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# |_|    |___/                          |___/                                                                          #
# ==================================================================================================================== #
# Authors:                                                                                                             #
#   Patrick Lehmann                                                                                                    #
#                                                                                                                      #
# License:                                                                                                             #
# ==================================================================================================================== #
# Copyright 2017-2024 Patrick Lehmann - Bötzingen, Germany                                                             #
# Copyright 2014-2016 Technische Universität Dresden - Germany, Chair of VLSI-Design, Diagnostics and Architecture     #
#                                                                                                                      #
# Licensed under the Apache License, Version 2.0 (the "License");                                                      #
# you may not use this file except in compliance with the License.                                                     #
# You may obtain a copy of the License at                                                                              #
#                                                                                                                      #
#   http://www.apache.org/licenses/LICENSE-2.0                                                                         #
#                                                                                                                      #
# Unless required by applicable law or agreed to in writing, software                                                  #
# distributed under the License is distributed on an "AS IS" BASIS,                                                    #
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.                                             #
# See the License for the specific language governing permissions and                                                  #
# limitations under the License.                                                                                       #
#                                                                                                                      #
# SPDX-License-Identifier: Apache-2.0                                                                                  #
# ==================================================================================================================== #
#
"""Basic abstraction layer for executables."""

# __keywords__ =  ["abstract", "executable", "cli", "cli arguments"]

from os                    import environ as os_environ
from pathlib               import Path
from platform              import system
from shutil                import which as shutil_which
from subprocess            import Popen as Subprocess_Popen, PIPE as Subprocess_Pipe, STDOUT as Subprocess_StdOut
from typing                import Dict, Optional as Nullable, ClassVar, Type, List, Tuple, Iterator, Generator, Any

try:
	from pyTooling.Decorators                import export, readonly
	from pyTooling.MetaClasses               import ExtendedType
	from pyTooling.Exceptions                import ToolingException, PlatformNotSupportedException
	from pyTooling.Attributes                import Attribute
	from pyTooling.CLIAbstraction.Argument   import CommandLineArgument, ExecutableArgument
	from pyTooling.CLIAbstraction.Argument   import NamedAndValuedArgument, ValuedArgument, PathArgument, PathListArgument, NamedTupledArgument
	from pyTooling.CLIAbstraction.ValuedFlag import ValuedFlag
except (ImportError, ModuleNotFoundError):  # pragma: no cover
	print("[pyTooling.CLIAbstraction] Could not import from 'pyTooling.*'!")

	try:
		from Decorators                import export, readonly
		from MetaClasses               import ExtendedType
		from Exceptions                import ToolingException, PlatformNotSupportedException
		from Attributes                import Attribute
		from CLIAbstraction.Argument   import CommandLineArgument, ExecutableArgument
		from CLIAbstraction.Argument   import NamedAndValuedArgument, ValuedArgument, PathArgument, PathListArgument, NamedTupledArgument
		from CLIAbstraction.ValuedFlag import ValuedFlag
	except (ImportError, ModuleNotFoundError) as ex:  # pragma: no cover
		print("[pyTooling.CLIAbstraction] Could not import directly!")
		raise ex


@export
class CLIAbstractionException(ToolingException):
	pass


@export
class DryRunException(CLIAbstractionException):
	"""This exception is raised if an executable is launched while in dry-run mode."""


@export
class CLIArgument(Attribute):
	"""An attribute to annotate nested classes as an CLI argument."""


@export
class Environment(metaclass=ExtendedType, slots=True):
	_variables: Dict[str, str]

	def __init__(self, variables: Nullable[Dict[str, str]] = None) -> None:
		if variables is None:
			variables = os_environ

		self._variables = {name:value for (name, value) in variables.items()}

	def __contains__(self, name: str) -> bool:
		return name in self._variables

	def __len__(self) -> len:
		return len(self._variables)

	def __getitem__(self, name: str) -> str:
		return self._variables[name]


@export
class Program(metaclass=ExtendedType, slots=True):
	"""Represent a simple command line interface (CLI) executable (program or script)."""

	_platform:         str                                                            #: Current platform the executable runs on (Linux, Windows, ...)
	_executableNames:  ClassVar[Dict[str, str]]                                       #: Dictionary of platform specific executable names.
	_executablePath:   Path                                                           #: The path to the executable (binary, script, ...).
	_dryRun:           bool                                                           #: True, if program shall run in *dry-run mode*.
	__cliOptions__:    ClassVar[Dict[Type[CommandLineArgument], int]]                 #: List of all possible CLI options.
	__cliParameters__: Dict[Type[CommandLineArgument], Nullable[CommandLineArgument]] #: List of all CLI parameters (used CLI options).

