#!/usr/bin/python
# simple script to take a v2d file and update the clock so that the reference
# date is the requested mjd (i.e. forward the rate from the given date to the
# requested date). The parser is a bit shoddy but will work for our usual files
# Cormac Reynolds: June 2010

import sys, re, optparse, os, mx.DateTime, math

separator = '/'

def parseparam(param, line, delimiter='\S+'):
    line = line.strip(';')
    delimiter = r'\s*=\s*(' + delimiter + ')'
    value = re.search(param + delimiter, line).group(1)
    return value

# program starts here

#parse the options
usage = '''%prog <site_id> <dbname> <expname.vex>
adjusts the position of <site_id> in <expname.vex> to be that of <dbname> in
$STADB'''

parser = optparse.OptionParser(usage=usage, version='%prog ' + '1.0')

(options, args) = parser.parse_args()
if len(args) != 3:
    parser.print_help()
    parser.error("3 arguments required")

vexfilename = args[2]
vexfile = open(vexfilename).readlines()
vexfile = [ vexfile[i].strip('\n') for i in range(len(vexfile)) ]
vexfile = [ vexfile[i].rstrip() for i in range(len(vexfile)) ]

station = args[0].upper()
pad_id = args[1].upper()


# read in the station db
stapath = os.getenv('STADB') 
stadb = open(stapath).readlines()

padfound = False
cache = str()
for line in stadb:
    line = re.sub('!.*', '', line)
    cache += line.upper()

    if separator in line:
        paragraph = cache
        cache = str()
        pad =  parseparam('DBNAME', paragraph) 

        if pad_id.upper() in pad:
            padfound = True
            pad_x = parseparam('X', paragraph)
            pad_y = parseparam('Y', paragraph)
            pad_z = parseparam('Z', paragraph)
            pad_dx = parseparam('DXDT', paragraph)
            pad_dy = parseparam('DYDT', paragraph)
            pad_dz = parseparam('DZDT', paragraph)
            pad_epoch = parseparam('EPOCH', paragraph)
            pad_frame = parseparam('FRAME', paragraph, "'.*'")

            break
    
if not padfound:
    raise Exception(pad_id + " not found in " + stapath)



# now process the vex file
siteblock = False
site_name = str()
site_id = str()
vexout = []
cache = []
comment = []
rate_adjust = float()
offset_adjust = float()
updatesite = False
sitefound = False
for line in vexfile:
    flushcache = True
    # extract the comments so we can put them back later
    try:
        comment.append(re.search(r'\*.*', line).group(0))
    except:
        comment.append('')

    # remove the comments so we can parse the line. Store the original line in
    # a cache so we can update it at the end of the v2d section if necessary
    line = re.sub('\*.*', '', line)
    cache.append(line)

    # find the site block
    if '$SITE' in line:
        siteblock = True
    # we leave the site block when we find the next block
    elif siteblock and '$' in line:
        siteblock = False

    # find the various names
    if siteblock:
        flushcache = False
        if re.match(r'\bdef\b', line):
            defname = re.search(r'def\s+(\w+)', line).group(1)
        if re.search(r'\bsite_name\b', line):
            site_name = parseparam(r'site_name', line).upper()
        if re.search(r'\bsite_ID\b', line):
            site_id = parseparam(r'site_ID', line).upper()

        # if the sitename or site_id matches the request, get ready to update
        # this def
        if site_name and site_id:
            if site_name == station or site_id == station:
                updatesite = True
                foundsite = True

        # at the end of the def, check if it's the station we're interested in.
        # Update the cached lines if we are.
        if 'enddef' in line:
            flushcache = True
            site_name = str()
            site_id = str()
            defname = str()
            if updatesite:
                updatesite = False
                for i in range(len(cache)):
                    if 'site_position' in cache[i]:
                        cache[i] = '*' + cache[i]
                    if 'site_velocity' in cache[i]:
                        cache[i] = '*' + cache[i]
                    if 'site_position_epoch' in cache[i]:
                        cache[i] = '*' + cache[i]

                indent = " " *5
                sitepos = indent + 'site_position = ' 
                for (pos, delim) in zip ((pad_x, pad_y, pad_z), (':',':',';')):
                    sitepos += ' ' + pos + ' m' + delim

                sitevel = indent + 'site_velocity = ' 
                for (vel, delim) in zip ((pad_dx, pad_dy, pad_dz), (':',':',';')):
                    sitevel += ' ' + vel + ' m/yr' + delim

                epoch = indent + 'site_position_epoch = ' 
                epoch += pad_epoch + ';'

                sitecomment = '* Added position of ' + pad_id + ' from ' + stapath
                cache.insert(-1, sitecomment)
                cache.insert(-1, '* ' + pad_frame)
                cache.insert(-1, sitepos)
                cache.insert(-1, sitevel)
                cache.insert(-1, epoch)
        
    # write the new telescope information to the output array
    if flushcache:
        for i in range(len(cache)):
            try:
                cache[i] += comment[i]
            except:
                pass
        vexout += cache
        cache = []
        comment = []

if not foundsite:
    raise Exception(station + " not found in " + vexfilename)

# save a copy of the original before overwriting
os.rename(vexfilename, vexfilename + '.bak')
OUTVEXFILE = open(vexfilename, 'w')

# print the output
for out_line in vexout:
    print>>OUTVEXFILE, out_line

OUTVEXFILE.close()