from libc.stdint cimport uint64_t
from libcpp.map cimport map
from libcpp.set cimport set
from libcpp.string cimport string

ctypedef uint64_t index
ctypedef index node

from .graph cimport _Graph, Graph

def stdstring(pystring):
	""" convert a Python string to a bytes object which is automatically coerced to std::string"""
	pybytes = pystring.encode("utf-8")
	return pybytes

cdef extern from "<networkit/scd/PageRankNibble.hpp>":

	cdef cppclass _PageRankNibble "NetworKit::PageRankNibble":
		_PageRankNibble(_Graph G, double alpha, double epsilon) except +
		map[node, set[node]] run(set[node] seeds) except +

cdef class PageRankNibble:
	"""
	Produces a cut around a given seed node using the PageRank-Nibble algorithm.
	see Andersen, Chung, Lang: Local Graph Partitioning using PageRank Vectors

	Parameters:
	-----------
	G : networkit.Graph in which the cut is to be produced, must be unweighted.
	alpha : Loop probability of random walk; smaller values tend to produce larger communities.
	epsilon: Tolerance threshold for approximation of PageRank vectors
	"""
	cdef _PageRankNibble *_this
	cdef Graph _G

	def __cinit__(self, Graph G, double alpha, double epsilon):
		self._G = G
		self._this = new _PageRankNibble(G._this, alpha, epsilon)

	def run(self, set[node] seeds):
		"""
		Produces a cut around a given seed node.

		Parameters:
		-----------
		seeds : the seed node ids.
		"""
		return self._this.run(seeds)

cdef extern from "<networkit/scd/GCE.hpp>":

	cdef cppclass _GCE "NetworKit::GCE":
		_GCE(_Graph G, string quality) except +
		map[node, set[node]] run(set[node] seeds) except +

cdef class GCE:
	"""
	Produces a cut around a given seed node using the GCE algorithm.

	Parameters:
	-----------
	G : networkit.Graph in which the cut is to be produced, must be unweighted.
	"""
	cdef _GCE *_this
	cdef Graph _G

	def __cinit__(self, Graph G, quality):
		self._G = G
		self._this = new _GCE(G._this, stdstring(quality))

	def run(self, set[node] seeds):
		"""
		Produces a cut around a given seed node.

		Parameters:
		-----------
		seeds : the seed node ids.
		"""
		return self._this.run(seeds)