# Creating a variables and assign their values in Ruby

age = 30

name = "Iqbal Farabi"

is_male = true

# Ruby
age = 30

# C and Java
int age;
age = 30;
# or
int age = 30;

width = 10
height = 15

# Ruby evaluates expression in the right side of operator "=" first
# then it names the result with variable in the left side of operator "="
area = width * height

# Ruby
a = 10
a = "Hello, World!"

# C and Java
int a;
a = 10;
a = "Hello, World!"; # this expression will cause an error in C and Java

# Conditional statement with 'if', 'else', dan 'elsif'

require 'date'

if Date.today < Date.new(2017, 9, 18)
  puts "Today's date is less than September 18th 2017"
elsif Date.today == Date.new(2017, 9, 18)
  puts "Today's date is September 18th 2017"
else
  puts "Today's date is greater than September 18th 2017"
end

# Conditional statement with 'if' can also be written inline
puts "Today's date is September 18th 2017" if Date.today == Date.new(2017, 9, 18)

# Conditional statement with 'unless' and 'else'

require 'date'

unless Date.today.saturday? || Date.today.sunday?
  puts "Work hard"
else
  puts "Play hard"
end

# Conditional statement with 'unless' can also be written inline
puts "Not freaky" unless Date.today.friday?

# Conditional statement with 'case' and 'when'

require 'date'

case Date.today.strftime("%A")
when "Monday"
  puts "Blue"
when "Tuesday"
  puts "Grey"
when "Wednesday"
  puts "Too"
when "Thursday"
  puts "I don't care about you"
when "Friday"
  puts "I'm in love"
end

# Conditional statement with ternary operator

Time.now.hour < 12 ? "AM" : "PM"

# Ternary operator can also be used to do inline conditional assignment

meridian = Time.now.hour < 12 ? "AM" : "PM"
puts meridian

# In some cases, ternary operator comes in handy

allowed_license_number = Time.now.day % 2 == 0 ? "even" : "odd"
puts "Only cars with #{allowed_license_number} license plate are allowed today"

a = 1
b = 2

a == b
# false

a > b
# false

a < b
# true

a >= b
# false

a <= b
# true

a != b
# true

# Operator &&
# What are the results of these:

true && true

true && false

false && true

true && true

false && false

# Operator ||
# What are the results of these:

true || true

true || false

false || true

true || true

false || false

# Operator &&
# What are the results of these:

true && true
# true

true && false
# false

false && true
# false

true && true
# true

false && false
# false

# Operator ||
# What are the results of these:

true || true
# true

true || false
# true

false || true
# true

true || true
# true

false || false
# false

# Spaceship Operator (also called compariosn operator) has special characteristic
# as it has three possible values as folow:

1 <=> 2
# -1

1 <=> 1
# 0

2 <=> 1
# 1

# There's one more value thoug
# if two non comparable things are compared,
# it will return nil
1 <=> 'a'
# nil

# Truthy and falsey in Ruby

# Only false and nils that are evaluated as falsey

if false
  puts "nil is truthy"
else
  puts "nil is falsey"
end

if nil
  puts "nil is truthy"
else
  puts "nil is falsey"
end

# Everything else is evaluated as truthy

[true, false, Object, 0, 1, nil, true, false, "", [1, 2, 3], {}].each do |value|
  if value
    puts "#{value.inspect} is truthy"
  else
    puts "#{value.inspect} is falsey"
  end
end

# Lazy Evaluation

# Which message printed by expression below?
puts("Ini pesan yang tidak penting") && puts("INI PESAN YANG PENTING")

# What is the value of c?
a = 1
b = 2
c = a || b

# Complete the following skeleton

def fav_programming_language
  puts "What is your favorite programming language?"
  language = gets.chomp
  # your code here
  # ......
end

how_many_times(40,15)
# will return 3

how_many_times(30,10)
# will return 3

how_many_times(80,15)
# will return 6

reverse_words("Hey fellow scholars") # returns "Hey wollef sralohcs" 
reverse_words("This is a test") # returns "This is a test" 
reverse_words("This is another test") # returns "This is rehtona test"

# Since we have not learned about basic data types and loop in Ruby
# you can follow this skeleton

def reverse_words(sentence)
  words = []
  sentence.split(" ").each do |word|
    # your code here
    # clue: 
    # 1. You can find the number of characters in a word using ".length" or ".size"
    # 2. You can reverse a string by using ".reverse"
    # 3. You can add element to an array using "<<"
  end
  words.join(" ")
end

mix_fruit(["banana","mango","avocado"]) # will resturn: 6
mix_fruit(["melon","Mango","kiwi"]) # will resturn: 8
mix_fruit(["watermelon","cherry","avocado"]) # will resturn: 8
mix_fruit(["watermelon","lime","tomato"]) # will resturn: 9
mix_fruit(["blackBerry","coconut","avocado"]) # will resturn: 8
mix_fruit(["waterMelon","mango"]) # will resturn: 8
mix_fruit(["watermelon","pEach"]) # will resturn: 9
mix_fruit(["watermelon","Orange","grapes"]) # will resturn: 6
mix_fruit(["watermelon"]) # will resturn: 9
mix_fruit(["BlACKbeRrY","cOcONuT","avoCaDo"]) # will resturn: 8

def mix_fruit(fruits)
  price = 0
  fruits.each do |fruit|
    # your code here
  end
  
  # your code here
  # clue: use ".size" method to get the size of an array
end