// Part 2 about Alcohol-Consumption Worldwide
//============================================

object CW6b {

import io.Source
import scala.util._

val url_alcohol =
  "https://raw.githubusercontent.com/fivethirtyeight/data/master/alcohol-consumption/drinks.csv"

val file_population =
  "population.csv"


//(1) Complete the get_csv_page function below. It takes a URL-string
//    as argument and generates a list of strings corresponding to each
//    line in the downloaded csv-list. The URL url_alcohol above is one
//    possible argument.

//def get_csv_page(url: String) : List[String] = ...
def get_csv_page(url: String) : List[String] = {
  val csv = Source.fromURL(url)
  val contents = csv.mkString.split("\n")
  contents.toList
}
//    Complete the get_csv_file function below. It takes a file name
//    as argument and reads the content of the given file. Like above,
//    it should generate a list of strings corresponding to each
//    line in the csv-list. The filename file_population is one possible
//    argument.

//def get_csv_file(file: String) : List[String] = ...
def get_csv_file(file: String) : List[String] = {
  val csv = Source.fromFile(file)
  val contents = csv.mkString.split("\n")
  contents.toList
}
//(2) Complete the functions that process the csv-lists. For
//    process_alcs extract the country name (as String) and the
//    pure alcohol consumption (as Double). For process_pops
//    generate a Map of Strings (country names) to Long numbers
//    (population sizes).

//def process_alcs(lines: List[String]) : List[(String, Double)] = ...
def process_alcs(lines: List[String]) : List[(String, Double)] = {
  val beheaded = lines.drop(1)
  val splitEntries = for (n <- beheaded) yield n.split(",").toList
  for (n <- splitEntries) yield (n.take(1).mkString, n.drop(4).mkString.toDouble)
}
//def process_pops(lines: List[String]) : Map[String, Long] = ...
def process_pops(lines: List[String]) : Map[String, Long] = {
  val beheaded = lines.drop(1);
  def toOnePair(line: String) : (String, Long) = {
    val splitAsList = line.split(",").toList
    (splitAsList.take(1).mkString, splitAsList.drop(1).mkString.toLong)
  }
  val splitEntries = for (n <- beheaded) yield toOnePair(n)
  splitEntries.toMap
}


//(3) Calculate for each country the overall alcohol_consumption using
//    the data from the alcohol list and the population sizes list. You
//    should only include countries on the alcohol list that are also
//    on the population sizes list with the exact same name. Note that
//    the spelling of some names in the alcohol list differs from the
//    population sizes list. You can ignore entries where the names differ.
//    Sort the resulting list according to the country with the highest alcohol
//    consumption to the country with the lowest alcohol consumption.

//def sorted_country_consumption() : List[(String, Long)] = ...
def sorted_country_consumption() : List[(String, Long)] = {
  val countryToPop = process_pops(get_csv_file(file_population))
  val countryAndAlc = process_alcs(get_csv_page(url_alcohol))
  val countryAndConsumption = countryAndAlc.collect {
    case oneCountryAndAlc
    if countryToPop.isDefinedAt(oneCountryAndAlc._1) =>
    (oneCountryAndAlc._1, (oneCountryAndAlc._2*countryToPop.get(oneCountryAndAlc._1).get).toLong)
  }
  countryAndConsumption.sortWith(_._2 > _._2)
}

//   Calculate the world consumption of pure alcohol of all countries, which
//   should be the first element in the tuple below. The second element is
//   the overall consumption of the first n countries in the sorted list
//   from above; and finally the double should be the percentage of the
//   first n countries drinking from the the world consumption of alcohol.

//def percentage(n: Int) : (Long, Long, Double) = ...
def percentage(n: Int) : (Long, Long, Double) = {
  val ctryConsump = sorted_country_consumption()
  val totalAlc = ctryConsump.map(_._2).sum
  val firstNAlc = ctryConsump.take(n).map(_._2).sum
  val pcntage = (firstNAlc*1.0/totalAlc)*100;
  (ctryConsump.map(_._2).sum, ctryConsump.take(n).map(_._2).sum, pcntage)
}
}