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

# SPDX-License-Identifier: CC0-1.0
#
# Written in 2022 by Noralf Trønnes <noralf@tronnes.org>
#
# To the extent possible under law, the author(s) have dedicated all copyright and related and
# neighboring rights to this software to the public domain worldwide. This software is
# distributed without any warranty.
#
# You should have received a copy of the CC0 Public Domain Dedication along with this software.
# If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.

from __future__ import print_function
import argparse
import sys


def hexstr(buf):
	return ' '.join('{:02x}'.format(x) for x in buf)


def parse_binary(buf):
	if len(buf) < 18:
		raise ValueError('file too short, len=%d' % len(buf))
	if buf[:15] != b'MIPI DBI\x00\x00\x00\x00\x00\x00\x00':
		raise ValueError('wrong magic: %s' % hexstr(buf[:15]))
	if buf[15] != 1:
		raise ValueError('wrong version: %d' % (buf[15]))

	result = ''
	cmds = buf[16:]
	i = 0
	while i < len(cmds):
		try:
			pos = i
			cmd = cmds[i]
			i += 1
			num_params = cmds[i]
			i += 1
			params = cmds[i:i+num_params]
			if len(params) != num_params:
				raise IndexError()

			if cmd == 0x00 and num_params == 1:
				s = 'delay %d\n' % params[0]
			else:
				s = 'command 0x%02x' % cmd
				if params:
					s += ' '
					s += ' '.join('0x{:02x}'.format(x) for x in params)
				s += '\n'
		except IndexError:
			raise ValueError('malformed file at offset %d: %s' % (pos + 16, hexstr(cmds[pos:])))
		i += num_params
		result += s

	return result


def print_file(fn):
	with open(args.fw_file, mode='rb') as f:
		fw = f.read()
	s = parse_binary(bytearray(fw))
	print(s)


def parse_values(parts):
	vals = []
	for x in parts:
		try:
			val = int(x, 0)
		except ValueError:
			raise ValueError('not a number: %s' % x)
		if val < 0 or val > 255:
			raise ValueError('value out of bounds: %s (%d)' % (hex(val), val))
		vals.append(val)
	return vals


def make_file(fw_file, input_file):
	with open(input_file, mode='r') as f:
		lines = f.readlines()

	buf = bytearray()
	buf.extend(b'MIPI DBI\x00\x00\x00\x00\x00\x00\x00') # magic
	buf.append(1) # version

	for idx, line in enumerate(lines):
		# strip off comments and skip empty lines
		comment_idx = line.find('#')
		if comment_idx >= 0:
			line = line[:comment_idx]
		line = line.strip()
		if not line:
			continue

		try:
			parts = line.split()
			if parts[0] == 'command':
				vals = parse_values(parts[1:])
				buf.append(vals[0])
				num_params = len(vals) - 1
				buf.append(num_params)
				if num_params:
					buf.extend(vals[1:])
			elif parts[0] == 'delay':
				vals = parse_values(parts[1:])
				if len(vals) != 1:
					raise ValueError('delay takes exactly one argument')
				buf.append(0x00)
				buf.append(1)
				buf.append(vals[0])
			else:
				raise ValueError('unknown keyword: %s' % parts[0])
		except ValueError as e:
			raise ValueError('error: %s\nline %d: %s' % (e, idx + 1, line))

	with open(fw_file, mode='wb') as f:
		f.write(buf)


if __name__ == '__main__':
	parser = argparse.ArgumentParser(description='MIPI DBI Linux driver firmware tool')
	parser.add_argument('fw_file', help='firmware binary file')
	parser.add_argument('input', nargs='?', help='Input commands file')
	parser.add_argument('-v', '--verbose', action='store_true', help='Verbose output')
	parser.add_argument('-d', '--debug', action='store_true', help='Print exception callstack')
	args = parser.parse_args()

	try:
		if args.input:
				make_file(args.fw_file, args.input)
				if args.verbose:
					print_file(args.fw_file)
		else:
			print_file(args.fw_file)
	except Exception as e:
		if args.debug:
			raise
		print(e, file=sys.stderr)
		sys.exit(1)