dialog.py

#! /usr/bin/python
# -*-  coding: utf-8 -*-
"""
Main dialog of the loan calculator.
"""

__author__ = "Sofie & Bernd Krietenstein"
__copyright__ = "Copyright (C) 2018 Sofie & Bernd Krietenstein"
__license__ = "see LICENSE file"

import os
import pathlib
import yaml

from PyQt5.QtWidgets import (
    QApplication,
    QWidget,
    QHBoxLayout,
    QVBoxLayout,
    QGridLayout,
    QLabel,
    QLineEdit,
    QDateEdit,
    QDateTimeEdit,
    QPushButton,
    QFileDialog,
    QDialog,
    QMessageBox
)
from PyQt5.QtCore import (
    QDate
)

import conf
import log
import util
from kredit import AnnuitaetenKredit
from plot import PlotWindow
from table import TableDialog
from soti import SotiDialog

class CreditSettings(object):
    """
    Stores the credit settings.
    """
    def __init__(self,
            kreditsumme=0.0,
            zins=0.0,
            tilgung=0.0,
            start_date="01/2000",
            extra_payments=[]):
        """
        C'tor.
        """
        self.kreditsumme = kreditsumme
        self.zins = zins
        self.tilgung = tilgung
        self.start_date = start_date
        self.extra_payments = extra_payments

class MainDialog(QWidget):
    """
    Main dialog of the loan calculator.
    """
    def __init__(self):
        super().__init__()

        self._vbox = None
        self._data_grid = None
        self._hbox_buttons = None
        self._hbox_close_button = None
        self._kredit_summe_edit = None
        self._tilgung_prozent_edit = None
        self._zins_prozent_edit = None
        self._start_month_edit = None
        self._monats_rate_label = None
        self._laufzeit_label = None
        self._kosten_label = None
        self._load_button = None
        self._save_button = None
        self._calc_button = None
        self._soti_button = None
        self._table_button = None
        self._table_button = None
        self._plot_button = None
        self._close_button = None

        self._window = None
        self._table_window = None

        self._current_project_file_name = None
        self._settings = None
        self._kredit_verlauf = []
        self._extra_payments = []
        
        self.init_ui()

        # Load/initialize settings
        self._credit_dir = os.path.join(pathlib.Path.home(), '.credit')
        self._credit_settings_file = os.path.join(self._credit_dir, 'settings.yaml')
        if not os.path.exists(self._credit_dir):
            os.makedirs(self._credit_dir)
        if not os.path.exists(self._credit_settings_file):
            self._settings = CreditSettings()
            self._save_settings(self._credit_settings_file)
        self._load_settings(self._credit_settings_file)

    def init_ui(self):
        self.setGeometry(300, 300, 300, 300)
        self.setWindowTitle('Annuity Loan Calculator')

        self.init_layout()
        self.init_project_buttons()
        self.init_input_fields()
        self.init_calc_buttons()
        self.init_output_fields()
        self.init_show_buttons()
        self.init_close_button()

        self._load_button.clicked.connect(self.load_button_pressed)
        self._save_button.clicked.connect(self.save_button_pressed)
        self._calc_button.clicked.connect(self.calc_button_pressed)
        self._soti_button.clicked.connect(self.soti_button_pressed)
        self._plot_button.clicked.connect(self.plot_button_pressed)
        self._table_button.clicked.connect(self.table_button_pressed)
        self._close_button.clicked.connect(self.close_button_pressed)

        self.show()

    def _load_settings(self, file_name):
        if os.path.exists(file_name):
            try:
                self._settings = yaml.load(open(file_name, 'r'))
                self._kredit_summe_edit.setText("{:.2f}".format(self._settings.kreditsumme))
                self._tilgung_prozent_edit.setText("{:.2f}".format(self._settings.tilgung))
                self._zins_prozent_edit.setText("{:.2f}".format(self._settings.zins))
                self._start_month_edit.lineEdit().setText(self._settings.start_date)
            except yaml.YAMLError as ex:
                log.LOGGER.error(ex)

