define Glyph [require './support/glyph'].Glyph
define Stroke [require './support/stroke'].Stroke

### COMMON FUNCTIONS

define [mix a b p] : a + [b - a] * p
define [linreg x0 y0 x1 y1 x] : y0 + [x - x0] * [y1 - y0] / [x1 - x0]
define [fallback] : for [local j 0] [j < arguments.length] [inc j] : if [arguments`j !== nothing] : return arguments`j

define [exports.build para] : begin {

define variantSelector para.variantSelector

define font [require './empty.json']

define glyphList font.glyf
define glyphs (.'.notdef' glyphList.0)
define unicodeGlyphs ()

define globalTransform (
	.xx 1
	.yx [Math.tan [para.italicangle / 180 * Math.PI]]
	.xy 0
	.yy 1
	.x 0
	.y 0
)

define ITALICCOR : 1 / [Math.sqrt [1 - globalTransform.yx * globalTransform.yx]]

define UPWARD (.x [-ITALICCOR] .y 0)
define DOWNWARD (.x ITALICCOR .y 0)
define RIGHTWARD (.x globalTransform.yx .y 1)
define LEFTWARD  (.x [- globalTransform.yx] .y [-1])

# metrics
define DESCENDER para.descender
define WIDTH para.width
define CAP para.cap
define XH para.xheight
define O para.o
define OXHOOK para.oxhook
define SB para.sb
define HOOK para.hook
define AHOOK para.ahook
define SHOOK para.shook
define RHOOK para.rhook
define SMOOTH para.smooth
define SMALLSMOOTH para.smallsmooth
define STROKE para.stroke
define DOTSIZE para.dotsize
define PERIODSIZE para.periodsize
define BARPOS para.barpos
define GBARPOS para.gbarpos
define FIVEBARPOS para.fivebarpos
define LONGJUT para.longjut
define ACCENT para.accent
define ACCENTX para.accentx


# derived metrics
define XO : XH - O
define CAPO : CAP - O
define HALFSTROKE : STROKE / 2
define RIGHTSB : WIDTH - SB
define MIDDLE : WIDTH / 2
define CAPMIDDLE : CAP / 2
define CAP_SMOOTH : CAP - SMOOTH
define DOTRADIUS : DOTSIZE / 2
define PERIODRADIUS : PERIODSIZE / 2

define SMOOTHA : SMOOTH - globalTransform.yx * para.smoothadjust
define SMOOTHB : SMOOTH + globalTransform.yx * para.smoothadjust
define SMALLSMOOTHA : SMALLSMOOTH - globalTransform.yx * para.smoothadjust
define SMALLSMOOTHB : SMALLSMOOTH + globalTransform.yx * para.smoothadjust
define ITALICCORS : STROKE * globalTransform.yx

# style parameters
define EBARPOS : para.ebarpos || BARPOS
define KAPPA para.kappa
define COKAPPA : 1 - KAPPA
define BKAPPA : para.bkappa || KAPPA + 0.1
define CKAPPA : para.ckappa || BKAPPA
define COBKAPPA : 1 - BKAPPA
define KAPPA_HOOK  : para.kappa_hook || BKAPPA + 0.1
define KAPPA_AHOOK : para.kappa_ahook || KAPPA_HOOK
define TAILADJX : WIDTH * 0.2
define TAILADJY : XH * 0.25
define TAILADJKAPPA 0.75
define TAILADJSX :   WIDTH * 0.2
define TAILADJSY     0
define TAILADJSKAPPA 0.75
define ILBALANCE : LONGJUT * 0.04
define JBALANCE :  para.jbalance   || HALFSTROKE + ILBALANCE
define TBALANCE :  para.tbalance   || JBALANCE
define TBALANCE2 : para.tbalance2  || TBALANCE
define RBALANCE :  para.rbalance   || JBALANCE * 0.3


# Anchor parameters
define BASE 'base'
define MARK 'mark'
define MARKBASE 'markbase'

define [tm anchor] : return (
	.x [anchor.x * globalTransform.xx + anchor.y * globalTransform.yx + globalTransform.x]
	.y [anchor.x * globalTransform.xy + anchor.y * globalTransform.yy + globalTransform.y]
	.type anchor.type
)

define markAboveLower (.anchors (.above [tm (.x MIDDLE .y XH           .type BASE)]))
define markAboveCap   (.anchors (.above [tm (.x MIDDLE .y [CAP * 0.97] .type BASE)]))
define markBelowLower (.anchors (.below [tm (.x MIDDLE .y DESCENDER    .type BASE)]))
define markBelowZero  (.anchors (.below [tm (.x MIDDLE .y 0            .type BASE)]))

define capitalMarks   (.anchors (.above markAboveCap.anchors.above .below markBelowZero.anchors.below))
define bMarks         (.anchors (.above markAboveCap.anchors.above .below markBelowZero.anchors.below))
define eMarks         (.anchors (.above markAboveLower.anchors.above .below markBelowZero.anchors.below))
define pMarks         (.anchors (.above markAboveLower.anchors.above .below markBelowLower.anchors.below))
define ifMarks        (.anchors (.above markAboveCap.anchors.above .below markBelowLower.anchors.below))

