Simple PathFinder

globals [vision-distance debug_patch destination]
breed [firefighters]
breed [pees]
patches-own [peanuts fire-intensity]

to find-fire
  let patch-in-fire nobody  
  if any? patches in-radius vision-distance with [pcolor = red]
  [set patch-in-fire one-of patches in-radius vision-distance with [pcolor = red]]
end 

to set-patch-on-fire
  let _patch selected-patch
  if _patch != nobody [
    ask _patch [
      set pcolor (hsb 4 255 250)
      set fire-intensity 25
    ]    
  ]
end 

to-report selected-patch
  if mouse-down? [report patch mouse-xcor mouse-ycor]
  report nobody
end 

to make-road
  colorize-patch white
end 

to colorize-patch [_color]
  let _patch nobody
  if mouse-down?  
  [ 
    set _patch patch mouse-xcor mouse-ycor
    if [pcolor] of _patch = black [ask _patch [set pcolor _color]]
  ]  
end 

to create-ff
  create-firefighters 1 [init-ff]
end 

to init-ff
  set shape "van top"
  set size 1
  set color red
  set heading 0
  goto-road
end 

to goto-road
  let road-patch one-of patches with [pcolor = white]
  setxy [pxcor] of road-patch [pycor] of road-patch
end 

to-report is-road? [_patch]
  report [pcolor] of _patch = white
end 

to turn
  ifelse random 100 > 95 [left 90] [right 90]
end 

to drive
  let  _patch min-one-of (neighbors4 with [pcolor = white]) [peanuts]
  drop-peanut
  move-to _patch
end 

to drive-time
  every 0.4 [ask firefighters [drive]]
end 

to drop-peanut
  ask patch-here [
    set peanuts (peanuts + 1)
    ifelse peanuts = 1
    [sprout-pees 1 [set shape "circle" set color 5 set size 0.5]]
    [ask pees-here [set color (hsb (peanuts * 10) 255 255)]]
  ]
end 

to clear
  ask patches [set peanuts 0]
  clear-turtles
  if destination != nobody
  [
    ask destination [set pcolor white]
    set destination nobody
  ]
end 

to go
  every 0.4 [
    if destination-set?
    [
      ask firefighters [advance-to-destination destination]
    ]
  ]
end 

to set-off
  if fire-intensity > 0
  [
    set fire-intensity (fire-intensity - 1)
    set pcolor hsb 4 255 (fire-intensity * 10)
  ]
end 

to-report destination-set?
  report destination != nobody
end 

to select-destination
  let target selected-patch
  if target != nobody and [pcolor] of target = white [ 
    set destination target 
    ask destination [set pcolor yellow]
    ]
end 

to advance-to-destination [_destination]
  if _destination != nobody
  [
    ifelse patch-here != _destination
    [
      ifelse member? _destination neighbors4 [face _destination fd 1]
      [
        let next_patch min-one-of (neighbors4 with [pcolor = white] with-min [peanuts]) [distance _destination]
        drop-peanut
        face next_patch
        fd 1
      ]
    ]
    [
      remove-destination
      remove-path
    ]
  ]
end 

to remove-destination
  ask destination [
    set pcolor white
    set peanuts 0
  ]
  set destination nobody
end 

to remove-path
  ask patches with [peanuts > 0] 
  [
    set pcolor white
    ask pees-here [die]
    set peanuts 0
  ]
end