;; targets.scm                         Daniel Azus                         12-4-2006

;; This program uses the world teachpack
;; Purpose:  Change an element in a list dynamically in a world program

;; This program allows the user to control the crosshair
;; When the mouse if clicked on a target it will change color the first time it is clicked

;; Constants for window
(define WindowWidth 800)            ;; The width of the window in pixels
(define WindowHeight 640)           ;; The height of the window in pixels
(define FrameRate 30)               ;; The target rate the window is updated per second (frames per second)
(define FrameDelay (/ 1 FrameRate)) ;; The delay between frames, based on the frame rate

;; Constants
(define CrosshairRadius 20)
(define TargetWidth 30)
(define TargetHeight 30)

;; Default values for variables
(define InitFrame 0)
(define InitCosshairX 0)
(define InitCosshairY 0)
(define InitPaused false)

;; Defining structures
(define-struct Target [x y Width Height Hit])

;; rand: start (num) end (num) --> random number >= start and <= end
(define (rand start end)
  (if (> (- end start) 0) (+ start (random (- (+ end 1) start))) 0)
)

;; =====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*
;; Defining and setting the default world

;; Defining the world
;; World variables
;; Frame = Frames since the program started
;; CrosshairX = X position of the crosshair
;; CrosshairY = Y position of the crosshair
;; TargetList = List of the targets
;; Paused = If the world is paused
(define-struct World [Frame CrosshairX CrosshairY TargetList Paused])

(define (CreateInitialTarget Hit)
  (make-Target
    (rand 0 (- WindowWidth (* TargetWidth 10)))
    (rand 0 (- WindowWidth (* TargetHeight 10)))
    TargetWidth TargetHeight Hit
  )
)

;; The first world that starts with the default values
(define InitialWorld
  (make-World
    InitFrame
    InitCosshairX
    InitCosshairY
    (list
      (CreateInitialTarget false)
      (CreateInitialTarget false)
      (CreateInitialTarget false)
      (CreateInitialTarget false)
      (CreateInitialTarget false)
      (CreateInitialTarget false)
      (CreateInitialTarget false)
      (CreateInitialTarget false)
      (CreateInitialTarget false)
      (CreateInitialTarget false)
    )
    InitPaused
  )
)

;; =====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*
;; List helpers

;; Checks the size of a list (length function does the same thing)
(define (size alist)
  (cond
    [(empty? alist) 0]
    [else (+ 1 (size (rest alist)))]
  )
)

;; Gets a specified element in a list
(define (GetElement AList Index)
  (cond
    [(empty? AList) empty]
    [(< Index 1) empty]
    [(= Index 1) (first AList)]
    [else (GetElement (rest AList) (- Index 1))]
  )
)

;; Gets the last element in a list
(define (last alist) (GetElement alist (size alist)))

;; Helps find a specified value in a list
(define (FindHelper AList Value Index)
  (cond
    [(empty? AList) 0]
    [(eqv? (first AList) Value) Index]
    [else (FindHelper (rest AList) Value (+ Index 1))]
  )
)

;; Finds a specified value in a list
;; Used to pass the initial index of 1 to the helper function
(define (Find AList Value)
  (FindHelper AList Value 1)
)

;; Chops off all elements after and including the AfterThis value
;; It should be called by ChopListA
(define (ChopListAHelper AList AfterThis SoFar)
  (cond
    [(empty? AList) empty]
    [(< AfterThis 1) empty]
    [(= AfterThis 1) empty]
    [else (cons SoFar (ChopListAHelper (rest AList) (- AfterThis 1) (first AList)))]
  )
)

;; Chops off all elements after and including the AfterThis value
(define (ChopListA AList AfterThis)
  (cond
    [(empty? AList) empty]
    [(< AfterThis 1) empty]
    [(= AfterThis 1) (rest AList)]
    [else (ChopListAHelper (rest AList) (- AfterThis 0) (first AList))]
  )
)

;; Chops off all elements before and including the BeforeThis value
(define (ChopListB AList BeforeThis)
  (cond
    [(empty? AList) empty]
    [(< BeforeThis 1) empty]
    [(= BeforeThis 1) (rest AList)]
    [else (ChopListB (rest AList) (- BeforeThis 1))]
  )
)

