# Copyright (C) 2006--2014  Kipp Cannon
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
# Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.


#
# =============================================================================
#
#                                   Preamble
#
# =============================================================================
#


from glue import git_version
from glue.text_progress_bar import ProgressBar
from .. import lsctables


__author__ = "Kipp Cannon <kipp.cannon@ligo.org>"
__version__ = "git id %s" % git_version.id
__date__ = git_version.date


#
# =============================================================================
#
#                                     I/O
#
# =============================================================================
#


def get_time_slide_id(xmldoc, time_slide, create_new = None, superset_ok = False, nonunique_ok = False):
	"""
	Return the time_slide_id corresponding to the offset vector
	described by time_slide, a dictionary of instrument/offset pairs.

	Example:

	>>> get_time_slide_id(xmldoc, {"H1": 0, "L1": 0})
	'time_slide:time_slide_id:10'

	This function is a wrapper around the .get_time_slide_id() method
	of the glue.ligolw.lsctables.TimeSlideTable class.  See the
	documentation for that class for the meaning of the create_new,
	superset_ok and nonunique_ok keyword arguments.

	This function requires the document to contain exactly one
	time_slide table.  If the document does not contain exactly one
	time_slide table then ValueError is raised, unless the optional
	create_new argument is not None.  In that case a new table is
	created.  This effect of the create_new argument is in addition to
	the affects described by the TimeSlideTable class.
	"""
	try:
		tisitable = lsctables.TimeSlideTable.get_table(xmldoc)
	except ValueError:
		# table not found
		if create_new is None:
			raise
		tisitable = lsctables.New(lsctables.TimeSlideTable)
		xmldoc.childNodes[0].appendChild(tisitable)
	# make sure the next_id attribute is correct
	tisitable.sync_next_id()
	# get the id
	return tisitable.get_time_slide_id(time_slide, create_new = create_new, superset_ok = superset_ok, nonunique_ok = nonunique_ok)


#
# =============================================================================
#
#                            Time Slide Comparison
#
# =============================================================================
#


def time_slides_vacuum(time_slides, verbose = False):
	"""
	Given a dictionary mapping time slide IDs to instrument-->offset
	mappings, for example as returned by the as_dict() method of the
	TimeSlideTable class in glue.ligolw.lsctables or by the
	load_time_slides() function in this module, construct and return a
	mapping indicating time slide equivalences.  This can be used to
	delete redundant time slides from a time slide table, and then also
	used via the applyKeyMapping() method of glue.ligolw.table.Table
	instances to update cross references (for example in the
	coinc_event table).

	Example:

	>>> slides = {"time_slide_id:0": {"H1": 0, "H2": 0},
	"time_slide_id:1": {"H1": 10, "H2": 10}, "time_slide_id:2": {"H1":
	0, "H2": 10}}
	>>> time_slides_vacuum(slides)
	{'time_slide_id:1': 'time_slide_id:0'}

	indicating that time_slide_id:1 describes a time slide that is
	equivalent to time_slide_id:0.  The calling code could use this
	information to delete time_slide_id:1 from the time_slide table,
	and replace references to that ID in other tables with references
	to time_slide_id:0.
	"""
	# convert offsets to deltas
	time_slides = dict((time_slide_id, offsetvect.deltas) for time_slide_id, offsetvect in time_slides.items())
	if verbose:
		progressbar = ProgressBar(max = len(time_slides))
	else:
		progressbar = None
	# old --> new mapping
	mapping = {}
	# while there are time slide offset dictionaries remaining
	while time_slides:
		# pick an ID/offset dictionary pair at random
		id1, deltas1 = time_slides.popitem()
		# for every other ID/offset dictionary pair in the time
		# slides
		ids_to_delete = []
		for id2, deltas2 in time_slides.items():
			# if the relative offset dictionaries are
			# equivalent record in the old --> new mapping
			if deltas2 == deltas1:
				mapping[id2] = id1
				ids_to_delete.append(id2)
		for id2 in ids_to_delete:
			time_slides.pop(id2)
		if progressbar is not None:
			progressbar.update(progressbar.max - len(time_slides))
	# done
	del progressbar
	return mapping


def time_slide_list_merge(slides1, slides2):
	"""
	Merges two lists of offset dictionaries into a single list with
	no duplicate (equivalent) time slides.
	"""
	deltas1 = set(frozenset(offsetvect1.deltas.items()) for offsetvect1 in slides1)
	return slides1 + [offsetvect2 for offsetvect2 in slides2 if frozenset(offsetvect2.deltas.items()) not in deltas1]