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


local m = require 'marigold-svg.marigold'


function capitalize(str)
	return string.gsub(str, "^.", string.upper)
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(theme)
	local size = 3
	return function(y) return m.rect{
		x=0, y=y, width=500, height=size,
		style="fill:"..theme.flair,
	} end, size
end
local divider = function(theme) return pad(0, 10, _divider(theme)) end


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


local function wrap_text(str, max_len, tbl)
	tbl = tbl or {}
	local len = 0
	local count = 0
	local in_tag = false
	for i = 1,#str do
		count = count+1
		local c = string.sub(str, i, i)
		if c == '>' then in_tag = false
		elseif c == '<' then in_tag = true
		end

		if not in_tag then len = len+1 end
		if len >= max_len then break end
	end
	local line = string.sub(str, 1,count)
	if len < max_len then
		table.insert(tbl, line)
		return tbl
	end

	-- remove word-end from line
	local start = string.find(line, '[^ ]+$')
	local word = string.sub(line, start or #line)
	local line = string.sub(line, 1, (start and start-1) or nil)
	local rest = word .. string.sub(str, count+1)
	table.insert(tbl, line)
	return wrap_text(rest, max_len, tbl)
end
local function wrapped_text(str, max_len, x, size, line_spacing, style)
	local lines = wrap_text(str, max_len)
	local transform = function(index, line)
		return function(y) return m.text(line, { 
			x=x, y=y+size,
			style="font-size:"..size.."px;"..(style or ''),
			textLength=(index ~= #lines and 480) or nil,
		}) end, size+line_spacing
	end
	local tbl = {}
	for index, line in ipairs(lines) do
		table.insert(tbl, {transform(index, line)})
	end
	return stack(unpack(tbl))
end


local function format(str)
	local str = string.gsub(str, "%*%*(.-)%*%*", '<tspan style="font-weight:bold">%1</tspan>')
	str = string.gsub(str, "%*(.-)%*", '<tspan style="font-style:italic">%1</tspan>')
	return str
end


local function text(str, size, style)
	return function(y) return m.text(
		str,
		{ style="font-size:"..size.."px;" .. (style or ''), x=10, y=y+size }
	) end, size
end


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

local function header(stats, theme)
	local f, h = stack(
		--{pad(10, 10, name(stats))},
		{pad(10, 10, text(
			stats.name, 40, 
			'font-variant-caps:small-caps;stroke:'..theme.text..';fill:'..theme.flair..';font-family:serif'
		))},
		{pad(0, 10, text(
			string.format("%s %s, %s", capitalize(stats.size), stats.type, stats.alignment),
			14, 'font-style:italic;fill:'..theme.text
		))}
	)
	return f, h
end

local function statline(name, value, theme)
	return pad(0, 2, wrapped_text(
		string.format('<tspan style="font-weight:bold">%s</tspan> %s', name, value),
		80, 10, 14, 2, 'fill:'..theme.flair
	))
end

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

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

local function optional_attribute(stats, name, key, theme)
	local value = stats[key]
	if value then
		local f, h = statline(name, value, theme)
		return f, h
	else
		local f, h = empty()
		return f, h
	end
end
local function misc_attributes(stats, theme)
	local f, h = stack(
		{optional_attribute(stats, 'Saving Throws', 'saving_throws', theme)},
		{optional_attribute(stats, 'Skills', 'skills', theme)},
		{optional_attribute(stats, 'Damage Vulnerabilities', 'vulnerabilities', theme)},
		{optional_attribute(stats, 'Damage Resistances', 'resistances', theme)},
		{optional_attribute(stats, 'Damage Immunities', 'immunities', theme)},
		{optional_attribute(stats, 'Condition Immunities', 'condition_immunities', theme)},
		{optional_attribute(stats, 'Senses', 'senses', theme)},
		{optional_attribute(stats, 'Languages', 'languages', theme)},
		{optional_attribute(stats, 'Challenge', 'cr', theme)}
	)
	if h > 0 then return stack({pad(0, 10, f, h)}, {divider(theme)})
	else return empty(), 0 end
end




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


--===== traits =====--

local function trait(t, theme)
	return pad(0, 10, wrapped_text(
		string.format('<tspan style="font-weight:bold;font-style:italic">%s.</tspan> %s', t.name, format(t.value)),
		80, 10, 14, 5, 'fill:'..theme.text
	))
end
local function traits(stats, theme)
	if not stats.traits then return empty() end

	local tbl = {}
	for _, t in ipairs(stats.traits) do
		table.insert(tbl, {trait(t, theme)})
	end
	return stack(unpack(tbl))
end


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

local function subheader(title, theme)
	return pad(0, 10, stack(
		{pad(0, 5, text(title, 25, 'font-variant-caps:small-caps;stroke:'..theme.text..';fill:'..theme.flair))},
		{divider(theme)}
	))
end

local function actions(stats, theme)
	if not stats.actions then return empty() end

	local tbl = {}
	for _, action in ipairs(stats.actions) do
		table.insert(tbl, {trait(action, theme)})
	end
	return stack(
		{subheader('Actions', theme)},
		unpack(tbl)
	)
end


local function reactions(stats, theme)
	if not stats.reactions then return empty() end

	local tbl = {}
	for _, reaction in ipairs(stats.reactions) do
		table.insert(tbl, {trait(reaction, theme)})
	end
	return stack(
		{subheader('Reactions', theme)},
		unpack(tbl)
	)
end


local function legendary(stats, theme)
	if not stats.legendary then return empty() end

	local tbl = {}
	for _, action in ipairs(stats.legendary.actions) do
		table.insert(tbl, {trait(action, theme)})
	end
	return stack(
		{subheader('Legendary Actions', theme)},
		{pad(0, 10, wrapped_text(stats.legendary.description, 80, 10, 14, 2, 'fill:'..theme.text))},
		unpack(tbl)
	)
end




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

function draw(stats, theme)
	local theme = theme or {
		bg = '#020202',
		text = 'beige',
		flair = 'tomato',
	}
	local f, h = stack(
		{base(stats, theme)},
		{traits(stats, theme)},
		{actions(stats, theme)},
		{reactions(stats, theme)},
		{legendary(stats, theme)}
	)
	return m.render(m.svg{
		viewBox = string.format("0 0 500 %d", h),
		width = 500,
		height = height,
		style = "font-family:sans-serif;",
		m.rect{x=0, y=0, width=500, height=h, style='fill:'..theme.bg},
		f(0),
	})
end


return module