# remote.py
# Copyright (C) 2008, 2009 Michael Trier (mtrier@gmail.com) and contributors
#
# This module is part of GitPython and is released under
# the BSD License: http://www.opensource.org/licenses/bsd-license.php
"""
Module implementing a remote object allowing easy access to git remotes
"""

from git.utils import LazyMixin, Iterable, IterableList
from objects import Commit
from refs import Reference, RemoteReference, SymbolicReference, TagReference
import re
import os

class _SectionConstraint(object):
	"""
	Constrains a ConfigParser to only option commands which are constrained to 
	always use the section we have been initialized with.
	
	It supports all ConfigParser methods that operate on an option
	"""
	__slots__ = ("_config", "_section_name")
	_valid_attrs_ = ("get", "set", "getint", "getfloat", "getboolean", "has_option")
	
	def __init__(self, config, section):
		self._config = config
		self._section_name = section
		
	def __getattr__(self, attr):
		if attr in self._valid_attrs_:
			return lambda *args: self._call_config(attr, *args)
		return super(_SectionConstraint,self).__getattribute__(attr)
		
	def _call_config(self, method, *args):
		"""Call the configuration at the given method which must take a section name 
		as first argument"""
		return getattr(self._config, method)(self._section_name, *args)
		
		
class FetchInfo(object):
	"""
	Carries information about the results of a fetch operation::
	
	 info = remote.fetch()[0]
	 info.ref			# Symbolic Reference or RemoteReference to the changed 
						# remote head or FETCH_HEAD
	 info.flags 		# additional flags to be & with enumeration members, 
						# i.e. info.flags & info.REJECTED 
						# is 0 if ref is SymbolicReference
	 info.note			# additional notes given by git-fetch intended for the user
	 info.commit_before_forced_update	# if info.flags & info.FORCED_UPDATE, 
						# field is set to the previous location of ref, otherwise None
	"""
	__slots__ = ('ref','commit_before_forced_update', 'flags', 'note')
	
	BRANCH_UPTODATE, REJECTED, FORCED_UPDATE, FAST_FORWARD, NEW_TAG, \
	TAG_UPDATE, NEW_BRANCH, ERROR = [ 1 << x for x in range(1,9) ]
	#                             %c    %-*s %-*s             -> %s       (%s)
	re_fetch_result = re.compile("^\s*(.) (\[?[\w\s\.]+\]?)\s+(.+) -> ([/\w_\.-]+)(  \(.*\)?$)?")
	
	_flag_map = { 	'!' : ERROR, '+' : FORCED_UPDATE, '-' : TAG_UPDATE, '*' : 0,
					'=' : BRANCH_UPTODATE, ' ' : FAST_FORWARD } 
	
	def __init__(self, ref, flags, note = '', old_commit = None):
		"""
		Initialize a new instance
		"""
		self.ref = ref
		self.flags = flags
		self.note = note
		self.commit_before_forced_update = old_commit
		
	def __str__(self):
		return self.name
		
	@property
	def name(self):
		"""
		Returns
			Name of our remote ref
		"""
		return self.ref.name
		
	@property
	def commit(self):
		"""
		Returns
			Commit of our remote ref
		"""
		return self.ref.commit
		
	@classmethod
	def _from_line(cls, repo, line, fetch_line):
		"""
		Parse information from the given line as returned by git-fetch -v
		and return a new FetchInfo object representing this information.
		
		We can handle a line as follows
		"%c %-*s %-*s -> %s%s"
		
		Where c is either ' ', !, +, -, *, or =
		! means error
		+ means success forcing update
		- means a tag was updated
		* means birth of new branch or tag
		= means the head was up to date ( and not moved )
		' ' means a fast-forward
		
		fetch line is the corresponding line from FETCH_HEAD, like
		acb0fa8b94ef421ad60c8507b634759a472cd56c	not-for-merge	branch '0.1.7RC' of /tmp/tmpya0vairemote_repo
		"""
		match = cls.re_fetch_result.match(line)
		if match is None:
			raise ValueError("Failed to parse line: %r" % line)
			
		# parse lines
		control_character, operation, local_remote_ref, remote_local_ref, note = match.groups()
		try:
			new_hex_sha, fetch_operation, fetch_note = fetch_line.split("\t")
			ref_type_name, fetch_note = fetch_note.split(' ', 1)
		except ValueError:	# unpack error
			raise ValueError("Failed to parse FETCH__HEAD line: %r" % fetch_line)
		
		# handle FETCH_HEAD and figure out ref type
		# If we do not specify a target branch like master:refs/remotes/origin/master, 
		# the fetch result is stored in FETCH_HEAD which destroys the rule we usually
		# have. In that case we use a symbolic reference which is detached 
		ref_type = None
		if remote_local_ref == "FETCH_HEAD":
			ref_type = SymbolicReference
		elif ref_type_name  == "branch":
			ref_type = RemoteReference
		elif ref_type_name == "tag":
			ref_type = TagReference
		else:
			raise TypeError("Cannot handle reference type: %r" % ref_type_name)
			