;; Helps SetElement add the 2 lists together
(define (SetElementHelper AList1 List1Size AList2)
  (cond
    [(empty? AList1) AList2]
    [(< List1Size 1) AList2]
    [else (SetElementHelper AList1 (- List1Size 1) (cons (GetElement AList1 List1Size) AList2))]
  )
)

;; Sets the given index in a list to the value given
(define (SetElement AList Index Value)
  (cond
    [(empty? AList) AList]
    [(<= Index 1) (cons Value (ChopListB AList 1))]
    [else
      (SetElementHelper
        (ChopListA AList Index)
        (size (ChopListA AList Index))
        (cons Value (ChopListB AList Index))
      )
    ]
  )
)
 
;; =====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*
;; Drawing helper functions

;; Used when drawing images in a world
(define (PutImage image x y image2)
  (place-image image (+ x (/ (image-width image) 2)) (+ y (/ (image-height image) 2)) image2)
)

;; Used when drawing images in a world with out offset
(define (PutImageNorm image x y image2)
  (place-image image x y image2)
)

;; Used when drawing text in a world
(define (PutText Text TextColor x y image2)
  (PutImageNorm (text Text 12 TextColor) x y image2)
)

;; Used when drawing text in a world with a font size
(define (PutTextSized Text TextColor fontsize x y image2)
  (PutImageNorm (text Text fontsize TextColor) x y image2)
)

;; Used when drawing a line in a world
(define (PutLine X1 Y1 X2 Y2 Color image2)
  (PutImageNorm (line (- X2 X1) (- Y2 Y1) Color) X1 Y1 image2)
)

;; =====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*
;; Other helper functions

;; Converts a number to true or false
(define (ConvertNumToTF Value)
  (if (= Value 0)
    false
    true
  )
)

;; Checks if two rectangles are intersecting
(define (CollTarget R1X1 R1Y1 R1X2 R1Y2 R2X1 R2Y1 R2X2 R2Y2)
  (if (and (<= R1X1 R2X2) (>= R1X2 R2X1) (<= R1Y1 R2Y2) (>= R1Y2 R2Y1))
    true
    false
  )
)

;; Checks if two rectangles are intersecting with relative width and heights
(define (CollTargetRel R1X R1Y R1W R1H R2X R2Y R2W R2H)
  (if (and (<= R1X (+ R2X R2W)) (>= (+ R1X R1W) R2X) (<= R1Y (+ R2Y R2H)) (>= (+ R1Y R1H) R2Y))
    true
    false
  )
)

;; Helper function for InTarget
;; Is recursive until a target is found or the list is empty
(define (CollTargetsHelper Target TargIndex TargetList Index)
  (cond
    [(empty? TargetList) 0]
    [else
      (if
        (and
        (CollTargetRel (Target-x Target) (Target-y Target) (Target-Width Target)  (Target-Height Target)
        (Target-x (first TargetList)) (Target-y (first TargetList))
        (Target-Width (first TargetList))  (Target-Height (first TargetList)))
        (not (= TargIndex Index))
        )
        Index
        (InTargetHelper Target TargIndex (rest TargetList) (+ Index 1))
      )
    ]
  )
)

;; Checks if a point is in a target
(define (CollTargets Target TargIndex TargetList)
  (InTargetHelper Target TargIndex TargetList 1)
)

;; Checks if a point is in a rect
(define (InRect X Y RectX RectY RectWidth RectHeight)
  (if (and (>= X RectX) (<= X (+ RectX RectWidth)) (>= Y RectY) (<= Y (+ RectY RectHeight)))
    true
    false
  )
)

;; Helper function for InTarget
;; Is recursive until a target is found or the list is empty
(define (InTargetHelper X Y TargetList Index)
  (cond
    [(empty? TargetList) 0]
    [else
      (if (InRect X Y (Target-x (first TargetList)) (Target-y (first TargetList))
        (Target-Width (first TargetList))  (Target-Height (first TargetList)))
        Index
        (InTargetHelper X Y (rest TargetList) (+ Index 1))
      )
    ]
  )
)

;; Checks if a point is in a target
(define (InTarget X Y TargetList)
  (InTargetHelper X Y TargetList 1)
)

