#! /usr/bin/env ruby
# automates a binary search between the specified revision and HEAD.

# comma-separated list of revisions to skip
skiprevs = "8827,8934,8947,8977,9812"
buildcmd = "ant clean build"
deploycmd = "ant webapp.deploy"

require 'optparse'
require 'ostruct'

options = OpenStruct.new
options.first = 0
options.help = false
options.verbose = false
options.last = 'HEAD'

opts = OptionParser.new do |opts|
  opts.banner = "Usage: binsearch.rb [options]"
  opts.on("-r", "--revision FIRST", "The first revision to start searching from, e.g. 8900.") do |s|
    options.first = s
  end
  opts.on("-l", "--last LAST", "The last revision to search to.  Defaults to HEAD.") do |l|
    options.last = l
  end
  opts.on("-v", "--verbose", "Show more information") do |v|
    options.verbose = v
  end
  opts.on_tail("-h", "--help", "Show this usage statement.") do |h|
    options.help = true
  end
end

begin
    opts.parse!(ARGV)
rescue Exception => e
    puts e, "", opts
    exit
end

if (options.help == true) then
    puts opts
    exit
elsif (options.first == 0) then
    puts "You must specify the first revision number to begin searching from, e.g 'binsearch.rb -f 8080'  See 'binsearch.rb -h' for help."
    exit
end

first = options.first
last = options.last

statstr = `svn stat --non-interactive .`
statstr.each_line do |line|
    line =~ /^M\s+(.+)/
    if $1 then
        print "\aWARNING: found changes in the repository: #{$1}\nWould you like to continue (y/n) "
        answer = gets.chomp
        if answer !~ /y|Y|yes|Yes/ then
            exit
        end
    end
end

revs = []
revstr = `svn log --non-interactive --xml -r#{first}:#{last} . | grep revision=`
revstr.each_line do |line|
    line =~ /(\d+)/
    if skiprevs.include? $1 then
        puts "Skipping revision #{$1}." if (options.verbose)
    else
        revs.push $1
    end
end

svninfo = `svn info`
svninfo =~ /Revision: (\d+)/
startrev = $1
puts "Current revision is #{startrev}." if (options.verbose)

curindex = first = 0
lastindex = last = revs.length - 1

puts "Searching between #{revs[first]} and #{revs[last]}."

error = false

while true do
    currev = revs[curindex]
    puts "Synchronizing and building #{currev}.  #{(lastindex - curindex + 1).abs} remaining."
    if (currev != startrev) then
        svncmd = "svn up -r#{currev} ."
        puts "> #{svncmd}" if (options.verbose)
        svnresult = `#{svncmd}`
        if "#{$?.exitstatus}" != "0" then
            puts svnresult
            puts "\n\nWARNING: '#{svncmd}' exited with an error.  Please make you are inside the top level directory of a clean working copy and restart binsearch.rb."
            error = true
            break
        end
        puts "#{svnresult}" if (options.verbose)
    else
        puts "Already at build #{currev}.  Skipping svn up." if (options.verbose)
    end

    puts "> #{buildcmd}" if (options.verbose)
    buildresult = `#{buildcmd}`
    if "#{$?.exitstatus}" != "0" then
        puts buildresult
        puts "\n\nWARNING: '#{buildcmd}' exited with an error.  Please be sure you're working on a clean branch with no changes.  If you're sure this revision is problematic, please add '#{currev}' to the list of skipped builds at the top of binsearch.rb."
        error = true
        break
    end
    puts "#{buildresult}" if (options.verbose)

    puts "> #{deploycmd}" if (options.verbose)
    deployresult = `#{deploycmd}`
    if "#{$?.exitstatus}" != "0" then
        puts deployresult
        puts "\n\nWARNING: '#{deploycmd}' exited with an error.  Please make sure your server is running."
        error = true
        break
    end
    puts "#{deployresult}" if (options.verbose)


    print "\aDone.  Do you still see the problem? (y/n) "
    answer = gets.chomp
    lastindex = curindex
    if answer =~ /y|Y|yes|Yes/ then
        if (curindex == first) then
            puts "You must start from a revision number that does not show the problem."
            exit
        end
        # problem is between first and curindex
        last = curindex
        d = first - curindex
        if d == 1 || d == -1 then
            break
        end
    else
        # problem is between last and curindex
        first = curindex
        d = last - curindex
        if d == 1 || d == -1 then
            curindex += 1
            break
        end
    end
    curindex += (d / 2).to_i 
end

if error == false then
    puts "r#{revs[curindex]} is the revision with the problem:"
    puts `svn log -r#{revs[curindex]}`
end