Generates contexts

generate_context.rb

require 'iconv'

def content_to_xml(context)
"<context number=\"#{context[:number]}\">
	<city>#{context[:city]}</city>
	<state>#{context[:state]}</state>
	<lat>#{context[:lat]}</lat>
	<long>#{context[:long]}</long>
	<day>#{context[:day]}</day>
	<time>#{context[:time]}</time>
	<season>#{context[:season]}</season>
</context>"
end

def weighted_sample(lst)
	w = Random.new.rand(1..lst.last[:pop_acc])
	lst.find do |item|
		w <= item[:pop_acc] && item[:population] != 0
	end
end

if ARGV.length < 1
	puts "usage: FILE [count] [population_min]"
	exit
end

# file comes from http://download.geonames.org/export/dump/
filename = ARGV[0]
count = [ARGV[1].to_i, 1].max
pop_min = ARGV[2] || 100000

content = IO.read(filename)
contnet = Iconv.conv('UTF8//UNKNOWN', 'UTF-8', content)
content = content.lines.map { |line| line.split("\t") }
content = content.each { |cols| cols[14] = cols[14].to_i }
content = content.find_all { |cols| cols[6] == 'P' && cols[14] > pop_min }
cities = content.map do |cols|
	{
		:city => cols[1],
		:state => cols[10],
		:population => cols[14],
		:lat => cols[4],
		:long => cols[5],
		:contexts => []
	}
end

days = %w(weekday weekend)
seasons = %w(spring summer fall winter)
times = %w(morning afternoon evening)

contexts = days.map do |day|
	seasons.map do |season|
		times.map do |time|
			{ :day => day, :season => season, :time => time }
		end
	end
end.flatten

cities.inject(0) do |pop_sum, city|
	result = pop_sum + city[:population] * contexts.length
	city[:pop_acc] = result
	result
end

(1..count).each do |number|
	city = weighted_sample(cities)
	city[:contexts] << (contexts - city[:contexts]).sample

	if (contexts - city[:contexts]).empty?
		index = cities.index(city)
		cities[index..-1].each do |item|
			item[:pop_acc] -= city[:population]
		end
		city[:population] = 0
	end
end

contexts = cities.map do |city|
	city[:contexts].map do |context|
		puts context
		{
			:city => city[:city],
			:state => city[:state],
			:lat => city[:lat],
			:long => city[:long],
			:day => context[:day],
			:time => context[:time],
			:season => context[:season]
		}
	end
end

contexts = contexts.flatten.shuffle

contexts.each_with_index do |context, number|
	context[:number] = number + 1
end

contexts.each do |context|
	puts content_to_xml(context)
end