    def _save_settings(self, file_name):
        save_dir = os.path.dirname(file_name)
        if os.path.exists(save_dir):
            try:
                self._settings.kreditsumme = float(self._kredit_summe_edit.text())
            except ValueError:
                self._settings.kreditsumme = 0.0
            try:
                self._settings.zins = float(self._zins_prozent_edit.text())
            except ValueError:
                self._settings.zins = 5.0
            try:
                self._settings.tilgung = float(self._tilgung_prozent_edit.text())
            except ValueError:
                self._settings.tilgung = 1.0
            try:
                self._settings.start_date = self._start_month_edit.lineEdit().text()
            except ValueError:
                self._settings.start_date = "2000-01-01"
            try:
                with open(file_name, mode='w') as file:
                    file.write(yaml.dump(self._settings))
            except yaml.YAMLError as ex:
                log.LOGGER.error(ex)
        else:
            QMessageBox.warning(
                self,
                "Project coud not be saved",
                "Target directory {} does not exist".format(save_dir))

    def init_layout(self):
        self._vbox = QVBoxLayout()
        self._data_grid = QGridLayout()
        self._hbox_buttons = QHBoxLayout()
        self._hbox_close_button = QHBoxLayout()

        self._vbox.addLayout(self._data_grid)
        self._vbox.addLayout(self._hbox_buttons)
        self._vbox.addLayout(self._hbox_close_button)
        self._vbox.addStretch(1)

        self.setLayout(self._vbox)

    def init_project_buttons(self):
        start_row = 0
        self._load_button = QPushButton("Load Project")
        self._save_button = QPushButton("Save Project")
        hbox = QHBoxLayout()
        hbox.addWidget(self._load_button)
        hbox.addWidget(self._save_button)
        self._data_grid.addLayout(hbox, start_row + 0, 0, 1, 2)

    def init_input_fields(self):
        start_row = 1
        self._data_grid.addWidget(QLabel("Loan Amount"), start_row + 0, 0)
        self._data_grid.addWidget(QLabel("Down Payment [%]"), start_row + 1, 0)
        self._data_grid.addWidget(QLabel("Nominal Interest [%]"), start_row + 2, 0)
        self._data_grid.addWidget(QLabel("Start Date"), start_row + 3, 0)
        self._kredit_summe_edit = QLineEdit()
        self._tilgung_prozent_edit = QLineEdit()
        self._zins_prozent_edit = QLineEdit()
        self._start_month_edit = QDateEdit(QDate.currentDate())
        self._start_month_edit.setDisplayFormat(conf.DATE_FORMAT)
        self._start_month_edit.currentSection = QDateTimeEdit.MonthSection
        # self._start_month_edit.setCalendarPopup(True)
        self._data_grid.addWidget(self._kredit_summe_edit, start_row + 0, 1)
        self._data_grid.addWidget(self._tilgung_prozent_edit, start_row + 1, 1)
        self._data_grid.addWidget(self._zins_prozent_edit, start_row + 2, 1)
        self._data_grid.addWidget(self._start_month_edit, start_row + 3, 1)

    def init_calc_buttons(self):
        start_row = 5
        self._calc_button = QPushButton("Calculate")
        self._soti_button = QPushButton("Extra Down Payments")
        hbox = QHBoxLayout()
        hbox.addWidget(self._calc_button)
        hbox.addWidget(self._soti_button)
        self._data_grid.addLayout(hbox, start_row + 0, 0, 1, 2)

    def init_output_fields(self):
        start_row = 6
        self._monats_rate_label = QLabel("...")
        self._laufzeit_label = QLabel("...")
        self._kosten_label = QLabel("...")
        self._data_grid.addWidget(QLabel("Monthly Rate:"), start_row + 0, 0)
        self._data_grid.addWidget(QLabel("Period:"), start_row + 1, 0)
        self._data_grid.addWidget(QLabel("Total Interest:"), start_row + 2, 0)
        self._data_grid.addWidget(self._monats_rate_label, start_row + 0, 1)
        self._data_grid.addWidget(self._laufzeit_label, start_row + 1, 1)
        self._data_grid.addWidget(self._kosten_label, start_row + 2, 1)

    def init_show_buttons(self):
        self._table_button = QPushButton("Show Schedue")
        self._plot_button = QPushButton("Show Chart")
        self._hbox_buttons.addWidget(self._table_button)
        self._hbox_buttons.addWidget(self._plot_button)

    def init_close_button(self):
        self._close_button = QPushButton("Close")
        self._hbox_close_button.addStretch(1)
        self._hbox_close_button.addWidget(self._close_button)

