#! /usr/bin/env python

doc="""
 Verify the checksum of the data sets used for a run. The data location is
 retrieved from either a run directory (-r) or a config-run.xml file, which is
 parsed for a specific platform (-p).

 If you do not specify a run directory, a config-run.xml file is
 used to find the data. The following are tried:
  ../classic/config-run.xml (relative to where the script is called)
  ../classic/config-run.xml (relative to where the script is located)

 You can specify the path and/or the filename of the config file. And if you
 do not specify a platform to read it, a list of available platforms is
 printed.

 Examples:

    # uses a rundir
    ece-data-check.py -r /scratch/ms/nl/nm6/ECEARTH-RUNS/Z6Yd 

    # uses a config file
    ece-data-check.py                # print list of available platforms in default config-run.xml
    ece-data-check.py -p cca-intel   # use cca-intel platform info from default config-run.xml
    
"""
from xml.etree import ElementTree, ElementInclude
import xml.sax
from io import StringIO

import hashlib
import re
import os, sys, glob
import argparse

def md5checksum(filepath):
    """Returns MD5 sum of one file"""
    with open(filepath, 'rb') as fh:
        m = hashlib.md5()
        while True:
            data = fh.read(8192)
            if not data:
                break
            m.update(data)
        return m.hexdigest()


def checksumfile(md5file, dataloc, verbose=False):
    """Read MD5 sums from the md5file and check them."""
    
    reg=re.compile(r"([^#]{32}) +(.+)")     # to parse md5 files

    # -- read md5sums
    checksum={}
    with open(md5file, 'r') as fobj:
        for line in fobj:
            ma = reg.match(line)
            if ma: checksum[ma.group(2)]=ma.group(1)

    # -- check the sums
    for k in checksum:
        qf = os.path.join(dataloc, k)
        if os.path.exists(qf):
            current = md5checksum( qf )
            if current == checksum[k]:
                if verbose: print k,": OK"
            else:
                print k,": DIFFER"
        else:
            print k,": MISSING"


def check_ini_data_dir(verb=False, rdir=None, platform='unknown-platform',
                       classic=None, config="config-run.xml"):
    """
    Find INI_DATA_DIR according to RUNDIR or config-run.xml. Verify the MD5
    sums read in the runtime/datacheck directory. 
    """
    
    # -- Dir with the sums files
    sumdir = os.path.dirname(os.path.realpath(__file__))

    # -- Find INI DATA DIR from a link to it in the rundir
    if rdir:
        testfile = os.path.realpath(os.path.join(rdir,'cf_name_table.txt'))
        datadir = testfile.replace('/oasis/cf_name_table.txt','')

    # -- Find INI DATA DIR from classic/config-run.xml
    else:
        # default classic
        if not classic:
            classic = os.path.join(os.path.dirname(sumdir), 'classic')
            if not os.path.exists(classic):
                classic = os.path.join(os.path.dirname(sumdir), 'no-classic-runtime-here')

        cnfg = os.path.join(classic, config)
        os.chdir(os.path.dirname(cnfg))
        #cnfg = os.path.join(classic, config)

        # parse
        parser = xml.sax.make_parser()
        try:
            tree = ElementTree.parse(cnfg)
        except IOError:
            print "*EE* Could not open file:",cnfg
            return 1
        except ElementTree.ParseError, v:
            row, column = v.position
            print "*EE* error on row", row, "column", column, ":", v
            return 1
        except:
            print "*EE* Could not parse XML file:",cnfg
            return 1

        found = False
        platforms=[]
        root = tree.getroot()
        ElementInclude.include(root)
        s = unicode(ElementTree.tostring(root))
        io = StringIO(s)
        parser.parse(io)
        
        for platf in root.findall('Platform'):
            platforms.append( platf.get('name'))
            if platf.get('name') == platform:
                for param in platf.findall('Parameter'):
                    if param.get('name') == "INI_DATA_DIR":
                        datadir=param.find('Value').text
                        found= True
                        break
        if not found:
            print "*EE* parameter 'INI_DATA_DIR' for platform {} not found in {}".format(platform, cnfg)
            print "\nAvailable platforms:\n\t", "\n\t".join(platforms)
            return 1
        
    # -- work
    print "*II* Checking data sets in", datadir
    print "*II* using the checksums from", sumdir
    if not verb: print "*II* Only errors are reported"

    if not os.path.exists(datadir):
        print "*EE* INI DATA DIR '{}' does not exist".format(datadir)
        return 1

    for fname in glob.glob(os.path.join(sumdir,"*.md5")):
        print '\nChecking',fname
        checksumfile(fname, datadir, verbose=verb)


if __name__ == "__main__":

    # Use ../classic dir if exists as default (path relative to where the script is called!) 
    cwd = os.getcwd()
    classic = os.path.join(os.path.dirname(cwd), 'classic')
    if not os.path.exists(classic):
        classic = None
    
    # options
    parser = argparse.ArgumentParser(description=doc, formatter_class=argparse.RawTextHelpFormatter)
    parser.add_argument("-v", "--verbose",  help="print OK for each successfully verified file", action="store_true")
    parser.add_argument("-r", "--rundir",   help="run dir (takes precedence over xml)",       metavar='DIR')
    parser.add_argument("-p", "--platform", help="platform to use when reading the config ",  metavar='PLATFORM', )
    parser.add_argument("-c", "--classic",  help="runtime/classic dir (default: ../classic)", metavar='CLASSIC', default=classic)
    parser.add_argument("-x", "--xml",      help="config file used (default: config-run.xml)",                   default='config-run.xml')

    args=parser.parse_args()

    sys.exit( check_ini_data_dir(verb=args.verbose, rdir=args.rundir, platform=args.platform, classic=args.classic, config=args.xml) )