Stroke.bindParameters para

### Font names
set font.name.fontFamily          para.family
set font.name.fontSubFamily       para.style
set font.name.preferredFamily     para.family
set font.name.preferredSubFamily  para.style
set font.name.uniqueSubFamily     : para.family + ' ' + para.style + ' ' + para.version
set font.name.version             para.version
set font.name.fullName            : if [para.style != 'Regular'] [para.family + ' ' + para.style] para.family
set font.name.postScriptName      : font.name.fullName.replace [regex ' ' 'g'] '-'
set font.name.copyright           para.copyright
set font.'OS/2'.usWeightClass     para.weight
set font.'OS/2'.bProportion       9 # Monospaced
set font.'OS/2'.bWeight           : 1 + para.weight / 100
set font.'OS/2'.fsSelection       : [if para.isBold 32 0] + [if para.isItalic 1 0] + [if [[not para.isBold] && [not para.isItalic]] 64 0] + 128
set font.head.macStyle            : [if para.isBold 1 0] + [if para.isItalic 2 0]

### Metric metadata
# Note: we use 1000upm in design, and 4096upm in production

define upmscale : fallback para.upmscale 1

set font.head.unitsPerEm          : upmscale * 1000
set font.hhea.ascent              : upmscale * CAP
set font.'OS/2'.usWinAscent       : upmscale * [CAP + CAP * 0.1]
set font.'OS/2'.sTypoAscender     : upmscale * CAP
set font.hhea.descent             : upmscale * DESCENDER
set font.'OS/2'.usWinDescent      : upmscale * [[Math.abs DESCENDER] + CAP * 0.1]
set font.'OS/2'.sTypoDescender    : upmscale * DESCENDER
set font.hhea.lineGap             : upmscale * CAP * 0.2
set font.'OS/2'.sTypoLineGap      : upmscale * CAP * 0.2
set font.'OS/2'.sxHeight          : upmscale * XH
set font.post.italicAnvle         : 0 - para.italicangle

### Necessary macros
define-macro glyph-construction : syntax-rules {
	@`[glyph-construction @::steps] ('.syntactic-closure' @`[lambda [] [begin {
		local currentGlyph this
		local set-width : this.set-width.bind this
		local assign-unicode : lambda [code] : begin {
			currentGlyph.assign-unicode code
			set unicodeGlyphs.(currentGlyph.unicode`[currentGlyph.unicode.length - 1]) currentGlyph
		}
		local start-from : this.start-from.bind this
		local line-to : this.line-to.bind this
		local curve-to : this.curve-to.bind this
		local cubic-to : this.cubic-to.bind this
		local put-shapes : this.put-shapes.bind this
		local reverse-last : this.reverse-last.bind this
		local include : this.include.bind this
		local create-stroke : this.create-stroke.bind this
		local set-anchor : this.set-anchor.bind this
		this.gizmo = globalTransform
		this.set-width WIDTH
		begin @::[steps.map formOf]
		return nothing
	}]] env)
}
define [create-glyph name actions] : begin {
	console.log : "Building /" + name
	define glyphObject [new Glyph name]
	glyphList.push glyphObject
	glyphs`name = glyphObject
	actions.call glyphObject
	return glyphObject
}

define [select-variant glyphid unicode default] : begin {
	local variant : variantSelector`glyphid || default
	local chosenGlyph glyphs`[glyphid + '.' + variant]
	set glyphs`glyphid chosenGlyph
	if unicode : begin {
		chosenGlyph.assign-unicode unicode
		set unicodeGlyphs.(chosenGlyph.unicode`[chosenGlyph.unicode.length - 1]) chosenGlyph
	}
}

###### HERE WE GO!

define [xgrid p] : mix SB RIGHTSB p

create-glyph 'space' : glyph-construction {
	set-width WIDTH
	assign-unicode ' '
	include eMarks
}