import argparse
import enum
import io
import itertools
import shutil
import sys
import typing

from . import __version__, api, compress

# The encoding to use when rendering bytes as text (in four-char codes, strings, hex dumps, etc.) or reading a quoted byte string (from the command line).
_TEXT_ENCODING = "MacRoman"

_REZ_ATTR_NAMES = {
	api.ResourceAttrs.resSysRef: None, # "Illegal or reserved attribute"
	api.ResourceAttrs.resSysHeap: "sysheap",
	api.ResourceAttrs.resPurgeable: "purgeable",
	api.ResourceAttrs.resLocked: "locked",
	api.ResourceAttrs.resProtected: "protected",
	api.ResourceAttrs.resPreload: "preload",
	api.ResourceAttrs.resChanged: None, # "Illegal or reserved attribute"
	api.ResourceAttrs.resCompressed: None, # "Extended Header resource attribute"
}

F = typing.TypeVar("F", bound=enum.Flag)


def decompose_flags(value: F) -> typing.Sequence[F]:
	"""Decompose an enum.Flags instance into separate enum constants."""
	
	return [bit for bit in type(value) if bit in value]


def is_printable(char: str) -> bool:
	"""Determine whether a character is printable for our purposes.
	
	We mainly use Python's definition of printable (i. e. everything that Unicode does not consider a separator or "other" character). However, we also treat U+F8FF as printable, which is the private use codepoint used for the Apple logo character.
	"""
	
	return char.isprintable() or char == "\uf8ff"


# Translation table to replace non-printable characters with periods.
_TRANSLATE_NONPRINTABLES = {ord(c): "." for c in bytes(range(256)).decode(_TEXT_ENCODING) if not is_printable(c)}


def bytes_unescape(string: str) -> bytes:
	"""Convert a string containing text (in _TEXT_ENCODING) and hex escapes to a bytestring.
	
	(We implement our own unescaping mechanism here to not depend on any of Python's string/bytes escape syntax.)
	"""
	
	out: typing.List[int] = []
	it = iter(string)
	for char in it:
		if char == "\\":
			try:
				esc = next(it)
				if esc in "\\\'\"":
					out.extend(esc.encode(_TEXT_ENCODING))
				elif esc == "x":
					x1, x2 = next(it), next(it)
					out.append(int(x1+x2, 16))
				else:
					raise ValueError(f"Unknown escape character: {esc}")
			except StopIteration:
				raise ValueError("End of string in escape sequence")
		else:
			out.extend(char.encode(_TEXT_ENCODING))
	
	return bytes(out)


def bytes_escape(bs: bytes, *, quote: typing.Optional[str] = None) -> str:
	"""Convert a bytestring to a string (using _TEXT_ENCODING), with non-printable characters hex-escaped.
	
	(We implement our own escaping mechanism here to not depend on Python's str or bytes repr.)
	"""
	
	out = []
	for byte, char in zip(bs, bs.decode(_TEXT_ENCODING)):
		if char in {quote, "\\"}:
			out.append(f"\\{char}")
		elif is_printable(char):
			out.append(char)
		else:
			out.append(f"\\x{byte:02x}")
	
	return "".join(out)


def bytes_quote(bs: bytes, quote: str) -> str:
	"""Convert a bytestring to a quoted string (using _TEXT_ENCODING), with non-printable characters hex-escaped.
	
	(We implement our own escaping mechanism here to not depend on Python's str or bytes repr.)
	"""
	
	return quote + bytes_escape(bs, quote=quote) + quote


MIN_RESOURCE_ID = -0x8000
MAX_RESOURCE_ID = 0x7fff


class ResourceFilter(object):
	type: bytes
	min_id: int
	max_id: int
	name: typing.Optional[bytes]
	
