Add distance class and distance_between_air method (#64)

* Add distance class and distance_between_air method

* Apply PR review changes

.rubocop.yml

@@ -5,7 +5,7 @@ AllCops:
     - 'turkish_cities.gemspec'
   NewCops: enable
 Layout/LineLength:
-  Max: 100
+  Max: 120
 Metrics/AbcSize:
   Max: 20
 Metrics/BlockLength:

CHANGELOG.md

@@ -2,11 +2,16 @@
 
 ## master (unreleased)
 
+### New features
+
+* [#13](https://github.com/sarslanoglu/turkish_cities/issues/13): Add ```distance``` class and ```distance_between``` method for calculating air travel distance and time estimation between cities
+
 ### Changes
 
-* [#45](https://github.com/sarslanoglu/turkish_cities/issues/45): Refactor `District` class
 * [#50](https://github.com/sarslanoglu/turkish_cities/issues/50): Additional improvements on `District` class methods
 
+* [#45](https://github.com/sarslanoglu/turkish_cities/issues/45): Refactor `District` class
+
 ## 0.2.1 (2020-06-29)
 
 ### Bug fixes

README.md

@@ -25,6 +25,9 @@
     * [With subdistrict info](#with-subdistrict-info)
     * [Without subdistrict info](#without-subdistrict-info)
   * [Finding city, district and subdistrict name by postcode](#finding-city-district-and-subdistrict-name-by-postcode)
+  * [Finding travel distance and time estimation between two cities](#finding-travel-distance-and-time-estimation-between-two-cities)
+    * [By air](#by-air)
+* [Data sources](#data-sources)
 * [Compatibility](#compatibility)
 * [Contributing](#contributing)
 * [Changelog](#changelog)
@@ -242,6 +245,41 @@ TurkishCities.find_by_postcode(34382)    # => "Couldn't find any subdistrict wit
 TurkishCities.find_by_postcode('100000') # => Given value [100000] is outside bounds of 1010 to 81952.
 ```
 
+### Finding travel distance and time estimation between two cities
+
+### By air
+
+City names can be given case and turkish character insensitive. Travel method should be lower case. Array with 3 elements will be return. First element is distance between cities in kilometers, second element is estimated travel time and last element is description created by first two element.
+
+```rb
+TurkishCities.distance_between('Eskişehir', 'Kastamonu', 'air')
+# => [327.74, 62, "Air travel distance between Eskişehir and Kastamonu is 327.74 km. Estimated air travel would take 62 minutes."]
+TurkishCities.distance_between('kirsehir', 'Ordu', 'air')
+# => [376.89, 67, "Air travel distance between Kırşehir and Ordu is 376.89 km. Estimated air travel would take 67 minutes."]
+TurkishCities.distance_between('İzmir', 'Antalya', 'air')
+# => [357.18, 65, "Air travel distance between İzmir and Antalya is 357.18 km. Estimated air travel would take 65 minutes."]
+TurkishCities.distance_between('istanbul', 'kars', 'air')
+# => [1187.94, 120, "Air travel distance between İstanbul and Kars is 1187.94 km. Estimated air travel would take 120 minutes."]
+TurkishCities.distance_between('Adana', 'Adıyaman', 'time')
+# => "Travel method 'time' is unsupported"
+TurkishCities.distance_between('filansa', 'falansa', 'air')
+# => "Couldn't find cities combination with 'filansa/falansa'"
+```
+
+## Data sources
+
+All information related with cities can be found at:
+
+```
+https://tr.wikipedia.org/wiki/{#city_name_here}
+```
+
+Districts, subdisctricts, neighborhoods and postcodes can be found at:
+
+```
+https://postakodu.ptt.gov.tr/
+```
+
 ## Compatibility
 
 | Ruby Version | Supported          |
@@ -251,7 +289,7 @@ TurkishCities.find_by_postcode('100000') # => Given value [100000] is outside bo
 | 2.5.8        | :white_check_mark: |
 | < 2.5.1      | :x:                |
 
-- This gem heavily depends on ```:turkic``` case mapping support of Ruby string downcase method. Below Ruby version 2.5.1 some functions will run buggy/false or even won't run at all.
+- TurkishCities heavily depends on ```:turkic``` case mapping support of Ruby string downcase method. Below Ruby version 2.5.1 some functions will run buggy/false or even won't run at all.
 
 ## Contributing
 
@@ -261,6 +299,10 @@ Contributing guidelines are available [here](CONTRIBUTING.md).
 
 Changelog is available [here](CHANGELOG.md).
 
+## Logo
+
+TurkishCities's logo created by [Nebal Çolpan](https://www.behance.net/nebalcolpan)
+
 ## Copyright
 
 Copyright (c) 2020 Semih Arslanoglu. See [LICENSE.txt](LICENSE.txt) for

lib/turkish_cities.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require_relative '../lib/turkish_cities/city'
+require_relative '../lib/turkish_cities/distance'
 require_relative '../lib/turkish_cities/district'
 require_relative '../lib/turkish_cities/postcode'
 require_relative '../lib/turkish_cities/version'
@@ -30,6 +31,10 @@ def self.list_districts(city_name)
     City.new.list_districts(city_name)
   end
 
+  def self.distance_between(from, to, travel_method)
+    Distance.new(from, to, travel_method).distance_between
+  end
+
   def self.list_subdistricts(city_name, district_name)
     District.new(city_name, district_name).subdistricts
   end

lib/turkish_cities/city.rb

@@ -26,9 +26,10 @@ def find_by_phone_code(phone_code)
     check_phone_code(phone_code)
 
     CITY_LIST.each do |city|
-      if city['phone_code'].is_a?(Array)
+      case city['phone_code']
+      when Array
         return city['name'] if city['phone_code'].include?(phone_code.to_i)
-      elsif city['phone_code'] == phone_code.to_i
+      when phone_code.to_i
         return city['name']
       end
     end