		# create ref instance
		if ref_type is SymbolicReference:
			remote_local_ref = ref_type(repo, "FETCH_HEAD") 
		else:
			remote_local_ref = Reference.from_path(repo, os.path.join(ref_type._common_path_default, remote_local_ref.strip()))
		# END create ref instance 
		
		note = ( note and note.strip() ) or ''
		
		# parse flags from control_character
		flags = 0
		try:
			flags |= cls._flag_map[control_character]
		except KeyError:
			raise ValueError("Control character %r unknown as parsed from line %r" % (control_character, line))
		# END control char exception hanlding 
		
		# parse operation string for more info - makes no sense for symbolic refs
		old_commit = None
		if isinstance(remote_local_ref, Reference):
			if 'rejected' in operation:
				flags |= cls.REJECTED
			if 'new tag' in operation:
				flags |= cls.NEW_TAG
			if 'new branch' in operation:
				flags |= cls.NEW_BRANCH
			if '...' in operation:
				old_commit = Commit(repo, operation.split('...')[0])
			# END handle refspec
		# END reference flag handling
		
		return cls(remote_local_ref, flags, note, old_commit)
	

class Remote(LazyMixin, Iterable):
	"""
	Provides easy read and write access to a git remote.
	
	Everything not part of this interface is considered an option for the current 
	remote, allowing constructs like remote.pushurl to query the pushurl.
	
	NOTE: When querying configuration, the configuration accessor will be cached
	to speed up subsequent accesses.
	"""
	
	__slots__ = ( "repo", "name", "_config_reader" )
	_id_attribute_ = "name"
	
	def __init__(self, repo, name):
		"""
		Initialize a remote instance
		
		``repo``
			The repository we are a remote of
			
		``name``
			the name of the remote, i.e. 'origin'
		"""
		self.repo = repo
		self.name = name
		
	def __getattr__(self, attr):
		"""
		Allows to call this instance like 
		remote.special( *args, **kwargs) to call git-remote special self.name
		"""
		if attr == "_config_reader":
			return super(Remote, self).__getattr__(attr)
		
		return self._config_reader.get(attr)
	
	def _config_section_name(self):
		return 'remote "%s"' % self.name
	
	def _set_cache_(self, attr):
		if attr == "_config_reader":
			self._config_reader = _SectionConstraint(self.repo.config_reader(), self._config_section_name())
		else:
			super(Remote, self)._set_cache_(attr)
			
	
	def __str__(self):
		return self.name 
	
	def __repr__(self):
		return '<git.%s "%s">' % (self.__class__.__name__, self.name)
		
	def __eq__(self, other):
		return self.name == other.name
		
	def __ne__(self, other):
		return not ( self == other )
		
	def __hash__(self):
		return hash(self.name)
	
	@classmethod
	def iter_items(cls, repo):
		"""
		Returns
			Iterator yielding Remote objects of the given repository
		"""
		# parse them using refs, as their query can be faster as it is 
		# purely based on the file system
		seen_remotes = set()
		for ref in RemoteReference.iter_items(repo):
			remote_name = ref.remote_name
			if remote_name in seen_remotes:
				continue
			# END if remote done already
			seen_remotes.add(remote_name)
			yield Remote(repo, remote_name)
		# END for each ref
		
	@property
	def refs(self):
		"""
		Returns
			IterableList of RemoteReference objects. It is prefixed, allowing 
			you to omit the remote path portion, i.e.::
			 remote.refs.master # yields RemoteReference('/refs/remotes/origin/master')
		"""
		out_refs = IterableList(RemoteReference._id_attribute_, "%s/" % self.name)
		for ref in RemoteReference.list_items(self.repo):
			if ref.remote_name == self.name:
				out_refs.append(ref)
			# END if names match
		# END for each ref
		assert out_refs, "Remote %s did not have any references" % self.name
		return out_refs
		
	@property
	def stale_refs(self):
		"""
		Returns 
			IterableList RemoteReference objects that do not have a corresponding 
			head in the remote reference anymore as they have been deleted on the 
			remote side, but are still available locally.
			
