# This Python (PyQt6) app calculates the number of full moons between two dates.
# The calculation is derived based on the first full moon of the 20th Century,
# which occurred on January 15, 1900 at 19:06 GMT, using the lunar synodic period
# of 29.53059 days to derive successive (or previous) full moon dates.
# All dates/times are with respect to Greenwich Meridian Time (GMT) and assume 
# that both start and end dates conform to the Gregorian Calendar.
#
# Initial version of Class Ui_FMFMainWindow created by PyQt6 UI code generator 6.4.2
# Ui_FMFMainWindow attributes specification: qss/FMFstyles.qss 
#
####################################################################################

from PyQt6 import QtCore, QtGui, QtWidgets
from PyQt6.QtCore import QDateTime, QDate
from PyQt6.QtGui import QCursor

# Generated code, with minor modifications.
class Ui_FMFMainWindow(object):
    def setupUi(self, FMFMainWindow):
        FMFMainWindow.setObjectName("FMFMainWindow")
        FMFMainWindow.setFixedSize(680, 720)
        self.centralwidget = QtWidgets.QWidget(parent=FMFMainWindow)
        self.centralwidget.setObjectName("centralwidget")

        self.groupBox_startDT = QtWidgets.QGroupBox(parent=self.centralwidget)
        self.groupBox_startDT.setGeometry(QtCore.QRect(10, 10, 660, 261))
        self.groupBox_startDT.setAlignment(QtCore.Qt.AlignmentFlag.AlignCenter)
        self.groupBox_startDT.setObjectName("groupBox_startDT")
        self.label_startheader = QtWidgets.QLabel(parent=self.groupBox_startDT)
        self.label_startheader.setGeometry(QtCore.QRect(220, 10, 200, 31))
        self.label_startheader.setObjectName("label_startheader")
        self.calendar_startDT = QtWidgets.QCalendarWidget(parent=self.groupBox_startDT)
        self.calendar_startDT.setGeometry(QtCore.QRect(16, 50, 351, 191))
        self.calendar_startDT.setGridVisible(True)
        self.calendar_startDT.setObjectName("calendar_startDT")
        self.calendar_startDT.clicked.connect(updateStartDTCalc)
        self.calendar_startDT.currentPageChanged.connect(updateStartDTCalc)
        self.timeEdit_startDT = QtWidgets.QTimeEdit(parent=self.groupBox_startDT)
        self.timeEdit_startDT.DateSections_Mask = False
        self.timeEdit_startDT.setGeometry(QtCore.QRect(390, 50, 100, 31))
        self.timeEdit_startDT.setTimeSpec(QtCore.Qt.TimeSpec.UTC)
        self.timeEdit_startDT.setObjectName("timeEdit_startDT")
        self.timeEdit_startDT.timeChanged.connect(updateStartDTCalc)
        self.line_startsep = QtWidgets.QFrame(parent=self.groupBox_startDT)
        self.line_startsep.setGeometry(QtCore.QRect(390, 120, 250, 16))
        self.line_startsep.setFrameShape(QtWidgets.QFrame.Shape.HLine)
        self.line_startsep.setFrameShadow(QtWidgets.QFrame.Shadow.Sunken)
        self.line_startsep.setObjectName("line_startsep")
        self.label_startDTcalc = QtWidgets.QLabel(parent=self.groupBox_startDT)
        self.label_startDTcalc.setGeometry(QtCore.QRect(390, 170, 250, 31))
        self.label_startDTcalc.setObjectName("label_startDTcalc")

