#!/usr/bin/env ruby
require 'twitter'
require 'erb'
require 'trollop'

options = Trollop.options do
  opt :tag,  "Hashtag to use as a filter",
              :type => :string, :required => true

  opt :from, "Restrict to tweets from a specific user",
              :type => :string

  opt :template, "ERB template used to render the stream",
              :type => :string, :required => true

  opt :output, "Output to this file",
              :type => :string
end

class Tweetstream
  def initialize(hashtag, from = nil)
    @hashtag, @from = sanitize_hashtag(hashtag), from
  end

  def render(template_path)
    perform_search!
    template = File.read(template_path)
    ERB.new(template).result(binding)
  end

  private

  def sanitize_hashtag(hashtag)
    "##{hashtag}".squeeze('#')
  end

  def perform_search!
    query = Twitter::Search.new(@hashtag)
    query = query.from(@from) if @from
    @tweets = query.map { |tweet| tweet }
  end
end

stream = Tweetstream.new(options[:tag], options[:from])
output = stream.render(options[:template])

if options[:output]
  File.open(options[:output], 'w') { |io| io.write(output) }
else
  puts output
end