	@classmethod
	def from_string(cls, filter: str) -> "ResourceFilter":
		if len(filter) == 4:
			restype = filter.encode("ascii")
			return cls(restype, MIN_RESOURCE_ID, MAX_RESOURCE_ID, None)
		elif filter[0] == filter[-1] == "'":
			restype = bytes_unescape(filter[1:-1])
			return cls(restype, MIN_RESOURCE_ID, MAX_RESOURCE_ID, None)
		else:
			pos = filter.find("'", 1)
			if pos == -1:
				raise ValueError(f"Invalid filter {filter!r}: Resource type must be single-quoted")
			elif filter[pos + 1] != " ":
				raise ValueError(f"Invalid filter {filter!r}: Resource type and ID must be separated by a space")
			
			restype_str, resid_str = filter[:pos + 1], filter[pos + 2:]
			
			if not restype_str[0] == restype_str[-1] == "'":
				raise ValueError(
					f"Invalid filter {filter!r}: Resource type is not a single-quoted type identifier: {restype_str!r}")
			restype = bytes_unescape(restype_str[1:-1])
			
			if resid_str[0] != "(" or resid_str[-1] != ")":
				raise ValueError(f"Invalid filter {filter!r}: Resource ID must be parenthesized")
			resid_str = resid_str[1:-1]
			
			if resid_str[0] == resid_str[-1] == '"':
				name = bytes_unescape(resid_str[1:-1])
				return cls(restype, MIN_RESOURCE_ID, MAX_RESOURCE_ID, name)
			elif ":" in resid_str:
				if resid_str.count(":") > 1:
					raise ValueError(f"Invalid filter {filter!r}: Too many colons in ID range expression: {resid_str!r}")
				start_str, end_str = resid_str.split(":")
				start, end = int(start_str), int(end_str)
				return cls(restype, start, end, None)
			else:
				resid = int(resid_str)
				return cls(restype, resid, resid, None)
	
	def __init__(self, restype: bytes, min_id: int, max_id: int, name: typing.Optional[bytes]) -> None:
		super().__init__()
		
		if len(restype) != 4:
			raise ValueError(f"Invalid filter: Type code must be exactly 4 bytes long, not {len(restype)} bytes: {restype!r}")
		elif min_id < MIN_RESOURCE_ID:
			raise ValueError(f"Invalid filter: Resource ID lower bound ({min_id}) cannot be lower than {MIN_RESOURCE_ID}")
		elif max_id > MAX_RESOURCE_ID:
			raise ValueError(f"Invalid filter: Resource ID upper bound ({max_id}) cannot be greater than {MAX_RESOURCE_ID}")
		elif min_id > max_id:
			raise ValueError(f"Invalid filter: Resource ID lower bound ({min_id}) cannot be greater than upper bound ({max_id})")
		
		self.type = restype
		self.min_id = min_id
		self.max_id = max_id
		self.name = name
	
	def __repr__(self) -> str:
		return f"{type(self).__name__}({self.type!r}, {self.min_id!r}, {self.max_id!r}, {self.name!r})"
	
	def matches(self, res: api.Resource) -> bool:
		return res.type == self.type and self.min_id <= res.id <= self.max_id and (self.name is None or res.name == self.name)


def filter_resources(rf: api.ResourceFile, filters: typing.Sequence[str]) -> typing.Iterable[api.Resource]:
	if not filters:
		# Special case: an empty list of filters matches all resources rather than none
		for reses in rf.values():
			yield from reses.values()
	else:
		filter_objs = [ResourceFilter.from_string(filter) for filter in filters]
		
		for reses in rf.values():
			for res in reses.values():
				if any(filter_obj.matches(res) for filter_obj in filter_objs):
					yield res


def hexdump_stream(stream: typing.BinaryIO) -> typing.Iterable[str]:
	last_line = None
	asterisk_shown = False
	line = stream.read(16)
	i = 0
	while line:
		# If the same 16-byte lines appear multiple times, print only the first one, and replace all further lines with a single line with an asterisk.
		# This is unambiguous - to find out how many lines were collapsed this way, the user can compare the addresses of the lines before and after the asterisk.
		if line == last_line:
			if not asterisk_shown:
				yield "*"
				asterisk_shown = True
		else:
			line_hex_left = " ".join(f"{byte:02x}" for byte in line[:8])
			line_hex_right = " ".join(f"{byte:02x}" for byte in line[8:])
			line_char = line.decode(_TEXT_ENCODING).translate(_TRANSLATE_NONPRINTABLES)
			yield f"{i:08x}  {line_hex_left:<{8*2+7}}  {line_hex_right:<{8*2+7}}  |{line_char}|"
			asterisk_shown = False
		last_line = line
		i += len(line)
		line = stream.read(16)
	
