#!/usr/bin/env python3
# -*- coding: utf-8 -*-

__version__ = "0.3.5"
__author__  = "spicyjpeg"

import sys
from argparse import ArgumentParser, FileType, Namespace
from typing   import ByteString, Mapping, Sequence, TextIO
from zlib     import decompress

from _common import *

## Utilities

# This encoding is similar to standard base45, but with some problematic
# characters (' ', '$', '%', '*') excluded.
_BASE41_CHARSET: str = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ+-./:"

def decodeBase41(data: str) -> bytearray:
	mapped: map[int]  = map(_BASE41_CHARSET.index, data)
	output: bytearray = bytearray()

	for a, b, c in zip(mapped, mapped, mapped):
		value: int = a + (b * 41) + (c * 1681)

		output.append(value >> 8)
		output.append(value & 0xff)

	return output

def serialNumberToString(_id: ByteString) -> str:
	value: int = int.from_bytes(_id[1:7], "little")

	#if value >= 100000000:
		#return "xxxx-xxxx"

	return f"{(value // 10000) % 10000:04d}-{value % 10000:04d}"

def toPrintableChar(value: int):
	if (value < 0x20) or (value > 0x7e):
		return "."

	return chr(value)

def hexdump(data: ByteString | Sequence[int], output: TextIO, width: int = 16):
	for i in range(0, len(data), width):
		hexBytes: map[str] = map(lambda value: f"{value:02x}", data[i:i + width])
		hexLine:  str      = " ".join(hexBytes).ljust(width * 3 - 1)

		asciiBytes: map[str] = map(toPrintableChar, data[i:i + width])
		asciiLine:  str      = "".join(asciiBytes).ljust(width)

		output.write(f"  {i:04x}: {hexLine} |{asciiLine}|\n")

## Dump parser

_DUMP_START: str = "573::"
_DUMP_END:   str = "::"

_CHIP_NAMES: Mapping[ChipType, str] = {
	ChipType.NONE:    "None",
	ChipType.X76F041: "Xicor X76F041",
	ChipType.X76F100: "Xicor X76F100",
	ChipType.ZS01:    "Konami ZS01 (PIC16CE625)"
}

def parseDumpString(data: str) -> Dump:
	_data: str = data.strip().upper()

	if not _data.startswith(_DUMP_START) or not _data.endswith(_DUMP_END):
		raise ValueError(f"dump string does not begin with '{_DUMP_START}' and end with '{_DUMP_END}'")

	_data = _data[len(_DUMP_START):-len(_DUMP_END)]

	return parseDump(decompress(decodeBase41(_data)))

def printDumpInfo(dump: Dump, output: TextIO):
	if dump.flags & DumpFlag.DUMP_SYSTEM_ID_OK:
		output.write("Digital I/O board:\n")
		output.write(f"  DS2401 ID:     {dump.systemID.hex('-')}\n")
		output.write(f"  Serial number: {serialNumberToString(dump.systemID)}\n\n")

	output.write("Security cartridge:\n")
	output.write(f"  Chip type:     {_CHIP_NAMES[dump.chipType]}\n")

	if dump.flags & DumpFlag.DUMP_CART_ID_OK:
		output.write(f"  DS2401 ID:     {dump.cartID.hex('-')}\n")
	if dump.flags & DumpFlag.DUMP_ZS_ID_OK:
		output.write(f"  ZS01 ID:       {dump.zsID.hex('-')}\n")
	if dump.flags & DumpFlag.DUMP_CONFIG_OK:
		output.write(f"  Configuration: {dump.config.hex('-')}\n")

	output.write("\nEEPROM dump:\n")
	hexdump(dump.data, output)
	output.write("\n")

## Main

def createParser() -> ArgumentParser:
	parser = ArgumentParser(
		description = "Decodes the contents of a QR code generated by the tool.",
		add_help    = False
	)

	group = parser.add_argument_group("Tool options")
	group.add_argument(
		"-h", "--help",
		action = "help",
		help   = "Show this help message and exit"
	)

	group = parser.add_argument_group("File paths")
	group.add_argument(
		"-i", "--input",
		type    = FileType("rb"),
		help    = "Read dump (.573 file) or QR string from specified path",
		metavar = "file"
	)
	group.add_argument(
		"-l", "--log",
		type    = FileType("at"),
		default = sys.stdout,
		help    = "Log cartridge info to specified file (stdout by default)",
		metavar = "file"
	)
	group.add_argument(
		"-e", "--export",
		type    = FileType("wb"),
		help    = "Export binary dump (.573 file) to specified path",
		metavar = "file"
	)

	group = parser.add_argument_group("Input data")
	group.add_argument(
		"data",
		type  = str,
		nargs = "?",
		help  = "QR string to decode (if -i was not passed)"
	)

	return parser

def main():
	parser: ArgumentParser = createParser()
	args:   Namespace      = parser.parse_args()

	if args.input:
		with args.input as _file:
			data: bytes = _file.read()

		try:
			dump: Dump = parseDump(data)
		except:
			dump: Dump = parseDumpString(data.decode("ascii"))
	elif args.data:
		dump: Dump = parseDumpString(args.data)
	else:
		parser.error("a dump must be passed on the command line or using -i")

	if args.log:
		printDumpInfo(dump, args.log)
	if args.export:
		with args.export as _file:
			_file.write(dump.serialize())

if __name__ == "__main__":
	main()