	def __init_subclass__(cls, *args: Any, **kwargs: Any):
		"""
		Whenever a subclass is derived from :class:``Program``, all nested classes declared within ``Program`` and which are
		marked with attribute ``CLIArgument`` are collected and then listed in the ``__cliOptions__`` dictionary.
		"""
		super().__init_subclass__(*args, **kwargs)

		# register all available CLI options (nested classes marked with attribute 'CLIArgument')
		cls.__cliOptions__: Dict[Type[CommandLineArgument], int] = {}
		order: int = 0
		for option in CLIArgument.GetClasses(scope=cls):
			cls.__cliOptions__[option] = order
			order += 1

	def __init__(self, executablePath: Nullable[Path] = None, binaryDirectoryPath: Nullable[Path] = None, dryRun: bool = False) -> None:
		self._platform =    system()
		self._dryRun =      dryRun

		if executablePath is not None:
			if isinstance(executablePath, Path):
				if not executablePath.exists():
					if dryRun:
						self.LogDryRun(f"File check for '{executablePath}' failed. [SKIPPING]")
					else:
						raise CLIAbstractionException(f"Program '{executablePath}' not found.") from FileNotFoundError(executablePath)
			else:
				raise TypeError(f"Parameter 'executablePath' is not of type 'Path'.")
		elif binaryDirectoryPath is not None:
			if isinstance(binaryDirectoryPath, Path):
				if not binaryDirectoryPath.exists():
					if dryRun:
						self.LogDryRun(f"Directory check for '{binaryDirectoryPath}' failed. [SKIPPING]")
					else:
						raise CLIAbstractionException(f"Binary directory '{binaryDirectoryPath}' not found.") from FileNotFoundError(binaryDirectoryPath)

				try:
					executablePath = binaryDirectoryPath / self.__class__._executableNames[self._platform]
				except KeyError:
					raise CLIAbstractionException(f"Program is not supported on platform '{self._platform}'.") from PlatformNotSupportedException(self._platform)

				if not executablePath.exists():
					if dryRun:
						self.LogDryRun(f"File check for '{executablePath}' failed. [SKIPPING]")
					else:
						raise CLIAbstractionException(f"Program '{executablePath}' not found.") from FileNotFoundError(executablePath)
			else:
				raise TypeError(f"Parameter 'binaryDirectoryPath' is not of type 'Path'.")
		else:
			try:
				executablePath = Path(self._executableNames[self._platform])
			except KeyError:
				raise CLIAbstractionException(f"Program is not supported on platform '{self._platform}'.") from PlatformNotSupportedException(self._platform)

			resolvedExecutable = shutil_which(str(executablePath))
			if dryRun:
				if resolvedExecutable is None:
					pass
					# XXX: log executable not found in PATH
					# self.LogDryRun(f"Which '{executablePath}' failed. [SKIPPING]")
				else:
					fullExecutablePath = Path(resolvedExecutable)
					if not fullExecutablePath.exists():
						pass
						# XXX: log executable not found
						# self.LogDryRun(f"File check for '{fullExecutablePath}' failed. [SKIPPING]")
			else:
				if resolvedExecutable is None:
					raise CLIAbstractionException(f"Program could not be found in PATH.") from FileNotFoundError(executablePath)

				fullExecutablePath = Path(resolvedExecutable)
				if not fullExecutablePath.exists():
					raise CLIAbstractionException(f"Program '{fullExecutablePath}' not found.") from FileNotFoundError(fullExecutablePath)

			# TODO: log found executable in PATH
			# TODO: check if found executable has execute permissions
			# raise ValueError(f"Neither parameter 'executablePath' nor 'binaryDirectoryPath' was set.")

		self._executablePath = executablePath
		self.__cliParameters__ = {}

	@staticmethod
	def _NeedsParameterInitialization(key):
		return issubclass(key, (ValuedFlag, ValuedArgument, NamedAndValuedArgument, NamedTupledArgument, PathArgument, PathListArgument))

	def __getitem__(self, key):
		"""Access to a CLI parameter by CLI option (key must be of type :class:`CommandLineArgument`), which is already used."""
		if not issubclass(key, CommandLineArgument):
			raise TypeError(f"Key '{key}' is not a subclass of 'CommandLineArgument'.")

