using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace TeamLabAssignment
{
    public partial class frmCGPACalculator : Form
    {
        const int MAX_COURSES = 40;
        const double GPA_90_100 = 5.0;
        const double GPA_85_89 = 4.5;
        const double GPA_80_84 = 4.0;
        const double GPA_75_79 = 3.5;
        const double GPA_70_74 = 3.0;
        const double GPA_65_69 = 2.5;
        const double GPA_60_64 = 2.0;
        const double GPA_55_59 = 1.5;
        const double GPA_50_54 = 1.0;
        const double GPA_BELOW_50 = 0;
        int arrayIndex = 0;
        //define the arrays in the class. cant be stored in click method, else data loss
        double[] coursesPercentages = new double[MAX_COURSES];
        double[] coursesGPA = new double[MAX_COURSES];

        public frmCGPACalculator()
        {
            InitializeComponent();
        }

        private void btnCalculate_Click(object sender, EventArgs e)
        {
            double coursePercentage;
            double courseHours;
            double hourTotal=0;
            double QualityPointValuesTotal=0;

            try
            {
                if (isValidData())
                {
                    coursePercentage = Convert.ToDouble(txtPercent.Text);
                    courseHours = Convert.ToDouble(txtHours.Text);

                    hourTotal += courseHours; //add all the hours as user enters them

                    QualityPointValuesTotal = QualityPointValues(courseHours, coursePercentage);
                    //Totals the Quality Point Value as user enters grades

                    //add the data to the array
                    coursesPercentages[arrayIndex] = coursePercentage;
                    coursesGPA[arrayIndex] = calculateGPA(coursePercentage);
                    //coursesGPA[arrayIndex] = courseHours;

                    lbGPAOutput.Items.Add(coursePercentage + "% - GPA: " + coursesGPA[arrayIndex]);
                    //calculate

                    txtHours.Clear();
                    txtPercent.Clear();
                    txtPercent.Focus();


                    arrayIndex++;
                }
            }
            //not a number
            catch (FormatException myFormatEx)
            {
                MessageBox.Show(myFormatEx.Message + "\nInvalid data type entered. Please check all entries.", "Entry Error");
            }
            //too large for decimal
            catch (OverflowException myOverflowEx)
            {
                MessageBox.Show(myOverflowEx.Message + "\nOverflow error. Please enter smaller values.", "Entry Error");
            }
            //other exception
            catch (Exception myEx)
            {
                MessageBox.Show(myEx.Message + "\n\n" + myEx.GetType().ToString() + "\n" + myEx.StackTrace, "Exception");
            }


            //Print to CGPA lable after calling and convering method
          // lblCGPAOutput.Text= Convert.ToString(CGPACalculate(hourTotal, QualityPointValuesTotal));


        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            txtHours.Clear();
            txtPercent.Clear();
            lbGPAOutput.Items.Clear();
            arrayIndex = 0;
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private bool isValidData()
        {
            const int MAX_PERCENTAGE = 100;
            const int MIN_PERCENTAGE = 0;

            return
                //validate hours
                isPresent(txtHours, "Hours") &&
                isDouble(txtHours, "Hours") &&

                //validate percentage
                isPresent(txtPercent, "Percentage") &&
                isDouble(txtPercent, "Percentage") &&

                isWithinRange(txtPercent, "Percent", MIN_PERCENTAGE, MAX_PERCENTAGE);
        }
        private double calculateGPA(double gradePercentage)
        {



            double calculatedResult = 0;

            if (gradePercentage >= 90 && gradePercentage <= 100)
            {
                calculatedResult = GPA_90_100;
            }
            else if (gradePercentage >= 85 && gradePercentage <= 89)
            {
                calculatedResult = GPA_85_89;
            }
            else if (gradePercentage >= 80 && gradePercentage <= 84)
            {
                calculatedResult = GPA_80_84;
            }
            else if (gradePercentage >= 75 && gradePercentage <= 79)
            {
                calculatedResult = GPA_75_79;
            }
            else if (gradePercentage >= 70 && gradePercentage <= 74)
            {
                calculatedResult = GPA_70_74;
            }
            else if (gradePercentage >= 65 && gradePercentage <= 69)
            {
                calculatedResult = GPA_65_69;
            }
            else if (gradePercentage >= 60 && gradePercentage <= 64)
            {
                calculatedResult = GPA_60_64;
            }
            else if (gradePercentage >= 55 && gradePercentage <= 59)
            {
                calculatedResult = GPA_55_59;
            }
            else if (gradePercentage >= 50 && gradePercentage <= 54)
            {
                calculatedResult = GPA_50_54;
            }
            else//gradePercentage < 50
            {
                calculatedResult = GPA_BELOW_50;
            }