	if i:
		yield f"{i:08x}"


def hexdump(data: bytes) -> typing.Iterable[str]:
	yield from hexdump_stream(io.BytesIO(data))


def raw_hexdump_stream(stream: typing.BinaryIO) -> typing.Iterable[str]:
	line = stream.read(16)
	while line:
		yield " ".join(f"{byte:02x}" for byte in line)
		line = stream.read(16)


def raw_hexdump(data: bytes) -> typing.Iterable[str]:
	yield from raw_hexdump_stream(io.BytesIO(data))


def translate_text(data: bytes) -> str:
	return data.decode(_TEXT_ENCODING).replace("\r", "\n")


def describe_resource(res: api.Resource, *, include_type: bool, decompress: bool) -> str:
	id_desc_parts = [f"{res.id}"]
	
	if res.name is not None:
		id_desc_parts.append(bytes_quote(res.name, '"'))
	
	id_desc = ", ".join(id_desc_parts)
	
	content_desc_parts = []
	
	if decompress and api.ResourceAttrs.resCompressed in res.attributes:
		try:
			res.compressed_info
		except compress.DecompressError:
			length_desc = f"unparseable compressed data header ({res.length_raw} bytes compressed)"
		else:
			assert res.compressed_info is not None
			length_desc = f"{res.length} bytes ({res.length_raw} bytes compressed)"
	else:
		length_desc = f"{res.length_raw} bytes"
	content_desc_parts.append(length_desc)
	
	attrs = decompose_flags(res.attributes)
	if attrs:
		content_desc_parts.append(" | ".join(attr.name for attr in attrs))
	
	content_desc = ", ".join(content_desc_parts)
	
	desc = f"({id_desc}): {content_desc}"
	if include_type:
		quoted_restype = bytes_quote(res.type, "'")
		desc = f"{quoted_restype} {desc}"
	return desc


def show_filtered_resources(resources: typing.Sequence[api.Resource], format: str, decompress: bool) -> None:
	if not resources:
		if format in ("dump", "dump-text"):
			print("No resources matched the filter")
		elif format in ("hex", "raw"):
			print("No resources matched the filter", file=sys.stderr)
			sys.exit(1)
		elif format == "derez":
			print("/* No resources matched the filter */")
		else:
			raise AssertionError(f"Unhandled output format: {format}")
	elif format in ("hex", "raw") and len(resources) != 1:
		print(f"Format {format} can only output a single resource, but the filter matched {len(resources)} resources", file=sys.stderr)
		sys.exit(1)
	
	for res in resources:
		if decompress:
			open_func = res.open
		else:
			open_func = res.open_raw
		
		with open_func() as f:
			if format in ("dump", "dump-text"):
				# Human-readable info and hex or text dump
				desc = describe_resource(res, include_type=True, decompress=decompress)
				print(f"Resource {desc}:")
				if format == "dump":
					for line in hexdump_stream(f):
						print(line)
				elif format == "dump-text":
					print(translate_text(f.read()))
				else:
					raise AssertionError(f"Unhandled format: {format!r}")
				print()
			elif format == "hex":
				# Data only as hex
				
				for line in raw_hexdump_stream(f):
					print(line)
			elif format == "raw":
				# Data only as raw bytes
				
				shutil.copyfileobj(f, sys.stdout.buffer)
			elif format == "derez":
				# Like DeRez with no resource definitions
				
				attrs = list(decompose_flags(res.attributes))
				
				if decompress and api.ResourceAttrs.resCompressed in attrs:
					attrs.remove(api.ResourceAttrs.resCompressed)
					attrs_comment = " /* was compressed */"
				else:
					attrs_comment = ""
				
