Sex-ratio Equilibrium_v1

;; sexual reproduction (XX-XY type) and growth model

;;
turtles-own [
  partner
  carrying?
  male-child-chance
  gestation
  age
  gender
]

;;set-up pupulation of males and females

to setup
  ca
  crt ini-number [
    setxy random-xcor random-ycor
    set shape "male" set size 3
    set gender "male"
    set color green
    set male-child-chance random-normal ini-average-male-child-chance 0.1
    set age 0
    set partner nobody
    set carrying? false
  ]
  ask n-of round ( ini-sex-ratio * ini-number ) turtles [
      set color blue
      set shape "female" set size 3
      set gender "female"
      set male-child-chance 0
  ]
  reset-ticks
end 

to go
  if not any? turtles [stop]
  check-if-dead
  move
  search-a-partner
  reproduce
  tick
end 

to move
  ask turtles [
    rt random 60
    lt random 60
    fd 1
  ]
end 

to search-a-partner
  let male-turtles turtles with [gender = "male"]
  ask male-turtles [
    set partner one-of (other turtles-here with [gender = "female" and not carrying?])
    if partner = nobody [stop]
    ifelse [partner] of partner != nobody [
      set partner nobody
      stop                        ;; just in case two males find the same partner
    ]
    [
      ifelse random-float 1 < mating-chance [
        ask partner [
          set partner myself
          set carrying? true
          set color orange    ;; color oragne indicates carrying female
          set male-child-chance [male-child-chance] of myself  ;; sex of a child is determined by male-child-chance (determined by father)
        ]
      ]
      [
        set partner nobody
      ]
    ]
  ]
end 

to reproduce
  let female-turtles turtles with [gender = "female"]
  ask female-turtles [
    if carrying? [
      ifelse gestation = gestation-period [   ;; genstation- period is 9 months. when it's over, a female produces a child and starts afrest and can have a new partner.
        set gestation 0
        set carrying? false
        set color green
        set partner nobody
        repeat litter-size [
          ifelse random-float 1 < male-child-chance [    ;; sex of a child is determined by male-child-chance (determined by father)
            hatch 1 [
              set gender "male"
              set shape "male"
              set color green
              set male-child-chance random-normal male-child-chance 0.1
              set age 0
            ]
          ][
          hatch 1 [
            set gender "female"
            set color blue
            set male-child-chance 0
            set age 0
          ]
          ]
        ]
      ][
      set gestation gestation + 1
      ]
    ]
  ]
end 

to check-if-dead
  ask turtles [
    ifelse random-float longevity < age [
      die
    ][
    set age age + 1
    ]
  ]
end 

to-report female-percentage
  ifelse any? turtles [
    report ( count turtles with [gender = "female"] / count turtles ) * 100
  ]
  [
    report 0
  ]
end 

to-report average-male-child-chance
  ifelse any? turtles with [gender = "male"] [
    report mean [male-child-chance] of turtles with [gender = "male"]
  ]
  [
    report 0
  ]
end