require 'hws_settings'
require 'projects/project_service'
require 'base64'

require 'hws_strings'

module HelixVersioningEngine
  # Define simple projects based on a single directory location in a Helix
  # Versioning Engine.
  #
  # This project service uses the HVE_PROJECTS_PATH setting to list available
  # projects on the particular server. If you only have one Helix Versioning
  # Engine, it's suitable to create this as a systemwide default. Otherwise,
  # you likely only want to specify this via headers.
  #
  # This will return everything as "helix versioning engine" project.
  class HVEProjectsService

    HVE_CONTENT_TYPE = 'application/vnd.perforce.project.hve.v1+json'

    HVE_ID = 'hveProject'

    # Rack environment.
    attr_accessor :env

    def initialize(env: nil)
      @env = env
    end

    # List HVE Projects as configured in the system.
    #
    # See the Appendix in the documentation for details on values.
    def list(details: false, extension: nil)
      return if extension and (extension != HVE_ID or extension != HVE_CONTENT_TYPE)

      project_dirs = list_project_names
      project_names = project_dirs.map { |d| File.basename(d) }

      if details
        project_names.map { |n| fetch_by_name(n) }
      else
        project_names.map { |n| encode_name(n) }
      end
    end

    def list_project_names
      pattern = "#{hve_projects_path}/*"
      results = p4.run_dirs(pattern)
      results.map { |r| r['dir'] }
    end

    # The ID is a URL encoded version of the directory name under
    # HVE_PROJECTS_PATH.
    #
    # This will unencode the ID and fetch by name.
    def fetch(id)
      name = unencode_name(id)
      fetch_by_name(name)
    end

    # Returns the project's "details" based on the project name.
    #
    # No validation is done to ensure this directory actually exists in the
    # system.
    def fetch_by_name(name)
      id = encode_name(name)

      {
          'id': id,
          'name': name,
          'server': server_uri_for_id(id),
          HVE_ID => {
              'depotPath': depot_path_for_name(name)
          }
      }
    end

    # Generate a new client that only contains the project mapping.
    #
    # The client name is a combination of user, project, and device. We prefix
    # it with "_hve" just for clarity.
    #
    # We do not host lock the client.
    #
    # @param project_id {String} Our encoded project name
    # @param device {String} A device ID, like a hostname
    # @param root {String} The `Root` value for the client parameter
    def create_client(project_id, device, root)
      client_name = "_hve_#{user}_#{project_id}_#{device}"

      client_spec = p4.fetch_client(client_name)

      client_spec._root = root;
      client_spec._host = nil;

      client_spec._options = 'allwrite noclobber nocompress unlocked nomodtime rmdir';

      project_name = unencode_name(project_id)

      client_spec._view = [
          %Q|"#{depot_path_for_name(project_name)}/..." "//#{client_name}/..."|
      ]

      results = p4.save_client(client_spec)
      puts "new client results: #{results}"

      client_name
    end

    # Find the latest submitted change for the project
    #
    # Use the 'p4 changes -m 1 -s submitted [depot path]'
    #
    # @param project_id [String] The encoded project ID
    def find_latest_change_for_project(project_id)
      project_name = unencode_name(project_id)
      depot_path = depot_path_for_name(project_name)

      results = p4.run_changes('-m', '1', '-s', 'submitted', "#{depot_path}/...")

      results.first['change'] unless results.empty?
    end

    # The HVE project 'changelist' is a pending changelist whose description is
    # `_hve_[user]_[project_id]`
    #
    # We use 'changes -l' to find the change to match potentially long project
    # names.
    def find_pending_change_for_project(project_id)
      results = p4.run_changes('-l', '-u', user, '-s', 'pending')

      change = results.find { |r| r['desc'].include?(project_id) }

      change['change'] if change
    end

    # If the user doesn't have a current pending change for the project,
    # create one, and return that.
    def create_pending_change(project_id)
      change = find_pending_change_for_project(project_id)

      return change if change

      change_spec = p4.fetch_change
      change_spec._description = "_hws_#{user}_#{project_id}"

      save_results = p4.save_change(change_spec)

      change = save_results.first.gsub(/Change (\d+) created./, '\1')

      # If we don't reset the client of this pending change, we won't be able
      # to cleanup the temporary client.
      change_spec = p4.fetch_change(change)
      change_spec._client = 'INVALID'
      p4.save_change(change_spec)

      change
    end

    def encode_name(name)
      HWSStrings.component_encode(name)
    end

    def unencode_name(name)
      HWSStrings.component_decode(name)
    end

    def server_uri_for_id(id)
      "p4://#{userinfo}#{server}#{safe_hve_projects_path}/#{id}"
    end

    def depot_path_for_name(name)
      "#{hve_projects_path}/#{name}"
    end

    def p4
      env['p4'] || fail('p4 required to use HVEProjects')
    end

    def hve_projects_path
      env['hws_settings'].HVE_PROJECTS_PATH || fail('HVE_PROJECTS_PATH not set')
    end

    def safe_hve_projects_path
      hve_projects_path.gsub('//', '/')
    end

    def user
      env['AUTH_CREDENTIALS'].first
    end

    # For HVE Projects, it may be interesting to people to see various
    # connection settings for each server URL.
    def userinfo
      data = {}
      if env['hws_settings'].P4CHARSET
        data['P4CHARSET'] = env['hws_settings'].P4CHARSET
      end
      if data.keys.empty?
        ''
      else
        encoded_data = data.map {|k,v| "#{k}=#{v}"}.join(';')
        "#{encoded_data}@"
      end
    end

    def server
      return p4port if p4port.include?(':')

      host = p4host ? p4host : 'localhost'
      port = p4port

      "#{host}:#{port}"
    end

    def p4port
      env['hws_settings'].P4PORT || fail('P4PORT setting not available')
    end

    def p4host
      env['hws_settings'].P4HOST
    end
  end
end