				attr_descs_with_none = [_REZ_ATTR_NAMES[attr] for attr in attrs]
				if None in attr_descs_with_none:
					attr_descs = [f"${res.attributes.value:02X}"]
				else:
					attr_descs = typing.cast(typing.List[str], attr_descs_with_none)
				
				parts = [str(res.id)]
				
				if res.name is not None:
					parts.append(bytes_quote(res.name, '"'))
				
				parts += attr_descs
				
				quoted_restype = bytes_quote(res.type, "'")
				print(f"data {quoted_restype} ({', '.join(parts)}{attrs_comment}) {{")
				
				bytes_line = f.read(16)
				while bytes_line:
					# Two-byte grouping is really annoying to implement.
					groups = []
					for j in range(0, 16, 2):
						if j >= len(bytes_line):
							break
						elif j+1 >= len(bytes_line):
							groups.append(f"{bytes_line[j]:02X}")
						else:
							groups.append(f"{bytes_line[j]:02X}{bytes_line[j+1]:02X}")
					
					s = f'$"{" ".join(groups)}"'
					comment = "/* " + bytes_line.decode(_TEXT_ENCODING).translate(_TRANSLATE_NONPRINTABLES) + " */"
					print(f"\t{s:<54s}{comment}")
					bytes_line = f.read(16)
				
				print("};")
				print()
			else:
				raise ValueError(f"Unhandled output format: {format}")


def list_resources(resources: typing.List[api.Resource], *, sort: bool, group: str, decompress: bool) -> None:
	if len(resources) == 0:
		print("No resources matched the filter")
		return
	
	if group == "none":
		if sort:
			resources.sort(key=lambda res: (res.type, res.id))
		print(f"{len(resources)} resources:")
		for res in resources:
			print(describe_resource(res, include_type=True, decompress=decompress))
	elif group == "type":
		if sort:
			resources.sort(key=lambda res: res.type)
		resources_by_type = {restype: list(reses) for restype, reses in itertools.groupby(resources, key=lambda res: res.type)}
		print(f"{len(resources_by_type)} resource types:")
		for restype, restype_resources in resources_by_type.items():
			quoted_restype = bytes_quote(restype, "'")
			print(f"{quoted_restype}: {len(restype_resources)} resources:")
			if sort:
				restype_resources.sort(key=lambda res: res.id)
			for res in restype_resources:
				print(describe_resource(res, include_type=False, decompress=decompress))
			print()
	elif group == "id":
		resources.sort(key=lambda res: res.id)
		resources_by_id = {resid: list(reses) for resid, reses in itertools.groupby(resources, key=lambda res: res.id)}
		print(f"{len(resources_by_id)} resource IDs:")
		for resid, resid_resources in resources_by_id.items():
			print(f"({resid}): {len(resid_resources)} resources:")
			if sort:
				resid_resources.sort(key=lambda res: res.type)
			for res in resid_resources:
				print(describe_resource(res, include_type=True, decompress=decompress))
			print()
	else:
		raise AssertionError(f"Unhandled group mode: {group!r}")


def format_compressed_header_info(header_info: compress.CompressedHeaderInfo) -> typing.Iterable[str]:
	yield f"Header length: {header_info.header_length} bytes"
	yield f"Compression type: 0x{header_info.compression_type:>04x}"
	yield f"Decompressed data length: {header_info.decompressed_length} bytes"
	yield f"'dcmp' resource ID: {header_info.dcmp_id}"
	
	if isinstance(header_info, compress.CompressedType8HeaderInfo):
		yield f"Working buffer fractional size: {header_info.working_buffer_fractional_size} 256ths of compressed data length"
		yield f"Expansion buffer size: {header_info.expansion_buffer_size} bytes"
	elif isinstance(header_info, compress.CompressedType9HeaderInfo):
		yield f"Decompressor-specific parameters: {header_info.parameters!r}"
	else:
		raise AssertionError(f"Unhandled compressed header info type: {type(header_info)}")


def make_subcommand_parser(subs: typing.Any, name: str, *, help: str, description: str, **kwargs: typing.Any) -> argparse.ArgumentParser:
	"""Add a subcommand parser with some slightly modified defaults to a subcommand set.
	