    @property
    def summe(self):
        """
        :returns loan amount
        """
        return float(self._kredit_summe_edit.text())

    @property
    def tilgung(self):
        """
        :returns redemption rate in %
        """
        return float(self._tilgung_prozent_edit.text())

    @property
    def zins(self):
        """
        :returns nominal interest in %
        """
        return float(self._zins_prozent_edit.text())

    @property
    def monatsrate(self):
        raise NotImplementedError("Setting is not allowed")

    @monatsrate.setter
    def monatsrate(self, x):
        self._monats_rate_label.setText("{0:.2f}".format(x))

    @property
    def laufzeit(self):
        raise NotImplementedError("Setting is not allowed")

    @laufzeit.setter
    def laufzeit(self, x):
        self._laufzeit_label.setText(str(x))

    @property
    def kosten(self):
        raise NotImplementedError("Setting is not allowed")

    @kosten.setter
    def kosten(self, x):
        """
        :param x (float): cost of the credit (sum of interest payments).
        """
        self._kosten_label.setText("{0:.2f}".format(x))

    def load_button_pressed(self, e):
        if self._current_project_file_name:
            start_file = self._current_project_file_name
        else:
            start_file = str(pathlib.Path.home())
        file_name = QFileDialog.getOpenFileName(
            self,
            "Open Project File",
            start_file,
            "Credit Project Files (*.yaml)")[0]
        self._load_settings(file_name)
        self._current_project_file_name = file_name

    def save_button_pressed(self, e):
        if self._current_project_file_name:
            start_file = self._current_project_file_name
        else:
            start_file = str(pathlib.Path.home())
        file_name = QFileDialog.getSaveFileName(
            self,
            "Save Project File",
            start_file,
            "Credit Project Files (*.yaml)")[0]
        self._save_settings(file_name)
        self._current_project_file_name = file_name

    def calc_button_pressed(self, e):
        kredit = AnnuitaetenKredit(self.summe, self.tilgung, self.zins)
        # Convert absolute to relative months
        extra_payments = {}
        for payment in self._settings.extra_payments:
            month = util.month_diff(
                QDate.fromString(payment[0], conf.DATE_FORMAT),
                QDate.fromString(self._settings.start_date, conf.DATE_FORMAT))
            extra_payments[month] = payment[1]
        self._kredit_verlauf = kredit.berechne_kreditverlauf(extra_payments)
        self.monatsrate = kredit.Monatsrate
        self.laufzeit = "{0:d} Years {1:d} Months".format(
            int(self._kredit_verlauf[-1].Monat) // 12,
            self._kredit_verlauf[-1].Monat % 12)
        self.kosten = kredit.GesamtKosten

    def soti_button_pressed(self, e):
        soti_dialog = SotiDialog(self, self._settings.extra_payments)
        ret = soti_dialog.exec()
        if ret == QDialog.Accepted:
            self._settings.extra_payments = soti_dialog.payments

    def table_button_pressed(self, e):
        if len(self._kredit_verlauf):
            table_dialog = TableDialog(self)
            table_dialog.show_table(self._kredit_verlauf, self._start_month_edit.date())
            table_dialog.exec()

    def plot_button_pressed(self, e):
        if len(self._kredit_verlauf):
            plot_dialog = PlotWindow(self)
            plot_dialog.plot(self._kredit_verlauf)
            plot_dialog.exec()

    def close_button_pressed(self):
        self._save_settings(self._credit_settings_file)
        self.close()