module Xampl

  #TODO -- this is **way** too big!
  #TODO -- FIX THIS PROBLEM
  #  increase the default cache size to 2000 (which is way too big, but there is
  #  a bug... removing from the cache does not remove from memory, so if a
  #  storybook exists that points (even indirectly) at something flushed, the
  #  thing flushed is still held in memory. What is needed is for the thing to
  #  be invalidated somehow withought DUPLICATES being created when the thing
  #  is read again next time)

  DEFAULT_CAPACITY = 2000

  class XamplCache
    require 'xamplr/indexed-array'

    attr_reader :cache, :capacity

    def initialize(capacity=DEFAULT_CAPACITY)
      @capacity = capacity
      @now = 0
      @size = 0
      @cache = {}
    end

    def size
      #@cache.size
      return @size
    end

    def delete(key)
      @cache.delete(key)
    end

    def limit
      victim = nil
      actual_victim = nil
      min = 1 + @now
      @size = 0
      @cache.each{ | key, pair |
        possibility = pair[0]
        if (not possibility.load_needed) and pair[1] < min then
          @size += 1
          victim = key
          actual_victim = possibility
          min = pair[1]
        end
      }
#puts
      #puts
      #puts "REMOVE FROM CACHE(XamplCache): victim: #{victim}, actual: #{actual_victim}"
      #puts " size: #{@size}, physical size: #{@cache.size}"
      #puts
      #puts
      #@cache.delete(victim)
      actual_victim.force_load if actual_victim
#puts ">>>>>>> #{actual_victim.load_needed} #{actual_victim.class.name}" if actual_victim
    end

    def fetch(key, default_value=nil)
      pair = @cache[key]
      if pair then
        pair[1] = (@now += 1)
        return pair[0]
      else
        return default_value
      end
    end

    def store(key, value)
      if (@capacity <= @size) then
        self.limit
      end

      pair = @cache[key]
      if pair then
        pair[0] = value
        pair[1] = (@now += 1)
      else
        @cache[key] = [value, (@now += 1)]
      end

      return value
    end

    def print(out = "")
      out << "Cache with capacity: #{@capacity}, current size: #{@size}\n"
      @cache.each{ | key, pair |
        out << sprintf("  key: '%s', value: '%s', accessed: %s\n",
                       key, pair[0], pair[1])
      }
      out
    end

    alias [] fetch
    alias []= store
  end

  class XamplCacheLFU
    require 'xamplr/indexed-array'

    attr_reader :cache, :capacity

    def initialize(capacity=DEFAULT_CAPACITY)
      @capacity = capacity
      @accesses = 0
      @size = 0
      @cache = {}
    end

    def size
      #@cache.size
      @size
    end

    def delete(key)
      @cache.delete(key)
    end

    def limit
      victim = nil
      actual_victim = nil
      min = 1 + @accesses
      live = 0
      @cache.each{ | key, pair |
        pair[1] -= 1
        possibility = pair[0]
        if (not possibility.load_needed) and pair[1] < min then
          live += 1
          victim = key
          actual_victim = possibility
          min = pair[1]
        end
      }
#puts
      #puts
      #puts "REMOVE FROM CACHE(XamplCacheLFU): victim: #{victim}, actual: #{actual_victim} -- live: #{live}, size: #{@size}"
      #puts
      #puts
      #@cache.delete(victim)
      actual_victim.force_load if actual_victim
    end

    def fetch(key, default_value=nil)
      @accesses += 1

      pair = @cache[key]
      if pair then
        pair[1] += 1
        return pair[0]
      else
        return default_value
      end
    end

    def store(key, value)
      @accesses += 1

      if (@capacity <= @size) then
        self.limit
      end

      pair = @cache[key]
      if pair then
        pair[0] = value
        pair[1] += 1
      else
        @cache[key] = [value, 1]
      end

      return value
    end

    def print(out = "")
      out << "Cache with capacity: #{@capacity}, current size: #{@size}\n"
      @cache.each{ | key, pair |
        out << sprintf("  key: '%s', value: '%s', count: %s\n",
                       key, pair[0], pair[1])
      }
      out
    end

    alias [] fetch
    alias []= store
  end
end