module OrigenTesters
  module Timing
    extend ActiveSupport::Concern

    included do
      # When set to true all pattern vectors will be converted to use the same period (the
      # shortest period used in the pattern).
      #
      # @example
      #   $tester.set_timeset("fast", 40)
      #   2.cycles                        #    fast   1 0 0 1 0
      #                                   #    fast   1 0 0 1 0
      #
      #   $tester.level_period = false  # Without levelling enabled
      #   $tester.set_timeset("slow", 80)
      #   2.cycles                        #    slow   1 0 0 1 0
      #                                   #    slow   1 0 0 1 0
      #
      #   $tester.level_period = true   # With levelling enabled
      #   $tester.set_timeset("slow", 80)
      #   2.cycles                        #    fast   1 0 0 1 0
      #                                   #    fast   1 0 0 1 0
      #                                   #    fast   1 0 0 1 0
      #                                   #    fast   1 0 0 1 0
      #
      # @see Timing#timing_toggled_pins
      attr_accessor :level_period
      alias_method :level_period?, :level_period
      attr_writer :timing_toggled_pins
    end

    class Timeset
      attr_accessor :name, :period_in_ns

      def initialize(attrs = {})
        attrs.each do |name, value|
          send("#{name}=", value)
        end
      end

      # Returns true if the timeset has a shorter period than the supplied timeset
      def shorter_period_than?(timeset)
        period_in_ns < timeset.period_in_ns
      end
    end

    # @see Timing#level_period
    #
    # When period levelling is enabled, vectors will be expanded like this:
    #   $tester.set_timeset("fast", 40)
    #   2.cycles                        #    fast   1 0 0 1 0
    #                                   #    fast   1 0 0 1 0
    #   # Without levelling enabled
    #   $tester.set_timeset("slow", 80)
    #   2.cycles                        #    slow   1 0 0 1 0
    #                                   #    slow   1 0 0 1 0
    #   # With levelling enabled
    #   $tester.set_timeset("slow", 80)
    #   2.cycles                        #    fast   1 0 0 1 0
    #                                   #    fast   1 0 0 1 0
    #                                   #    fast   1 0 0 1 0
    #                                   #    fast   1 0 0 1 0
    #
    # The overall time of the levelled/expanded vectors matches that of the unlevelled
    # case. i.e. 4 cycles at fast speed (4 * 40ns = 160ns) is equivalent to 2 cycles
    # at slow speed (2 * 80ns = 160ns).
    #
    # However, what if pin 1 in the example above was a clk pin where the 1 -> 0 transition
    # was handled by the timing setup for that pin.
    # In that case the levelled code is no longer functionally correct since it contains
    # 4 clock pulses while the unlevelled code only has 2.
    #
    # Such pins can be specified via this attribute and the levelling logic will then
    # automatically adjust the drive state to keep the number of pulses correct.
    # It would automatically adjust to the alternative logic state where 0 means 'on'
    # and 1 means 'off' if applicable.
    #
    #   $tester.timing_toggled_pins << $dut.pin(:tclk)  # This is pin 1
    #
    #   $tester.set_timeset("fast", 40)
    #   2.cycles                        #    fast   1 0 0 1 0
    #                                   #    fast   1 0 0 1 0
    #   # Without levelling enabled
    #   $tester.set_timeset("slow", 80)
    #   2.cycles                        #    slow   1 0 0 1 0
    #                                   #    slow   1 0 0 1 0
    #   # With levelling enabled
    #   $tester.set_timeset("slow", 80)
    #   2.cycles                        #    fast   1 0 0 1 0
    #                                   #    fast   0 0 0 1 0
    #                                   #    fast   1 0 0 1 0
    #                                   #    fast   0 0 0 1 0
    #
    # Multiple pins an be specified like this:
    #   $tester.timing_toggled_pins = [$dut.pin(:tclk), $dut.pin(:clk)]   # Overrides any pins added elsewhere
    #   $tester.timing_toggled_pins << [$dut.pin(:tclk), $dut.pin(:clk)]  # In addition to any pins added elsewhere
    def timing_toggled_pins
      @timing_toggled_pins ||= []
      @timing_toggled_pins.flatten!
      @timing_toggled_pins
    end

