#!/usr/bin/env python
#
# Script to modify a c.in file
# Chris LeBlanc, Dalhousie University, 2004
#
# Dependencies: Rayinvr, c2v, Python >= 2.3, Bash or similar shell
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU program 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
# program General Public License for more details.
#
# You should have received a copy of the GNU program General Public
# License along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307	USA

import sys
from optparse import OptionParser

usage = """
	Script for manipulation of Rayinvr c.in format velocity files
	(not v.in format, use c2v and v2c to convert between the two).
	This script is useful for moving the depth of a layer, or setting
	all the depth nodes to be used for inversion.  Not currently 
	able to modify the velocity nodes (because these are easy enough
	to modify by hand).
	
	This example adds 1 km to each depth node in layer 4, but leaves 
	the last column as it was originally.  The output is written to 
	c_mod.in by default:
	  c_modify.py --layer 4 --shift 1
	
	Or as short options (with input and output set):
	  c_modify.py -l 4 -s 1 -i c.in -o c_mod.in
	
	Or to set all nodes in layer 4 for inversion:
	  c_modify.py --layer 4 --shift 1 --invert

	Or to set all nodes in layer 4 to have no shift and
	not be inverted (regarless of whether input is set 
	to be inverted or not):
	  c_modify.py --layer 4 --no-invert
"""

def getCmdLineArgs():
	parser = OptionParser()
	parser.add_option("-i", "--input", dest="inFile", \
		help="Specify input file in the Rayinvr 'c.in' format [c.in].", \
		type="string", metavar="INPUT", default="c.in")
	parser.add_option("-o", "--output", dest="outFile", \
		help="Specify output filename (in c.in format) [c_mod.in].", \
		type="string", metavar="OUTPUT", default="c_mod.in")
	parser.add_option("-l", "--layer", dest="layer", \
		help="Layer number to modify, mandatory", \
		type="int", metavar="LAYER", default=0)
	parser.add_option("-s", "--shift", dest="shift", \
		help="Shift to apply to depth values of specified layer.", \
		type="float", metavar="SHIFT", default=0.0)
	parser.add_option("--invert", action="store_true", dest="invert", \
		help="Set all depth nodes to be inverted (number 1 " + \
		"in the last column).  Default is to leave it as is.")
	parser.add_option("--no-invert", action="store_true", dest="noInvert", \
		help="Set all depth nodes to NOT be inverted (number 0 " + \
		"in the last column).  Default is to leave it as is.")
	
	return parser.parse_args()


if __name__ == "__main__":
	# getting the command line options from the parser
	(options,args)= getCmdLineArgs()

	# seeing if the single mandatory option is present
	if not options.layer:
		print "Error: must define a layer to adjust.\n" + \
		"Type 'c_modify.py --help' to see all options available."
		sys.exit(usage)

	velModel = []
	for line in file(options.inFile, "r").readlines():
		velModel.append([line])
	
	adjustedModel = []
	adjustLayer = False
	for line in velModel:
		for text in line:
			fields = text.split()
			
			# evaluating if it is the proper depth layer:
			if (fields[0] == "B") and (fields[1] == str(options.layer)):
				adjustLayer = True
				adjustedModel.append(text)
				continue
			elif (fields[0] == ("B")) and (fields[1] != str(options.layer)):
				adjustLayer = False
			elif (fields[0] == ("V")):
				adjustLayer = False
			
			# if reading the nodes of interest, replace with modified values
			if adjustLayer:
				offset = float(fields[0])
				depth = float(fields[1])
				invert = float(fields[2])
				
				# if the invert option is used, set all nodes to be inverted (1)
				if options.invert:
					invert = 1
				elif options.noInvert:
					invert = 0
				
				adjustedModel.append("%7.2f   %4.2f  %d\n" % (offset, depth + options.shift, invert))
			# otherwise just write out original values (to a new list)
			else:
				adjustedModel.append(text)

	# writing out the file
	outFileObj = open(options.outFile, "w")
	for line in adjustedModel:
		outFileObj.write(line)
	outFileObj.close()