#!/usr/bin/python
# -*- coding: utf-8 -*-
"""
Created on Sat Dec  1 10:04:12 2012

@author: bob02
"""

import codecs
import csv
import argparse
import glob
import json
import os

FileNamePattern = 'gnucash2.4.*.json'
CsvHdrLine = ["['downloads']", 'Date']

class RelStatObj(object):
    """
    Release Stats Object
    """
    def __init__(self, pathname, monthCntList):
        """
        Initialize a Release Stats Object
        
        @param self:  instance to initialize
        @param pathname:  Pathname of the json file containing the stats.
        @param monthCntList:  The month, count list
        """

        _, filename = os.path.split(pathname)
        params = filename[len('gnucash'):]
        partsList = params.split('.')
        major, minor, bf, _ = partsList
        self.major = int(major)
        self.minor = int(minor)
        self.bf = int(bf)
        monthCntList.sort()
        self.monthCntList = monthCntList
        
        
def cmdLineHandler():
    """
    Command Line Handler
    
    @param return:  Instance of class argparse.Namespace containing all the parsed command line arguments.
    """

    parser = argparse.ArgumentParser(description="GnuCash Stats for Cristian Marchi", 
                                     usage='%(prog)s [options] jsonPath csvOpath')
    parser.add_argument('jsonPath', help='Pathname of the directory containing all the '
            'json files containing stats.')
    parser.add_argument('csvOpath', help='Pathname of csv file to create')
    args = parser.parse_args()
    return args

"""
http://docs.python.org/2/library/csv.html#examples

The csv module doesn’t directly support reading and writing Unicode, 
but it is 8-bit-clean save for some problems with ASCII NUL characters. 
So you can write functions or classes that handle the encoding and decoding
for you as long as you avoid encodings like UTF-16 that use NULs.
UTF-8 is recommended.

"""

def main():
    """
    Function executed when this file is executed.
    This function is NOT executed when this module is imported.
    """

    args = cmdLineHandler()
    pathNamePattern = os.path.join(args.jsonPath, FileNamePattern)
    globx = glob.glob(pathNamePattern)
    relStatObjList = list()
    for pathName in globx:
        jsonFD = codecs.open(pathName, 'r', encoding='UTF-8')
        try:
            jsonTree = json.load(jsonFD)
        except Exception as exception:
           raise type(exception)('File: {0} - {1}'.format(pathName, exception.message))
        finally:
            jsonFD.close()
        relStatObjList.append(RelStatObj(pathName, jsonTree['downloads']))
    
    # Sort into ascending major, then ascending minor, then ascending bf.    
    relStatObjList.sort(key=lambda x: x.bf)
    relStatObjList.sort(key=lambda x: x.minor)
    relStatObjList.sort(key=lambda x: x.major)

    # Calculate the header line and the column for each json file.
    for rso in relStatObjList:
        CsvHdrLine.append('GnuCash {0}.{1}.{2}'.format(rso.major, rso.minor, rso.bf))
    
    # Allow the files to contain different sets of dates.
    dateSet = set()
    for rso in relStatObjList:
        dateSet = dateSet | set([mcl[0] for mcl in rso.monthCntList])
    dateList = list(dateSet)
    dateList.sort()

    # Set the dates column
    outList = [CsvHdrLine]
    for datx in dateList:
        outList.append([None, datx])

    # Set the counts Columns
    for rso in relStatObjList:
        mcl = rso.monthCntList
        idxMcl = 0
        for idx1, datx in enumerate(dateList):
            linex = outList[1 + idx1]
            if datx == mcl[idxMcl][0]:
                linex.append(mcl[idxMcl][1])
                idxMcl = idxMcl + 1
            else:
                linex.append(None)

    csvFD = open(args.csvOpath, 'w')
    csvWriter = csv.writer(csvFD, dialect='excel')
    csvWriter.writerows(outList)
    csvFD.close()
            
if __name__ == "__main__":
    main()