#!/usr/bin/env python3

import binascii
import os
import sys

keyboard = {
    'protocol': 1,
    'subclass': 1,
    'report_length': 8,
    'report_desc': bytes([
        0x05, 0x01, # Usage Page (Generic Desktop Ctrls)
        0x09, 0x06, # Usage (Keyboard)
        0xA1, 0x01, # Collection (Application)

        # Control key bitmask
        0x05, 0x07, #   Usage Page (Kbrd/Keypad)
        0x19, 0xE0, #   Usage Minimum (0xE0)
        0x29, 0xE7, #   Usage Maximum (0xE7)
        0x15, 0x00, #   Logical Minimum (0)
        0x25, 0x01, #   Logical Maximum (1)
        0x75, 0x01, #   Report Size (1)
        0x95, 0x08, #   Report Count (8)
        0x81, 0x02, #   Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)

        # Reserved byte
        0x95, 0x01, #   Report Count (1)
        0x75, 0x08, #   Report Size (8)
        0x81, 0x03, #   Input (Const,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)

        # LED status
        0x95, 0x05, #   Report Count (5)
        0x75, 0x01, #   Report Size (1)
        0x05, 0x08, #   Usage Page (LEDs)
        0x19, 0x01, #   Usage Minimum (Num Lock)
        0x29, 0x05, #   Usage Maximum (Kana)
        0x91, 0x02, #   Output (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)

        # Padding
        0x95, 0x01, #   Report Count (1)
        0x75, 0x03, #   Report Size (3)
        0x91, 0x03, #   Output (Const,Var,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)

        # 6 general buttons
        0x95, 0x06, #   Report Count (6)
        0x75, 0x08, #   Report Size (8)
        0x15, 0x00, #   Logical Minimum (0)
        0x25, 0x65, #   Logical Maximum (101)
        0x05, 0x07, #   Usage Page (Kbrd/Keypad)
        0x19, 0x00, #   Usage Minimum (0x00)
        0x29, 0x65, #   Usage Maximum (0x65)
        0x81, 0x00, #   Input (Data,Array,Abs,No Wrap,Linear,Preferred State,No Null Position)

        0xC0,       # End Collection
    ]),
}


mouse = {
    'protocol': 2,
    'subclass': 1,
    'report_length': 4,
    'report_desc': bytes([
        0x05, 0x01, # Usage Page (Generic Desktop Ctrls)
        0x09, 0x02, # Usage (Mouse)
        0xA1, 0x01, # Collection (Application)
        0x09, 0x01, #   Usage (Pointer)
        0xA1, 0x00, #   Collection (Physical)
        0x05, 0x09, #     Usage Page (Button)
        0x19, 0x01, #     Usage Minimum (0x01)
        0x29, 0x05, #     Usage Maximum (0x05)
        0x15, 0x00, #     Logical Minimum (0)
        0x25, 0x01, #     Logical Maximum (1)
        0x95, 0x05, #     Report Count (5)
        0x75, 0x01, #     Report Size (1)
        0x81, 0x02, #     Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
        0x95, 0x01, #     Report Count (1)
        0x75, 0x03, #     Report Size (3)
        0x81, 0x01, #     Input (Const,Array,Abs,No Wrap,Linear,Preferred State,No Null Position)
        0x05, 0x01, #     Usage Page (Generic Desktop Ctrls)
        0x09, 0x30, #     Usage (X)
        0x09, 0x31, #     Usage (Y)
        0x09, 0x38, #     Usage (Wheel)
        0x15, 0x81, #     Logical Minimum (-127)
        0x25, 0x7F, #     Logical Maximum (127)
        0x75, 0x08, #     Report Size (8)
        0x95, 0x03, #     Report Count (3)
        0x81, 0x06, #     Input (Data,Var,Rel,No Wrap,Linear,Preferred State,No Null Position)
        0xC0,       #   End Collection
        0xC0,       # End Collection
    ])
}


try:
    UDC = os.listdir('/sys/class/udc')
    if len(UDC) != 1:
        print("Expected a single entry in '/sys/class/udc'")
        sys.exit(1)
    UDC = UDC[0]
except FileNotFoundError:
    print ("Unable to query UDC")
    UDC='foo'
    #sys.exit (1)


files = {
    'idVendor': '0x1d6b', # Linux Foundation
    'idProduct': '0x0104', # Multifunction Composite Gadget
    'bcdDevice': '0x0100', # v1.0.0
    'bcdUSB': '0x0200',

    'strings': {
        '0x409': {
            'serialnumber': "fedcba9876543210",
            'manufacturer': "Raspberry Pi",
            'product': "pizero keyboard Device",
        }
    },

    'configs': {
        'c.1': {
            'strings': {
                '0x0409': {
                    'configuration': 'Config 1: ECM network'
                }
            },
            'MaxPower': 250
        }
    },

    'functions': {
        'hid.usb0': keyboard,
        'hid.usb1': mouse,
    }
}


name = 'quimby'
root = os.path.join('/sys/kernel/config/usb_gadget/', name)
try:
    os.mkdir(root)
except FileExistsError:
    pass

def serialise(root, tree):
    for key,val in tree.items():
        child = os.path.join(root, key)

        if isinstance(val, dict):
            try:
                os.mkdir(child)
            except FileExistsError:
                pass

            serialise(child, val)
        else:
            with open(child, 'wb') as dst:
                print(child,val)
                if not isinstance(val, bytes):
                    val = bytes(str(val).encode())
                dst.write(val)

serialise(root, files)

# Link the functions in
for key in files['functions'].keys():
    src = os.path.join(root, 'functions', key)
    dst = os.path.join(root, 'configs', 'c.1', key)
    os.symlink(src, dst)

# UDC needs to be written last
with open(f"{root}/UDC", 'w') as dst:
    dst.write(UDC)