Delivery Drone System

;; ============================================================
;; DELIVERY DRONE SYSTEM  -  Agent-Based Simulation (NetLogo)
;; SE404.3 Agent-Based Systems - Group Assignment
;; ------------------------------------------------------------
;; Autonomous drones pick up parcels at a depot and deliver them
;; to customers while managing battery, avoiding obstacles and
;; other drones, and coping with weather. System-level patterns
;; (congestion at the depot / charging stations, delivery
;; throughput) EMERGE from simple local agent rules.
;;
;; HOW TO USE:
;;   Paste this whole block into the NetLogo "Code" tab.
;;   Then build the interface widgets listed at the bottom.
;; ============================================================

;; ---------- AGENT TYPES (breeds) ----------
breed [ drones drone ]
breed [ customers customer ]
breed [ depots depot ]
breed [ stations station ]      ;; charging stations

;; ---------- GLOBAL VARIABLES ----------
globals [
  completed-deliveries          ;; total parcels delivered
  failed-deliveries             ;; missions lost to a flat battery
  depot-x
  depot-y
]

;; ---------- AGENT ATTRIBUTES ----------
drones-own [
  battery                       ;; energy level 0-100
  carrying?                     ;; is it holding a parcel?
  target                        ;; the customer being served
  state                         ;; FSM state: to-depot / to-customer / to-charge
  deliveries-made               ;; parcels this drone delivered
]

customers-own [
  waiting?                      ;; still needs a parcel?
  assigned?                     ;; already claimed by a drone?
  wait-time                     ;; ticks spent waiting
]

patches-own [
  obstacle?                     ;; no-fly zone / building
  bad-weather?                  ;; slows drones and drains battery
]

;; ============================================================
;; SETUP
;; ============================================================

to setup
  clear-all
  setup-environment
  setup-depot
  setup-stations
  setup-customers
  setup-drones
  set completed-deliveries 0
  set failed-deliveries 0
  reset-ticks
end 

to setup-environment
  ask patches [
    set obstacle? false
    set bad-weather? false
    set pcolor black
  ]
  ;; scatter buildings / no-fly zones (keep the depot area clear)
  ask n-of number-of-obstacles patches with [ distancexy 0 0 > 3 ] [
    set obstacle? true
    set pcolor gray
  ]
  ;; seed weather cells if the weather switch is on
  if weather? [ seed-weather ]
end 

to seed-weather
  ask patches with [ bad-weather? ] [ set bad-weather? false set pcolor black ]
  ask n-of 30 patches with [ not obstacle? ] [
    set bad-weather? true
    set pcolor blue - 3
  ]
end 

to setup-depot
  set depot-x 0
  set depot-y 0
  create-depots 1 [
    setxy depot-x depot-y
    set shape "house"
    set color yellow
    set size 3
  ]
end 

to setup-stations
  create-stations number-of-charging-stations [
    move-to one-of patches with [ not obstacle? and distancexy 0 0 > 6 ]
    set shape "circle"
    set color green
    set size 2
  ]
end 

to setup-customers
  create-customers number-of-customers [
    move-to one-of patches with [ not obstacle? and distancexy 0 0 > 4 ]
    set shape "person"
    set color white
    set size 1.5
    set waiting? true
    set assigned? false
    set wait-time 0
  ]
end 

to setup-drones
  create-drones number-of-drones [
    setxy depot-x depot-y
    set shape "airplane"
    set color sky
    set size 2
    set battery 100
    set carrying? false
    set target nobody
    set state "to-depot"
    set deliveries-made 0
  ]
end 

;; ============================================================
;; MAIN LOOP
;; ============================================================

to go
  ;; stop when every parcel has been delivered
  if not any? customers with [ waiting? ] [ stop ]

  ask drones [
    consume-battery                 ;; behaviour 1: use energy
    run-behaviour                   ;; behaviour 2: act on the current state
  ]

  update-weather                    ;; dynamic environment
  ask customers with [ waiting? ] [ set wait-time wait-time + 1 ]
  tick
end 

;; ---------- ENERGY (with dead-battery handling) ----------

to consume-battery
  let drain drain-rate
  if [ bad-weather? ] of patch-here [ set drain drain * 2 ]   ;; env. interaction
  set battery battery - drain
  if battery <= 0 [
    ;; DECISION RULE: flat battery = failed mission, drone is replaced
    set failed-deliveries failed-deliveries + 1
    if target != nobody [ ask target [ set assigned? false ] ]
    set target nobody
    set carrying? false
    setxy depot-x depot-y
    set battery 100
    set state "to-depot"
  ]
end 

