Virus Spread

globals [ ; general globals
  healthy
  infected
  dead
  total-infected
]
breed [people person]
breed [cities city] ; megacities with over 10 million people
breed [infecthalo infects] ; highlights patient zero
people-own [
  mode ; 0 (human) or "plane" (plane)
  destination ; for when mode = "plane", decides what city to land at
  ; infection variables
  infected? ; true (yes) or 0 (no)
  time-till-symptoms ; decided by avg.-incubation-period and incubation-period-range
  symptom-length ; days till recover or die, decided by symptom-length-(lowest/highest)
  reproductive-ratio ; how many people someone with the disease can spread it to? decided by avg.-reproductive-ratio and reproductive-ratio-range
  die-from-disease? ; how long till die? true or false (will recover)
  got-disease? ; if someone gets and recovers from disease, true or 0 (false)
]
cities-own [
  name
  population
]

to Setup
  ca ; clears everything
  reset-ticks ; resets clock
  decide-disease-variables
  make-cities
  import-pcolors "World Map with Country Borders.png"; image seen in background gets loaded in (must be in same folder)
  ask patches with [pcolor >= 8.1 and pcolor <= 8.3] [set pcolor 7.8] ; make more patches land
  ask patches with [pcolor >= 7.2 and pcolor <= 7.5] [set pcolor 7.8] ; make more patches land
  ask patches with [pcolor = 7.8] [if count neighbors with [pcolor = 7.8] = 0 [set pcolor 7]] ; so turtles don't get stuck on single patches of land
  ask patches with [pxcor > max-pxcor - 4 or pxcor < min-pxcor + 4 or pcolor = 39.9] [set pcolor 9.9] ; so more of white is water
  set-default-shape people "person"
  set-default-shape infecthalo "thin ring"
  let pre-move 100
  while [pre-move > 0] [ ; people move out from cities for (pre-move) number of cycles
    ask people [move]
    set pre-move pre-move - 1
  ]
  set healthy count people
  first-infected ; patient zero setup
end 

to decide-disease-variables ; depending on disease, inputs variables automatically
  if disease-variables = "SARS" [
    set patient0-x 205
    set patient0-y -21
    set fatality-rate 11
    set avg.-reproductive-ratio 2.5
    set reproductive-ratio-range .5
    set avg.-incubation-period 6.4
    set incubation-period-range 5
    set symptom-length-lowest 14
    set symptom-length-highest 24
    set get-again? true
  ]
  if disease-variables = "Measles" [
    set patient0-x -254
    set patient0-y 5
    set fatality-rate 10
    set avg.-reproductive-ratio 15
    set reproductive-ratio-range 3
    set avg.-incubation-period 14
    set incubation-period-range 14
    set symptom-length-lowest 7
    set symptom-length-highest 14
    set get-again? false
  ]
  if disease-variables = "Ebola" [
    set patient0-x -9
    set patient0-y -55
    set fatality-rate 50
    set avg.-reproductive-ratio 2
    set reproductive-ratio-range .5
    set avg.-incubation-period 10
    set incubation-period-range 8
    set symptom-length-lowest 8
    set symptom-length-highest 10
    set get-again? false
  ]
end 

