#! /usr/bin/env ruby

# Fetches every revision of a file from subversion.
# Usage: svn_explode [file...]

require 'yaml'
require 'open3'

def capture_output(*args)
  output = ""
  Open3.popen3(*args) do |stdin, stdout, stderr|
    output = stdout.read
    $stderr.print stderr.read
  end
  return output
end

def get_url(file)
  url = ""
  capture_output("svn", "info", file).each_line do |line|
    next unless line =~ /^URL: (.*)/
    return $1
  end
  raise "Couldn't get the URL for #{file}"
end

def get_version_history(file)
  versions = []
  capture_output("svn", "log", "-q", file).each_line do |line|
    next unless line =~ /r(\d+)/
    versions.push $1.to_i
  end
  return versions
end

def checkout_file(file, revision)
  url = get_url file
  puts "Getting r#{revision}"
  contents = capture_output "svn", "cat", "-r", revision.to_s, url
  open("#{file}.r#{revision}", "w+") {|f| f.write contents}
end

ARGV.each do |file|
  puts "Examining #{file}"
  versions = get_version_history(file)
  versions.each do |version|
    checkout_file file, version
  end
end