		# TODO: is nested check
		return self.__cliParameters__[key]

	def __setitem__(self, key, value):
		if not issubclass(key, CommandLineArgument):
			raise TypeError(f"Key '{key}' is not a subclass of 'CommandLineArgument'.")
		elif key not in self.__cliOptions__:
			raise KeyError(f"Option '{key}' is not allowed on executable '{self.__class__.__name__}'")
		elif key in self.__cliParameters__:
			raise KeyError(f"Option '{key}' is already set to a value.")

		if self._NeedsParameterInitialization(key):
			self.__cliParameters__[key] = key(value)
		else:
			self.__cliParameters__[key] = key()

	@readonly
	def Path(self) -> Path:
		return self._executablePath

	def ToArgumentList(self) -> List[str]:
		result: List[str] = []

		result.append(str(self._executablePath))

		def predicate(item: Tuple[Type[CommandLineArgument], int]) -> int:
			return self.__cliOptions__[item[0]]

		for key, value in sorted(self.__cliParameters__.items(), key=predicate):
			param = value.AsArgument()
			if isinstance(param, str):
				result.append(param)
			elif isinstance(param, (Tuple, List)):
				result += param
			else:
				raise TypeError(f"")  # XXX: needs error message

		return result

	def __repr__(self):
		return "[" + ", ".join([f"\"{item}\"" for item in self.ToArgumentList()]) + "]"

	def __str__(self):
		return " ".join([f"\"{item}\"" for item in self.ToArgumentList()])


@export
class Executable(Program):  # (ILogable):
	"""Represent a CLI executable derived from :class:`Program`, that adds an abstraction of :class:`subprocess.Popen`."""

	_BOUNDARY: ClassVar[str] = "====== BOUNDARY pyTooling.CLIAbstraction BOUNDARY ======"

	_workingDirectory: Nullable[Path]
	_environment: Nullable[Dict[str, str]]
	_process: Nullable[Subprocess_Popen]
	_iterator: Nullable[Iterator]

	def __init__(
		self,
		executablePath: Path = None,
		binaryDirectoryPath: Path = None,
		workingDirectory: Path = None,
		# environment: Environment = None,
		dryRun: bool = False
	):
		super().__init__(executablePath, binaryDirectoryPath, dryRun)

		self._workingDirectory = None
		self._environment = None
		self._process = None
		self._iterator = None

	def StartProcess(self):
		# start child process

		if self._dryRun:
			self.LogDryRun(f"Start process: {self!r}")
			return

		if self._environment is not None:
			envVariables = self._environment.Variables
		else:
			envVariables = None

		# FIXME: verbose log start process
		# FIXME: debug log - parameter list
		try:
			self._process = Subprocess_Popen(
				self.ToArgumentList(),
				stdin=Subprocess_Pipe,
				stdout=Subprocess_Pipe,
				stderr=Subprocess_StdOut,
				cwd=self._workingDirectory,
				env=envVariables,
				universal_newlines=True,
				bufsize=256
			)

		except OSError as ex:
			raise CLIAbstractionException(f"Error while launching a process for '{self._executablePath}'.") from ex

	def Send(self, line: str, end: str = "\n") -> None:
		try:
			self._process.stdin.write(line + end)
			self._process.stdin.flush()
		except Exception as ex:
			raise CLIAbstractionException(f"") from ex     # XXX: need error message

	# This is TCL specific ...
	# def SendBoundary(self):
	# 	self.Send("puts \"{0}\"".format(self._pyIPCMI_BOUNDARY))

	def GetLineReader(self) -> Generator[str, None, None]:
		if self._dryRun:
			raise DryRunException()  # XXX: needs a message

		try:
			for line in iter(self._process.stdout.readline, ""):     # FIXME: can it be improved?
				yield line[:-1]
		except Exception as ex:
			raise CLIAbstractionException() from ex     # XXX: need error message
		# finally:
			# self._process.terminate()

	def Terminate(self):
		self._process.terminate()

	@readonly
	def ExitCode(self) -> int:
		if self._process is None:
			raise CLIAbstractionException(f"Process not yet started, thus no exit code.")

		# TODO: check if process is still running

		return self._process.returncode

	# This is TCL specific
	# def ReadUntilBoundary(self, indent=0):
	# 	__indent = "  " * indent
	# 	if self._iterator is None:
	# 		self._iterator = iter(self.GetReader())
	#
	# 	for line in self._iterator:
	# 		print(__indent + line)
	# 		if self._pyIPCMI_BOUNDARY in line:
	# 			break
	# 	self.LogDebug("Quartus II is ready")


@export
class OutputFilteredExecutable(Executable):
	_hasOutput:   bool
	_hasWarnings: bool
	_hasErrors:   bool
	_hasFatals:   bool

	def __init__(self, platform, dryrun, executablePath): #, environment=None, logger=None) -> None:
		super().__init__(platform, dryrun, executablePath)  #, environment=environment, logger=logger)

		self._hasOutput =   False
		self._hasWarnings = False
		self._hasErrors =   False
		self._hasFatals =   False

	@readonly
	def HasWarnings(self):
		"""True if warnings were found while processing the output stream."""
		return self._hasWarnings

	@readonly
	def HasErrors(self):
		"""True if errors were found while processing the output stream."""
		return self._hasErrors

	@readonly
	def HasFatals(self):
		"""True if fatals were found while processing the output stream."""
		return self._hasErrors