    # Set the timeset for the next vectors, this will remain in place until the next
    # time this is called.
    #
    #   $tester.set_timeset("bist_25mhz", 40)
    #
    # This method also accepts a block in which case the contained vectors will generate
    # with the supplied timeset and subsequent vectors will return to the previous timeset
    # automatically.
    #
    #   $tester.set_timeset("bist_25mhz", 40) do
    #     $tester.cycle
    #   end
    #
    # The arguments can also be supplied as a single array, or not at all. In the latter case
    # the existing timeset will simply be preserved. This is useful if you have timesets that
    # can be conditionally set based on the target.
    #
    #   # Target 1
    #   $soc.readout_timeset = ["readout", 120]
    #   # Target 2
    #   $soc.readout_timeset = false
    #
    #   # This code is compatible with both targets, in the first case the timeset will switch
    #   # over, in the second case the existing timeset will be preserved.
    #   $tester.set_timeset($soc.readout_timeset) do
    #     $tester.cycle
    #   end
    def set_timeset(timeset, period_in_ns = nil)
      if timeset.is_a?(Array)
        timeset, period_in_ns = timeset[0], timeset[1]
      end
      timeset ||= @timeset
      unless timeset.is_a?(Timeset)
        fail 'You must supply a period_in_ns argument to set_timeset' unless period_in_ns
        timeset = Timeset.new(name: timeset.to_s.chomp, period_in_ns: period_in_ns)
      end
      called_timesets << timeset unless called_timesets.map(&:name).include?(timeset.name)
      if @min_period_timeset
        @min_period_timeset = timeset if timeset.shorter_period_than?(@min_period_timeset)
      else
        @min_period_timeset = timeset
      end
      if block_given?
        original = @timeset
        timeset_changed(timeset)
        @timeset = timeset
        yield
        timeset_changed(original)
        @timeset = original
      else
        timeset_changed(timeset)
        @timeset = timeset
      end
    end

    # Returns the timeset (a Timeset object) with the shortest period that has been
    # encountered so far in the course of generating the current pattern.
    #
    # A tester object is re-instantiated at the start of every pattern which will reset
    # this variable.
    def min_period_timeset
      @min_period_timeset
    end

    def timeset_changed(timeset)
      if last_vector && last_vector.timeset != timeset
        change = { old: last_vector.timeset, new: timeset }
        # Suppress any duplicate calls
        if !@_last_timeset_change ||
           (@_last_timeset_change[:new] != change[:new] &&
             @_last_timeset_change[:old] != change[:old])
          before_timeset_change(change)
        end
        @_last_timeset_change = change
      end
    end

    def before_timeset_change(options = {})
    end

    # Cause the pattern to wait.
    # The following options are available to help you specify the time to wait:
    # * :cycles - delays specified in raw cycles, the test model is responsible for translating this into a sequence of valid repeat statements
    # * :time_in_ns - time specified in nano-seconds
    # * :time_in_us - time specified in micro-seconds
    # * :time_in_ms - time specified in milli-seconds
    # * :time_in_s - time specified in seconds
    # If more than one option is supplied they will get added together to give a final
    # delay time expressed in cycles.
    # ==== Examples
    #   $tester.wait(cycles: 100, time_in_ns: 200)   # Wait for 100 cycles + 200ns
    # This method can also be used to trigger a match loop in which case the supplied time
    # becomes the time out for the match. See the J750#match method for full details of the
    # available options.
    #   $tester.wait(match: true, state: :high, pin: $dut.pin(:done), time_in_ms: 500)
    def wait(options = {})
      options = {
        cycles:         0,
        time_in_cycles: 0,
        time_in_us:     0,
        time_in_ns:     0,
        time_in_ms:     0,
        time_in_s:      0,
        match:          false,   # Set to true to invoke a match loop where the supplied delay
        # will become the timeout duration
      }.merge(options)

      cycles = 0
      cycles += options[:cycles] + options[:time_in_cycles]
      cycles += s_to_cycles(options[:time_in_s])
      cycles += ms_to_cycles(options[:time_in_ms])
      cycles += us_to_cycles(options[:time_in_us])
      cycles += ns_to_cycles(options[:time_in_ns])

      time = cycles * current_period_in_ns   # Total delay in ns
      case
        when time < 1000                      # When less than 1us
          cc "Wait for #{'a maximum of ' if options[:match]}#{time}ns"
        when time < 1_000_000                   # When less than 1ms
          cc "Wait for #{'a maximum of ' if options[:match]}#{(time.to_f / 1000).round(1)}us"        # Display delay in us
        when time < 1_000_000_000                # When less than 1s
          cc "Wait for #{'a maximum of ' if options[:match]}#{(time.to_f / 1_000_000).round(1)}ms"
        else
          cc "Wait for #{'a maximum of ' if options[:match]}%.2fs" % (time.to_f / 1_000_000_000)
      end

      if cycles > 0   # Allow this function to be called with 0 in which case it will just return
        if options[:match]
          if block_given?
            match_block(cycles, options) { yield }
          else
            match(options[:pin], options[:state], cycles, options)
          end
        else
          delay(cycles)
        end
      end
    end