	This function is used to ensure that all subcommands use the same base configuration for their ArgumentParser.
	"""
	
	ap = subs.add_parser(
		name,
		formatter_class=argparse.RawDescriptionHelpFormatter,
		help=help,
		description=description,
		allow_abbrev=False,
		add_help=False,
		**kwargs,
	)
	
	ap.add_argument("--help", action="help", help="Display this help message and exit.")
	
	return ap


def add_resource_file_args(ap: argparse.ArgumentParser) -> None:
	"""Define common options/arguments for specifying an input resource file.
	
	This includes a positional argument for the resource file's path, and the ``--fork`` option to select which fork of the file to use.
	"""
	
	ap.add_argument("--fork", choices=["auto", "data", "rsrc"], default="auto", help="The fork from which to read the resource file data, or auto to guess. Default: %(default)s")
	ap.add_argument("file", help="The file from which to read resources, or - for stdin.")


RESOURCE_FILTER_HELP = """
The resource filters use syntax similar to Rez (resource definition) files.
Each filter can have one of the following forms:

An unquoted type name (without escapes): TYPE
A quoted type name: 'TYPE'
A quoted type name and an ID: 'TYPE' (42)
A quoted type name and an ID range: 'TYPE' (24:42)
A quoted type name and a resource name: 'TYPE' ("foobar")

Note that the resource filter syntax uses quotes, parentheses and spaces,
which have special meanings in most shells. It is recommended to quote each
resource filter (using double quotes) to ensure that it is not interpreted
or rewritten by the shell.
"""


def add_resource_filter_args(ap: argparse.ArgumentParser) -> None:
	"""Define common options/arguments for specifying resource filters."""
	
	ap.add_argument("filter", nargs="*", help="One or more filters to select resources. If no filters are specified, all resources are selected.")


def open_resource_file(file: str, *, fork: str) -> api.ResourceFile:
	"""Open a resource file at the given path, using the specified fork."""
	
	if file == "-":
		if fork != "auto":
			print("Cannot specify an explicit fork when reading from stdin", file=sys.stderr)
			sys.exit(1)
		
		return api.ResourceFile(sys.stdin.buffer)
	else:
		return api.ResourceFile.open(file, fork=fork)


def do_read_header(ns: argparse.Namespace) -> typing.NoReturn:
	with open_resource_file(ns.file, fork=ns.fork) as rf:
		if ns.format in {"dump", "dump-text"}:
			if ns.format == "dump":
				dump_func = hexdump
			elif ns.format == "dump-text":
				def dump_func(data: bytes) -> typing.Iterable[str]:
					yield translate_text(data)
			else:
				raise AssertionError(f"Unhandled --format: {ns.format!r}")
			
			if ns.part in {"system", "all"}:
				print("System-reserved header data:")
				for line in dump_func(rf.header_system_data):
					print(line)
			
			if ns.part in {"application", "all"}:
				print("Application-specific header data:")
				for line in dump_func(rf.header_application_data):
					print(line)
		elif ns.format in {"hex", "raw"}:
			if ns.part == "system":
				data = rf.header_system_data
			elif ns.part == "application":
				data = rf.header_application_data
			elif ns.part == "all":
				data = rf.header_system_data + rf.header_application_data
			else:
				raise AssertionError(f"Unhandled --part: {ns.part!r}")
			
			if ns.format == "hex":
				for line in raw_hexdump(data):
					print(line)
			elif ns.format == "raw":
				sys.stdout.buffer.write(data)
			else:
				raise AssertionError(f"Unhandled --format: {ns.format!r}")
		else:
			raise AssertionError(f"Unhandled --format: {ns.format!r}")
	
	sys.exit(0)


def do_info(ns: argparse.Namespace) -> typing.NoReturn:
	with open_resource_file(ns.file, fork=ns.fork) as rf:
		print("System-reserved header data:")
		for line in hexdump(rf.header_system_data):
			print(line)
		print()
		print("Application-specific header data:")
		for line in hexdump(rf.header_application_data):
			print(line)
		print()
		
