#!/usr/bin/ruby

require 'net/http'
require 'rexml/document'
require 'rss/0.9'
require 'tempfile'
require 'uri'
require 'yaml'

include REXML

ISSUE_NUMBER=/[A-Z]{1}[A-Z0-9]{1,7}-[0-9]{1,4}/

class Issue

  attr_accessor :issue, :category, :description
  def initialize(url)
    @issue = id(url)
    @links = [url]
  end

  def to_wiki  
    links = @links.map { |url| "[#{id(url)}|#{url}]" }.join("/")
    "#{links} - #{@description}"
  end

  def id(url)
    url.scan(ISSUE_NUMBER)[0]
  end

  def <=>(other)
    return (@issue <=> other.issue)
  end
  
  def ==(other)
    @issue == other.issue
  end
  
  def hash
    @issue.hash
  end
  
  def eql?(other)
    self == other
  end

end


class ReleaseNotes

  def initialize(version)
    @version = version
    @issues = Array.new
  end

  def read_svn(revision)
    temp_file = Tempfile.new('release_notes')
    system("svn log -r #{revision}:HEAD > #{temp_file.path}")
    
    IO.foreach(temp_file.path) { |line|
      line.scan(ISSUE_NUMBER).uniq.each { |id|
        readRssFeed("http://issues.apache.org/activemq/si/jira.issueviews:issue-xml/#{id}/#{id}.xml") { |issue,item|
          @issues << issue unless nil == issue
        }
      }
    }
  end
  
  def readRssFeed(url)
    response = Net::HTTP.get_response(URI.parse(url))
    if (response.code == '302') then
      response = Net::HTTP.get_response(URI.parse(response['Location']))
    end
    
    begin
      response.value();     # this raises an HTTP error if status != 2xx
      doc = Document.new(response.body)

      XPath.each(doc, "//item") do |item|  
        issue = Issue.new(XPath.first(item, "link/text()").to_s)
        issue.category = XPath.first(item, "type/text()").to_s
        issue.description = XPath.first(item, "title/text()").to_s.gsub(/\[\(?[A-Z0-9]{2,7}-[0-9]{1,4}\)?\]/, "").strip
        yield issue, item
      end	
    rescue Exception => e
      puts "Error while reading #{url}: #{e}"
      yield nil, nil
    end
  end

  def to_wiki
    puts
    puts "h3. {excerpt}Release notes - #{@version}{excerpt}"
    
    categories = @issues.map { |issue| issue.category }.uniq.sort
    categories.each { |category|
      puts 
      puts "h4. #{category}"
      @issues.uniq.select { |issue| issue.category == category }.sort.each { |issue|
        puts "* #{issue.to_wiki}"
      }
    }
  end

end

class Project

  def initialize
    @versions = Array.new
  
    trunk = svn_info(".")['URL']
    @tags = trunk.sub(/\/trunk/, "/tags/").sub(/https/, "http")

    
    response = Net::HTTP.get_response(URI.parse(@tags))

      response.value();     # this raises an HTTP error if status != 2xx
      response.body.scan(/<ul>[<>.="'\/\-\w\s]*<\/ul>/) { |ul|
        doc = Document.new(ul)
        XPath.each(doc, "//li/a/text()") do |version|  
          @versions << version.to_s
        end	
      }
  end
  
  def current_release 
    @versions.last.gsub(/\//, "")
  end 
  
  def previous_release_revision
    tag = @tags + @versions[@versions.size - 2]
    svn_info(tag)['Last Changed Rev']
  end
  
  def svn_info(url)
    temp_file = Tempfile.new('svn_info')
    system("svn info #{url} > #{temp_file.path}")
    
    YAML::load(temp_file.open)
  end

end

project = Project.new
puts "Release notes for version #{project.current_release}"
puts "Reading commit logs from revision #{project.previous_release_revision}"

notes = ReleaseNotes.new(project.current_release)
notes.read_svn(project.previous_release_revision)
notes.to_wiki