local stringx = require "pl.stringx"
local svg = {}


function svg.start_document (title)
	return stringx.dedent[==[
		<?xml version="1.0" encoding="utf-8"?>
		<svg xmlns="http://www.w3.org/2000/svg" version="1.1" viewBox="0 0 663 95">
		<title>%s</title>
		<defs>
			<style type="text/css"><![CDATA[
			.label { font: 11px sans-serif; }
			.cell {
				width: 11px;
				height: 11px;
				rx: 2px;
			}
			.cell.level0 { fill: #ccc; }
			.cell.level1 { fill: #9be9a8; }
			.cell.level2 { fill: #40c463; }
			.cell.level3 { fill: #30a14e; }
			.cell.level4 { fill: #216e39; }
			]]></style>
		</defs>]==]:format(title)  -- dedent appends newline
end


function svg.end_document ()
	return "</svg>\n"
end


local row_offset = 0  -- Format(s) should be stateful and instantiable.


function svg.start_table ()
	row_offset = 0
	return ""
end


function svg.end_table ()
	return ""
end


local cell_offset


function svg.start_row ()
	local row = ([[<g transform="translate(0,%d)">]]):format(row_offset)
	cell_offset = 28
	row_offset = row_offset + 14
	return row
end


function svg.end_row ()
	return "</g>\n"
end


function svg.label (name)
	return ([[<text y="10px" class="label">%s</text>]]):format(name)
end


function svg.spot ()
	cell_offset = cell_offset + 12
	return ""
end


function svg.cell (level)
	local cell = ([[<rect class="cell level%d" x="%d"/>]]):format(level, cell_offset)
	svg.spot()  -- Increment cell_offset in one place in code.
	return cell
end


return svg