# encoding: utf-8

require 'one_apm/support/traced_method_stack'

module OneApm

  # This is THE location to store thread local information during a transaction
  # Need a new piece of data? Add a method here, NOT a new thread local variable.
  class TransactionState
    def self.tl_get
      tl_state_for(Thread.current)
    end

    # This method should only be used by TransactionState for access to the
    # current thread's state or to provide read-only accessors for other threads
    #
    # If ever exposed, this requires additional synchronization
    def self.tl_state_for(thread)
      state = thread[:oneapm_transaction_state]

      if state.nil?
        state = TransactionState.new
        thread[:oneapm_transaction_state] = state
      end

      state
    end

    def self.tl_clear_for_testing
      Thread.current[:oneapm_transaction_state] = nil
    end

    def initialize
      @untraced = []
      @traced_method_stack =OneApm::Support::TracedMethodStack.new
      @current_transaction = nil
    end

    # This starts the timer for the transaction.
    def reset(transaction=nil)
      # We purposefully don't reset @untraced, @record_tt and @record_sql
      # since those are managed by OneApm::Agent.disable_* calls explicitly
      # and (more importantly) outside the scope of a transaction

      @timings = nil
      @request = nil
      @current_transaction = transaction

      @traced_method_stack.clear

      @is_cross_app_caller = false
      @client_cross_app_id = nil
      @referring_transaction_info = nil

      @transaction_sample_builder = nil
      @sql_sampler_transaction_data = nil

      @busy_entries = 0
    end

    def timings
      @timings ||= TransactionTimings.new(transaction_queue_time, transaction_start_time, transaction_name)
    end

    # Cross app tracing
    # Because we need values from headers before the transaction actually starts
    attr_accessor :client_cross_app_id, :referring_transaction_info, :is_cross_app_caller

    def is_cross_app_caller?
      @is_cross_app_caller
    end

    def is_cross_app_callee?
      referring_transaction_info != nil
    end

    def is_cross_app?
      is_cross_app_caller? || is_cross_app_callee?
    end

    # Request data
    attr_accessor :request

    def request_guid
      return nil unless current_transaction
      current_transaction.guid
    end

    # Current transaction stack and sample building
    attr_reader   :current_transaction
    attr_accessor :transaction_sample_builder

    def transaction_start_time
      current_transaction.start_time if current_transaction
    end

    def transaction_queue_time
      current_transaction.nil? ? 0.0 : current_transaction.queue_time
    end

    def transaction_name
      current_transaction.nil? ? nil : current_transaction.best_name
    end

    def in_background_transaction?
      !current_transaction.nil? && !current_transaction.recording_web_transaction?
    end

    def in_web_transaction?
      !current_transaction.nil? && current_transaction.recording_web_transaction?
    end

    # Execution tracing on current thread
    attr_accessor :untraced

    def push_traced(should_trace)
      @untraced << should_trace
    end

    def pop_traced
      @untraced.pop if @untraced
    end

    def is_execution_traced?
      @untraced.nil? || @untraced.last != false
    end

    # TT's and SQL
    attr_accessor :record_tt, :record_sql

    def is_transaction_traced?
      @record_tt != false
    end

    def is_sql_recorded?
      @record_sql != false
    end

    # Busy calculator
    attr_accessor :busy_entries

    # Sql Sampler Transaction Data
    attr_accessor :sql_sampler_transaction_data

    # Scope stack tracking from OneApm::StatsEngine::Transactions
    # Should not be nil--this class manages its initialization and resetting
    attr_reader :traced_method_stack
  end
end