Halo Grazing

breed [ fish a-fish]
breed [ predators a-predator]
breed [ reefs a-reef]
breed [ seagrass a-grass]

fish-own [
  energy
  carried-seagrass
  found-reef?
]

seagrass-own [
  count-down
]

patches-own [
  reef?
  reef-scent
]

Globals
[
  home-base                                ;; xxx location for fish and for need to figure out how to code this
  seagrass-amount                          ;; amount of grass to start out with
]

;=============== Content ===============================================================================================================
; 1. Setup
; 2. Go
; 3. Rules
; 4. Extra Code


;;                                        ================ 1. Setup =======================

to setup
  clear-all
  reset-ticks
  set seagrass-amount starting-seagrass-coverage
  set-default-shape fish "fish 3"
  set-default-shape seagrass "plant"
  set-default-shape reefs "reef1"
  set-default-shape predators "fish"
  set-up-seagrass
  Create-sand
  generate-fish
  generate-predators
end 

to set-up-seagrass
  ;; create seagrass turtles at random locations
  create-seagrass seagrass-amount
  ask seagrass [
    setxy random-xcor random-ycor
  ]
end 

to create-sand
  ask patches [
    if pcolor = black  [set pcolor 49]
  ]  ; patches not green or reef, sandy color
end 

to Generate-fish
 create-fish starting-num-fish ; from the slider
 ask fish [
    setxy 0 0 ; xxx would change with home-base
    set size 3
    set energy .5
  ]
end 

to Generate-predators
 create-predators num-predators
 ask predators [
    setxy random-xcor random-ycor
    set size 4
  ]
  ask seagrass [
    if any? predators-on neighbors
    [ die ]
  ]
end 


;;                                        ================ 2. GO =========================

to go
  if not any? fish [stop ]
  if not any? reefs [ stop ]
  if not any? seagrass [stop ]
  ask fish [
    if 2 >= ticks [ stop ]
    fish-eat-food
    wiggle
    fd 1
  ]
  ask predators [
    wiggle
    predator-walk
    Predators-eat-fish
  ]
  tick
  ask fish [ regrow-fish ]
  ask seagrass [ regrow-seagrass ]
  tick
end 


; to create-reef-with-mouse ----------------------------xxx would set xcor and ycor as home base Not working, revisit later
; if mouse-down? [
;   ask patch mouse-xcor mouse-ycor [
;      set pcolor grey
;    ]
;    display
;  ]
; End

to seed-one
  ;; tell the center to be a reef
   if any? reefs [ stop ]
  ask patch 0 0 [
    set pcolor grey
  ]
  create-reefs 1 [
    setxy 0 0 ; xxx would be xcor and ycor of reef from mouse click
    set shape "reef1"
    set size 15
    ask neighbors [ set pcolor grey ]
  ]
  ; set reef? variable to true inside the reef, false elsewhere
  ask patches [
    set reef? (distancexy 0 0) < 5 ; xxx would use xcor, ycor of mouse click
   ;; spread a reef-scent over the whole world -- stronger nearer the reef
    set reef-scent 200 - distancexy 0 0
  ]
  ask reefs [
    ask seagrass in-radius 3 [ die ]
  ]
end 



;;                                             =============== 3. Rules ===================
;----------------fish------------

to fish-eat-food
  ;energy levels 0 = die, .5 = seek food 1 = found food, now return to reef
    if energy <= 0 [ die ]
    ifelse energy = .5
    [ search-for-seagrass ]
    [ go-to-home-base ]
end 

to search-for-seagrass
  ;; fish procedure to seek out new food
  ask fish [
  let yum one-of seagrass-here
  if yum != nobody [
    ask yum [ die ]
  set energy energy + .5
    ]
  ]
end 

to go-to-home-base
  ; fish procedure for returning to the reef, combines with uphill-reef-scent and reef-scent-at-angle
  ifelse reef?
  [set energy .5]
  [ uphill-reef-scent ]
end 

to uphill-reef-scent
  let scent-ahead reef-scent-at-angle 0
  let scent-right reef-scent-at-angle 45
  let scent-left reef-scent-at-angle -45
  if (scent-right > scent-ahead) or (scent-left > scent-ahead)
  [ ifelse scent-right > scent-left
    [ rt 45 ]
    [ lt 45 ]
  ]
end 

to-report reef-scent-at-angle [angle]
  ;feeds into uphill-reef-scent
  let p patch-right-and-ahead angle 1
  if p = nobody [ report 0 ]
  report [ reef-scent ] of p
end 

;---------------predators----------

to predators-eat-fish
  ; predators contact fish and the fish lose enough energy to die, connected to fish-eat-food
  let prey one-of fish-here
  if prey != nobody [
    ask prey [ set energy energy - 1 ]
  ]
end 


;                                             ================ 4. Extra Code =======================

to regrow-seagrass
  ; xxx need to figure out the scale of this amount
    if count seagrass <= 5000
  [ hatch-seagrass 1000 * seagrass-regrowth-rate [ setxy random-xcor random-ycor ] ; xxx would love to have this outgrow the eating rate
  ]
end 

to regrow-fish
;; new fish, use same code from regrow-seagrass
  let num-fish count fish
  if num-fish <= 1
  [ hatch-fish seagrass-amount / 5000 [ setxy random-xcor random-ycor ] ; xxx
  ]
end 

to predator-walk
  ;; look for reefs, and rotate to head away from them
  ifelse not any? reefs-on patch-ahead 1
  [ fd 1 ]
  [ wiggle predator-walk ]
end 

to wiggle
  ;; fish and predator change heading procedure
  rt random 50 - random 50
end