Simple Quasi-Market

breed [students student]
breed [schools school]

students-own [
  social-class    ; "favorise", "moyen", ou "defavorise"
  year           ; année scolaire (1-6)
  tolerance      ; seuil de tolérance
  my-school      ; école assignée
  waiting        ; en attente d'une place ou non
]

schools-own [
  capacity-per-year  ; capacité par année (60 places en 1ère année, etc.)
  nb-favorises
  nb-moyens
  nb-defavorises
]

to setup
  clear-all

  ; Création des écoles
  create-schools 4 [
    set shape "house"
    set color 9.9
    set capacity-per-year 60
    set nb-favorises 0
    set nb-moyens 0
    set nb-defavorises 0
    set size 3
    ; Positionnement en carré
    if who = 0 [ setxy -10 10 ]  ; Nord-Ouest
    if who = 1 [ setxy 10 10 ]   ; Nord-Est
    if who = 2 [ setxy -10 -10 ] ; Sud-Ouest
    if who = 3 [ setxy 10 -10 ]  ; Sud-Est
  ]

  reset-ticks
end 

to go
  ; Faire avancer les élèves d'une année (sauf les nouveaux)
  ask students with [year > 0] [
    set year year + 1
    if year > 6 [ die ]  ; Les élèves sortent du système après 6 ans
  ]

  ; Créer de nouveaux élèves
  create-students 100 [
    set shape "person"
    set size 1
    set year 1
    set waiting true
    ; Assigner une classe sociale aléatoirement (distribution égale)
    set social-class one-of ["favorise" "moyen" "defavorise"]
    ; Définir la couleur selon la classe sociale
    if social-class = "favorise" [ set color red ]
    if social-class = "moyen" [ set color green ]
    if social-class = "defavorise" [ set color blue ]

    ; Définir le seuil de tolérance selon la classe sociale
    if social-class = "favorise" [
      set tolerance tolerance-favorises
    ]
    if social-class = "moyen" [
      set tolerance tolerance-moyens
    ]
    if social-class = "defavorise" [
      set tolerance tolerance-defavorises
    ]
  ]

  ; Phase 1 : Les nouveaux élèves choisissent leur école préférée
  ask students with [waiting = true] [
    choose-preferred-school
  ]

  ; Phase 2 : Les écoles sélectionnent les élèves selon leurs critères
  ask schools [
    select-students
  ]

  ; Mettre à jour les statistiques des écoles
  update-school-stats

  tick
end 

to choose-preferred-school
  ifelse count students = 0 or tolerance = 1  ; Si premiers élèves OU tolérance totale
  [
    ; Attribution purement aléatoire
    move-to one-of schools
  ]
  [
    ; Sinon, utiliser le système de préférences
    let school0-discomfort calculate-discomfort self school 0
    let school1-discomfort calculate-discomfort self school 1
    let school2-discomfort calculate-discomfort self school 2
    let school3-discomfort calculate-discomfort self school 3

    let min-discomfort min (list school0-discomfort school1-discomfort school2-discomfort school3-discomfort)

    if min-discomfort = school0-discomfort [ move-to school 0 ]
    if min-discomfort = school1-discomfort [ move-to school 1 ]
    if min-discomfort = school2-discomfort [ move-to school 2 ]
    if min-discomfort = school3-discomfort [ move-to school 3 ]
  ]
end 

to-report calculate-discomfort [student-agent school-agent]
  let total-students ([nb-favorises + nb-moyens + nb-defavorises] of school-agent)
  if total-students = 0 [ report 0 ]

  let discomfort 0
  let my-class [social-class] of student-agent
  let my-tolerance [tolerance] of student-agent

  ; Les favorisés regardent la proportion d'élèves non-favorisés
  if my-class = "favorise" [
    let prop-non-favorises (([nb-moyens + nb-defavorises] of school-agent) / total-students)
    ifelse prop-non-favorises > my-tolerance
      [ set discomfort 1 ]
      [ set discomfort prop-non-favorises / my-tolerance ]
  ]

  ; Les moyens regardent la proportion d'élèves aux extrêmes
  if my-class = "moyen" [
    let prop-extremes (([nb-favorises + nb-defavorises] of school-agent) / total-students)
    ifelse prop-extremes > my-tolerance
      [ set discomfort 1 ]
      [ set discomfort prop-extremes / my-tolerance ]
  ]

  ; Les défavorisés regardent la proportion d'élèves non-défavorisés
  if my-class = "defavorise" [
    let prop-non-defavorises (([nb-favorises + nb-moyens] of school-agent) / total-students)
    ifelse prop-non-defavorises > my-tolerance
      [ set discomfort 1 ]
      [ set discomfort prop-non-defavorises / my-tolerance ]
  ]

  report discomfort
end 

to select-students
  let year1-students students-here with [waiting = true]
  if count year1-students > capacity-per-year [
    let selected-students nobody

    ifelse selectivite-ecoles = 0 [
      ; Mode aléatoire pur
      set selected-students n-of capacity-per-year year1-students
    ][
      ; Mode avec sélection selon composition sociale
      ; Déterminer le type majoritaire dans l'école
      let major-type "favorise"
      if nb-moyens > nb-favorises and nb-moyens > nb-defavorises [
        set major-type "moyen"
      ]
      if nb-defavorises > nb-favorises and nb-defavorises > nb-moyens [
        set major-type "defavorise"
      ]

      ; Première vague : type majoritaire
      let first-priority year1-students with [social-class = major-type]

      ; Mélanger entre prioritaires et non-prioritaires selon le niveau de sélectivité
      let nb-prioritaires floor (capacity-per-year * selectivite-ecoles)
      let nb-random floor (capacity-per-year * (1 - selectivite-ecoles))

      ; Sélectionner d'abord les prioritaires
      ifelse count first-priority <= nb-prioritaires [
        set selected-students first-priority
        set nb-random (capacity-per-year - count first-priority)
      ][
        set selected-students n-of nb-prioritaires first-priority
      ]

      ; Compléter avec des élèves aléatoires parmi les non-sélectionnés
      let remaining-students year1-students with [not member? self selected-students]
      if any? remaining-students and nb-random > 0 [
        set selected-students (turtle-set selected-students
          n-of (min list nb-random count remaining-students) remaining-students)
      ]
    ]

    ; Les élèves sélectionnés restent, les autres doivent partir
    ask year1-students [
      ifelse member? self selected-students [
        set waiting false
        set my-school myself
        ; Position autour de l'école
        fd 3
        rt random 360
      ][
        ; Aller à une autre école si possible
        let other-possible-schools schools with [
          self != myself and
          count students-here with [waiting = true] < capacity-per-year
        ]
        if any? other-possible-schools [
          move-to min-one-of other-possible-schools [
            calculate-discomfort myself self
          ]
        ]
      ]
    ]
  ]
end 

to update-school-stats
  ask schools [
    set nb-favorises count students-here with [social-class = "favorise"]
    set nb-moyens count students-here with [social-class = "moyen"]
    set nb-defavorises count students-here with [social-class = "defavorise"]
  ]

  ; Calcul de l'indice de Duncan pour les défavorisés
  let total-defavorises sum [nb-defavorises] of schools
  let total-autres sum [nb-favorises + nb-moyens] of schools

  let duncan-index 0

  if total-defavorises > 0 and total-autres > 0 [
    set duncan-index 0.5 * sum [
      abs(
        (nb-defavorises / total-defavorises) -
        ((nb-favorises + nb-moyens) / total-autres)
      )
    ] of schools
  ]

  ; Mise à jour du graphique
  set-current-plot "Indice de ségrégation (défavorisés)"
  plot duncan-index
end