local module = {}
setmetatable(module, {__index=_G})
setfenv(1, module)


local m = require 'marigold-svg.marigold'


local function merge2(a, b)
	local tbl = {}
	for k, v in pairs(a) do tbl[k] = v end
	for k, v in pairs(b) do tbl[k] = v end
	return tbl
end
local function merge_recursive(array, acc)
	local tbl = array[1]
	table.remove(array, 1)
	local acc = merge2(acc, tbl)
	if #array == 0 then return acc end
	return merge_recursive(array, acc)
end
local function merge(...)
	return merge_recursive({...}, {})
end


function capitalize(str)
	return string.gsub(str, "^.", string.upper)
end

--===== boxes =====--

Box = {}
function Box.new(_, tbl)
	local parent = tbl.parent or { x0=0, y0=0 }
	local width = tbl.width or parent.width
	local height = tbl.height or parent.width
	local offset = tbl.offset or { x=0, y=0 }
	local padding = tbl.padding or { left=0, right=0, top=0, bottom=0 }
	padding.left = padding.left or 0
	padding.right = padding.right or 0
	padding.top = padding.top or 0
	padding.bottom = padding.bottom or 0
	local self = {
		x0 = parent.x0 + offset.x + padding.left,
		y0 = parent.y0 + offset.y + padding.top,
		width = width - padding.left - padding.right,
		height = height - padding.top - padding.bottom,
	}
	setmetatable(self, {__index=Box})
	return self
end
setmetatable(Box, {__call=Box.new})


function Box.point(self, x, y)
	return x + self.x0, y + self.y0
end

function Box.center(self)
	return self.x0 + (self.width/2), self.y0 + (self.height/2)
end

local function hsplit(box, acc, count, settings)
	local index = #acc
	if index == count then return acc end

	local z = box.width / count
	table.insert(
		acc, 
		Box(merge({
			parent=box,
			width=z,
			offset= { x=index*z, y=0 }
		}, settings))
	)
	return hsplit(box, acc, count, settings)
end
function Box.hsplit(self, count, settings)
	local count = count or 2
	local settings = settings or {}
	return hsplit(self, {}, count, settings)
end

local function vsplit(box, acc, count, settings)
	local index = #acc
	if index == count then return acc end

	local z = box.height / count
	table.insert(
		acc, 
		Box(merge({
			parent=box,
			height=z,
			offset= { y=index*z, x=0 }
		}, settings))
	)
	return vsplit(box, acc, count, settings)
end
function Box.vsplit(self, count, settings)
	local count = count or 2
	local settings = settings or {}
	return vsplit(self, {}, count, settings)
end


function Box.split_down(self, height)
	local a = Box{
		parent=self,
		height=height,
	}
	local b = Box{
		parent=self,
		height=self.height - height,
		offset={x=0, y=height},
	}
	return a, b
end


--===== misc =====--

local function stack(...)
	local array = {...}
	local l
	l = function(acc_f, acc_h)
		if #array == 0 then return acc_f, acc_h end
		local f, h = array[1][1], array[1][2]
		table.remove(array, 1)
		local acc_f = function(y)
			local tbl = acc_f(y)
			table.insert(tbl, f(y+acc_h))
			return tbl
		end
		local acc_h = acc_h + h
		return l(acc_f, acc_h)
	end
	local f, h = l(function(y) return {} end, 0)
	return function(y) return m.g(f(y)) end, h
end

local function pad(top, bottom, f, h)
	return function(y) return f(y+top) end, top + h + bottom
end


local function _divider()
	local size = 3
	return function(y) return m.rect{
		x=0, y=y, width=500, height=size,
		style="fill:darkred;",
	} end, size
end
local divider = function() return pad(0, 10, _divider()) end


--===== basic stats =====--

local function title(stats)
	local size = 40
	return function(y)
		return m.text(stats.title, {
			x=10, y=y+size,
			style="font-size:"..size.."px;font-variant-caps:small-caps;stroke:black;fill:darkred;font-family:serif",
		})
	end, size
end
local function subheading(stats)
	local size = 14
	return function(y)
		return m.text(
			string.format("%s %s, %s", capitalize(stats.size), stats.type, stats.alignment),
			{
				x=10, y=y+size, style="font-size:"..size.."px;font-style:italic;"
			}
		)
	end, size
end

local function header(stats)
	local f, h = stack(
		{pad(10, 10, title(stats))},
		{pad(0, 10, subheading(stats))}
	)
	return f, h
end

local function _statline(name, value)
	local size = 14
	return function(y) return m.text(
		'<tspan style="font-weight:bold">'..name..'</tspan> '..value,
		{ x=10, y=y+size, style="font-size:"..size.."px;fill:darkred;" }
	) end, 14
end
local statline = function(name, value) return pad(0, 2, _statline(name, value)) end

local function armor_hp(stats)
	local f, h = pad(0, 10, stack(
		{statline('Armor Class', stats.ac)},
		{statline('Hit Points', stats.hp)},
		{statline('Speed', stats.speed)}
	))
	return f, h
end

local function bonus(raw)
	return math.floor( (raw-10)/2 )
end
local function rawbox(name, raw, x, y)
	local raw = tonumber(raw)
	local value = string.format("%d (%s%d)", raw, (raw<0 and '-') or '+', bonus(raw))
	return m.g{
		m.text(name, { x=x+10, y=y+15, style="font-weight:bold;font-size:15px;fill:darkred" }),
		m.text(value, {x=x, y=y+30, style="font-size:15px;fill:darkred;" }),
	}
end
local function raw(stats)
	return function(y) return m.g{
		rawbox('STR', stats.str, 10, y),
		rawbox('DEX', stats.dex, 90, y),
		rawbox('CON', stats.con, 170, y),
		rawbox('INT', stats.int, 250, y),
		rawbox('WIS', stats.wis, 330, y),
		rawbox('CHA', stats.cha, 410, y),
	} end, 40
end

local function base(stats)
	local f, h = stack(
		{header(stats)},
		{divider()},
		{armor_hp(stats)},
		{divider()},
		{raw(stats)},
		{divider()}
	)
	return f, h
end


--===== attributes =====--

local function attribs(stats)
	return function(y) return m.rect{
		x=0, y=y, width=500, height=20,
		style="fill:blue",
	} end, 20
end


--===== actions =====-- 

local function actions(stats)
	return function(y) return m.g{} end, 0
end


--===== draw =====--

function draw(stats)
	local f, h = stack({base(stats)}, {attribs(stats)}, {actions(stats)})
	return m.render(m.svg{
		viewBox = string.format("0 0 500 %d", h),
		width = 500,
		height = height,
		style = "font-family:sans-serif;",
		f(0),
	})
end


return module