#!/usr/bin/env ruby

USAGE = <<-EOS
--------------------------------------------------------------------------------
  update_puppetfile <puppetfile_branch> <module_name> <git_ref> <module_workspace>
--------------------------------------------------------------------------------
  <puppetfile_branch>
    Name of the branch to checkout for puppetfile repo (in dynamic environments, this 
    will be the same as the git_ref for the module)

  <module_name>
    Name of the module to update in the Puppetfile

  <git_ref>
    The git ref (branch, tag, sha) that we want to set for the module_name in
    the Puppetfile.
    NOTE: production Puppetfile will only have release tags as git refs

  <module_workspace>
    The module's workspace where we will clone the puppetfile repo into

EOS

class PuppetfileRepo
  attr_accessor :git_work_dir, :git_dir, :git_branch

  def puppetfile_exists?() File.file?("#{git_work_dir}/Puppetfile") end

end

class ModuleInfo
  attr_accessor :module_name, :module_git_ref, :module_workspace
end

# instantiate ModuleInfo class with arguments passed in to this script at runtime
def get_module_info_from_args(mod_name, mod_git_ref, mod_workspace)
  module_info = ModuleInfo.new
  module_info.module_name = mod_name
  module_info.module_git_ref = mod_git_ref
  module_info.module_workspace = mod_workspace
  puts "#{module_info.module_git_ref}"
  return module_info
end

# instantiate and return a PuppetfileRepo object with git info
def checkout_puppetfile_repo(puppetfile_branch, module_info)

  repo = PuppetfileRepo.new
  puppetfile_git_repo = "git@github.com:maju6406/control-repo.git"
  git_work_dir = File.expand_path(module_info.module_workspace + "/p_file_repo")
  git_dir = git_work_dir + "/.git"
  repo.git_work_dir = git_work_dir
  repo.git_dir = git_dir
  repo.git_branch = puppetfile_branch
  git_checkout_production_cmd = "git --git-dir=#{git_dir} --work-tree=#{git_work_dir} checkout production"
  git_checkout_new_branch_cmd = "git --git-dir=#{git_dir} --work-tree=#{git_work_dir} checkout -b #{puppetfile_branch}"
  git_checkout_existing_branch_cmd = "git --git-dir=#{git_dir} --work-tree=#{git_work_dir} checkout #{puppetfile_branch}"
  git_clone_cmd = "git clone #{puppetfile_git_repo} #{module_info.module_workspace}/p_file_repo"
  git_pull_cmd = "git --git-dir=#{git_dir} --work-tree=#{git_work_dir} pull origin #{puppetfile_branch}"
  git_fetch_cmd = "git --git-dir=#{git_dir} --work-tree=#{git_work_dir} fetch --prune"
  git_merge_prod_cmd = "git --git-dir=#{git_dir} --work-tree=#{git_work_dir} merge origin/production -X ours --no-edit"
  # if the puppetfile repo doesn't exist yet, clone it
  if(!repo.puppetfile_exists?)
    puts "Puppetfile repo doesn't exist. Cloning it now..."
    clone_out = `#{git_clone_cmd}`
    puts "clone output: \n#{clone_out}" 
  end
  # see if module's branch name exists in puppetfile repo
  git_remote_branch_cmd = "git ls-remote --heads #{puppetfile_git_repo} | grep #{puppetfile_branch}"
  puts "\n#{git_remote_branch_cmd}\n"
  `#{git_remote_branch_cmd}`
  if($?.success?) # branch already exists, so check it out
    `#{git_checkout_production_cmd}`
    `#{git_fetch_cmd}`
    puts "The puppetfile repo already has a branch called #{puppetfile_branch}, so checking it out."
    `#{git_checkout_existing_branch_cmd}`
    puts "pull to ensure latest"
    `#{git_pull_cmd}`
    puts "merge production to get latest production version"
    `#{git_merge_prod_cmd}`
  else # branch not found, need to create it and check it out
    puts "The puppetfile repo does not have a branch called #{puppetfile_branch}, so creating it."
    `#{git_checkout_production_cmd}`
    `#{git_checkout_new_branch_cmd}`
  end
  return repo

end

# This is how the Puppetfile with our module def gets its git :ref value automatically updated.
def update_puppetfile_module_ref(puppetfile_repo, module_info)

  begin
    contents = File.read("#{puppetfile_repo.git_work_dir}/Puppetfile")
    puts "original file contents = #{contents}"
    regex = /mod (["'])#{module_info.module_name}\1(.*?)[\n]\s*:commit\s*=>\s*(['"])(\w+|\w+\.\d+\.\d+)\3/m

    new_contents = contents.gsub(regex, """
mod '#{module_info.module_name}'\\2
  :ref => '#{module_info.module_git_ref}'
""".strip)

    puts "after regex, file contents = #{new_contents}"
    
    file = File.open("#{puppetfile_repo.git_work_dir}/Puppetfile", "w")
    file.write(new_contents)
    file.close()
    p_file_after_write = `cat #{puppetfile_repo.git_work_dir}/Puppetfile`
    puts "\npuppetfile after writing: #{p_file_after_write}"

    commit_msg = "changing :ref for #{module_info.module_name} to #{module_info.module_git_ref}"
    git_commit_cmd = "git --git-dir=#{puppetfile_repo.git_dir} --work-tree=#{puppetfile_repo.git_work_dir}"
    git_commit_cmd += " add #{puppetfile_repo.git_work_dir}/Puppetfile"
    git_commit_cmd += " && "
    git_commit_cmd += "git --git-dir=#{puppetfile_repo.git_dir} --work-tree=#{puppetfile_repo.git_work_dir}"
    git_commit_cmd += " commit -m \"#{commit_msg}\""
    git_commit_cmd += " && "
    git_commit_cmd += "git --git-dir=#{puppetfile_repo.git_dir} --work-tree=#{puppetfile_repo.git_work_dir}"
    git_commit_cmd += " push origin #{puppetfile_repo.git_branch}"
    puts "executing git commands:\n#{git_commit_cmd}"
    puts ""
    commit_result = `#{git_commit_cmd}`
    puts "commit results:\n#{commit_result}\n"

    exit(true)

  rescue RuntimeError => e
    puts "!!! ERROR: " + e.message
    exit(false)
  end
end

def update_puppetfile(args)

  if(args == nil || args[0] == nil)
    puts USAGE
    exit(false)
  elsif (args[0].include?("help"))
    puts USAGE
    exit(true)
  end

  begin
    module_info = get_module_info_from_args(args[1], args[2], args[3])
    puppetfile_repo = checkout_puppetfile_repo(args[0], module_info)
    update_puppetfile_module_ref(puppetfile_repo, module_info)
  end

end

update_puppetfile(ARGV)