import os.path

import git
from git import Repo
from git.exc import NoSuchPathError, InvalidGitRepositoryError, GitCommandError
from git import RemoteProgress
import logging
import time
from typing import Union, Optional
from repo_cloner.lib.checksum import gen_repo_hashed_name
from io import BytesIO

log = logging.getLogger("rc.repo")


class GitRemoteProgress(RemoteProgress):
	OP_CODES = [
		"BEGIN",
		"CHECKING_OUT",
		"COMPRESSING",
		"COUNTING",
		"END",
		"FINDING_SOURCES",
		"RECEIVING",
		"RESOLVING",
		"WRITING",
	]
	OP_CODE_MAP = {
		getattr(RemoteProgress, _op_code): _op_code for _op_code in OP_CODES
	}

	last_step_time = time.time()
	time_thr = 0.5

	cur_task: str = ""
	cur_task_max: int = 0

	def __init__(self) -> None:
		super().__init__()
		self.last_step_time = time.time() - self.time_thr
		self.cur_task_max = 0
		self.cur_task = ""

	def __del__(self) -> None:
		self.finish()

	@classmethod
	def get_curr_op(cls, op_code: int) -> str:
		"""Get OP name from OP code."""
		# Remove BEGIN- and END-flag and get op name
		op_code_masked = op_code & cls.OP_MASK
		return cls.OP_CODE_MAP.get(op_code_masked, "?").title()

	def finish(self):
		log.info(f"GIT {self.cur_task}: 100.00% ({self.cur_task_max})")

	def update(
			self,
			op_code: int,
			cur_count: Union[float, str],
			max_count: Union[float, str, None] = None,
			message: Optional[str] = "",
	) -> None:
		# Do i need to update?
		# -> begin : YES
		# -> end : YES
		# -> timer: YES

		# so check timer
		if (self.last_step_time + self.time_thr) > time.time():
			# timer not passed yet		repo.head.reset(commit = 'origin/master', index = True, working_tree = True)
			if not ((op_code & self.BEGIN) or (op_code & self.BEGIN)):
				# skip -> no begin or end
				return
		# update timer
		self.last_step_time = time.time()

		# Start new bar on each BEGIN-flag
		if op_code & self.BEGIN:
			self.cur_task = self.get_curr_op(op_code).upper()
			try:
				self.cur_task_max = int(max_count)
			except ValueError:
				self.cur_task_max = 100

			log.info(f"GIT {self.cur_task} started")

		percent = round(100 * (cur_count / self.cur_task_max), 2)

		# End progress monitoring on each END-flag
		if op_code & self.END:
			# logger.info("Done: %s", self.curr_op)
			percent = 100

		log.info(f"GIT {self.cur_task}: {percent}% ({cur_count}; {message})")


class RepoTool:
	_repo: Repo = None
	_initialized: bool = False
	_bare: bool = False
	_path: str = ""
	_last_fetch_data = []
	_recursive_discovery_urls: set = set()
	_recursive_discovery_cloned: set = set()
	_submodule_discovery_history: list = []

	def __init__(self, path: str):
		log.info(f"Initializing repository at {path}")
		self._path = str(path)
		self._recursive_discovery_cloned = set()
		self._recursive_discovery_urls = set()
		self._submodule_discovery_history: list = []
		try:
			self._repo = Repo(path, expand_vars = False)
			self._initialized = True
			self._bare = self._repo.bare

		except (NoSuchPathError, InvalidGitRepositoryError) as e:
			log.warning(f"Init failed: {str(e)}, continuing with uninitialized repo")
			self._initialized = False
			self._bare = False

	@property
	def initialized(self) -> bool:
		return self._initialized

	@property
	def bare(self) -> bool:
		return self._bare

	@property
	def path(self) -> str:
		return self._path

	@property
	def cloned_submodules_url_list(self) -> list:
		return list(self._recursive_discovery_cloned)

	@property
	def discovered_submodules_commits(self) -> list:
		return self._submodule_discovery_history

	def _persist_submodule_commits(self, path: str):
		with open(path, "w") as f:
			for commit in self.discovered_submodules_commits:
				line = f"{commit}\n"
				f.write(line)

	def __check_initialized(self):
		def inner(*args):
			fake_self: RepoTool = args[0]
			if not fake_self._initialized:
				log.critical(f"Repo {fake_self.path} is not initialized!")
				return False
			return self(*args)

		return inner

	def clone(self, url: str) -> bool:
		if self._initialized:
			log.warning(f"Trying to clone to initialized repository!")
			return False

		log.info(f"Cloning repository from url: {url}")
		try:
			self._repo = Repo.clone_from(
				url,
				to_path = self._path,
				progress = GitRemoteProgress(),
				bare = True,
				mirror = True
			)
		except GitCommandError as e:
			log.critical(f"Clone of {url} failed!")
			log.critical(f"Exception: {e}")
			self._initialized = False
			return False

		self._initialized = True
		self._bare = self._repo.bare

		return True

	@__check_initialized
	def fetch(self) -> bool:
		log.info("Fetching repo :)")
		if not len(self._repo.remotes):
			log.warning(f"Repo: {self._path} does not contain any remotes!")
			return False
		# fetch all remotes
		remote = self._repo.remotes[0]
		log.debug(f"Fetching remote: {remote.name} url: {next(remote.urls)}")
		self._last_fetch_data = remote.fetch(
			["+refs/heads/*:refs/heads/*", "+refs/tags/*:refs/tags/*"],
			progress = GitRemoteProgress(),
			kill_after_timeout = 60,
			prune = True
		)
		log.debug("Fetch finished!")
		return True

