Module:Historical populations

--
-- This template implements {{Historical populations}}
--
local p = {}

local function page_exists( title )
    -- This function implements #ifexist
    local noError, titleObject = pcall(mw.title.new, title)
    if not noError then
        return false
    else
        if titleObject then
            return titleObject.exists
        else
            return false
        end
    end
end

local function formatnum(num)
    return frame:callParserFunction{ name = 'formatnum', args = num }
end

local function formatnumR(num)
    return frame:callParserFunction{ name = 'formatnum', args = {num, 'R'} }
end

local function isempty( s ) 
	return not s or s:match( '^%s*(.-)%s*$' ) == '' 
end

local function popheader(percentages, popname)
	local percent = ''
	local yearwidth = '20%'
	if( popname == '' ) then
		popname = '<abbr title="Population">Pop.</abbr>'
	end
	if( percentages == 'off' ) then
		yearwidth = 'auto'
	else
		local pstr = ''
		if( percentages == 'pagr' ) then
			pstr = '<abbr title="Per annum growth rate">±% p.a.</abbr>'
		else
			pstr = '<abbr title="Percent change">±%</abbr>'
		end
		percent = '<th style="border-bottom: 1px solid black; padding: 1px; text-align: right;">' .. pstr .. '&nbsp;&nbsp;</th>'
	end
	return mw.ustring.formt( [==[
	<tr style="font-size: 95%%"><th style="border-bottom: 1px solid black; padding: 1px; width: %s;">Year</th>
    <th style="border-bottom: 1px solid black; padding: 1px; text-align: right;">%s&nbsp;&nbsp;</th>%s
    </tr>]==], yearwidth, popname, percent)
end

local function poprow( year, pop, pyear, ppop, linktype, percentages, shading)
	local percent = ''
	local yearnum = tonumber(formatnumR(mw.ustring.gsub(year, '^([%d]+).*$', '%1') or ''))
	local pyearnum = tonumber(formatnumR(mw.ustring.gsub(pyear, '^([%d]+).*$', '%1') or ''))
	local popnum = tonumber(formatnumR(pop or ''))
	local ppopnum = tonumber(formatnumR(ppop or ''))
	if( linktype == 'US' or linktype == 'USA' ) then
		if( page_exists(tostring(yearnum) .. ' United States Census') ) then
			year = '[[' .. tostring(yearnum) .. ' United States Census|' .. tostring(yearnum) .. ']]'
		end
	end
	if( shading == 'off' ) then
		shading = ''
	else
		shading = ' border-bottom: 1px solid #bbbbbb;'
	end
	if(percentages ~= 'off') then
		local pstr = '—&nbsp;&nbsp;&nbsp;&nbsp;'
		if(popnum ~= nil and ppopnum ~= nil) then
  			if(percentages == 'pagr') then
				pstr = mw.ustring.format('%f.2', 100*(math.pow(popnum/ppopnum,1/(yearnum-pyearnum)) - 1))
			else
				pstr = mw.ustring.format('%f.1', 100*math.abs(popnum/ppopnum - 1))
				if( popnum < ppopnum ) then
					pstr = '−' .. pstr
				else
					pstr = '+' .. pstr
				end
			end
	    end
	    percent = '<td style="text-align: right; padding: 1px;' .. shading .. '">' .. pstr .. '%</td>'
	end
	
	return mw.ustring.format( [==[
	<tr>
	<th style="text-align: center; padding: 1px;%s">%s</th>
	<td style="text-align: right; padding: 1px;%s">%s</td>%s
	</tr>]==], shading, year, shading, formatnum(tonumber(pop)) or pop, percent)
end

function p.poptable(frame)
	local t = {}
	local args = frame:getParent().args

	local title = args['title'] or 'Historical population'
	local align = args['align'] or 'right'
	local clear = args['clear'] or align
	local percentages = args['percentages'] or ''
	local state = args['state'] or ''
	local linktype = args['type'] or ''
	local shading = args['shading'] or 'on'
	local width = args['width'] or '15em'
	local widthnum = mw.ustring.gsub( width, '^%s*([%d]+)([%w]+)%s*$', '%1' )
	local widthunit = mw.ustring.gsub( width, '^%s*([%d]+)([%w]+)%s*$', '%2' )
	local popname = args['pop_name'] or ''
	local footnote = args['footnote'] or ''
	local source = args['source'] or ''
	local cols = tonumber(args['cols']) or 1
	local colspan = 3

	local class = 'toccolours'
	if( state == 'collapsed' ) then
		class = class .. ' collapsible collapsed'
	end
	
	local margin = '0 0 1em 1em'
	if( align == 'left' ) then
		margin = '0 1em 1em 0'
	else
		if( align == 'none' ) then
			margin = '0.5em 1em 0.5em 0'
		end
    end

    if( source ~= '' ) then
   		source = 'Source: ' .. source
	    if( footnote ~= '' ) then
     		footnote = footnote .. '<br/>'
 		end
    end

    if( cols > 1 ) then
    	colspan = cols
	else
		if (percentages == 'off') then 
			colspan = 2
		else
			colspan = 3
		end
 	end
 	
	local rowcount = 0
	local row = 1
	while( not isempty(args[2*row - 1]) ) do
		rowcount = rowcount + 1
		row = row + 1
	end

    local head = mw.ustring.format([==[
	<table class="%s" style="clear: %s; width: %d%s; text-align: center; border-spacing: 0; float: %s; margin: %s">
<tr>
<th colspan="%d" class="navbox-title" style="font-size:110%;">%s</th>
</tr>]==], class, clear, widthnum*cols, widthunit, align, margin, colspan, title)
    
    local foot = ''
    if( footnote ~= '' or source ~= '' ) then
       foot = mw.ustring.format([==[
<tr>
<td colspan="%d" style="border-top: 1px solid black; font-size: 85%; text-align: left;">%s%s</td>
</tr>]==], colspan, footnote, source)
    end

	local perrow = math.floor( (rowcount - 1) / cols ) + 1
	if( cols > 1 ) then
		t.insert(t, '<tr valign="top">')
		t.insert(t, '<td style="padding:0 0.5em;"><table style="border-spacing:0; width:' .. width .. '">')
	end
	t.insert(t, popheader(percentages, popname))
	for c = 1,cols do
		if( c > 1 ) then
			t.insert(t, '<td style="padding:0 0.5em; border-left:solid 1px #aaa"><table style="border-spacing:0; width:' .. width .. '">')
			t.insert(t, popheader(percentages, popname) )
        end
		for r = 1,perrow do
			row = perrow*(c - 1) + r
			if(row <= rowcount) then
				local s = 'off'
				if( math.mod(row, 5) == 0 ) then
					local s = shading
				end
				t.insert(t, poprow( args[2*row - 1], args[2*row], args[2*row - 3] or '', args[2*row - 2] or '', linktype, percentages, s) )
			else
				if( percentages == 'off' ) then
					t.insert(t, '<tr><th></th><td></td></tr>')
				else
					t.insert(t, '<tr><th></th><td></td><td></td></tr>')
				end
			end
       	end
		if( c > 1 ) then
			t.insert(t, '</table></td>')
		end
 	end
    return head .. '\n' .. table.concat( t ) .. '\n' .. foot
end