require 'base64'

require_relative 'util'

module HelixVersioningEngine
  # This class assists in creating changelists based on an array of file
  # changes, some of which may be file uploads.
  #
  # This is the implementation for file uploads and change creation.
  class ChangeService
    # The P4 connection we're using, that should already be logged in for a
    # particular user.
    attr_reader :p4

    # The name of the temporary client
    attr_reader :client_name

    # The root directory of the temporary client
    attr_reader :client_root

    def initialize(p4: nil, client_name: nil, client_root: nil)
      @p4 = p4
      @client_name = client_name
      @client_root = client_root
    end

    def submit(files: [], description: 'Updating files')
      change_id = Util.init_changelist(p4, description)

      begin
        files = files.map { |f| f.is_a?(ChangeService::File) ? f : ChangeService::File.new(f) }

        collect_file_results(files)

        files.each { |f| f.call(p4, change_id, client_root) }

        p4.run_submit('-c', change_id)

      rescue StandardError => ex
        # Delete the changelist
        p4.at_exception_level(P4::RAISE_NONE) do
          p4.run('revert', '-c', change_id, '//...')
          p4.run_change('-d', change_id)
          if Util.error?(p4)
            puts "possible issues deleting change #{change_id}: #{p4.messages}"
          end
        end
        raise ex
      end
    end

    # Handles tracking 'file modification' operations on a single file for a
    # change.
    #
    # One important aspect of initializing these files is assigning a 'files'
    # result. The ChangeHelper pretty much grabs the output of 'p4 files' for
    # all file changes, which lets us know if a file exists or not in the
    # system, which changes downstream behavior during an upload process.
    class File
      attr_accessor :depot_file

      attr_accessor :action

      attr_accessor :content

      # For *some* actions, like a move, we need this indicated by the user.
      attr_accessor :from_depot_file

      # The output of p4 files on this depot_file path, if it exists.
      attr_accessor :file_result

      # If set, this should be the version number we require before running.
      # If you want to require a new file, this should be set to 0. Otherwise
      # specify the version directly.
      attr_accessor :require_version

      # Notice how the file *must* be specified using our 'external normalized'
      # data style.
      def initialize(depot_file: nil, action: nil, content: nil,
                     from_depot_file: nil,
                     require_version: nil)

        @depot_file = depot_file
        @action = action
        @content = content
        @from_depot_file = from_depot_file
        @require_version = require_version
      end

      # The "external" JSON representation uses a CamelCase style string.
      def self.from_json(obj)
        args = {}

        args[:depot_file] = obj['DepotFile'] if obj.key?('DepotFile')
        args[:action] = obj['Action'] if obj.key?('Action')
        args[:from_depot_file] = obj['FromDepotFile'] if obj.key?('FromDepotFile')
        args[:require_version] = obj['RequireVersion'] if obj.key?('RequireVersion')

        content_base64 = obj['Content'] if obj.key?('Content')
        args[:content] = Base64.decode64(content_base64) if content_base64

        self.new(args)
      end

      def exists?
        !file_result.nil? && file_result['action'] != 'delete'
      end

      #
      # This really should only be called by ChangeHelper::call to do work
      # once we have associated any file_result and from_file properties.
      def call(p4, change_id, client_root)
        case action
        when 'upload'
          upload_file(p4, change_id, client_root)
        when 'branch'
          integrate_file(p4, change_id)
        when 'move'
          move_file(p4, change_id)
        end
      end

      def upload_file(p4, change_id, client_root)
        Util.assert_no_special_paths(@depot_file.split('/'))

        if !require_version.nil?
          if require_version == 0 && exists?
            msg = "assertion failed: file #{@depot_file} exists"
            raise P4Error.default_error(msg)
          end

          cur_version = 0
          cur_version = file_result['rev'].to_i if exists?
          if cur_version != require_version.to_i
            msg = "assertion failed: file #{@depot_file} not at required " \
                  "version #{require_version}, " \
                  "current version is #{cur_version}"
            raise P4Error.default_error(msg)
          end
        end

        if exists?
          p4.run_sync(depot_file)
          Util.mark_change('edit', p4, change_id, client_root, depot_file)
          Util.save_content(client_root, depot_file, content)
        else
          Util.save_content(client_root, depot_file, content)
          Util.mark_change('add', p4, change_id, client_root, depot_file)
        end
      end

      def integrate_file(p4, change_id)
        p4.run_integrate('-c', change_id, from_depot_file, depot_file)
      end

      def move_file(p4, change_id)
        p4.run_move('-c', change_id, from_depot_file, depot_file)
      end
    end

    private

    # Runs p4 files on all our depot paths, then updates each file model
    # that exists.
    def collect_file_results(files)
      file_results = p4.run_files(depot_files(files))
      file_results.each do |file_result|
        file = file_for_depot_file(files, file_result['depotFile'])
        file.file_result = file_result if file
      end
    end

    def depot_files(files)
      files.map(&:depot_file)
    end

    def file_for_depot_file(files, depot_file)
      files.find { |f| f.depot_file == depot_file }
    end
  end
end