#!/usr/bin/python3
# This script depends on PyUSB. You can get it with pip install pyusb.
# You will also need libusb installed

import usb.core
import usb.util
import struct
import sys
import time
import threading

from binascii import hexlify as hx, unhexlify as uhx
from pathlib import Path

from tkinter import filedialog
import tkinter as tk
from tkinter import *

from tkinter import scrolledtext

CMD_ID_EXIT = 0
CMD_ID_LIST_OLD = 1
CMD_ID_FILE_RANGE = 2
CMD_ID_LIST = 3

CMD_TYPE_REQUEST = 0
CMD_TYPE_RESPONSE = 1
CMD_TYPE_ACK = 2

BUFFER_SEGMENT_DATA_SIZE = 0x100000

in_ep = None
out_ep = None

file_list = {}

def LOG(line):
    if int(text1.index('end').split('.')[0]) - 1 > 1000: # max 1000 lines of log are shown
            text1.delete('1.0', tk.END)
    text1.insert(tk.END, line+'\n')
    text1.see(tk.END)

def process_file_range_command(data_size):
    global file_list

    LOG('File range')
    out_ep.write(struct.pack('<4sIII', b'DBI0', CMD_TYPE_ACK, CMD_ID_FILE_RANGE, data_size))

    file_range_header = in_ep.read(data_size)

    range_size = struct.unpack('<I', file_range_header[:4])[0]
    range_offset = struct.unpack('<Q', file_range_header[4:12])[0]
    nsp_name_len = struct.unpack('<I', file_range_header[12:16])[0]
    nsp_name = bytes(file_range_header[16:]).decode('utf-8')

    LOG('Range Size: {}, Range Offset: {}, Name len: {}, Name: {}'.format(range_size, range_offset, nsp_name_len, nsp_name))

    response_bytes = struct.pack('<4sIII', b'DBI0', CMD_TYPE_RESPONSE, CMD_ID_FILE_RANGE, range_size)
    out_ep.write(response_bytes)

    ack = bytes(in_ep.read(16, timeout=0))
    magic = ack[:4]
    cmd_type = struct.unpack('<I', ack[4:8])[0]
    cmd_id = struct.unpack('<I', ack[8:12])[0]
    data_size = struct.unpack('<I', ack[12:16])[0]

    # LOG('Cmd Type: {}, Command id: {}, Data size: {}'.format(cmd_type, cmd_id, data_size))
    # LOG('Ack')

    with open(file_list[nsp_name].__str__(), 'rb') as f:
        f.seek(range_offset)

        curr_off = 0x0
        end_off = range_size
        read_size = BUFFER_SEGMENT_DATA_SIZE

        while curr_off < end_off:
            if curr_off + read_size >= end_off:
                read_size = end_off - curr_off

            buf = f.read(read_size)
            out_ep.write(data=buf, timeout=0)
            curr_off += read_size

def poll_commands():
    LOG('Entering command loop')
    while True:
        try:
            cmd_header = bytes(in_ep.read(16, timeout=0))
            magic = cmd_header[:4]

            if magic != b'DBI0':
                continue

            cmd_type = struct.unpack('<I', cmd_header[4:8])[0]
            cmd_id = struct.unpack('<I', cmd_header[8:12])[0]
            data_size = struct.unpack('<I', cmd_header[12:16])[0]

            # LOG('Cmd Type: {}, Command id: {}, Data size: {}'.format(cmd_type, cmd_id, data_size))

            if cmd_id == CMD_ID_EXIT:
                process_exit_command()
            elif cmd_id == CMD_ID_FILE_RANGE:
                process_file_range_command(data_size)
            elif cmd_id == CMD_ID_LIST:
                process_list_command()
        except usb.core.USBError:
            LOG('Switch connection lost')
            connect_to_switch()

def process_exit_command():
    LOG('Exit')
    out_ep.write(struct.pack('<4sIII', b'DBI0', CMD_TYPE_RESPONSE, CMD_ID_EXIT, 0))
    global root
    root.quit()


def process_list_command():
    global file_list
    LOG('Get list')
    nsp_path_list = ""
    nsp_path_list_len = 0

    for i, (k, v) in enumerate(file_list.items()):
        nsp_path_list += k + '\n'

    nsp_path_list_bytes = nsp_path_list.encode('utf-8')
    nsp_path_list_len = len(nsp_path_list_bytes)

    out_ep.write(struct.pack('<4sIII', b'DBI0', CMD_TYPE_RESPONSE, CMD_ID_LIST, nsp_path_list_len))

    if nsp_path_list_len > 0:
        ack = bytes(in_ep.read(16, timeout=0))
        magic = ack[:4]
        cmd_type = struct.unpack('<I', ack[4:8])[0]
        cmd_id = struct.unpack('<I', ack[8:12])[0]
        data_size = struct.unpack('<I', ack[12:16])[0]