            return calculatedResult;
        }

        private bool isDouble(TextBox aTextBox, string name)
        {
            //check if the textbox is a double, assume true
            bool doubleValue = true;

            try
            {
                //try to convert it, catch otherwise
                Convert.ToDouble(aTextBox.Text);
            }
            catch (FormatException)
            {
                MessageBox.Show(name + " must be a decimal value.", "Entry Error");
                //sets the textBox with a problem as the focus and highlight
                aTextBox.Focus();
                aTextBox.SelectAll();

                //textbox is not a double
                doubleValue = false;
            }
            catch (OverflowException myOverflowEx)
            {
                throw myOverflowEx; // throw to the calling method to handle
            }
            catch (Exception myEx)
            {
                throw myEx; // throw to the calling method to handle
            }
            return doubleValue;
        }

        private bool isPresent(TextBox aTextBox, string name)
        {
            //check if the textbox has an entry, assume true
            bool doesExist = true;

            //empty textBox
            if (aTextBox.Text == "")
            {
                MessageBox.Show(name + " is a required field.", "Entry Error");
                //sets the textBox with a problem as the focus
                aTextBox.Focus();
                aTextBox.SelectAll();
                doesExist = false;
            }

            return doesExist;
        }

        private bool isWithinRange(TextBox aTextBox, string name, decimal RANGE_MIN, decimal RANGE_MAX)
        {
            bool withinRange = true;
            decimal aNumber;

            try
            {
                aNumber = Convert.ToDecimal(aTextBox.Text);

                //outside of range
                if (aNumber > RANGE_MAX || aNumber < RANGE_MIN)
                {
                    MessageBox.Show(name + " must be between " + RANGE_MIN + " and " + RANGE_MAX, "Entry Error");
                    //select the text of the error textBox for user friendliness
                    aTextBox.Focus();
                    aTextBox.SelectAll();

                    //not within range
                    withinRange = false;
                }
            }
            catch (FormatException myFormatEx)
            {
                throw myFormatEx;
            }
            catch (Exception myEx)
            {
                throw myEx;
            }

            return withinRange;
        }


        private double QualityPointValues(double courseHours, double coursePercentage )
        {
            double QualityPointValue;

            if (coursePercentage >= 90 && coursePercentage <= 100)
            {
                QualityPointValue=courseHours*GPA_90_100;
            }
            else if (coursePercentage >= 85 && coursePercentage <= 89)
            {
               QualityPointValue=courseHours*GPA_85_89;
            }
            else if (coursePercentage >= 80 && coursePercentage <= 84)
            {
                QualityPointValue=courseHours*GPA_80_84;
            }
            else if (coursePercentage >= 75 && coursePercentage <= 79)
            {
               QualityPointValue=courseHours*GPA_75_79;
            }
            else if (coursePercentage >= 70 && coursePercentage <= 74)
            {
                QualityPointValue=courseHours*GPA_70_74;
            }
            else if (coursePercentage >= 65 && coursePercentage <= 69)
            {
                QualityPointValue=courseHours*GPA_65_69;
            }
            else if (coursePercentage >= 60 && coursePercentage <= 64)
            {
                QualityPointValue=courseHours*GPA_60_64;
            }
            else if (coursePercentage >= 55 && coursePercentage <= 59)
            {
                QualityPointValue=courseHours*GPA_55_59;
            }
            else if (coursePercentage >= 50 && coursePercentage <= 54)
            {
                QualityPointValue=courseHours*GPA_50_54;
            }
            else//gradePercentage < 50
            {
                QualityPointValue=courseHours*GPA_BELOW_50;
            }

            return QualityPointValue;
        }

        private double CGPACalculate(double hourTotal, double QualityPointValueTotal)
        {
            double CGPA;

            CGPA = QualityPointValueTotal / hourTotal;

            return CGPA;
        }




    }
}