		print(f"Resource data starts at {rf.data_offset:#x} and is {rf.data_length:#x} bytes long")
		print(f"Resource map starts at {rf.map_offset:#x} and is {rf.map_length:#x} bytes long")
		attrs = decompose_flags(rf.file_attributes)
		if attrs:
			attrs_desc = " | ".join(attr.name for attr in attrs)
		else:
			attrs_desc = "(none)"
		print(f"Resource map attributes: {attrs_desc}")
		print(f"Resource map type list starts at {rf.map_type_list_offset:#x} (relative to map start) and contains {len(rf)} types")
		print(f"Resource map name list starts at {rf.map_name_list_offset:#x} (relative to map start)")
	
	sys.exit(0)


def do_list(ns: argparse.Namespace) -> typing.NoReturn:
	with open_resource_file(ns.file, fork=ns.fork) as rf:
		if not rf:
			print("No resources (empty resource file)")
		else:
			resources = list(filter_resources(rf, ns.filter))
			list_resources(resources, sort=ns.sort, group=ns.group, decompress=ns.decompress)
	
	sys.exit(0)


def do_resource_info(ns: argparse.Namespace) -> typing.NoReturn:
	with open_resource_file(ns.file, fork=ns.fork) as rf:
		resources = list(filter_resources(rf, ns.filter))
		
		if ns.sort:
			resources.sort(key=lambda res: (res.type, res.id))
		
		if not resources:
			print("No resources matched the filter")
			sys.exit(0)
		
		for res in resources:
			quoted_restype = bytes_quote(res.type, "'")
			print(f"Resource {quoted_restype} ({res.id}):")
			
			if res.name is None:
				print("\tName: none (unnamed)")
			else:
				assert res.name_offset is not None
				quoted_name = bytes_quote(res.name, '"')
				print(f'\tName: {quoted_name} (at offset {res.name_offset} in name list)')
			
			attrs = decompose_flags(res.attributes)
			if attrs:
				attrs_desc = " | ".join(attr.name for attr in attrs)
			else:
				attrs_desc = "(none)"
			print(f"\tAttributes: {attrs_desc}")
			
			print(f"\tData: {res.length_raw} bytes stored at offset {res.data_raw_offset} in resource file data")
			
			if api.ResourceAttrs.resCompressed in res.attributes and ns.decompress:
				print()
				print("\tCompressed resource header info:")
				try:
					res.compressed_info
				except compress.DecompressError:
					print("\t\t(failed to parse compressed resource header)")
				else:
					assert res.compressed_info is not None
					for line in format_compressed_header_info(res.compressed_info):
						print(f"\t\t{line}")
			
			print()
	
	sys.exit(0)


def do_read(ns: argparse.Namespace) -> typing.NoReturn:
	with open_resource_file(ns.file, fork=ns.fork) as rf:
		resources = list(filter_resources(rf, ns.filter))
		
		if ns.sort:
			resources.sort(key=lambda res: (res.type, res.id))
		
		show_filtered_resources(resources, format=ns.format, decompress=ns.decompress)
	
	sys.exit(0)


def do_raw_compress_info(ns: argparse.Namespace) -> typing.NoReturn:
	if ns.input_file == "-":
		in_stream = sys.stdin.buffer
		close_in_stream = False
	else:
		in_stream = open(ns.input_file, "rb")
		close_in_stream = True
	
	try:
		for line in format_compressed_header_info(compress.CompressedHeaderInfo.parse_stream(in_stream)):
			print(line)
	finally:
		if close_in_stream:
			in_stream.close()
	
	sys.exit(0)


def do_raw_decompress(ns: argparse.Namespace) -> typing.NoReturn:
	if ns.input_file == "-":
		in_stream = sys.stdin.buffer
		close_in_stream = False
	else:
		in_stream = open(ns.input_file, "rb")
		close_in_stream = True
	
	try:
		header_info = compress.CompressedHeaderInfo.parse_stream(in_stream)
		