to make-cities
  create-cities 35 [ ; creates the 35 mega-cities in the world (over 10 million population)
    set size 3
    set shape "circle"
    set color black
    set label-color black
    if who = 0 [ set name "Tokyo" set population 38 setxy 257 6] ; populations rounded to nearest half million
    if who = 1 [ set name "New Delhi" set population 27 setxy 135 -13]
    if who = 2 [ set name "Seoul" set population 26 setxy 232 7]
    if who = 3 [ set name "Shanghai" set population 25 setxy 216 -7]
    if who = 4 [ set name "Mumbai" set population 24 setxy 127 -33]
    if who = 5 [ set name "Mexico City" set population 22 setxy -221 -28]
    if who = 6 [ set name "Beijing" set population 22 setxy 208 14]
    if who = 7 [ set name "Sao Paulo" set population 21 setxy -112 -113]
    if who = 8 [ set name "Jakarta" set population 21 setxy 194 -85]
    if who = 9 [ set name "New York City" set population 20 setxy -165 20]
    if who = 10 [ set name "Karachi" set population 20 setxy 115 -19]
    if who = 11 [ set name "Osaka" set population 20 setxy 247 3]
    if who = 12 [ set name "Manila" set population 20 setxy 219 -39]
    if who = 13 [ set name "Cairo" set population 19 setxy 44 -9]
    if who = 14 [ set name "Dhaka" set population 18 setxy 159 -23]
    if who = 15 [ set name "Los Angeles" set population 18 setxy -254 5]
    if who = 16 [ set name "Moscow" set population 17 setxy 49 64]
    if who = 17 [ set name "Buenos Aires" set population 17 setxy -137 -143]
    if who = 18 [ set name "Kolkata" set population 16 setxy 151 -24]
    if who = 19 [ set name "London" set population 16 setxy -22 50]
    if who = 20 [ set name "Bangkok" set population 15 setxy 180 -42]
    if who = 21 [ set name "Lagos" set population 15 setxy -9 -55]
    if who = 22 [ set name "Istanbul" set population 15 setxy 40 16]
    if who = 23 [ set name "Rio de Janeiro" set population 15 setxy -104 -112]
    if who = 24 [ set name "Tehran" set population 14 setxy 83 4]
    if who = 25 [ set name "Guangzhou" set population 13 setxy 205 -21]
    if who = 26 [ set name "Kinshasa" set population 13 setxy 15 -78]
    if who = 27 [ set name "Shenzhen" set population 12 setxy 202 -23]
    if who = 28 [ set name "Lahore" set population 12 setxy 127 -3]
    if who = 29 [ set name "Rhine-Ruhr" set population 11 setxy -4 48]
    if who = 30 [ set name "Tianjin" set population 11 setxy 211 9]
    if who = 31 [ set name "Bengaluru" set population 11 setxy 133 -44]
    if who = 32 [ set name "Paris" set population 11 setxy -14 38]
    if who = 33 [ set name "Chennai" set population 10 setxy 136 -43]
    if who = 34 [ set name "Hyderabad" set population 10 setxy 134 -37]
  ]
  let citypop sum [population] of cities
  let worldpop 7300 / #-people-per-agent ; 7.30 billion people, if each agent = 5mil people, then 1460 agents
  ask cities [
    hatch-people (round ((population / citypop * worldpop) + .02)) [ ; each city creates proportional amount of people based on population
      set infected? false
      set color green
      set size 1
      set heading random 360
    ]
  ]
end 

to first-infected
  ifelse patient0-x = 0 and patient0-y = 0 ; if no patch chosen,
  [
    ask one-of people [ ; ask random person to be infected
      become-infected
      make-infecthalo
    ]
  ]
  [
    ask patch patient0-x patient0-y [ ; else, ask person closest to patch chosen
      ask min-one-of people [distance myself] [
        become-infected
        make-infecthalo
      ]
    ]
  ]
end 

to make-infecthalo
  hatch-infecthalo 1 [
    set size 10
    ;; Use an RGB color to make halo three fourths transparent
    set color lput 64 extract-rgb color
    ;; set thickness of halo to half a patch
    ;; We create an invisible directed link from the runner
    ;; to the halo.  Using tie means that whenever the
    ;; runner moves, the halo moves with it.
    create-link-from myself [
      tie
      hide-link
    ]
  ]
end 