			The IterableList is prefixed, hence the 'origin' must be omitted. See
			'refs' property for an example.
		"""
		out_refs = IterableList(RemoteReference._id_attribute_, "%s/" % self.name)
		for line in self.repo.git.remote("prune", "--dry-run", self).splitlines()[2:]:
			# expecting 
			# * [would prune] origin/new_branch
			token = " * [would prune] " 
			if not line.startswith(token):
				raise ValueError("Could not parse git-remote prune result: %r" % line)
			fqhn = "%s/%s" % (RemoteReference._common_path_default,line.replace(token, ""))
			out_refs.append(RemoteReference(self.repo, fqhn))
		# END for each line 
		return out_refs
	
	@classmethod
	def create(cls, repo, name, url, **kwargs):
		"""
		Create a new remote to the given repository
		``repo``
			Repository instance that is to receive the new remote
		
		``name``
			Desired name of the remote
		
		``url``
			URL which corresponds to the remote's name
			
		``**kwargs``
			Additional arguments to be passed to the git-remote add command
			
		Returns
			New Remote instance
			
		Raise
			GitCommandError in case an origin with that name already exists
		"""
		repo.git.remote( "add", name, url, **kwargs )
		return cls(repo, name)
	
	# add is an alias
	add = create
	
	@classmethod
	def remove(cls, repo, name ):
		"""
		Remove the remote with the given name
		"""
		repo.git.remote("rm", name)
		
	# alias
	rm = remove
		
	def rename(self, new_name):
		"""
		Rename self to the given new_name
		
		Returns
			self
		"""
		if self.name == new_name:
			return self
		
		self.repo.git.remote("rename", self.name, new_name)
		self.name = new_name
		del(self._config_reader)		# it contains cached values, section names are different now
		return self
		
	def update(self, **kwargs):
		"""
		Fetch all changes for this remote, including new branches which will 
		be forced in ( in case your local remote branch is not part the new remote branches
		ancestry anymore ).
		
		``kwargs``
			Additional arguments passed to git-remote update
		
		Returns
			self
		"""
		self.repo.git.remote("update", self.name)
		return self
	
	def _get_fetch_info_from_stderr(self, stderr):
		# skip first line as it is some remote info we are not interested in
		output = IterableList('name')
		err_info = stderr.splitlines()[1:]
		
		# read head information 
		fp = open(os.path.join(self.repo.path, 'FETCH_HEAD'),'r')
		fetch_head_info = fp.readlines()
		fp.close()
		
		output.extend(FetchInfo._from_line(self.repo, err_line, fetch_line) 
						for err_line,fetch_line in zip(err_info, fetch_head_info))
		return output
	
	def fetch(self, refspec=None, **kwargs):
		"""
		Fetch the latest changes for this remote
		
		``refspec``
			A "refspec" is used by fetch and push to describe the mapping 
			between remote ref and local ref. They are combined with a colon in 
			the format <src>:<dst>, preceded by an optional plus sign, +. 
			For example: git fetch $URL refs/heads/master:refs/heads/origin means 
			"grab the master branch head from the $URL and store it as my origin 
			branch head". And git push $URL refs/heads/master:refs/heads/to-upstream 
			means "publish my master branch head as to-upstream branch at $URL". 
			See also git-push(1).
			
			Taken from the git manual
		
		``**kwargs``
			Additional arguments to be passed to git-fetch
			
		Returns
			IterableList(FetchInfo, ...) list of FetchInfo instances providing detailed 
			information about the fetch results
		"""
		status, stdout, stderr = self.repo.git.fetch(self, refspec, with_extended_output=True, v=True, **kwargs)
		return self._get_fetch_info_from_stderr(stderr)
		
	def pull(self, refspec=None, **kwargs):
		"""
		Pull changes from the given branch, being the same as a fetch followed 
		by a merge of branch with your local branch.
		
		``refspec``
			see 'fetch' method
		
		``**kwargs``
			Additional arguments to be passed to git-pull
			
		Returns
			Please see 'fetch' method
		"""
		status, stdout, stderr = self.repo.git.pull(self, refspec, v=True, with_extended_output=True, **kwargs)
		return self._get_fetch_info_from_stderr(stderr)
		
	def push(self, refspec=None, **kwargs):
		"""
		Push changes from source branch in refspec to target branch in refspec.
		
		``refspec``
			see 'fetch' method
		
		``**kwargs``
			Additional arguments to be passed to git-push
			
		Returns
			IterableList(PushInfo, ...) iterable list of PushInfo instances, each 
			one informing about an individual head which had been updated on the remote 
			side
		"""
		proc = self.repo.git.push(self, refspec, porcelain=True, as_process=True, **kwargs)
		print "stdout"*10
		print proc.stdout.read()
		print "stderr"*10
		print proc.stderr.read()
		proc.wait()
		return self
		
	@property
	def config_reader(self):
		"""
		Returns
			GitConfigParser compatible object able to read options for only our remote.
			Hence you may simple type config.get("pushurl") to obtain the information
		"""
		return self._config_reader
	
	@property
	def config_writer(self):
		"""
		Return
			GitConfigParser compatible object able to write options for this remote.
			
		Note
			You can only own one writer at a time - delete it to release the 
			configuration file and make it useable by others.
			
			To assure consistent results, you should only query options through the 
			writer. Once you are done writing, you are free to use the config reader 
			once again.
		"""
		writer = self.repo.config_writer()
		
		# clear our cache to assure we re-read the possibly changed configuration
		del(self._config_reader)
		return _SectionConstraint(writer, self._config_section_name())