		# Open the output file only after parsing the header, so that the file is only created (or its existing contents deleted) if the input file is valid.
		if ns.output_file == "-":
			if ns.debug:
				print("Cannot use --debug if the decompression output file is - (stdout).", file=sys.stderr)
				print("The debug output goes to stdout and would conflict with the decompressed data.", file=sys.stderr)
				sys.exit(2)
			
			out_stream = sys.stdout.buffer
			close_out_stream = False
		else:
			out_stream = open(ns.output_file, "wb")
			close_out_stream = True
		
		try:
			for chunk in compress.decompress_stream_parsed(header_info, in_stream, debug=ns.debug):
				out_stream.write(chunk)
		finally:
			if close_out_stream:
				out_stream.close()
	finally:
		if close_in_stream:
			in_stream.close()
	
	sys.exit(0)


def main() -> typing.NoReturn:
	"""Main function of the CLI.
	
	This function is a valid setuptools entry point. Arguments are passed in sys.argv, and every execution path ends with a sys.exit call. (setuptools entry points are also permitted to return an integer, which will be treated as an exit code. We do not use this feature and instead always call sys.exit ourselves.)
	"""
	
	ap = argparse.ArgumentParser(
		description="""
%(prog)s is a tool for working with Classic Mac OS resource files.
Currently this tool can only read resource files; modifying/writing resource
files is not supported yet.

Note: This tool is intended for human users. The output format is not
machine-readable and may change at any time. The command-line syntax usually
does not change much across versions, but this should not be relied on.
Automated scripts and programs should use the Python API provided by the
rsrcfork library, which this tool is a part of.
""",
		formatter_class=argparse.RawDescriptionHelpFormatter,
		allow_abbrev=False,
		add_help=False,
	)
	
	ap.add_argument("--help", action="help", help="Display this help message and exit.")
	ap.add_argument("--version", action="version", version=__version__, help="Display version information and exit.")
	
	subs = ap.add_subparsers(
		dest="subcommand",
		# TODO Add required=True (added in Python 3.7) once we drop Python 3.6 compatibility.
		metavar="SUBCOMMAND",
	)
	
	ap_read_header = make_subcommand_parser(
		subs,
		"read-header",
		help="Read the header data from a resource file.",
		description="""
Read and output a resource file's header data.

The header data consists of two parts:

The system-reserved data is 112 bytes long and used by the Classic Mac OS
Finder as temporary storage space. It usually contains parts of the
file metadata (name, type/creator code, etc.).

The application-specific data is 128 bytes long and is available for use by
applications. In practice it usually contains junk data that happened to be in
memory when the resource file was written.

Mac OS X does not use the header data fields anymore. Resource files written
on Mac OS X normally have both parts of the header data set to all zero bytes.
""",
	)
	
	ap_read_header.add_argument("--format", choices=["dump", "dump-text", "hex", "raw"], default="dump", help="How to output the header data: human-readable info with hex dump (dump) (default), human-readable info with newline-translated data (dump-text), data only as hex (hex), or data only as raw bytes (raw). Default: %(default)s")
	ap_read_header.add_argument("--part", choices=["system", "application", "all"], default="all", help="Which part of the header to read. Default: %(default)s")
	add_resource_file_args(ap_read_header)
	
	ap_info = make_subcommand_parser(
		subs,
		"info",
		help="Display technical information about the resource file.",
		description="""
Display technical information and stats about the resource file.
""",
	)
	add_resource_file_args(ap_info)
	
	ap_list = make_subcommand_parser(
		subs,
		"list",
		help="List the resources in a file.",
		description=f"""
List the resources stored in a resource file.

Each resource's type, ID, name (if any), attributes (if any), and data length
are displayed. For compressed resources, the compressed and decompressed data
length are displayed, as well as the ID of the 'dcmp' resource used to
decompress the resource data.

{RESOURCE_FILTER_HELP}
""",
	)
	
	ap_list.add_argument("--no-decompress", action="store_false", dest="decompress", help="Do not parse the data header of compressed resources and only output their compressed length.")
	ap_list.add_argument("--group", action="store", choices=["none", "type", "id"], default="type", help="Group resources by type or ID, or disable grouping. Default: %(default)s")
	ap_list.add_argument("--no-sort", action="store_false", dest="sort", help="Output resources in the order in which they are stored in the file, instead of sorting them by type and ID.")
	add_resource_file_args(ap_list)
	add_resource_filter_args(ap_list)
	
	ap_resource_info = make_subcommand_parser(
		subs,
		"resource-info",
		help="Display technical information about resources.",
		description=f"""
Display technical information about one or more resources.

