app.py

from io import BytesIO
from pathlib import Path
import numpy as np
import matplotlib.pyplot as plt

import viktor as vkt


class Parametrization(vkt.ViktorParametrization):

    intro = vkt.Text("# Invoice app 💰 \n This app makes an invoice based on your own Word template")

    client_name = vkt.TextField("Name of client")
    company = vkt.TextField("Company name")
    lb1 = vkt.LineBreak()  # This is just to separate fields in the parametrization UI
    date = vkt.DateField("Date")

    # Table
    table_price = vkt.Table("Products")
    table_price.qty = vkt.NumberField("Quantity", suffix="-")
    table_price.desc = vkt.TextField("Description", suffix="-")
    table_price.price = vkt.NumberField("Price", suffix="€")

    # Downloadbutton
    download_word_file = vkt.DownloadButton('Download report', method='download_word_file')


class Controller(vkt.ViktorController):

    label = 'reporting'
    parametrization = Parametrization

    def generate_word_document(self, params):

        total_price = self.calc_total_price(params)
        table = self.process_table(params)

        # Create emtpy components list to be filled later
        components = []

        # Fill components list with data
        components.append(vkt.word.WordFileTag("Client_name", params.client_name))
        components.append(vkt.word.WordFileTag("company", params.company))
        components.append(vkt.word.WordFileTag("date", str(params.date))) # Convert date to string format
        components.append(vkt.word.WordFileTag("total_price", str(total_price)))  # Convert price float to string
        components.append(vkt.word.WordFileTag("table1", table))
        components.append(vkt.word.WordFileTag("table2", table))

        # Place image
        figure = self.create_figure(params)
        word_file_figure = vkt.word.WordFileImage(figure, "figure_sales", width=500)
        components.append(word_file_figure)

        # Get path to template and render word file
        template_path = Path(__file__).parent / "files" / "Template.docx"
        with open(template_path, 'rb') as template:
            word_file = vkt.word.render_word_file(template, components)

        return word_file

    @vkt.PDFView("PDF viewer", duration_guess=5)
    def pdf_view(self, params, **kwargs):
        word_file = self.generate_word_document(params)

        with word_file.open_binary() as f1:
            pdf_file = vkt.convert_word_to_pdf(f1)

        return vkt.PDFResult(file=pdf_file)

    @staticmethod
    def calc_total_price(params):
        # Get user entry from params
        product_table = params.table_price

        # Calculate total price from quantities and unit price
        quantities = [row["qty"] for row in product_table]
        prices = [row["price"] for row in product_table]
        total_price = 0
        for qty, price in zip(quantities, prices):
            total_price += qty * price

        return total_price

    def process_table(self, params):
        total_price = self.calc_total_price(params)
        product_table = params.table_price
        for row in product_table:
            row["total"] = row["qty"] * row["price"]
            row["perc"] = str(round((row["total"] / total_price) * 100, 2)) + "%"

        return product_table

    @staticmethod
    def create_figure(params):
        product_table = params.table_price
        # Create figure
        fig, ax = plt.subplots(figsize=(16, 8))
        products = [row["desc"] for row in product_table]
        qty = [np.round(row["qty"], 2) for row in product_table]
        ax.pie(qty, labels=products, autopct="%1.1f%%")
        ax.set_title("Pie chart total sold products")
        png_data = BytesIO()
        fig.savefig(png_data, format='png')
        plt.close()

        return png_data

    def download_word_file(self, params, **kwargs):
        word_file = self.generate_word_document(params)

        return vkt.DownloadResult(word_file, "Invoice.docx")