        self.groupBox_endDT = QtWidgets.QGroupBox(parent=self.centralwidget)
        self.groupBox_endDT.setGeometry(QtCore.QRect(10, 290, 660, 261))
        self.groupBox_endDT.setAlignment(QtCore.Qt.AlignmentFlag.AlignCenter)
        self.groupBox_endDT.setObjectName("groupBox_endDT")
        self.label_endheader = QtWidgets.QLabel(parent=self.groupBox_endDT)
        self.label_endheader.setGeometry(QtCore.QRect(230, 10, 200, 31))
        self.label_endheader.setObjectName("label_endheader")
        self.calendar_endDT = QtWidgets.QCalendarWidget(parent=self.groupBox_endDT)
        self.calendar_endDT.setGeometry(QtCore.QRect(16, 50, 351, 191))
        self.calendar_endDT.setGridVisible(True)
        self.calendar_endDT.setObjectName("calendar_endDT")
        self.calendar_endDT.clicked.connect(updateEndDTCalc)
        self.calendar_endDT.currentPageChanged.connect(updateEndDTCalc)
        self.timeEdit_endDT = QtWidgets.QTimeEdit(parent=self.groupBox_endDT)
        self.timeEdit_endDT.setGeometry(QtCore.QRect(390, 50, 100, 31))
        self.timeEdit_endDT.setTimeSpec(QtCore.Qt.TimeSpec.UTC)
        self.timeEdit_endDT.setObjectName("timeEdit_endDT")
        self.timeEdit_endDT.timeChanged.connect(updateEndDTCalc)
        self.line_endsep = QtWidgets.QFrame(parent=self.groupBox_endDT)
        self.line_endsep.setGeometry(QtCore.QRect(390, 120, 250, 16))
        self.line_endsep.setFrameShape(QtWidgets.QFrame.Shape.HLine)
        self.line_endsep.setFrameShadow(QtWidgets.QFrame.Shadow.Sunken)
        self.line_endsep.setObjectName("line_endsep")
        self.label_endDTcalc = QtWidgets.QLabel(parent=self.groupBox_endDT)
        self.label_endDTcalc.setGeometry(QtCore.QRect(390, 170, 250, 31))
        self.label_endDTcalc.setObjectName("label_endDTcalc")

        self.calcResults = QtWidgets.QLabel(parent=self.centralwidget)
        self.calcResults.setGeometry(QtCore.QRect(10, 650, 660, 31))
        self.calcResults.setObjectName("calcResults")

        self.resultButton = QtWidgets.QPushButton(parent=self.centralwidget)
        self.resultButton.setGeometry(QtCore.QRect(300, 570, 72, 72))
        self.resultButton.setIcon(QtGui.QIcon('img/moon.png'))
        self.resultButton.setIconSize(QtCore.QSize(64,64))
        self.resultButton.setCursor(QtCore.Qt.CursorShape.PointingHandCursor)
        self.resultButton.setToolTip("Click or Press to Calculate")
        self.resultButton.setObjectName("resultButton")
        self.resultButton.clicked.connect(reportFMResults)

        FMFMainWindow.setCentralWidget(self.centralwidget)
        self.retranslateUi(FMFMainWindow)
        QtCore.QMetaObject.connectSlotsByName(FMFMainWindow)

        # initialize the date selection fields to the current date/time.
        updateStartDTCalc()
        updateEndDTCalc()
        
    def retranslateUi(self, FMFMainWindow):
        _translate = QtCore.QCoreApplication.translate
        FMFMainWindow.setWindowTitle(_translate("FMFMainWindow", "Full Moon Fever"))
        self.label_startheader.setText(_translate("FMFMainWindow", "Start Date and Time"))
        self.label_startDTcalc.setText(_translate("FMFMainWindow", ""))
        self.label_endDTcalc.setText(_translate("FMFMainWindow", ""))
        self.label_endheader.setText(_translate("FMFMainWindow", "End Date and Time"))
        self.calcResults.setText(_translate("FMFMainWindow", "Calculation Results"))
        #self.resultButton.setText(_translate("FMFMainWindow", "Results"))
        #self.menuFull_Moon_Fever.setTitle(_translate("FMFMainWindow", "Full Moon Fever"))

#########################################################################################
# Function to calculate the number of full moons in an interval
def number_of_full_moons(dt_start, dt_end):
    # Synodic period of the moon (in minutes)
    m_moon_period = 29.53059 * 24 * 60 

    # datetime of first full moon after earliest start time
    dt_first_20c_full_moon = QDateTime(1900, 1, 15, 19, 6)

    # difference in minutes between dt_start and first 20c full moon
    m_prior_to_start = qdtdiff(dt_first_20c_full_moon, dt_start)
    n_prior_to_start = int(m_prior_to_start / m_moon_period)

    # difference in minutes between dt_end and first 20c full moon
    m_prior_to_end = qdtdiff(dt_first_20c_full_moon, dt_end)
    n_prior_to_end = int(m_prior_to_end / m_moon_period)
    
    full_moons = n_prior_to_end - n_prior_to_start
    return int(full_moons)

# Function to format the result
def format_results(dt_start, dt_end, full_moons):
    start_date = convert(dt_start)
    end_date = convert(dt_end)
    fm = str(full_moons)

    if full_moons == 0:
        out = "There are no full moons between " + start_date + " and " + end_date
    elif full_moons == 1:
        out = "There is one full moon between " + start_date + " and " + end_date
    else:
        out = "There are " + fm + " full moons between " + start_date + " and " + end_date
    return out

