Piechart

Documentation for this module may be created at Module:Piechart/doc

local p = {}
--[[
	Smooth piechart module.

	Draws charts in HTML with an accessible legend (optional).
	A list of all features is in the "TODO" section of the main `p.pie` function.

	Use with a helper template that adds required CSS.

	{{{1}}}:
	[
		{ "label": "pie: $v", "color": "wheat", "value": 40 },
		{ "label": "cheese pizza $v", "color": "#fc0", "value": 20 },
		{ "label": "mixed pizza: $v", "color": "#f60", "value": 20 },
		{ "label": "raw pizza $v", "color": "#f30" }
	]
    Where $v is a formatted number (see `function prepareLabel`).

	{{{meta}}}:
		{"size":200, "autoscale":false, "legend":true}
	All meta options are optional (see `function p.setupOptions`).
]]
-- Author: [[User:Nux|Maciej Nux]] (pl.wikipedia.org).

--[[
	Debug:
	
	-- labels and auto-value
	local json_data = '[{"label": "k: $v", "value": 33.1}, {"label": "m: $v", "value": -1}]'
	local html = p.renderPie(json_data)
	mw.logObject(html)
	
	-- autoscale values
	local json_data = '[{"value": 700}, {"value": 300}]'
	local html = p.renderPie(json_data, options)
	mw.logObject(html)	
	
	-- size option
	local json_data = '[{"label": "k: $v", "value": 33.1}, {"label": "m: $v", "value": -1}]'
	local options = '{"size":200}'
	local html = p.renderPie(json_data, options)
	mw.logObject(html)	

	-- custom colors
	local json_data = '[{"label": "k: $v", "value": 33.1, "color":"black"}, {"label": "m: $v", "value": -1, "color":"green"}]'
	local html = p.renderPie(json_data)
	mw.logObject(html)
	
	-- 4-cuts
	local entries = {
	    '{"label": "ciastka: $v", "value": 2, "color":"goldenrod"}',
	    '{"label": "słodycze: $v", "value": 4, "color":"darkred"}',
	    '{"label": "napoje: $v", "value": 1, "color":"lightblue"}',
	    '{"label": "kanapki: $v", "value": 3, "color":"wheat"}'
	}
	local json_data = '['..table.concat(entries, ',')..']'
	local html = p.renderPie(json_data, '{"autoscale":true}')
	mw.logObject(html)

	-- colors
	local fr = { args = { " 123 " } }
	local ret = p.color(fr)
]]

--[[
	Color for a slice (defaults).

	{{{1}}}: slice number
]]
function p.color(frame)
	local index = tonumber(trim(frame.args[1]))
	return ' ' .. defaultColor(index)
end

--[[
	Piechart.
	
    TODO:
    - [x] basic 2-element pie chart
        - read json
        - calculate value with -1
        - generate html
        - new css + tests
        - provide dumb labels (just v%)
    - [x] colors in json
    - [x] 1st value >= 50%
    - [x] custom labels support
    - [x] pie size from 'meta' param (options json)
    - [x] pl formatting for numbers?
    - [x] support undefined value (instead of -1)
    - [x] undefined in any order
    - [x] scale values to 100% (autoscale)
    - [x] order values clockwise (not left/right)
    - [x] multi-cut pie
    - [x] sanitize user values
    - [x] auto colors
    - [x] function to get color by number (for custom legend)
	- [x] remember and show autoscaled data
    - [x] generate a legend
	- [x] simple legend positioning by (flex-)direction
    - legend2: customization
		- (?) itemTpl support
			- replace default item with tpl
			- can I / should I sanitize it?
			- support for $v, $d, $p
		- (?) custom head
    - (?) validation of input
		- check if required values are present
		- message showing whole entry, when entry is invalid
		- pre-sanitize values?
		- sane info when JSON fails? Maybe dump JSON and show example with quotes-n-all...
    - (?) option to sort entries by value
]] 
function p.pie(frame)
	local json_data = trim(frame.args[1])
	local options = nil
	if (frame.args.meta) then
		options = trim(frame.args.meta)
	end
	
	local html = p.renderPie(json_data, options)
	return trim(html)
end

-- Setup chart options.
function p.setupOptions(json_options)
	local options = {
		-- circle size in [px]
		size = 200,
		-- autoscale values (otherwise assume they sum up to 100)
		autoscale = false,
		-- hide chart for screen readers (when you have a table, forced for legend)
		ariahidechart = false,
		-- show legend (defaults to the left side)
		legend = false,
		-- direction of legend-chart flexbox (flex-direction)
		direction = "",
	}   
	if json_options then
		local rawOptions = mw.text.jsonDecode(json_options)
		if rawOptions then
			if type(rawOptions.size) == "number" then
				options.size = math.floor(rawOptions.size)
			end
			options.autoscale = rawOptions.autoscale or false 
			if rawOptions.legend then
				options.legend = true
			end
			if rawOptions.ariahidechart then
				options.ariahidechart = true
			end
			if (type(rawOptions.direction) == "string") then
				-- Remove unsafe/invalid characters
				local sanitized = rawOptions.direction:gsub("[^a-z0-9%-]", "")
				-- also adjust width so that row-reverse won't push things to the right
				options.direction = 'width: max-content; flex-direction: ' .. sanitized
			end
		end
	end
	if (options.legend) then
		options.ariahidechart = true
	end
	return options
end

--[[
	Render piechart.
	
