"""
Convert csv data to a dictionary with namedtuples as values. However, a string
csv-file look-a-like may be used directly. Currently, the latter option is
used.

ToDo:
* Add usage examples!
* Clean up which test to use for which csv file!
* Clean up which transform function to use according to csv file!
* Clean again...
* Deduplication!
"""

# based on: <http://pastebin.com/tnyhmCJz>
# see: <http://stackoverflow.com/q/29141609/1172302>

# real data
AE_STRING = '''Emissivity Class|TIRS10|TIRS11
Cropland|0.971|0.968
Forest|0.995|0.996
Grasslands|0.97|0.971
Shrublands|0.969|0.97
Wetlands|0.992|0.998
Waterbodies|0.992|0.998
Tundra|0.98|0.984
Impervious|0.973|0.981
Barren Land|0.969|0.978
Snow and ice|0.992|0.998'''

CWV_STRING = '''Range|CWV|b0|b1|b2|b3|b4|b5|b6|b7|RMSE
Range 1|(0.0, 2.5)|-2.78009|1.01408|0.15833|-0.34991|4.04487|3.55414|-8.88394|0.09152|0.34
Range 2|(2.0, 3.5)|11.00824|0.95995|0.17243|-0.28852|7.11492|0.42684|-6.62025|-0.06381|0.60
Range 3|(3.0, 4.5)|9.62610|0.96202|0.13834|-0.17262|7.87883|5.17910|-13.26611|-0.07603|0.71
Range 4|(4.0, 5.5)|0.61258|0.99124|0.10051|-0.09664|7.85758|6.86626|-15.00742|-0.01185|0.86
Range 5|(5.0, 6.3)|-0.34808|0.98123|0.05599|-0.03518|11.96444|9.06710|-14.74085|-0.20471|0.93
Range 6|(0.0, 6.3)|-0.41165|1.00522|0.14543|-0.27297|4.06655|-6.92512|-18.27461|0.24468|0.87'''

# required librairies
import sys
import csv
from collections import namedtuple
import random


# helper functions
def set_csvfile():
    """
    Set user defined csvfile, if any
    """
    if len(sys.argv) > 1:
        return sys.argv[1]
    else:
        return False


def is_number(value):
    '''
    Check if input is a number
    '''
    try:
        float(value)  # for int, long and float
    except ValueError:
        try:
            complex(value)  # for complex
        except ValueError:
            return False
    return float(value)

def to_tuple(string):
    """
    Convert string to tuple.
    """
    return tuple(map(float, string[1:-1].split(',')))

def replace_dot_comma_space(string):
    """
    Source: <http://stackoverflow.com/a/9479972/1172302>
    """
    replacements = ('.', ''), (', ', '_'), (',', '_'), (' ', '_'), ('(', ''), (')', ''), ('/', '_')
    return reduce(lambda alpha, omega: alpha.replace(*omega),
                  replacements, string)


def csv_reader(csv_file):
    '''
    Transforms csv from a file into a multiline string. For example,
    the following csv

    --%<---
    Emissivity Class|TIRS10|TIRS11
    Cropland|0.971|0.968
    Forest|0.995|0.996
    Grasslands|0.97|0.971
    Shrublands|0.969|0.97
    Wetlands|0.992|0.998
    Waterbodies|0.992|0.998
    Tundra|0.98|0.984
    Impervious|0.973|0.981
    Barren Land|0.969|0.978
    Snow and ice|0.992|0.998
    --->%--

    will be returned as:

    """Emissivity Class|TIRS10|TIRS11
    Cropland|0.971|0.968
    Forest|0.995|0.996
    Grasslands|0.97|0.971
    Shrublands|0.969|0.97
    Wetlands|0.992|0.998
    Waterbodies|0.992|0.998
    Tundra|0.98|0.984
    Impervious|0.973|0.981
    Barren Land|0.969|0.978
    Snow and ice|0.992|0.998"""
    '''
    with open(csv_file, 'rb') as csvfile:
        csvreader = csv.reader(csvfile, delimiter="|")  # delimiter?
        string = str()
        for row in csvreader:
            string += '\n' + str('|'.join(row))
        string = string.strip('\n')  # remove first newline!
        return string


def csv_to_dictionary(csv):
    '''
    Transform input from "special" csv into a python dictionary with namedtuples
    as values. Note, "strings" of interest are hardcoded!

