import sys
import json
import xlrd3 as xlrd
from openpyxl import load_workbook


class Writer:
    """
    This class is made to update existing excel file.
    First it will open the file in python and then we can do multiple writes and once everything is update we can use
    save method in order to save the updated excel file. Hence, this class is very useful is saving time while updating
    excel files.
    """
    def __init__(self, path, sheet):
        self.path = path
        self.sht = sheet
        self.workbook = load_workbook(self.path)
        self.sheet = self.workbook[self.sht]

    def write(self, row, col, data):
        # Update the values using row and col number.
        # Note :- We are using openpyxl so row & column index will start from 1 instead of 0
        self.sheet.cell(row, col).value = data

    def save(self):
        # Call this method to save the file once every updates are written
        self.workbook.save(self.path)
        self.workbook.close()


class Mover:
    """
    This class is used to copy data from one excel file to another. We can also use some filters to copy only targeted
    data.
    """
    def __init__(self, source_file_path, source_sheet, destination_file_path, destination_sheet, lines=0):
        """

        :param source_file_path: Path with filename of source excel file
        :param source_sheet: Sheet name of the source
        :param destination_file_path: Path with filename of Destination excel file
        :param destination_sheet: Sheet name of the destination
        :param lines: Number of lines starting from 1 to be considered for moving from source.
        """
        self.source_file_path = source_file_path
        self.source_sheet = source_sheet
        self.destination_file_path = destination_file_path
        self.destination_sheet = destination_sheet
        self.lines = lines

    def move(self, filters={}, add_missing_columns=False):
        """

        :param filters: dictionary of filters with header as key and data as value or list of data as value
        :param add_missing_columns: True if we need all headers from source file to destination file which are currently
        not in destination file.
        :return:
        """
        source = self.read_xlsx(self.source_file_path, self.source_sheet)
        destination = self.read_xlsx(self.destination_file_path, self.destination_sheet)
        destination_wb = Writer(self.destination_file_path, self.destination_sheet)  # Writer class object used to update existing file
        if add_missing_columns:
            self.add_missing_columns(source, destination, destination_wb)
            # again opening destination file as it is updated with the source file columns
            destination = self.read_xlsx(self.destination_file_path, self.destination_sheet)

        end = self.lines or source.nrows  # if number of rows to be considered from source is not predefined the take all
        new_data = [source.row(row) for row in range(1, end)]  # create a new list of all data and remove the filtered data
        remove_data = []  # rows not matching filter are stored here which is used later to remove data from new_data
        for filter in filters:  # iterate through the dictionary of filter and
            ind = [x.value for x in source.row(0)].index(filter)  # getting index of filter header then use the same index to check data
            if type(filters[filter]) is not list:
                filters[filter] = [filters[filter]]
            for row in new_data:
                if row[ind].value not in filters[filter]:  # check if data is matching with filter
                    remove_data.append(row)
            for row in remove_data:  # removing unmatched data from new_data list
                new_data.remove(row)
        row_num = destination.nrows  # used to maintain new row number
        for data in new_data:  # iterating through the data to be written and writing then on the correct cells
            row_num += 1
            for cell in range(len(data)):
                try:
                    # getting column number where new data is to be written with the help of indexing header in destination file
                    ind = [x.value for x in destination.row(0)].index(source.row(0)[cell].value) + 1
                except ValueError:
                    # if add_missing_columns is false then ValueError is thrown for the headers which are not present in destination
                    continue
                destination_wb.write(row_num, ind, data[cell].value)
        destination_wb.save()

    def read_xlsx(self, path, sheet):
        # reading xlsx file using xlrd
        wb = xlrd.open_workbook(path)
        sht = wb.sheet_by_name(sheet)
        return sht

    def add_missing_columns(self, source, destination, destination_wb):
        # looking for the headers which are not present in destination file and then updating destination file
        source_headers = [x.value for x in source.row(0)]
        destination_headers = [x.value for x in destination.row(0)]
        col = len(destination_headers)
        for headers in source_headers:
            if headers not in destination_headers:
                col += 1
                destination_wb.write(1, col, headers)
        destination_wb.save()


def parse_json(path):
    """
    Takes parameter from a json file.
    :param path:
    :return:
    """
    js = json.load(open(path))
    lines = int(js["lines"]) or 0
    mover = Mover(js["source_file"], js["source_sheet"], js["destination_file"], js["destination_sheet"], lines)
    if js["add_missing_columns"].lower() == "true":
        add_missing = True
    else:
        add_missing = False
    mover.move(js["filters"], add_missing)


if __name__ == "__main__":
    js = sys.argv[-1]
    if ".json" in js.lower():
        parse_json(js)