import sys
import csv

from PyQt5.QtWidgets import QApplication, QMainWindow, QMessageBox
from PyQt5.QtGui import QPixmap

#ADD IMPORT STATEMENT FOR YOUR GENERATED UI.PY FILE HERE
import worldCountriesLIB

#CHANGE THE SECOND PARAMETER HERE TO MATCH YOUR GENERATED UI.PY FILE
class MyForm(QMainWindow, worldCountriesLIB.Ui_MainWindow):

    # --- Variables that will be used throughout the program ---
    changesMade = False             # Will keep track of changes made to prompt saving
    totalPopulation = 0             # Used in calculating the total population loaded from the text file

        # DO NOT MODIFY THIS CODE
    def __init__(self, parent=None):
        super(MyForm, self).__init__(parent)
        self.setupUi(self)
        # END DO NOT MODIFY

        # ADD SLOTS HERE
        self.actionLoadCountries.triggered.connect(self.loadCountries)
        self.actionExitProgram.triggered.connect(self.exitProgram)
        self.listWidgetCountry.currentRowChanged.connect(self.changeCountry)
        self.pushButtonPopulationUpdate.clicked.connect(self.updateCountryPopulation)
        self.radioButtonMiles.clicked.connect(self.showMilesDensity)
        self.radioButtonKilometers.clicked.connect(self.showKiloDensity)
        self.comboBoxArea.currentIndexChanged.connect(self.changeAreaDisplay)

        self.frameCountryInfo.hide()

    # ADD SLOT FUNCTIONS HERE
    # Triggered when country data is loaded in using the menu
    def loadCountries(self):
        self.loadCountriesFromFile()
        self.loadCountriesIntoWidget()

    # Triggers when a user selects a country from the list
    def changeCountry(self, newIndex):
        countryName = self.countryList[newIndex][0].lower()
        flagImage = QPixmap("Flags\\" + countryName.replace(" ", "_"))
        populationPercent = (int(self.countryList[newIndex][1]) / self.totalPopulation) * 100
        self.frameCountryInfo.show()
        self.labelCountryName.setText(self.countryList[newIndex][0])
        self.lineEditPopulationValue.setText("{:,}".format(int(self.countryList[newIndex][1])))
        self.labelAreaValue.setText("{:,}".format(int(self.countryList[newIndex][2])))
        self.labelFlagDisplay.setPixmap(flagImage)
        self.labelPopulationPercentValue.setText("{:,}%".format(round(populationPercent, 4)))
        self.comboBoxArea.setCurrentIndex(0)
        self.updatePopulationDensity()


    # Triggers when the user selects exit from the menu
    def exitProgram(self):
        # Will check if changes have been made to prompt user to save to file
        if self.changesMade:
            saveChanges = QMessageBox.question(self, "Save Changes?",
                                 "There are unsaved changes, would you like to save before exiting?",
                                 QMessageBox.Yes, QMessageBox.No)
        if saveChanges == QMessageBox.Yes:
            self.saveChangesToFile()
        QApplication.closeAllWindows()

    # Triggers when the update button is clicked
    def updateCountryPopulation(self):
        self.saveChangesToMemory()
        self.changesMade = True             # Flags that a change has been made

    # Triggers when a new country is selected
    def updatePopulationDensity(self):
        if self.radioButtonMiles.isChecked() == True:           # Checking radio buttons for correct display
            self.showMilesDensity()
        elif self.radioButtonKilometers.isChecked() == True:    # Checking radio buttons for correct display
            self.showKiloDensity()

    # Triggers when a country is selected
    # Defaults to square miles
    def changeAreaDisplay(self, newIndex):
        currentRow = self.listWidgetCountry.currentRow()
        if newIndex == 0:                                       # Checking combo box for correct display
            countryArea = int(self.countryList[currentRow][2])
        elif newIndex == 1:                                     # Checking combo box for correct display
            countryArea = int(int(self.countryList[currentRow][2]) * 2.58999)
        self.labelAreaValue.setText("{:,}".format(countryArea))

    #ADD HELPER FUNCTIONS HERE
    # Used to read data from the text file
    def loadCountriesFromFile(self):
        fileName = "countries.txt"
        accessMode = "r"
        with open(fileName, accessMode) as countryFile:
            countryData = csv.reader(countryFile)

            self.countryList = []
            for item in countryData:
                self.countryList.append(item)

    # Populates the list widget from the data collected from the text file
    def loadCountriesIntoWidget(self):
        self.listWidgetCountry.clear()
        for country in self.countryList:
            self.listWidgetCountry.addItem(country[0])
        self.calculateTotalPopulation()

    # Saves user inputted data to memory only
    def saveChangesToMemory(self):
        currentRow = self.listWidgetCountry.currentRow()
        # --- Error checking ---
        # User must enter a value
        # Value entered must be an integer value(or converted to an integer) before saving
        try:
            updatedPopulation = self.lineEditPopulationValue.text().replace(",", "")
            if updatedPopulation == "":
                QMessageBox.information(self, "Error", "Please enter a value before updating.", QMessageBox.Ok)
            else:
                self.countryList[currentRow][1] = int(updatedPopulation)
                QMessageBox.information(self, "Message", "Population Updated", QMessageBox.Ok)
        except ValueError:
            QMessageBox.information(self, "Error", "Invalid entry for population total.", QMessageBox.Ok)
        self.loadCountriesIntoWidget()
        self.listWidgetCountry.setCurrentRow(currentRow)

    # Runs when country data is loaded into the widget
    def calculateTotalPopulation(self):
        self.totalPopulation = 0
        for row in self.countryList:
            self.totalPopulation += int(row[1])

    # Saves user inputted data to the text file
    def saveChangesToFile(self):
        fileName = "countries.txt"
        accessMode = "w"
        with open(fileName, accessMode) as newCountryFile:
            for row in self.countryList:
                newCountryFile.write(",".join(row) + "\n")
        self.changesMade = False                # Flags that any changes made have been saved
        QMessageBox.information(self, "Data Saved", "Your changes have been saved.", QMessageBox.Ok)

    # Triggers when the radio button is clicked
    def showMilesDensity(self):
        currentRow = self.listWidgetCountry.currentRow()
        currentPopulation = int(self.countryList[currentRow][1])
        currentArea = int(self.countryList[currentRow][2])
        self.labelPopulationDensityValue.setText(str(round(currentPopulation / currentArea, 4)))

    # Triggers when the radio button is clicked
    def showKiloDensity(self):
        currentRow = self.listWidgetCountry.currentRow()
        currentPopulation = int(self.countryList[currentRow][1])
        currentArea = int(self.countryList[currentRow][2]) * 2.58999
        self.labelPopulationDensityValue.setText(str(round(currentPopulation / currentArea, 4)))

# DO NOT MODIFY THIS CODE
if __name__ == "__main__":
    app = QApplication(sys.argv)
    the_form = MyForm()
    the_form.show()
    sys.exit(app.exec_())
# END DO NOT MODIFY