    Also, fix the re-definition of the function transform(). See
    <http://stackoverflow.com/q/30204197/1172302>
    '''
    # split input in rows
    rows = csv.split('\n')
    dictionary = {}  # empty dictionary
    fields = rows.pop(0).split('|')[1:]  # header

    strings = ('TIRS10', 'TIRS11')
    if any(string in fields for string in strings):

        def transform(row):
            '''
            Transform an input row in to a named tuple, then feed it in to a
            dictionary.
            '''
            # split row in elements
            elements = row.split('|')

            # key: 1st column, replace
            key = replace_dot_comma_space(elements[0])

            # namedtuple
            ect = namedtuple(key, [fields[0], fields[1]])

            # feed namedtuples
            ect.TIRS10 = is_number(elements[1])
            ect.TIRS11 = is_number(elements[2])

            # feed dictionary
            dictionary[key] = dictionary.get(key, ect)

    strings = ('b0', 'b1', 'b2', 'b3', 'b4', 'b5', 'b6', 'b7')
    if any(string in fields for string in strings):

        def transform(row):
            '''
            Transform an input row in to a named tuple, then feed it in to a
            dictionary.
            '''
            # split row in elements
            elements = row.split('|')

            # key: 1st column, replace
            key = replace_dot_comma_space(elements[0])

            # *** small modification for the CWV field ***
            fields[0] = 'cwv'

            # named tuples
            cwv = namedtuple(key,
                             [replace_dot_comma_space(fields[0]),
                              replace_dot_comma_space(fields[1]),
                              replace_dot_comma_space(fields[2]),
                              replace_dot_comma_space(fields[3]),
                              replace_dot_comma_space(fields[4]),
                              replace_dot_comma_space(fields[5]),
                              replace_dot_comma_space(fields[6]),
                              replace_dot_comma_space(fields[7]),
                              replace_dot_comma_space(fields[8]),
                              replace_dot_comma_space(fields[9])])

            # feed named tuples
            cwv.subrange = to_tuple(elements[1])
            cwv.b0 = is_number(elements[2])
            cwv.b1 = is_number(elements[3])
            cwv.b2 = is_number(elements[4])
            cwv.b3 = is_number(elements[5])
            cwv.b4 = is_number(elements[6])
            cwv.b5 = is_number(elements[7])
            cwv.b6 = is_number(elements[8])
            cwv.b7 = is_number(elements[9])
            cwv.rmse = is_number(elements[10])
            dictionary[key] = dictionary.get(key, cwv)  # feed dictionary

    map(transform, rows)
    return dictionary


def get_average_emissivities():
    """
    Read comma separated values for average emissivities and return a
    dictionary wiht named tuples
    """

    try:
        # read csv for average emissivities, convert to string
        csvstring = csv_reader("average_emissivity.csv")

    except:
        csvstring = AE_STRING

    # convert string to dictionary
    average_emissivities = csv_to_dictionary(csvstring)

    # return the dictionary with coefficients
    return average_emissivities


def get_column_water_vapor():
    """
    Read comma separated values for column water vapor coefficients and return
    a dictionary wiht named tuples
    """

    try:
        # read csv for average emissivities, convert to string
        csvstring = csv_reader("cwv_coefficients.csv")
    except:
        csvstring = CWV_STRING

    # convert string to dictionary
    column_water_vapor_coefficients = csv_to_dictionary(csvstring)

    # return the dictionary with coefficients
    return column_water_vapor_coefficients


# main
def main():
    """
    Main function:
    - reads a special csv file (or a multi-line string)
    - converts and returns a dictionary which contains named tupples

    - accepted csv are:
      - average emissivity coefficients
      - column water vapor
    """

    # user requested file?
    global CSVFILE

    if set_csvfile():
        CSVFILE = set_csvfile()
        print " * Reading comma separated values from:", CSVFILE

    else:
        raise IOError('Please define a file to read comma-separated-values from!')