	@__check_initialized
	def repo_fingerprint(self) -> Union[str, bool]:
		log.debug("Getting repo fingerprint")
		# reference count
		ref_count = self._repo.git.rev_list(count = True, all = True)
		tags = [f"{tag.name}/{tag.commit}" for tag in self._repo.tags]
		branches = [f"{branch.name}/{branch.commit}" for branch in self._repo.branches]
		log.debug(f"{ref_count} references, {len(tags)} tags,  {len(branches)} branches")
		cumulative = f"{ref_count} {'.'.join(tags)} {' '.join(branches)}".encode()
		import hashlib
		x = hashlib.sha256(cumulative).hexdigest()
		log.debug(f"Repo fingerprint is {x}")
		return x

	@__check_initialized
	def list_commits(self, max_depth: Optional[int] = None):
		return self._repo.iter_commits(all = True, max_count = max_depth, reverse = True)

	@__check_initialized
	def list_branches(self) -> Union[dict, bool]:
		log.debug(f"Listing branches of repo")
		branches = {}
		for branch in self._repo.branches:
			branches[branch.name] = branch.commit.hexsha
		log.debug(f"Found {len(branches)}")
		return branches

	@__check_initialized
	def list_tags(self):
		log.debug(f"Listing tags of repo")
		tags = {}
		for tag in self._repo.tags:
			tags[tag.name] = tag.commit.hexsha
		log.debug(f"Found {len(tags)} tags")
		return tags

	@__check_initialized
	def list_submodules(self, commit: str = "HEAD") -> Union[list, bool]:
		commit = self._repo.commit(commit)
		submodules = []

		if '.gitmodules' in commit.tree:
			git_modules: git.Blob = commit.tree['.gitmodules']
			x = BytesIO(git_modules.data_stream.read())
			x.name = git_modules.name

			try:
				parser = git.GitConfigParser(x, read_only = True)
				for section in parser.sections():
					if parser.has_option(section, "url"):
						submodules.append(parser.get_value(section, "url"))
			except BaseException:
				return False

		if commit.hexsha not in self._submodule_discovery_history:
			self._submodule_discovery_history.append(commit.hexsha)

		return submodules

	@__check_initialized
	def list_submodules_history(self, limit_of_commits: Optional[int] = None) -> Union[list, bool]:

		log.info(f"Listing repository submodule history")
		iterator = self.list_commits(limit_of_commits)
		submodules = set()
		counter: int = 0
		last_status = time.time()
		status_offset = 0.5
		for commit in iterator:
			counter += 1
			commit_submodules = self.list_submodules(commit)
			if not type(commit_submodules) == bool:
				submodules.update(commit_submodules)
			if time.time() >= last_status + status_offset:
				log.info(f"Submodule discovery: {counter} commits finished, {len(submodules)} discovered")
				last_status = time.time()
		return list(submodules)

	def clone_recursive(
			self,
			main_url: str,
			scan_cache_dir: Optional[str] = None,
			scan_depth: Optional[int] = None
	) -> bool:

		log.info(f"Started recursive clone of {main_url} with recursive discovery limited to {scan_depth} commits")
		# clone main repo
		if not self.clone(main_url):
			log.critical(f"Clone of main repository failed!")
			return False

		# discover submodules for repository
		submodules = self.list_submodules_history(scan_depth)
		if submodules:
			for submodule in submodules:
				self._recursive_discovery_urls.add(submodule)

		everything_succeed: bool = True
		everything_cloned: bool = False
		while not everything_cloned:
			# recursively scan and clone repositories
			everything_cloned = True
			# for every url in list
			# list() is needed - Runtime Error for set() changed during iteration
			for url in list(self._recursive_discovery_urls):
				if url not in self._recursive_discovery_cloned:
					everything_cloned = False
					# generate new path
					directory = os.path.dirname(self.path)
					submodule_cloner = RepoTool(os.path.join(directory, gen_repo_hashed_name(url)))
					# clone
					cloned: bool = submodule_cloner.clone(url)
					# mark cloned even if failed afterwards - while loop stuck solution
					self._recursive_discovery_cloned.add(url)
					if not cloned:
						log.critical(f"Clone of submodule: {url} failed")
						everything_succeed = False
						continue
					# scan for submodules
					submodules = submodule_cloner.list_submodules_history(scan_depth)
					if type(submodules) == bool and not submodules:
						log.critical(f"Submodule discovery for {url} failed!")
						everything_succeed = False
						continue

					# persistor
					if scan_cache_dir:
						cache_file = os.path.join(scan_cache_dir, gen_repo_hashed_name(url))
						log.debug(
							f"Saving {len(submodule_cloner.discovered_submodules_commits)} commits into {cache_file}")
						submodule_cloner._persist_submodule_commits(cache_file)

					for submodule in submodules:
						self._recursive_discovery_urls.add(submodule)

		if scan_cache_dir:
			# persist main repo commits
			cache_file = os.path.basename(self.path)
			cache_file = os.path.join(scan_cache_dir, cache_file)
			self._persist_submodule_commits(cache_file)

			# persist discovered submodule urls
			with open(os.path.join(scan_cache_dir, "submodules.cache"), "w") as f:
				f.write("\n".join(self.cloned_submodules_url_list))

		return everything_succeed