MIHS-18 P2 HB, SM, MF

globals [ max-sheep ]
breed [ sheep a-sheep ]
breed [ wolves wolf ]
breed [ people person ]
turtles-own [ energy ]
patches-own [ countdown ]

to setup
  clear-all
  ifelse netlogo-web? [set max-sheep 10000] [set max-sheep 30000]

  ifelse model-version = "sheep-wolves-people-grass" [
    ask patches [
      set pcolor one-of [ green brown ]
      ifelse pcolor = green
        [ set countdown grass-regrowth-time ]
      [ set countdown random grass-regrowth-time ]
    ]
  ]
  [
    ask patches [ set pcolor green ]
  ]

  create-sheep initial-number-sheep
  [
    set shape  "sheep"
    set color white
    set size 1.5
    set label-color blue - 2
    set energy random (2 * sheep-gain-from-food)
    setxy random-xcor random-ycor
  ]

  create-wolves initial-number-wolves
  [
    set shape "wolf"
    set color black
    set size 2
    set energy random (2 * wolf-gain-from-food)
    setxy random-xcor random-ycor
  ]

  create-people initial-number-people
  [
    set shape "person"
    set color pink
    set size 2.5
    set energy random (2 * person-gain-from-food)
    setxy random-xcor random-ycor
  ]

  display-labels
  reset-ticks
end 

to go
  if not any? turtles [ stop ]
  ask sheep [
    move
    if model-version = "sheep-wolves-people-grass" [
      set energy energy - 1
      eat-grass
      death
    ]
    reproduce-sheep
  ]
  ask wolves [
    move
    set energy energy - 1
    eat-sheep
    death
    reproduce-wolves
  ]
  ask people [
    move
    set energy energy - 1
    eat-sheep
    eat-wolves
    death
    reproduce-people
  ]
  if model-version = "sheep-wolves-people-grass" [ ask patches [ grow-grass ] ]
  ; set grass count patches with [pcolor = green]
  tick
  display-labels
end 

to move  ; turtle procedure
  rt random 50
  lt random 50
  fd 1
end 

to eat-grass  ; sheep procedure
  if pcolor = green [
    set pcolor brown
    set energy energy + sheep-gain-from-food
  ]
end 

to reproduce-sheep  ; sheep procedure
  if random-float 100 < sheep-reproduce [
    set energy (energy / 2)
    hatch 1 [ rt random-float 360 fd 1 ]
  ]
end 

to reproduce-wolves  ; wolf procedure
  if random-float 100 < wolf-reproduce [
    set energy (energy / 2)
    hatch 1 [ rt random-float 360 fd 1 ]
  ]
end 

to reproduce-people
  if random-float 100 < person-reproduce [
    set energy (energy / 2)
    hatch 1 [ rt random-float 360 fd 1 ]
  ]
end 

to eat-sheep
  let prey one-of sheep-here
  if prey != nobody  [
    ask prey [ die ]
    set energy energy + wolf-gain-from-food + person-gain-from-food
  ]
end 

to eat-wolves
  let prey one-of wolves-here
  if prey != nobody  [
    ask prey [ die ]
    set energy energy + person-gain-from-food
  ]
end 

to death
  if energy < 0 [ die ]
end 

to grow-grass
  if pcolor = brown [
    ifelse countdown <= 0
      [ set pcolor green
        set countdown grass-regrowth-time ]
      [ set countdown countdown - 1 ]
  ]
end 

to-report grass
  ifelse model-version = "sheep-wolves-people-grass" [
    report patches with [pcolor = green]
  ]
  [ report 0 ]
end 

to display-labels
  ask turtles [ set label "" ]
  if show-energy? [
    ask wolves [ set label round energy ]
    if model-version = "sheep-wolves-people-grass" [ ask sheep [ set label round energy ] ]
    ask people [ set label round energy ]
    if model-version = "sheep-wolves-people-grass" [ ask wolves [ set label round energy ] ]
  ]
end