    # convert csv file to string
    csvstring = csv_reader(CSVFILE)

    # convert string to dictionary
    coefficients_dictionary = csv_to_dictionary(csvstring)  # csv < from string

    # report on user requested file
    if set_csvfile():
        msg = '   > Dictionary with coefficients '
        msg += str('(note, it contains named tuples):\n\n')
        print msg, coefficients_dictionary

    # return the dictionary with coefficients
    return coefficients_dictionary


# Test data
def test_csvfile(infile):
    '''
    Test helper and main functions using as input a csv file.
    '''
    global CSVFILE
    CSVFILE = infile
    print "CSVFILE (global variable) = ", CSVFILE

    print 'Test helper and main functions using as input a csv file.'
    print

    number = random.randint(1., 10.)
    print " * Testing helper function 'is_number':", is_number(number)

    if not infile:
        csvfile = "average_emissivity.csv"
    else:
        csvfile = infile

    print " * Testing 'csv_reader' on", csvfile, ":\n\n", csv_reader(csvfile)
    print

    csvstring = csv_reader(csvfile)
    print " * Testing 'csv_to_dictionary':\n\n", csv_to_dictionary(csvstring)
    print

    d = csv_to_dictionary(csvstring)
    somekey = random.choice(d.keys())
    print "* Some random key:", somekey

    fields = d[somekey]._fields
    print "* Fields of namedtuple:", fields

    random_field = random.choice(fields)
    print "* Some random field:", random_field
    # print "* Return values (namedtuple):", d[somekey].TIRS10, d[somekey].TIRS11
    print "* Return values (namedtuple):", ('subrange', d[somekey].subrange,
                                            'b0', d[somekey].b0,
                                            'b1', d[somekey].b1,
                                            'b2', d[somekey].b2,
                                            'b3', d[somekey].b3,
                                            'b4', d[somekey].b4,
                                            'b5', d[somekey].b5,
                                            'b6', d[somekey].b6,
                                            'b7', d[somekey].b7,
                                            'rmse', d[somekey].rmse)

#test_using_file(CSVFILE)  # Ucomment to run test function!
#CSVFILE = "cwv_coefficients.csv"
#test_csvfile("cwv_coefficients.csv")
#CSVFILE = ''


def test(testdata):
    '''
    Test helper and main functions using as input a multi-line string.
    '''
    number = random.randint(1., 10.)
    print " * Testing 'is_number':", is_number(number)
    print

    '''
    Testing the process...
    '''
    d = csv_to_dictionary(testdata)
    print "Dictionary is:\n", d
    print

    somekey = random.choice(d.keys())
    print "Some random key:", somekey
    print

    fields = d[somekey]._fields
    print "Fields of namedtuple:", fields
    print

    random_field = random.choice(fields)
    print "Some random field:", random_field
    print "Return values (namedtuple):", d[somekey].TIRS10, d[somekey].TIRS11

testdata = '''LandCoverClass|TIRS10|TIRS11
Cropland|0.971|0.968
Forest|0.995|0.996
Grasslands|0.970|0.971
Shrublands|0.969|0.970
Wetlands|0.992|0.998
Waterbodies|0.992|0.998
Tundra|0.980|0.984
Impervious|0.973|0.981
Barren_Land|0.969|0.978
Snow_and_Ice|0.992|0.998'''

#test(testdata)  # Ucomment to run the test function!

''' Output ------------------------------
{'Wetlands': <class '__main__.Wetlands'>,
 'Snow_and_Ice': <class '__main__.Snow_and_Ice'>,
 'Impervious': <class '__main__.Impervious'>,
 'Grasslands': <class '__main__.Grasslands'>,
 'Shrublands': <class '__main__.Shrublands'>,
 'Cropland': <class '__main__.Cropland'>,
 'Tundra': <class '__main__.Tundra'>,
 'Barren_Land': <class '__main__.Barren_Land'>,
 'Forest': <class '__main__.Forest'>,
 'Waterbodies': <class '__main__.Waterbodies'>}
------------------------------------ '''

if __name__ == "__main__":
    main()