	@param json_data JSON string with pie data.
]]
function p.renderPie(json_data, json_options)
	local data = mw.text.jsonDecode(json_data)
	local options = p.setupOptions(json_options)

	-- prepare
	local ok, total = p.prepareEntries(data, options)

	-- init render
	local html = "<div class='smooth-pie-container' style='"..options.direction.."'>"

	-- error info
	if not ok then
		html = html .. renderErrors(data)
	end

	-- render legend
	if options.legend then
		html = html .. p.renderLegend(data, options)
	end

	-- render items
	local header, items, footer = p.renderEntries(ok, total, data, options)
	html = html .. header .. items .. footer

	-- end .smooth-pie-container
	html = html .. "\n</div>"

	return html
end

-- Prepare data (slices etc)
function p.prepareEntries(data, options)
	local sum = sumValues(data);
	-- force autoscale when over 100
	if (sum > 100) then
		options.autoscale = true
	end
	-- pre-format entries
	local ok = true
	local no = 0
	local total = #data
	for index, entry in ipairs(data) do
		no = no + 1
		if not prepareSlice(entry, no, sum, total, options) then
			no = no - 1
			ok = false
		end
	end
	total = no -- total valid

	return ok, total
end

function sumValues(data)
	local sum = 0;
	for _, entry in ipairs(data) do
		local value = entry.value
		if not (type(value) ~= "number" or value < 0) then
		    sum = sum + value
		end
	end
	return sum
end

-- render error info
function renderErrors(data)
	local html = "\n<ol class='chart-errors' style='display:none'>"
	for _, entry in ipairs(data) do
		if entry.error then
			entryJson = mw.text.jsonEncode(entry)
			html = html .. "\n<li>".. entryJson .."</li>"
		end
	end
	return html .. "\n</ol>\n"
end

-- Prepare single slice data (modifies entry).
function prepareSlice(entry, no, sum, total, options)
	local autoscale = options.autoscale
	local value = entry.value
	if (type(value) ~= "number" or value < 0) then
		if autoscale then
			entry.error = "cannot autoscale unknown value"
			return false
		end
		value = 100 - sum
	end
	-- entry.raw only when scaled
	if autoscale then
		entry.raw = value
		value = (value / sum) * 100
	end
	entry.value = value

	-- prepare final label
	entry.label = prepareLabel(entry.label, entry)
	-- prepare final slice bg color
	local index = no
	if no == total then
		index = -1
	end
	entry.bcolor = backColor(entry, index)

	return true
end

-- render legend for pre-processed entries
function p.renderLegend(data, options)
	local html = "\n<ol class='smooth-pie-legend'>"
	for _, entry in ipairs(data) do
		if not entry.error then
			html = html .. renderLegendItem(entry, options)
		end
	end
	return html .. "\n</ol>\n"
end
-- render legend item
function renderLegendItem(entry, options)
	local label = entry.label
	local bcolor = entry.bcolor
	local html = "\n<li>"
	html = html .. '<span class="l-color" style="'..bcolor..'"></span>'
	html = html .. '<span class="l-label">'..label..'</span>'
	return html .. "</li>"
end

-- Prepare data (slices etc)
function p.renderEntries(ok, total, data, options)
	-- cache for some items (small slices)
	p.cuts = mw.loadJsonData('Module:Piechart/cuts.json')

	local first = true
	local previous = 0
	local no = 0
	local items = ""
	local header = ""
	for index, entry in ipairs(data) do
		if not entry.error then
			no = no + 1
			if no == total then
				header = renderFinal(entry, options)
			else
				items = items .. renderOther(previous, entry, options)
			end
			previous = previous + entry.value
		end
	end
	local footer = '\n</div>'

	return header, items, footer
end
-- final, but header...
function renderFinal(entry, options)
	local label = entry.label
	local bcolor = entry.bcolor
	local size = options.size

	-- hide chart for readers, especially when legend is there
	local aria = ""
	if (options.ariahidechart) then
		aria = 'aria-hidden="true"'
	end

	-- slices container and last slice
	local style = 'width:'..size..'px; height:'..size..'px;'..bcolor
	local html = [[
<div class="smooth-pie"
	style="]]..style..[["
	title="]]..label..[["
	]]..aria..[[
>]]
	return html
end
-- any other then final
function renderOther(previous, entry, options)
	local value = entry.value
	local label = entry.label
	local bcolor = entry.bcolor