;; ---------- FINITE-STATE DECISION MODEL ----------

to run-behaviour
  if state = "to-depot"    [ head-to-depot ]
  if state = "to-customer" [ head-to-customer ]
  if state = "to-charge"   [ head-to-charge ]
end 

;; State: go to the depot, pick up a parcel, choose a customer

to head-to-depot
  ;; DECISION RULE: recharge before it is too late
  if battery < battery-threshold [ set state "to-charge" stop ]

  ifelse distancexy depot-x depot-y < 1 [
    ifelse any? customers with [ waiting? and not assigned? ] [
      set target one-of customers with [ waiting? and not assigned? ]
      ask target [ set assigned? true ]
      set carrying? true
      set state "to-customer"
    ]
    [ ;; nothing to deliver right now: wait at the depot
    ]
  ]
  [ move-toward depot-x depot-y ]
end 

;; State: deliver the parcel to the assigned customer

to head-to-customer
  if target = nobody [ set state "to-depot" stop ]
  ifelse distance target < 1 [
    ask target [ set waiting? false set assigned? false ]
    set completed-deliveries completed-deliveries + 1
    set deliveries-made deliveries-made + 1
    set carrying? false
    set target nobody
    ;; DECISION: recharge if low, otherwise fetch the next parcel
    ifelse battery < battery-threshold [ set state "to-charge" ] [ set state "to-depot" ]
  ]
  [ move-toward [ xcor ] of target [ ycor ] of target ]
end 

;; State: fly to the nearest charging station and refill

to head-to-charge
  let nearest-station min-one-of stations [ distance myself ]
  ifelse nearest-station = nobody [
    ;; no station available: recharge at the depot
    ifelse distancexy depot-x depot-y < 1 [
      set battery 100 set state "to-depot"
    ]
    [ move-toward depot-x depot-y ]
  ]
  [
    ifelse distance nearest-station < 1 [
      set battery battery + charge-rate            ;; interaction with the station
      if battery >= 100 [ set battery 100 set state "to-depot" ]
    ]
    [ move-toward [ xcor ] of nearest-station [ ycor ] of nearest-station ]
  ]
end 

;; ---------- MOVEMENT + AVOIDANCE ----------

to move-toward [ tx ty ]
  facexy tx ty

  ;; INTERACTION RULE: veer away from other drones just ahead
  if collision-avoidance? [
    if any? other drones in-cone 2 45 [ rt 40 ]
  ]

  ;; ENVIRONMENT INTERACTION: steer around obstacles
  let ahead patch-ahead 1
  if ahead != nobody and [ obstacle? ] of ahead [
    rt 60
    set ahead patch-ahead 1
    if ahead != nobody and [ obstacle? ] of ahead [ lt 120 ]
  ]

  ;; weather slows the drone down
  let spd drone-speed
  if [ bad-weather? ] of patch-here [ set spd spd * 0.5 ]
  fd spd
end 

;; ---------- DYNAMIC WEATHER ----------

to update-weather
  if not weather? [ stop ]
  if ticks mod 50 = 0 [ seed-weather ]   ;; weather shifts periodically
end 

;; ============================================================
;; OUTPUT REPORTERS (used by monitors / plots)
;; ============================================================

to-report avg-battery
  ifelse any? drones [ report precision (mean [ battery ] of drones) 1 ] [ report 0 ]
end 

to-report drones-charging
  report count drones with [ state = "to-charge" ]
end 

to-report avg-wait
  let w customers with [ waiting? ]
  ifelse any? w [ report precision (mean [ wait-time ] of w) 1 ] [ report 0 ]
end 

;; ============================================================
;; INTERFACE WIDGETS TO ADD (if you build the interface by hand)
;; ------------------------------------------------------------
;; BUTTONS : setup  |  go (tick the "forever" box)
;; SLIDERS : number-of-drones            1  - 30   (8)
;;           number-of-customers         5  - 80   (40)
;;           number-of-obstacles         0  - 150  (50)
;;           number-of-charging-stations 1  - 10   (4)
;;           drone-speed                 0.1- 2    (0.5, step 0.1)
;;           drain-rate                  0.1- 3    (0.5, step 0.1)
;;           battery-threshold           5  - 50   (25)
;;           charge-rate                 1  - 20   (5)
;; SWITCHES: collision-avoidance?   |   weather?
;; MONITORS: completed-deliveries | failed-deliveries |
;;           avg-battery | drones-charging | avg-wait
;; PLOTS   : "Deliveries" -> pen1: plot completed-deliveries
;;                           pen2: plot failed-deliveries
;;           "Average Battery" -> pen: plot avg-battery
;; ============================================================