;; Sets a target to hit
(define (SetTargetHit ATarget)
  (make-Target (Target-x ATarget) (Target-y ATarget) (Target-Width ATarget) (Target-Height ATarget) true)
)

;; =====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*
;; Everything that has to do with drawing

;; Constant drawing colors
(define ColorWhite (make-color 0 0 0))
(define ColorBlack (make-color 0 0 0))
(define ColorRed (make-color 255 0 0))
(define ColorGreen (make-color 0 255 0))
(define ColorBlue (make-color 0 0 255))
(define ColorDarkGrey (make-color 100 100 100))
(define ColorDarkGreen (make-color 0 150 0))

;; Constants for drawing
(define Background (rectangle WindowWidth WindowHeight 'solid ColorDarkGrey))
(define Crosshair (circle CrosshairRadius 'outline ColorGreen))

;; Draws a target
(define (DrawTarget ATarget)
  (rectangle (Target-Width ATarget) (Target-Height ATarget) 'solid (if (Target-Hit ATarget) ColorRed ColorBlue))
)

;; Drawing the rest of the targets
(define(DrawTargets2 image1 TargetList image2)
  (cond
    [(empty? TargetList) image1]
    [else (PutImage (DrawTarget (first TargetList)) (Target-x (first TargetList)) (Target-y (first TargetList))
      (DrawTargets2 image1 (rest TargetList) image2))]
  )
)

;; Drawing the first target
(define (DrawTargets TargetList image2)
  (DrawTargets2 (PutImage (DrawTarget (first TargetList)) (Target-x (first TargetList))
    (Target-y (first TargetList)) image2) (rest TargetList) image2)
)

;; This takes care of making sure everything gets drawn
(define (Draw-Window aworld)
  (PutLine (+ (World-CrosshairX aworld) CrosshairRadius)
    (- (+ (World-CrosshairY aworld) CrosshairRadius) CrosshairRadius)
    (+ (World-CrosshairX aworld) CrosshairRadius)
    (+ (+ (World-CrosshairY aworld) CrosshairRadius) CrosshairRadius) ColorDarkGreen
  (PutLine (- (+ (World-CrosshairX aworld) CrosshairRadius) CrosshairRadius)
    (+ (World-CrosshairY aworld) CrosshairRadius)
    (+ (+ (World-CrosshairX aworld) CrosshairRadius) CrosshairRadius)
    (+ (World-CrosshairY aworld) CrosshairRadius) ColorDarkGreen
  (PutImage Crosshair (World-CrosshairX aworld) (World-CrosshairY aworld)
  (PutTextSized (number->string (World-Frame aworld)) ColorWhite 18 (/ WindowWidth 2) 0
  (DrawTargets (World-TargetList aworld)
  (PutImage Background 0 0
  (empty-scene WindowWidth WindowHeight)
  ))))))
)

;; =====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*
;; Everything that has to do with updating

;; Update a single target
(define (UpdateTarget ATarget)
  (make-Target
    (Target-x ATarget)
    (Target-y ATarget)
    (Target-Width ATarget)
    (Target-Height ATarget)
    (Target-Hit ATarget)
  )
)

;; Updates a list of targets
(define (UpdateTargets TargetList)
  (cond
    [(empty? TargetList) empty]
    [else (cons (UpdateTarget (first TargetList)) (UpdateTargets (rest TargetList)))]
  )
)

;; Takes care of updating all the world variables of the current world
(define (UpdateWorld aworld)
  (cond
    [(World-Paused aworld) aworld] ;; Check if this world is paused
    [else
      (make-World
        (+ (World-Frame aworld) 1) ;; Increment the frame count
        (World-CrosshairX aworld) ;; The crosshair's x position
        (World-CrosshairY aworld) ;; The crosshair's y position
        (UpdateTargets (World-TargetList aworld)) ;; The target list
        false ;; Paused
      )
    ]
  )
)

;; This takes care of making sure everything gets updated
(define (Update aworld)
  (cond
    [(World-Paused aworld) aworld] ; If world is paused nothing changes
    [else (UpdateWorld aworld)]
  )
)

;; =====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*
;; Everything that has to do with mouse input