	-- value too small to see
	if (value < 0.03) then
		mw.log('value too small', value, label)
		return ""
	end
	
	local html =  ""
	
	local size = ''
	-- mw.logObject({'v,p,l', value, previous, label})
	if (value >= 50) then
		html = sliceWithClass('pie50', 50, value, previous, bcolor, label)
	elseif (value >= 25) then
		html = sliceWithClass('pie25', 25, value, previous, bcolor, label)
	elseif (value >= 12.5) then
		html = sliceWithClass('pie12-5', 12.5, value, previous, bcolor, label)
	elseif (value >= 7) then
		html = sliceWithClass('pie7', 7, value, previous, bcolor, label)
	elseif (value >= 5) then
		html = sliceWithClass('pie5', 5, value, previous, bcolor, label)
	else
		-- 0-5%
		local cutIndex = round(value*10)
		if cutIndex < 1 then
		    cutIndex = 1
		end
		local cut = p.cuts[cutIndex]
		local transform = rotation(previous)
		html = sliceX(cut, transform, bcolor, label)
	end	
	-- mw.log(html)

	return html
end

-- round to int
function round(number)
    return math.floor(number + 0.5)
end

-- render full slice with specific class
function sliceWithClass(sizeClass, sizeStep, value, previous, bcolor, label)
	local transform = rotation(previous)
	local html =  ""
	html = html .. sliceBase(sizeClass, transform, bcolor, label)
	-- mw.logObject({'sliceWithClass:', sizeClass, sizeStep, value, previous, bcolor, label})
	if (value > sizeStep) then
		local extra = value - sizeStep
		transform = rotation(previous + extra)
		-- mw.logObject({'sliceWithClass; extra, transform', extra, transform})
		html = html .. sliceBase(sizeClass, transform, bcolor, label)
	end
	return html
end

-- render single slice
function sliceBase(sizeClass, transform, bcolor, label)
	local style = bcolor
	if transform ~= "" then
        style = style .. '; ' .. transform
    end
	return '\n\t<div class="'..sizeClass..'" style="'..style..'" title="'..label..'"></div>'
end

-- small slice cut to fluid size.
-- range in theory: 0 to 24.(9)% reaching 24.(9)% for cut = +inf
-- range in practice: 0 to 5%
function sliceX(cut, transform, bcolor, label)
	local path = 'clip-path: polygon(0% 0%, '..cut..'% 0%, 0 100%)'
	return '\n\t<div style="'..transform..'; '..bcolor..'; '..path..'" title="'..label..'"></div>'
end

-- translate value to turn rotation
function rotation(value)
	if (value > 0) then
		return string.format("transform: rotate(%.3fturn)", value/100)
	end
	return ''
end

-- Language sensitive float.
function formatNum(value)
	local lang = mw.language.getContentLanguage()
	
	-- doesn't do precision :(
	-- local v = lang:formatNum(value)
	
	local v = string.format("%.1f", value)
	if (lang:getCode() == 'pl') then
		v = v:gsub("%.", ",")
	end
	return v
end

--[[
	Prepare final label.

	Typical tpl:
		"Abc: $v"
	will result in:
		"Abc: 23%" -- when values are percentages
		"Abc: 1234 (23%)" -- when values are autoscaled
	
	Advanced tpl:
		"Abc: $d ($p)" -- only works with autoscale
]]
function prepareLabel(tpl, entry)
	-- static tpl
	if tpl and not string.find(tpl, '$') then
		return tpl
	end

	-- format % value without %
	local p = formatNum(entry.value)

	-- default template
	if not tpl then
		tpl = "$v"
	end

	local label = "" 
	if entry.raw then
		label = tpl:gsub("%$p", p .. "%%"):gsub("%$d", entry.raw):gsub("%$v", entry.raw .. " (" .. p .. "%%)")
	else
		label = tpl:gsub("%$v", p .. "%%")
	end
	return label
end

-- default colors
local colorPalette = {
    '#005744',
    '#006c52',
    '#00814e',
    '#009649',
    '#00ab45',
    '#00c140',
    '#00d93b',
    '#00f038',
}
local lastColor = '#cdf099'
-- background color from entry or the default colors
function backColor(entry, no)
    if (type(entry.color) == "string") then
    	-- Remove unsafe characters from entry.color
    	local sanitizedColor = entry.color:gsub("[^a-zA-Z0-9#%-]", "")
        return 'background-color: ' .. sanitizedColor
    else
    	local color = defaultColor(no)
        return 'background-color: ' .. color
    end
end
-- color from the default colors
-- last entry color for 0 or -1
function defaultColor(no)
	local color = lastColor
	if (no > 0) then 
		local cIndex = (no - 1) % #colorPalette + 1
		color = colorPalette[cIndex]
	end
	return color
end

--[[
	trim string
	
	note:
	`(s:gsub(...))` returns only a string
	`s:gsub(...)` returns a string and a number
]]
function trim(s)
	return (s:gsub("^%s+", ""):gsub("%s+$", ""))
end

return p