# Function to calculate the difference between two QDateTime values
def qdtdiff(dt1, dt2):
    msdiff = dt1.msecsTo(dt2) / 60000
    return msdiff
        
# Function to convert QDateTime to string
def convert(date_time):
    fmt = "ddd MMM d, yyyy hh:mm"
    return date_time.toString(fmt)

# Functions to update the Start D/T based on user date and time selections
def updateStartDTCalc():
    date = updateStartDate()
    time = ui.timeEdit_startDT.time()
    datetime = convert(QDateTime(date, time))
    ui.label_startDTcalc.setText(datetime)

def updateStartDate():
    year = ui.calendar_startDT.yearShown()
    month = ui.calendar_startDT.monthShown()
    day = ui.calendar_startDT.selectedDate().day()
    return QDate(year, month, day)

# Functions to update the End D/T based on user date and time selections
def updateEndDTCalc():
    date = updateEndDate()
    time = ui.timeEdit_endDT.time()
    datetime = convert(QDateTime(date, time))
    ui.label_endDTcalc.setText(datetime)

def updateEndDate():
    year = ui.calendar_endDT.yearShown()
    month = ui.calendar_endDT.monthShown()
    day = ui.calendar_endDT.selectedDate().day()
    return QDate(year, month, day)

# Function to display the results in a consistent format, 
# switching the start/end DTs if necessary.
def reportFMResults():
    date_start = updateStartDate()
    date_end = updateEndDate()
    time_start = ui.timeEdit_startDT.time()
    time_end = ui.timeEdit_endDT.time()
    dt_start = QDateTime(date_start, time_start)
    dt_end = QDateTime(date_end, time_end)

    if dt_start > dt_end:
        temp = dt_end
        dt_end = dt_start
        dt_start = temp

    full_moons = number_of_full_moons(dt_start, dt_end)
    result = format_results(dt_start, dt_end, full_moons)

    ui.calcResults.setText(result)

#####################################################################
if __name__ == "__main__":
    import sys, os

    basedir = os.path.dirname(__file__)
    app = QtWidgets.QApplication(sys.argv)
    app.setWindowIcon(QtGui.QIcon(os.path.join(basedir, 'img/moon.ico')))
    stylesheet = os.path.join(basedir, 'qss/FMFstyles.qss') 

    with open(stylesheet, 'r') as f:
        style = f.read()
#        print("QSS Contents: " + style)
        app.setStyleSheet(style)
    FMFMainWindow = QtWidgets.QMainWindow()
    ui = Ui_FMFMainWindow()
    ui.setupUi(FMFMainWindow)
    FMFMainWindow.show()
    sys.exit(app.exec())
    
######################################################################
### QSS specification - the following code is in the file
### qss/FMFstyles.qss
######################################################################

text/x-generic FMFstyles.qss ( ASCII text )

QMainWindow#FMFMainWindow {
    background-image: url('img/twilight2b.jpg');
}

QLabel#label_startheader {
    font-size: 20px;
    font-weight: bold;
    text-align: center;
    color: #000;
}

QLabel#label_endheader {
    font-size: 20px;
    font-weight: bold;
    text-align: center;
    color: #000;
}

QLabel#label_startDTcalc {
    font-size: 20px;
    font-weight: bold;
    text-align: left;
    color: #000;
    border-style: inset;
    border-radius: 2px;
    background-color: #999; 
}

QLabel#label_endDTcalc {
    font-size: 20px;
    font-weight: bold;
    text-align: left;
    color: #000;
    border-style: inset;
    border-radius: 2px;
    background-color: #999; 
}

QCalendarWidget#calendar_startDT {
    border-style: inset;
    border-radius: 2px;
    background-color: #999; 
}

QCalendarWidget#calendar_endDT {
    border-style: inset;
    border-radius: 2px;
    background-color: #999; 
}

QGroupBox#groupBox_startDT {
    border: 5px solid #999;
    border-style: outset;
    border-radius: 8px;
    background-color: #ddd 
}

QGroupBox#groupBox_endDT {
    border: 5px solid #999;
    border-style: outset;
    border-radius: 8px;
    background-color: #ddd 
}

QLabel#label_startDTcalc {
    margin-left: 4px;
}

QLabel#label_endDTcalc {
    margin-left: 4px; 
}

QLabel#calcResults {
    margin-left: 4px;
    background-color: #003366;
    color: #ffffff;
    font-size: 16px;
    font-weight: bold;
    text-align: left;
    border-style: inset;
}

QPushButton {
    border-style: outset;
    border-radius: 5px;
    font-size: 16px;
    font-weight: bold;
    text-align: center;
}