{RESOURCE_FILTER_HELP}
""",
	)
	
	ap_resource_info.add_argument("--no-decompress", action="store_false", dest="decompress", help="Do not parse the contents of compressed resources, only output regular resource information.")
	ap_resource_info.add_argument("--no-sort", action="store_false", dest="sort", help="Output resources in the order in which they are stored in the file, instead of sorting them by type and ID.")
	add_resource_file_args(ap_resource_info)
	add_resource_filter_args(ap_resource_info)
	
	ap_read = make_subcommand_parser(
		subs,
		"read",
		help="Read data from resources.",
		description=f"""
Read the data of one or more resources.

{RESOURCE_FILTER_HELP}
""",
	)
	
	ap_read.add_argument("--no-decompress", action="store_false", dest="decompress", help="Do not decompress compressed resources, output the raw compressed resource data.")
	ap_read.add_argument("--format", choices=["dump", "dump-text", "hex", "raw", "derez"], default="dump", help="How to output the resources: human-readable info with hex dump (dump), human-readable info with newline-translated data (dump-text), data only as hex (hex), data only as raw bytes (raw), or like DeRez with no resource definitions (derez). Default: %(default)s")
	ap_read.add_argument("--no-sort", action="store_false", dest="sort", help="Output resources in the order in which they are stored in the file, instead of sorting them by type and ID.")
	add_resource_file_args(ap_read)
	add_resource_filter_args(ap_read)
	
	ap_raw_compress_info = make_subcommand_parser(
		subs,
		"raw-compress-info",
		help="Display technical information about raw compressed resource data.",
		description="""
Display technical information about raw compressed resource data that is stored
in a standalone file and not as a resource in a resource file.
""",
	)
	
	ap_raw_compress_info.add_argument("input_file", help="The file from which to read the compressed resource data, or - for stdin.")
	
	ap_raw_decompress = make_subcommand_parser(
		subs,
		"raw-decompress",
		help="Decompress raw compressed resource data.",
		description="""
Decompress raw compressed resource data that is stored in a standalone file
and not as a resource in a resource file.

This subcommand can be used in a shell pipeline by passing - as the input and
output file name, i. e. "%(prog)s - -".

Note: All other rsrcfork subcommands natively support compressed resources and
will automatically decompress them as needed. This subcommand is only needed
to decompress resource data that has been read from a resource file in
compressed form (e. g. using --no-decompress or another tool that does not
handle resource compression).
""",
	)
	
	ap_raw_decompress.add_argument("--debug", action="store_true", help="Display debugging output from the decompressor on stdout. Cannot be used if the output file is - (stdout).")
	
	ap_raw_decompress.add_argument("input_file", help="The file from which to read the compressed resource data, or - for stdin.")
	ap_raw_decompress.add_argument("output_file", help="The file to which to write the decompressed resource data, or - for stdout.")
	
	ns = ap.parse_args()
	
	if ns.subcommand is None:
		# TODO Remove this branch once we drop Python 3.6 compatibility, because this case will be handled by passing required=True to add_subparsers (see above).
		print("Missing subcommand", file=sys.stderr)
		sys.exit(2)
	elif ns.subcommand == "read-header":
		do_read_header(ns)
	elif ns.subcommand == "info":
		do_info(ns)
	elif ns.subcommand == "list":
		do_list(ns)
	elif ns.subcommand == "resource-info":
		do_resource_info(ns)
	elif ns.subcommand == "read":
		do_read(ns)
	elif ns.subcommand == "raw-compress-info":
		do_raw_compress_info(ns)
	elif ns.subcommand == "raw-decompress":
		do_raw_decompress(ns)
	else:
		raise AssertionError(f"Subcommand not handled: {ns.subcommand!r}")


if __name__ == "__main__":
	sys.exit(main())