;; This is called when a mouse button is pressed.
;; It is unable to tell which button.
(define (Mouse-Button-Down x y aworld)
  (make-World
    (World-Frame aworld)
    (- x CrosshairRadius 2)
    (- y CrosshairRadius 2)
    (if
      (ConvertNumToTF (InTarget x y (World-TargetList aworld)))
      (SetElement (World-TargetList aworld) (InTarget x y (World-TargetList aworld))
        (make-Target
          (Target-x (GetElement (World-TargetList aworld) (InTarget x y (World-TargetList aworld))))
          (Target-y (GetElement (World-TargetList aworld) (InTarget x y (World-TargetList aworld))))
          (Target-Width (GetElement (World-TargetList aworld) (InTarget x y (World-TargetList aworld))))
          (Target-Height (GetElement (World-TargetList aworld) (InTarget x y (World-TargetList aworld))))
          true
        )
      )
      (World-TargetList aworld)
    )
    (World-Paused aworld)
  )
)

;; This is called when a mouse button is released.
;; It is unable to tell which button.
(define (Mouse-Button-Released x y aworld)
  (make-World
    (World-Frame aworld)
    (- x CrosshairRadius 2)
    (- y CrosshairRadius 2)
    (World-TargetList aworld)
    (World-Paused aworld)
  )
)

;; This is called when the mouse is moved.
;; It is unable to tell which button.
(define (Mouse-Move x y aworld)
  (make-World
    (World-Frame aworld)
    (- x CrosshairRadius 2)
    (- y CrosshairRadius 2)
    (World-TargetList aworld)
    (World-Paused aworld)
  )
)

;; This is called when the mouse is dragged.
;; It is unable to tell which button.
(define (Mouse-Drag x y aworld)
  (make-World
    (World-Frame aworld)
    (- x CrosshairRadius 2)
    (- y CrosshairRadius 2)
    (World-TargetList aworld)
    (World-Paused aworld)
  )
)

;; This is called anytime the mouse changes.
;; It is unable to tell which button is pressed or released.
(define (Handle-Mouse a b c d)
  (cond
    [(eqv? d 'button-down) (Mouse-Button-Down b c a)]
    [(eqv? d 'button-up) (Mouse-Button-Released b c a)]
    [(eqv? d 'drag) (Mouse-Drag b c a)]
    [(eqv? d 'move) (Mouse-Move b c a)]
    [else a]
  )
)

;; =====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*
;; Everything that has to do with keyboard input

;; The up arrow key was pressed
(define (Key-UpArrow aworld)
  (make-World
    (World-Frame aworld)
    (World-CrosshairX aworld)
    (World-CrosshairY aworld)
    (World-TargetList aworld)
    (World-Paused aworld)
  )
)

;; The down arrow key was pressed
(define (Key-DownArrow aworld)
  (make-World
    (World-Frame aworld)
    (World-CrosshairX aworld)
    (World-CrosshairY aworld)
    (World-TargetList aworld)
    (World-Paused aworld)
  )
)

;; The left arrow key was pressed
(define (Key-LeftArrow aworld)
  (make-World
    (World-Frame aworld)
    (World-CrosshairX aworld)
    (World-CrosshairY aworld)
    (World-TargetList aworld)
    (World-Paused aworld)
  )
)

;; The right arrow key was pressed
(define (Key-RightArrow aworld)
  (make-World
    (World-Frame aworld)
    (World-CrosshairX aworld)
    (World-CrosshairY aworld)
    (World-TargetList aworld)
    (World-Paused aworld)
  )
)

;; This is called anytime a key to pressed or released.
;; It is unable to tell if a key is still pressed or which key was released.
;; If a key is held down then the function will get called multiple times.
(define (Handle-Keys a b)
  (cond
    [(eqv? b 'up) (Key-UpArrow a)]
    [(eqv? b 'down) (Key-DownArrow a)]
    [(eqv? b 'left) (Key-LeftArrow a)]
    [(eqv? b 'right) (Key-RightArrow a)]
    [else a]
  )
)

;; =====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*=====*
;; Sets up the window and what functions to call and when they should be called

;; Creates the window
(big-bang WindowWidth WindowHeight FrameDelay InitialWorld)

;; Set the drawing function
(on-redraw Draw-Window)

;; Set the updating function
(on-tick-event Update)

;; Set the key press function
(on-key-event Handle-Keys)

;; Set the mouse handler function
(on-mouse-event Handle-Mouse)