import sys
import os

import json
import datetime

# テンポラリファイル名
tmp_file = 'tmp.json'

def usage() :
    print( '==== USAGE =========================')
    print(f'    {sys.argv[0]} <JSON file> <CSV file>')
    print( '====================================')

if len(sys.argv) == 3 :
    json_file = sys.argv[1]
    csv_file  = sys.argv[2]
else :
    usage()
    sys.exit(1)

if not os.path.isfile(json_file) :
    print( 'Error: JSON file not exist!!')
    usage()
    sys.exit(1)

# "usb" キーが複数あるので、これをリストに変換したJSONファイルを作成する
# かなり力技...
def modify_json(json_file, tmp_file) :
    with open(json_file) as f_json, open(tmp_file, 'w') as f_tmp:
        line_number = 0;
        line = f_json.readline()
        
        find_flag = False
        
        while line:
            line_number = line_number + 1           # 行番号
            # line = line.rstrip('\r\n')              # CRLFを削除
            if find_flag :
                line = line.replace('"usb": ', '')      # key名称 "usb"を削除
                if first_flag :
                    # print(f'START: {line_number} {line}')
                    f_tmp.write(f'          "usb_data": [\n')
                    first_flag = False
                brackets = brackets + line.count('{')
                brackets = brackets - line.count('}')
                if brackets < 0 :
                    # print(f'END: {line_number} {line}')
                    f_tmp.write(f'          ]\n')
                    find_flag = False
            else :
                if line.startswith('          "usb.iso.numdesc":') :
                    f_pos = f_json.tell()
                    next_line = f_json.readline()        # 次の行を読み込んで
                    f_json.seek(f_pos)                   # ファイル位置を戻す
                    if next_line.startswith('          "usb":') :
                        find_flag = True
                        first_flag = True
                        brackets = 0                    # 括弧の数
            f_tmp.write(line)
            line = f_json.readline()

# JSONファイルの修正
modify_json(json_file, tmp_file)

# パケット解析用変数
stream_number = 0
frame_number = 0

# JSONファイルの読み込み
with open(tmp_file) as f:
    json_load = json.load(f)
    # print(json_load)

with open(csv_file, 'w') as f_csv :
    # ヘッダの出力
    f_csv.write('PacketNo,Date,Relative_time,Delta_time,Packet Size,Video Stream Size,Video Stream offset,Frame No,Stream No,Stream Data\n')
    for json_data in json_load :
        # フレームデータ
        frame_data          = json_data["_source"]["layers"]["frame"]
        frame_index         = frame_data["frame.number"]
        frame_time_epoc     = frame_data["frame.time_epoch"]
        frame_time_delta    = frame_data["frame.time_delta_displayed"]
        frame_time_relative = frame_data["frame.time_relative"]
        frame_time_dt       = datetime.datetime.fromtimestamp(float(frame_time_epoc))
        frame_time          = str(frame_time_dt)
        frame_len           = frame_data["frame.len"]
        # print(f'{frame_index},"\'{frame_time}",{frame_len},', end='')
        f_csv.write(f'{frame_index},"\'{frame_time}",{frame_time_relative},{frame_time_delta},{frame_len},')
        
        # USBデータ
        usb_datas  = json_data["_source"]["layers"]["usb"]["usb_data"]
        first_flag = True
        for usb_data in usb_datas :
            if first_flag :
                first_flag = False
            else :
                # print(f',,,,,', end='')
                f_csv.write(f',,,,,')
            iso_len  = int(usb_data['usb.iso.iso_len'])
            iso_off  = usb_data['usb.iso.iso_off']
            if (iso_len > 0) :
                iso_data = usb_data["usb.iso.data"]
                iso_data = '0x'+iso_data.replace(':', ',0x')
                if stream_number == 0 :
                    frame_number = frame_number + 1
                    frame_number_str = str(frame_number)
                else :
                    frame_number_str = ''
                
                # print(f'{iso_len},{iso_off},{stream_number},{iso_data}')
                f_csv.write(f'{iso_len},{iso_off},{frame_number_str},{stream_number},{iso_data}\n')
                if iso_data.startswith('0x02,0x02') or iso_data.startswith('0x02,0x03') :
                    stream_number = 0
                else :
                    stream_number = stream_number + 1
            else :
                # print(f'{iso_len},{iso_off},,')
                f_csv.write(f'{iso_len},{iso_off},,\n')


# テンポラリファイルの削除
os.remove(tmp_file)