# Events Endpoint
Major Revisions:

Changes in details method:
1. Time is returned from Meetup as milliseconds since epoch. This needs to be converted to seconds, converted to a time unit, then converted to datetime. ✅
2. Meetup does not provide an end time, only a duration. The duration is not required, so if duration is nil the duration/1000 crashes the program. I added an if/else statement at the start of the method to make sure duration exists. ✅
3. Meetup does not provide a scholarship available option (commented it out). ✅

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### Code Review

I added comments in the code block below:
<hr/>

Details_for method in meetup.rb:

def details_for(event)
  # Perhaps extract this duration logic into a private method
  # that is dedicated to calculating event duration.
  # And then call that private method in this method.
  # That way, each method has their own discrete, single purpose.
    start_date = Time.at(event['time']/1000)
    if event['duration'].exists? 
      duration = event['duration']/1000
    else
      duration = 0
    end
  	{
  		meetup_id:event['id'],
      meetup_updated: Time.at(event['updated']).to_datetime,
  		name:event['name'],
  		description: event['description'],
  		url:event['link'],
  		start_date:start_date.to_datetime,
  		end_date: (start_date+duration).to_datetime, #end time is not provided, only start time and duration. 
      address1:event['venue']['address_1'],
  		address2:event['venue']['address_2'],
  		city: event['venue']['city'],
  		state: event['venue']['state'],
  		zip: event['venue']['zip']  
  		#scholarship_available: event[]
  	}
  end

Changes in database:
Note: I wrote the original database table based on feedback from Rick, but that was before we knew what Meetup provided.
1. Created a migration to add the columns meetup_id and meetup_updated to the events table. Added an index to meetup_id because that is how I'm searching for a record.

<hr/>

### Code Review

Instead of adding these columns unique to Meetups, perhaps go the [polymorphic association route](http://guides.rubyonrails.org/association_basics.html#polymorphic-associations). This will allow you to keep the door open to capturing similar information, for other `Event` sources. For example, from Facebook, etc.

So instead of creating a `meetup_id` column, you would create two new generic columns like:

:source_id, :string
:source_type, :string

And for the Meetup case, the `source_id` would be the Meetup's event ID, and the `source_type` would be "Meetup". And if this were a Facebook `Event`, the `source_id` would be the Facebook's event ID, and the `source_type` would be "Facebook".

You'll note that this is not exactly a polymorhpic association, because the `source_id` is a `string` instead of an `integer`, but it fits the desired behavior well.

And then add a third `source_updated` column if you like.

Feel free to use another term than `source_*`. Whatever works best.

<hr/>

add_columns_to_events.rb

class AddColumnsToEvents < ActiveRecord::Migration[5.0]
  def change
  	add_column :events, :meetup_id, :string, index: true, unique: true 
  	add_column :events, :meetup_updated, :datetime
  end
end

Changes in Event Class Validations (I wrote this as well originally)
1. Problem - Meetup doesn't require all the fields I originally required. So I commented out almost all the validations. I did add validations for meetup_id and meetup_updated. Meetup_id has a uniqueness validation so we don't write duplicate meetings to our database.

class Event < ApplicationRecord
	#Allowing URL, end_date, and address2 to be empty 
	  validates :name, presence: true
	# validates :description, presence: true
	  validates :start_date, presence: true
	  validates :meetup_id, presence: true, uniqueness: {case_sensitive: false}
	  validates :meetup_updated, presence: true 
	# validates :address1, presence: true
	# validates :city, presence: true
	# validates :state, presence: true, length: {is: 2} #Dropdown selection on front end?  
	# VALID_ZIP_REGEX= /\A\d{5}-?\d{4}?\z/
	# #validates :zip, presence: true, format:{with:VALID_ZIP_REGEX}
	# #validates :scholarship_available, inclusion: {in: [true, false]}
	# VALID_URL_REGEX = URI::regexp 
	# validates :url, format: {with:VALID_URL_REGEX}

end

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### Code Review

Good call. Based on the above polymorphic'ish implementation, you'll want to consider validating uniqueness against the combination of two fields. For example:

#This is ok:
#event 1
source_id: "22"
source_type: "Meetup"

#event 2
source_id: "22"
source_type: "Facebook"

#This is not ok:
#event 3
source_id: "33"
source_type: "Meetup"

#event 4
source_id: "33"
source_type: "Meetup"

Here is a [stackoverflow post](https://stackoverflow.com/a/5659281/3899985) that talks about how to do that.
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Here is the good stuff! This is the rake task to actually create and write the events to the database. events is a hash with the group url as the key. The value can be an array (if a group has multiple meetups scheduled)
meetup.rake

<hr/>

### Code Review

I added comments in the code block below:
<hr/>

namespace :meetup do
  desc "Rake task to get Meetup API data"
  task :fetch => :environment do 
    # Perhaps change this method to return a flattened array of hashes,
    # and add an attribute in each hash for the url?  For example,
    # [
    #   { url: group_url_1, ...remaining event attributes... },
    #   { url: group_url_1, ...remaining event attributes... },
    #   { url: group_url_2, ...remaining event attributes... },
    #   ...
    # ]
    # This way, you won't have to do nested looping inside of a loop.   
    # You can just take action directly on each hash in the array.
    events = Meetup.new.event_details_by_group
    
    events.each do |group, event|
      event.each do |event|
        # Instead of creating the event, and then if something goes wrong
        # because the Event already existed, update attributes, you can try 
        # the find_or_create_by! method here:  
        # https://apidock.com/rails/v4.0.2/ActiveRecord/Relation/find_or_create_by

        # And you would want to use the "!" version of this method so that
        # if there is an issue saving the record, it will throw an error, 
        # and not fail silently.  
        
        # Then you can catch the error in a rescue block, so you can
        # easily troubleshoot the issues, should any appear.
        # Here is an example of that:
        # https://github.com/OperationCode/operationcode_backend/blob/master/lib/tasks/users.rake#L18-L27
        new_event = Event.new(event) #Validation requires meetup_id be unique 
        new_event.save 

        if !new_event.valid? #It didn't save, so the meetup id exists 
          temp_event = Event.find_by(meetup_id: event[:meetup_id])
          temp_event.update_attributes(event)
        end
      end
    end
  end
end

IT WORKS!!! If I run docker-compose run web rake meetup:fetch all the events are pulled from Meetup and populated in the Events database. If I then load local host I can see the events in my browser as json.