        # LOG('Cmd Type: {}, Command id: {}, Data size: {}'.format(cmd_type, cmd_id, data_size))
        # LOG('Ack')

        out_ep.write(nsp_path_list_bytes)

def connect_to_switch():
    global in_ep
    global out_ep
    global text1
    while True:
        dev = usb.core.find(idVendor=0x057E, idProduct=0x3000)
        if dev is None:
            LOG('Waiting for switch...')
            time.sleep(1)
            continue

        dev.reset()
        print('Waiting for switch reset...')
        time.sleep(1)
        dev.set_configuration()
        cfg = dev.get_active_configuration()

        is_out_ep = lambda ep: usb.util.endpoint_direction(ep.bEndpointAddress) == usb.util.ENDPOINT_OUT
        is_in_ep = lambda ep: usb.util.endpoint_direction(ep.bEndpointAddress) == usb.util.ENDPOINT_IN
        out_ep = usb.util.find_descriptor(cfg[(0,0)], custom_match=is_out_ep)
        in_ep = usb.util.find_descriptor(cfg[(0,0)], custom_match=is_in_ep)

        assert out_ep is not None
        assert in_ep is not None
        break

def start_server():
    print(file_list)
    connect_to_switch()
    poll_commands()    

def do_start_server():
    global server_thread
    global addFolderButton
    global addFilesButton
    global clearListButton
    global startServerButton

    addFolderButton['state'] = 'disabled'
    addFilesButton['state'] = 'disabled'
    clearListButton['state'] = 'disabled'
    startServerButton['state'] = 'disabled'

    server_thread = threading.Thread(target=start_server)
    server_thread.daemon = True
    server_thread.start()

def updateFileList():
    global flist1
    global file_list
    global startServerButton

    flist1.delete('1.0', tk.END)
    for i, (k, v) in enumerate(sorted(file_list.items())):
        flist1.insert(tk.END, v.__str__()+'\n')

    if len(file_list) > 0:
        startServerButton['state'] = 'normal'
    else:
        startServerButton['state'] = 'disabled'

def gui_choose_dir():  
    global file_list
    filename = filedialog.askdirectory()
    if filename == () or filename == '':
        return
    d = Path(filename)
    for file_path in [f for f in d.iterdir() if f.is_file()]:
        file_list.update({file_path.name : file_path.resolve()})

    updateFileList()

def gui_choose_files():  
    global file_list
    filenames = filedialog.askopenfilenames()
    for file_path in filenames:
        d = Path(file_path)
        file_list.update({d.name : d.resolve()})

    updateFileList()

def gui_clear_list():  
    global file_list

    file_list.clear()
    updateFileList()

def start_gui(start):
    global addFolderButton
    global addFilesButton
    global clearListButton
    global startServerButton
    global text1
    global flist1
    global root

    root = tk.Tk()
    root.resizable(False, False)
    root.title('DBI backend GUI')

    canvas1 = tk.Canvas(root, width = 800, height = 500)
    canvas1.pack()
    addFolderButton = tk.Button(text='Add folder',command=gui_choose_dir,width=10)
    canvas1.create_window(0, 0, window=addFolderButton, anchor=tk.NW)
    addFilesButton = tk.Button(text='Add files',command=gui_choose_files,width=10)
    canvas1.create_window(100, 0, window=addFilesButton, anchor=tk.NW)
    clearListButton = tk.Button(text='Clear list',command=gui_clear_list,width=10)
    canvas1.create_window(200, 0, window=clearListButton, anchor=tk.NW)

    flist1 = tk.scrolledtext.ScrolledText(height=20, width=112)
    canvas1.create_window(0, 30, window=flist1, anchor=tk.NW)

    startServerButton = tk.Button(text='Start server',state=tk.DISABLED, command=do_start_server,width=10)
    canvas1.create_window(0, 325, window=startServerButton, anchor=tk.NW)

    text1 = tk.scrolledtext.ScrolledText(height=10, width=112)
    canvas1.create_window(0, 355, window=text1, anchor=tk.NW)

    if start:
        updateFileList()
        do_start_server()
    root.mainloop()


if len(sys.argv) < 2:
    start_gui(False)
else:
    for filename in sys.argv[1:]:
        d = Path(filename)
        if d.is_file():
            file_list.update({d.name: d.resolve()})
        else:
            for file_path in [f for f in d.iterdir() if f.is_file()]:
                file_list.update({file_path.name : file_path.resolve()})

    start_gui(True)