(defMathConstants 'mconst)
mfgGrid = 100.0
debug = nil

; SNAPS STUFF TO GRID
; uses global mfgGrid to do so, which gets redefined in generator 
; to the tech mfg grid using the techFile
(defun snap (p)
	floor(p*mfgGrid)/mfgGrid
)

; DEBUG output function, uncomment to get all output
(procedure output( @rest args)
	(when debug (apply 'printf args))
	;()
)

; VECTOR HELPER FUNCTIONS
; add a vector vect to a point p
(defun addVect (p vect) 
	(car(p)+car(vect)):(cadr(p)+cadr(vect))
)
; multiplies a vector vect with a scalar
(defun multVect (vect scalar)
	(car(vect)*scalar):(cadr(vect)*scalar)
)
; multiplies a vector vect with -1 (inverse)
(defun invVect (vect)
	(multVect vect -1)
)
; subtracts two vectors from one another
; (does vect2 - vect1)
(defun subVect (vect1 vect2) 
	(car(vect2)-car(vect1)):(cadr(vect2)-cadr(vect1))
)
; returns length of a vector
(defun lenVect (vect)
	sqrt((1.0*car(vect)**2)+(1.0*cadr(vect)**2))
)
; rotates a vector vect by 90 CCW
(defun rotVect (vect)
	cadr(vect):-car(vect)
)
; normalizes a vector vect by its length
(defun normalizeVect (vect)
	(multVect vect 1.0/(lenVect vect))
)

; DRAWING HELPER FUNCTIONS
; creates a pin using database functions
; and a corresponding net with name name
; does so on the layer layer 
(defun ind_createPin (id name points layer)
	(leCreatePin
		id 
		layer
		"polygon"
		points
		name
		"inputOutput"
		'("none")
	)

	/*
	net = dbCreateNet(id name)
	fig = dbCreatePolygon(id layer points)
	trm = dbCreateTerm(net name "inputOutput")
	pin = dbCreatePin(net fig name trm)
	pin~>accessDir = '( "none" )
	*/

	lab = dbCreateLabel(id '("TEXT") cadr(points) name "centerLeft" "R0" "roman" 3)
	
	;output("created pin %s\n", name)
) 

; Creates the end connection for the inductor and 
; places a pin there
; TODO: create underpass here
(defun ind_createEnd (id start w dir)
	(output "[createEnd] start=%P dir=%P\n", start, dir)
	(let 
		(center points left right up)
		center = (addVect start (multVect dir (snap -w/2)))
		left = (addVect center (multVect dir (snap -w/2)))
		right = (addVect center (multVect dir (snap w/2)))
		up = (multVect (rotVect dir) (snap w/2))

		points = list(	
			(addVect left up)
			(addVect right up)
			(addVect right (invVect up))
			(addVect left (invVect up))
		)
		
		(ind_createPin 
			id 
			"inner"
			points
			list("TopMetal2" "drawing")
		)
	)
)

; Creates the start of the inductor 
; and places a pin there
(defun ind_createStart (id start width dir)
	center = start; (addVect start multVect((invVect dir) width/2))

	points = list(
		(addVect center (-width):width)
		(addVect center width:width)
		(addVect center width:(-width))
		(addVect center (-width):(-width))
	)
	(ind_createPin
		id
		"outer"
 		points
		list("TopMetal2" "drawing")
	)
)

; creates one segment of the inductor and calls itself recursively to complete
; one inductor
(defun ind_drawSegment (id n seg start r) 
	dx = snap(r*talpha)

	(case mod(seg, 8)
		(0 
			end = dx:r
			)
		(1
			end = r:dx
			)
		(2
			end = r:-dx
			)
		(3
			end = dx:-r		
			)
		(4
			end = -dx:-r
			)
		(5
			end = -r:-dx
			)
		(6
			end = -r:dx
			)
		(7
			r -= pitch
			end = (addVect start (r-dx):(r-dx))
			)
	)
	
	dir = (subVect start end)
	ndir = (normalizeVect dir)

	isstart = (seg == 0)
	isend   = (n < 1)

	; DEBUG
	output("seg: %d, n: %L (start: %L, end: %L)\n", mod(seg, nseg), n, isstart, isend)

	when(isend 
		l = (lenVect dir)
		
		if((mod(seg,2)==0)
		then
			end = addVect(end multVect(ndir (snap l*(n-1))))
		else
			end = addVect(start multVect(ndir (snap l*(n-1))))
		)
	)

	if((mod(seg, 2) == 0)
	then
		(dbCreatePathSeg
			id
			inductorLayer
			start
			end
			w
			if(!isstart then "custom" else "extend")
			if(!isend  then "custom" else "truncate")
			list(if(isstart then 0 else whalv) if(isend then 0 else whalv) list(w2halv w2halv whalv w2halv w2halv whalv))
		)
	else
		(dbCreatePathSeg
			id
			inductorLayer
			start
			end
			w2
			"truncate"
			"truncate"
		)
	)

	when(isstart ind_createStart(id start whalv ndir))
	when((n<=1) ind_createEnd(id end whalv ndir))

	n -= 1
	(output "n=%L\n", n)

	(when (n > 0)
		(ind_drawSegment id n seg+1 end r)
	) ; when
)

; uses ind_drawSegment to create a complete inductor with 
; the given specification
defun(drawInductor (n r width pitch)
	; the PCell cell view id
	id    = pcCellView

	(when (not id)
		(error "could not find cell view")
	) ; when


	; get manufacturing grid spacing and set global accordingly
	mfgGrid=1/techGetMfgGridResolution(techGetTechFile(id))
	(output "using manufacturing grid of %L\n", mfgGrid)

	; set multiple globals
	inductorLayer = '("TopMetal2", "drawing")
	output("generating inductor with r=%L, turns=%L, pitch=%L and width=%L\n" r n pitch width)

	whalv  = snap(width/2)
	w      = whalv*2
	; diagonal segment width 
	w2halv = snap(width*sqrt(2)/2)   
	w2     = 2*w2halv 


	pitch  = snap(pitch + w) ; pitch from segment sides
	r = snap(r - whalv)   ; middle radius
	nseg   = 8     ; octagonal inductor

	; calculation globals
	ahalv = mconst.PI/nseg            ; angle between segments
	talpha = tan(ahalv)      
	hl    = snap((r-w/2)*talpha) ; start point

	; draw inductor
	(ind_drawSegment id n*nseg 0 -hl:r r)
)

; defines the inductor PCell 
(pcDefinePCell 
	list( (ddGetObj "mmic14_inductors") "inductorPcell" "layout")
	list(
		( turns  "float" 1.0 )
		( radius "float" 100.0 )
		( width  "float" 2.1 ); techGetSpacingRule(techGetTechFile(pcCellView) "minWidth" "TopMetal2" ))
		( pitch  "float" 2.1 )
	)
	(let 
		()
		drawInductor(turns radius width pitch)
	)
)