Evolution of sustainability through monitoring and punishment

turtles-own [
  harvestPref
  harvest-amount
  punisher?
  aware-of-who
  energy
  harvest
  punished?
  rs
     ]

patches-own [ resource ]

globals [
  commons
  commonsResources
  harvestTraits

   ]

to setup
  clear-all
   ask n-of Number-Agents patches [
    sprout 1 [
    set shape "circle"
      set size 0.8
      set punished? false
      set aware-of-who []
      set rs 0
    ifelse random-float 100 < Percent-Sustainables
     [set harvestPref "low"]  ;; determine the harvest preference (high or low)
     [set harvestPref "high"]
    ifelse random-float 100 < Percent-Punishers
     [set punisher? true]  ;; determine the harvest preference (high or low)
     [set punisher? false]
    update-color  ;; change the color of the agent on the basis of the strategy
    set energy Living-costs + 1]
  ]

  ask patches [
    set resource Carrying-capacity
    set pcolor scale-color brown resource  0 (Carrying-capacity + 30) ]

  reset-ticks
end 


;;;;;;; Main routine ;;;;;;

to go
  if count turtles = 0 [stop]

  ask turtles
   [ifelse harvestPref = "low"
      [set harvest-amount Harvest-sustainable]
      [ set harvest-amount Harvest-greedy]

    set aware-of-who []
    harvesting
   ]

    sense-cheaters
    punish

   ask turtles
  [ set energy energy + harvest

    expend-energy
    reproduce

    death]

  ask patches [
    regrow
    recolor]
  tick
end 

to harvesting
 ifelse Punishment = "suspend harvest once"
  [ifelse punished? = false
    [harvest-commons]
    [set harvest 0]
   ]
  [harvest-commons]
  set punished?  false
end 

to harvest-commons  ;; from Waring et al., 2017

   set harvest 0

      ; define the patches withing the local Moore neighborhood on which the current agent may harvest.
      set Commons (patch-set neighbors patch-here) ;; set list of patches to harvest from to include all neighboring patches

      set commonsResources sum ([resource] of Commons)  ;; sums all of the resources in my commons
      let commonsList sort-on [resource] Commons  ;; sort the list by the amount of resource on the patch
      set commonsList reverse commonsList  ;; reverse the sort list so it is largest to smallest

      ifelse commonsResources < harvest-amount  ;; if the total commons are less than what the agent wants to harvest
      [ set harvest (commonsResources); - ( count myCommons * 0.1 ))
        ask Commons [ set resource 0 ]
        move-away
      ]

      [
        while [harvest < harvest-amount][  ;; while you are still in need
        ;; harvest some resource from the neighborhood
          foreach commonsList [ ?1 ->
            ifelse [resource] of ?1 <= (harvest-amount - harvest)
              [set harvest (harvest + [resource] of ?1 )
               ask ?1 [set resource 0]
              ]

              [ask ?1 [
                set resource (resource - ([harvest-amount] of myself - [harvest] of myself))
              ]
                set harvest harvest-amount
              ]
          ]  ;; end foreach
        ]  ;; end while
     ] ;; end second part of ifelse commonsResources
end 

to move-away
  let next-patch max-one-of (neighbors with [not any? turtles-here]) [resource]
  if next-patch != nobody
    [move-to next-patch
     set energy energy - 1
     ]
end 

to sense-cheaters
  ask turtles with [punisher? = true]
   [ set harvest harvest - Costs-perception
     let cheaters  (turtles-on neighbors) with [harvestPref = "high"]
     set aware-of-who n-of  ( Perception-accuracy  / 100 * count cheaters) cheaters
   ]
end 

to punish
  ask turtles with [ harvestPref = "high" and punished? = false]
  [let punishers  (turtles-on neighbors) with [ member? myself [aware-of-who] of self]
    if any? punishers
   [ set punished? true
      if Punishment = "kill"[die]
      if Punishment = "pay fine"
       [set harvest harvest  - Fine
        set punished? false
        ask turtles-on neighbors [set harvest harvest  + (Fine / (count turtles-on neighbors) )]
       ]
      ask punishers [
        set harvest harvest  - ( Costs-punishment / count punishers)

      ]
     ]
  ]
end 

to expend-energy
  set energy energy - Living-costs
end 

to reproduce
  let birthrate 0.001 * energy
  if random-float 1 < birthrate [
    let destination one-of neighbors with [not any? turtles-here]
    if destination != nobody [
        hatch 1 [
        move-to destination
        set punished? false
        set aware-of-who []
        mutate
        set energy ([energy] of myself / 2)]
       ]
    set energy (energy / 2)
          ]
end 

;; modify the children of agents according to the mutation rate

to mutate  ;; turtle procedure
    if random-float 100 < Mutation-rate
    [
    ifelse harvestPref = "high"
    [set harvestPref "low"]
    [set harvestPref "high"]
    ]
    if random-float 100 < Mutation-rate
    [ ifelse punisher? = true
    [set punisher?  false]
    [set punisher?  true ]
    ]
   update-color
end 

to update-color
   ifelse harvestPref = "low"
      [ ifelse punisher? = true
        [set color green ]
        [set color turquoise]
      ]
      [ ifelse punisher? = true
          [set color orange ]
          [set color red]
      ]
end 

to death
    if energy <= 0 [ die ]
    if random-float 100 < Death-rate [ die ]
end 

to regrow
  ifelse resource > 0
  [set resource ceiling (resource + ((Growth-rate * resource) * (1 - (resource / Carrying-capacity )))) ]
  [set resource 0.1 ]
end 

to recolor
  set pcolor scale-color brown resource  0 (Carrying-capacity + 30)
end