#!/usr/bin/env python3

import sys
from pathlib import Path
from typing import BinaryIO, TextIO
import re


label_invalid = re.compile(r"\W")      # Turn invalid label chars into underscores
label_lstrip = re.compile(r"^[\d_]+")  # Trim all underscores or numbers from the beginning


def sanitise_label(label: str) -> str:
	tmp = label_invalid.sub("_", label, re.I)
	return label_lstrip.sub("", tmp, re.I)


def bin2h(name: str, binf: BinaryIO, h: TextIO):
	raise NotImplementedError


def txt2h(name: str, txt: TextIO, h: TextIO):
	h.write(f"static const char* const {sanitise_label(name)} = \n")
	h.write("\"")

	remap = {
		"\a": "\\a", "\b": "\\b", "\f": "\\f", "\n": "\\n", "\r": "\\r",
		"\t": "\\t", "\v": "\\v", "\\": "\\\\", "\"": "\\\""}
	esc_numeric = False
	for idx, c in enumerate(txt.read()):
		if m := remap.get(c):
			h.write(m)
		else:
			if (i := ord(c)) < 0x7F:
				if c.isprintable() and not (esc_numeric and c.isnumeric()):
					h.write(c)
				else:
					if i < 8:
						h.write(f"\\{i:o}")
					else:
						h.write(f"\\x{i:02X}")
					esc_numeric = True
					continue
			elif i < 0x10000:
				h.write(f"\\u{i:04X}")
			else:
				h.write(f"\\U{i:08X}")
		esc_numeric = False

	h.write("\";\n")


def main():
	usage = "Usage [-b data.bin] [-t text.txt] <out.h>"

	binfiles = []
	txtfiles = []
	out = None
	opt = None
	for arg in sys.argv[1:]:
		if opt is not None:
			if opt == "b":
				binfiles.append(arg)
			elif opt == "t":
				txtfiles.append(arg)
			else:
				sys.exit(usage)
			opt = None
		if arg.startswith("-"):
			opt = arg[1:]
		else:
			out = Path(arg)

	if opt is not None or out is None:
		sys.exit(usage)
	if len(binfiles) == 0 and len(txtfiles) == 0:
		sys.exit(usage)

	with out.open("w") as h:
		guard = f"BIN2H_{sanitise_label(out.name).upper()}"
		if not guard.endswith("_H"):
			guard += "_H"
		h.writelines([
			"/*DO NOT EDIT*/\n",
			"// Autogenerated by bin2h\n",
			"\n",
			f"#ifndef {guard}\n",
			f"#define {guard}\n",
			"\n"])

		# Write binaries
		for i in binfiles:
			path = Path(i)
			with path.open("rb") as file:
				bin2h(path.name, file, h)

		# Write texts
		for i in txtfiles:
			path = Path(i)
			with path.open("r") as file:
				txt2h(path.name, file, h)

		h.writelines([
			"\n",
			f"#endif//{guard}\n"])


if __name__ == "__main__":
	main()