    # @see Timing#wait
    # @api private
    # This should not be called directly, call via tester#wait
    def delay(cycles, options = {})
      (cycles / max_repeat_loop).times do
        if block_given?
          yield options.merge(repeat: max_repeat_loop)
        else
          cycle(options.merge(repeat: max_repeat_loop))
        end
      end
      if block_given?
        yield options.merge(repeat: (cycles % max_repeat_loop))
      else
        cycle(options.merge(repeat: (cycles % max_repeat_loop)))
      end
    end

    def max_repeat_loop
      @max_repeat_loop || 65_535
    end

    def min_repeat_loop
      @min_repeat_loop
    end

    def called_timesets
      @called_timesets ||= []
    end

    def current_period_in_ns
      if @timeset
        @timeset.period_in_ns
      else
        fail 'No timeset has been specified yet!'
      end
    end
    alias_method :current_period, :current_period_in_ns
    alias_method :period, :current_period_in_ns

    def current_timeset
      @timeset
    end
    alias_method :timeset, :current_timeset

    # Convert the supplied number of cycles to a time, based on the SoC defined cycle period
    def cycles_to_time(cycles) # :nodoc:
      (cycles * current_period_in_ns).to_f / 1_000_000_000
    end

    # This function can be used to generate a clock or some other repeating function
    # that spans accross a range of vectors.
    # The period of each cycle and the duration of the sequence are supplied via the following
    # options:
    # * :period_in_cycles
    # * :period_in_ns
    # * :period_in_us
    # * :period_in_ms
    # * :duration_in_cycles
    # * :duration_in_ns
    # * :duration_in_us
    # * :duration_in_ms
    # If multiple definitions for either option are supplied then they will be added
    # together.
    # ==== Example
    #   # Supply a clock pulse on :pinA for 100ms
    #   $tester.count(:period_in_cycles => 10, :duration_in_ms => 100) do
    #       $top.pin(:pinA).drive!(1)
    #       $top.pin(:pinA).drive!(0)
    #   end
    def count(options = {})
      options = { period_in_cycles: 0, period_in_ms: 0, period_in_us: 0, period_in_ns: 0,
                  duration_in_cycles: 0, duration_in_ms: 0, duration_in_us: 0, duration_in_ns: 0
                }.merge(options)

      period_cycles = options[:period_in_cycles] + ms_to_cycles(options[:period_in_ms]) +
                      us_to_cycles(options[:period_in_us]) + ns_to_cycles(options[:period_in_ns])

      duration_cycles = options[:duration_in_cycles] + ms_to_cycles(options[:duration_in_ms]) +
                        us_to_cycles(options[:duration_in_us]) + ns_to_cycles(options[:duration_in_ns])

      total = 0
      while total < duration_cycles
        wait(time_in_cycles: period_cycles)
        yield								# Return control back to caller
        total += period_cycles
      end
    end

    private

    def s_to_cycles(time) # :nodoc:
      ((time.to_f) * 1000 * 1000 * 1000 / current_period_in_ns).to_int
    end

    def ms_to_cycles(time) # :nodoc:
      ((time.to_f) * 1000 * 1000 / current_period_in_ns).to_int
    end

    def us_to_cycles(time) # :nodoc:
      ((time.to_f * 1000) / current_period_in_ns).to_int
    end

    def ns_to_cycles(time) # :nodoc:
      (time.to_f / current_period_in_ns).to_int
    end

    def cycles_to_us(cycles) # :nodoc:
      ((cycles.to_f * current_period_in_ns) / (1000)).ceil
    end

    def cycles_to_ms(cycles) # :nodoc:
      ((cycles.to_f * current_period_in_ns) / (1000 * 1000)).ceil
    end

    # Cycles to tenths of a second
    def cycles_to_ts(cycles) # :nodoc:
      ((cycles.to_f * current_period_in_ns) / (1000 * 1000 * 100)).ceil
    end
  end
end