;;=========================================;;

to become-infected
  set infected? true
  set infected infected + 1 ; updates appropriate globals
  if got-disease? != true [set total-infected total-infected + 1]
  set healthy healthy - 1
  set color red
  set time-till-symptoms round (avg.-incubation-period + random-float (.5 * incubation-period-range) - random-float (.5 * incubation-period-range)) ; days until can spread disease
  set symptom-length symptom-length-highest - round (random-float symptom-length-lowest) ; how long symptoms last until heal or die
  set reproductive-ratio round (avg.-reproductive-ratio + random-float (.5 * reproductive-ratio-range) - random-float (.5 * reproductive-ratio-range)) ; number of people that infected can infect
  ifelse random 100 < fatality-rate ; determines if will die from disease
  [
    set die-from-disease? true
  ]
  [
    set die-from-disease? false
  ]
end 

to become-healthy
  set infected? false
  set healthy healthy + 1 ; updates appropriate globals
  set infected infected - 1
  set color green
  set got-disease? true
end 

to become-dead
  set dead dead + 1 ; updates appropriate globals
  set infected infected - 1
  die ; a dead agent ceases to exist
end 

;;=========================================;;

to StartVirus
  city-selector ; visual to show city name
  ask people with [mode = 0] [
    move
    if infected? [ ; red person
      if time-till-symptoms = 0 [
        infect
        if symptom-length = 0 [
          ifelse die-from-disease?
          [
            become-dead
          ]
          [
            become-healthy
          ]
        ]
        if symptom-length > 0 [
          set symptom-length symptom-length - 1
        ]
      ]
      if time-till-symptoms > 0 [
        set time-till-symptoms time-till-symptoms - 1
      ]
    ]
  ]
  ask people with [mode = "plane"] [
    fd 1
    if distance destination <= 5 [ ; turn into person if close to city
      set mode 0
      set size 1
      move-to destination
      set destination 0
      set shape "person"
      set heading random 360
    ]
  ]
  ask cities [
    attract
    airport-run
  ]
  ask infecthalo [
    if infected != 1 [
      die
    ]
  ]
  tick
  wait .005
end 

to city-selector
  ask patch mouse-xcor mouse-ycor [ ; if mouse is over city, display name
    let x (cities in-radius 3)
    if any? x [
      ask x [
        set label name
        if mouse-down? [; if mouse clicks on city, displays city info
          clear-output
          output-print name
          output-type "Population = " output-type population output-print " million"
        ]
      ]
    ]
    ask cities with [label != "" and distance myself > 3] [ ; if mouse goes off city that is displaying info, resets
      set label ""
      clear-output
    ]
  ]
end 

to move
  if random 2 = 0 [ ; 50% chance to change direction
    set heading heading + random 20 - random 20 ; change direction
  ]
  while [patch-ahead 1 = nobody or [pcolor] of patch-ahead 1 = 9.9] [ ; change direction if water is ahead
    set heading heading + random 20 - random 20
  ]
  fd 1 ; moves forword a patch per day
  if distance min-one-of cities [distance myself] > 50 [ ; if too far from cities, face closest city
    face min-one-of cities [distance myself]
  ]
end 

to infect
  let x people in-radius 2 with [infected? = false and mode = 0] ; who can be infected
  if get-again? = false [ ; if disease cannot infect a person more than once, new restraint
    set x people in-radius 2 with [infected? = false and mode = 0 and got-disease? = 0]
  ]
  if any? x and reproductive-ratio > 0 [ ; if any people to infect and can infect more people
    ifelse count x <= reproductive-ratio ; if less people to infect than can infect
    [ ; infect those people and reduce reproductive-ratio
      set reproductive-ratio reproductive-ratio - count x
      ask x [
        become-infected
      ]
    ]
    [ ; else infect all people possible and set reproductive ratio 0
      ask n-of reproductive-ratio x [
        become-infected
      ]
      set reproductive-ratio 0
    ]
  ]
end 

to attract
  if count people with [mode = 0] in-radius 5 < population / 10  and count people with [mode = 0] > population / 10[ ; if less people in-radius than population,
    ask min-n-of (population / 10 - count people with [mode = 0] in-radius 5) people with [mode = 0] [distance myself] [ ; ask closest people to face city
      face myself
    ]
  ]
end 

to airport-run
  if random 175 = 0 and count people with [mode = 0] in-radius 5 > population / 10[ ; random chance to create airplane
    ask one-of people with [mode = 0] in-radius 5 [
      set mode "plane"
      set shape "airplane"
      set size 5
      set destination one-of cities
      face destination
    ]
  ]
end