using System.ComponentModel.Design;
using System.Reflection.Metadata.Ecma335;
using System.Security.Cryptography;
using System.Text.RegularExpressions;

Console.WriteLine("Section 2 Examples");
Console.WriteLine("==================");
Console.WriteLine("Chapter 4");

// Built in value types page 93

// Variable Declaration page 95
// 1. Did I declare it?
// 2. Did I give it value? value or operational value
// 3. Did I return it? itself or something else

// Method 1. 2 step process
// declare the variable
string firstname;
string lastname;

// set the value of the variable in memory
firstname = "Bob";
lastname = "Smith";

// page 110 join strings +
// Method 2. one statement that declares and sets the value
string fullname = firstname + " " + lastname; //Bob Smith

// return
Console.WriteLine(fullname); // Bob Smith

// page 113 literal vs logical code
string quoted = "Bob said \"Type code for readability\".";
Console.WriteLine(quoted);

// Page 119 Converting and Parsing
// Parse "parses" for just that moment in code
// Convert "converts" the actual object type
decimal productPrice = 25.52m; // decorate decimal with 'm'
// en/US locale setting

string productDesc = "Widget 1 costs " + productPrice.ToString();
Console.WriteLine(productDesc);

// Convert Class
// All inputs in OOP by default are strings
// input options > form webpage, readline terminal, json, csv, txt, databases, etc...
string i_zipCode = "32765";
// use the zipCode as an int
// create a NEW variabale int and convert the string
int zipCode = Convert.ToInt32(i_zipCode);

// Page 123 "scope" or "context"
// defines a block of codes operations or variables
// scope of a class
// scope of a function
// scope of a method
void myCalc()
{
    int x = 7;
    int y = 3;
    int z = x + y;
    Console.WriteLine(z); // does exist in the scope of the method
    // do something to access outside of this scope
}

// Console.WriteLine(z); // does not exist in the scope of class

Console.WriteLine("Chapter 5 \n\n"); // add 2 line breaks to the output
Console.WriteLine(); // also add an empty line to the output

// page 139 relational operators  == != >= <= > < ...
// page 140 logical operators & | ! test variable has to be defined on BOTH sides of the logical operator
// page 143 if-else statement keywords if, else if, else
// return type boolean
// Not a requirment to define the FALSE return "aka, you do not need to use the else keyword"


// Ask the user for their age "input" type default string
Console.WriteLine("Enter your age: "); // type string
string i_age = Console.ReadLine(); // as a string

// page 148 regualar expressions
// test the pattern of a string
// regex101.com testing
// regexlib.com examples

// regular expression test for ^\d{7}$
string agePattern = "^[0-9][0-9]$";
if (Regex.IsMatch(i_age, agePattern))
{
    Console.WriteLine("You entered a valid age");
}
else
{
    Console.WriteLine("You entered an invalid age, must be a number between 0-99");
    // loop back to askign the user for a new input
}

int age = Convert.ToInt32(i_age); // converted to int

// int age = 43; // declare a variable named age as type integer assigned value of 16

string state = "FL";

// drive 16 "add another condition"  if
// vote 18  else if
// drink 21 else if
// retire 65 else if
// else < 16

if (age >= 18 && age < 21) {
    Console.WriteLine("You can vote but not drink or retire");
}
else if (age >= 21 && age < 65)
{
    Console.WriteLine("You can vote and drink but not retire");
}
else if (age > 65)
{
    Console.WriteLine("You can vote, drink and retire");
}
else
{
    Console.WriteLine("You are not 18 or over");
}

// switch case statement page 144
// test variable is age on line 77 currenly assigned as 43 years old
// keywords switch case break goto default

switch (age)
{
    case >= 65:
        Console.WriteLine("You can drive, vote, drink and retire.");
        break;
        
    case >= 21:
        Console.WriteLine("You can drive, vote and drink.");
        break;
    case >= 18:
        Console.WriteLine("You can drive and vote");
       break;
    case >= 16:
        Console.WriteLine("You can drive");
        break;
    default:
        Console.WriteLine("You are too young to drive, vote, drink ro retire.");
        break;

} // switch

Console.WriteLine("Chapter 5 \n\n");

// pages 156 & 158
// for (control, condition, return) { operation }

for (int i = 1; i < 10; i++)
{
    Console.WriteLine(i);
    // 1<10;  1;  i=2
    // 2<10;  2; i=3
    // 9<10; 9; i=10
    // 10<10; break
} // return to the next scope
// scope of this context

// for loop using a ListSet, loop thru firstnames
string first_name = "Bob"; // type: string name: first_name
// type: string is "data" type 
// types: data,Class,reference,Service,Custom,delegate

List<string> first_names = new List<string>
    {
    "Bob",
    "Joe",
    "Mary"
    };

// length of List 3
// positional index 0:2
// Joe first_names[1]

Console.WriteLine("List of Contact First Names");
Console.WriteLine("===========================");
for (int i = 0; i < first_names.Count; i++)
{
    int id = i + 1;
    Console.WriteLine(id + ". " + first_names[i]);
    // increment of i
}

Console.WriteLine("Record id to update: ");
string i_id = Console.ReadLine();  // "1"
int r_id = Convert.ToInt32(i_id); // 1
int u_i = r_id - 1; // 0

Console.WriteLine("What do you want the new first name to be");
string u_firstname = Console.ReadLine(); // read user input
first_names[u_i] = u_firstname;
// first_names[0] = "Robert";

Console.WriteLine("New List of First Names");
Console.WriteLine("===========================");
for (int i = 0; i < first_names.Count; i++)
{
    int id = i + 1;
    Console.WriteLine(id + ". " + first_names[i]);
    // increment of i
} // for loop

Console.WriteLine("Chapter 6");
Console.WriteLine("=========");
// page 170

// accessType returnType methodName()  { ops; }  page 171
//// accessType -> nothing(scope) public private "protected"
//// returnType -> void any boolean "something else"
//// () empty params  (x,y) parameterized (x,y="0") query string params
//// methodName best practice to be camelCase or underscore_case

// declare or "define" the method

void myCalculator(int x, int y) {
    // 2 values are passed outside the method

    // calculate z
    int z = x + y;

    // return of z last step
    // test z for condition
    // if  ( z < 100 ) {true}

    Console.WriteLine(z);  // Last step defines the return

} // myCalculator

// somewhere else in life.... call a function
// if you can not see the function in the drop down, you can not access it

myCalculator(7, 3); // call the function and passing the arguments to the parameters  "call, pass, args, params"