# ********** Copyright Viacom, Inc. Apache 2.0 **********

module RokuBuilder

  # Change stage of roku application
  class Stager

    def initialize(key: nil, method:, root_dir:, logger:)
      @method = method
      @key = key
      @root_dir = root_dir
      @logger = logger
      @stage_success = true
      @stash_key = "roku-builder-temp-stash"
    end

    # Helper method to get the staging method being used
    # @return [Symbol] staging method being used
    def method
      @method
    end


    # Change the stage of the app depending on the method
    # @return [Boolean] whether the staging was successful or not
    def stage
      @orginal_directory = Dir.pwd
      Dir.chdir(@root_dir) unless @root_dir == @orginal_directory
      case @method
      when :current
        # Do Nothing
      when :working
        # Do Nothing
      when :git
        begin
          git_switch_to(branch: @key)
        rescue Git::GitExecuteError
          git_rescue
          @stage_success = false
        end
      when :script
        Controller.system(command: @key[:stage])
      end
      @stage_success
    end

    # Revert the change that the stage method made
    # @return [Boolean] whether the revert was successful or not
    def unstage
      @orginal_directory ||= Dir.pwd
      Dir.chdir(@root_dir) unless @root_dir == @orginal_directory
      unstage_success = true
      case @method
      when :current
        # Do Nothing
      when :working
        # Do Nothing
      when :git
        begin
          git_switch_from(branch: @key, checkout: @stage_success)
        rescue Git::GitExecuteError
          git_rescue
          unstage_success = false
        end
      when :script
        Controller.system(command: @key[:unstage])  if @key[:unstage]
      end
      Dir.chdir(@orginal_directory) unless @root_dir == @orginal_directory
      unstage_success
    end

    private

    # Switch to the correct branch
    # @param branch [String] the branch to switch to
    def git_switch_to(branch:)
      if branch
        @git ||= Git.open(@root_dir)
        @git.branch.stashes.save(@stash_key)
        if @git and branch != @git.current_branch
          @current_branch = @git.current_branch
          @git.checkout(branch)
          save_state
        end
      end
    end

    # Switch back to the previous branch
    # @param branch [String] teh branch to switch from
    # @param checkout [Boolean] whether to actually run the checkout command
    def git_switch_from(branch:, checkout: true)
      @current_branch ||= nil
      if branch
        @git ||= Git.open(@root_dir)
        if @git and (@current_branch or load_state)
          @git.checkout(@current_branch) if checkout
        end
        if @git
          index = 0
          @git.branch.stashes.each do |stash|
            if stash.message == @stash_key
              @git.branch.stashes.pop("stash@{#{index}}")
              break
            end
            index += 1
          end
        end
      end
    end

    # Save staging state to file
    def save_state
      store = PStore.new(File.expand_path("~/.roku_pstore"))
      store.transaction do
        store[:current_branch] = @current_branch.to_s
      end
    end

    # Load staging state from file
    def load_state
      store = PStore.new(File.expand_path("~/.roku_pstore"))
      store.transaction do
        @git.branches.each do |branch|
          if branch.to_s == store[:current_branch]
            @current_branch = branch
            store[:current_branch] = nil
            break
          end
        end
        !!@current_branch
      end
      !!@current_branch
    end

    # Called if resuce from git exception
    def git_rescue
      @logger.error "Branch or ref does not exist"
    end
  end
end