;; Each patch stores a value for amount of nutrients, color, and number of dead yeast cells.
patches-own [nutrients saved_color dead_yeast]

;; Each turtles stores a value for an advantage amount.
turtles-own [advantage]

;; There are two kinds of turtles: red yeast cells and white yeast cells
breeds [yred ywhite]


;; The go procedure (called by pressing the "go" button)
;; This is the program's main loop.
;; For each turtle, this procedure randomly selects a value between 0 and 99
;; If that value is less than the value of (birth_factor * nutrients * advantage)
;; (birth_factor is a user-specified value on the slider called birth factor)
;; then this turtle give birth to a new turtle to simulate budding.
;; This new bud grows one step away from the parent, gets its variable initialized
;; and then eats.
;; Regardless of whether a turtle has given birth or not, each turtle then
;; checks to see whether it should die and whether it should eat.

to go
  if ((random 100) < (birth_factor * nutrients * advantage))
  [
   hatch
   [
     seth random 360
     fd 1
     set_newbud_variables
     newbud_eats
   ]
  ]
  die?
  eat?
end


;; The die? procedure (called from within the go procedure or main loop)
;; A turtle should die if the randomly selects a number is less than the user-specified
;; death_rate.  (death_rate is a slider value.)
;; If it should die, the turtle stamps its color on the current patch.
;; Then dead yeast count at this patch is incremented by 1 and the turtle dies.

to die?
  if (random 100) < (death_rate) [stamp color setdead_yeast dead_yeast + 1 die]
end


;; The eat? procedure
;; A turtle should eat if the randomly selected number is less than the user-specified
;; consumption_rate.  (consumption_rate is a slider value.)
;; If it should eat and nutrients are available at the current patch, then the nutrient
;; value of the current patch goes down by 1.

to eat?
  if (random 100) < (consumption_rate) [if nutrients > 0 [setnutrients (nutrients - 1)]]
end


;; The set_newbud_variables procedure
;;

to set_newbud_variables
     ifelse (((random 100) < white_mutation_rate) or (breed = ywhite))
       [
        scale-color ywhite (count-turtles-here + dead_yeast) -5 5 setbreed ywhite
        setadvantage (1 + (white_growth_advantage / 100))
        ifelse (count-yred-here > 0) and (breed - ywhite)
          [ht]  ;; hide turtle
          [st]  ;; show turtle
       ]
       [
        scale-color red (count-turtles-here + dead_yeast) 0 15
       ]
end


to newbud_eats
     if nutrients > 0
       [setnutrients (nutrients - 1) if nutrients < 0 [setnutrients 0]]
end


;; DISPERSE procedure (called by setup-agents observer procedure)
;; moves turtle forward 1 until it reaches an uninhabited patch

to disperse
  if count-turtles-here > 1 [fd 1 disperse]
end