array(frame_buffer.data, dtype="bytes")
                data[start_byte_image:stop_byte_image] = frame_data

            else:
                _logger.debug(f"{output_prefix} no data in buffer")
                metadata["is_good_frame"] = False

        if not metadata_init:
            metadata["is_good_frame"] = False

        data_shape = [self.n_modules * MODULE_Y_SIZE, MODULE_X_SIZE]
        data = data.view("uint16").reshape(data_shape)
        return metadata, data



def get_file_frame_index(pulse_id):
    file_base = int((pulse_id // FILE_MOD) * FILE_MOD)
    return pulse_id - file_base

def get_filename(root_folder, device_name, pulse_id):
    folder_base = int((pulse_id // FOLDER_MOD) * FOLDER_MOD)
    file_base = int((pulse_id // FILE_MOD) * FILE_MOD)
    return f"{root_folder}/{device_name}/{folder_base}/{file_base}{FILE_EXTENSION}"





def main():
    parser = ArgumentParser(description="Read DAQ Binary Buffer")

    parser.add_argument("root_folder", type=str, help="Absolute path to root folder of device.")
    parser.add_argument("n_modules",   type=int, help="Number of modules to read from this device.")
    parser.add_argument("pulse_id",    type=int, help="Pulse_id to retrieve.")

    clargs = parser.parse_args()

    reader = BinaryBufferReader(clargs.root_folder, clargs.n_modules)

    metadata, _data = reader.read_pulse_id(clargs.pulse_id)
    print(metadata)



if __name__ == "__main__":
    main()