local line_begin = require("luasnip.extras.expand_conditions").line_begin

return {
	s(
		{ trig = ";dcenvelope", dscr = "A LaTeX equation environment" },
		fmta(
			[[
       % https://en.wikibooks.org/wiki/LaTeX/Letters#Envelopes

       % https://tex.stackexchange.com/questions/268693/how-do-you-print-c4-envelopes
       \documentclass{letter}
       \usepackage{geometry}
       \geometry{paperheight=9.25in,paperwidth=4.13in}
       \usepackage{graphics}
       \usepackage{envlab}
       \usepackage[AutoFallBack=true]{xeCJK}
       \setCJKmainfont<>

       % from envlab
       \SetEnvelope{9.25in}{4.13in}
       % from envlab
       \setlength{\ToAddressTopMargin}{0in} %Arbitrarily decided by me
       % from envlab
       \setlength{\ToAddressLeftMargin}{1in} %Arbitrarily decided by me

       % from envlab
       \makelabels

       \begin{document}
       \startlabels
       % from envlab
       \mlabel
         {% This "%" is required to make alignment right
          %
          % Sender Address
          %
          % append \\ at the end of the line before inserting newline
          %
          % e.g.    Title\\
          %         Address line1\\
          %         Address line2\\
          %         Address line3
           <>
         }
         {% This "%" is required to make alignment right
          %
          % Reciever Address
          %
          % append \\ at the end of the line before inserting newline
          %
          % e.g.    Title\\
          %         Address line1\\
          %         Address line2\\
          %         Address line3
           <>
          % if print with lpr use command "lpr -o media=EnvYou4"
         }
       \end{document}

      ]],
			{
				c(1, {
					t({
						"{Source Han Serif TC}",
						"\\newCJKfontfamily\\secondaryfont{Source Han Sans TC}",
						"\\newcommand*{\\sfont}[1]{{\\secondaryfont #1}}",
					}),
					t({
						"{Source Han Sans TC}",
						"\\newCJKfontfamily\\secondaryfont{Source Han Serif TC}",
						"\\newcommand*{\\sfont}[1]{{\\secondaryfont #1}}",
					}),
					t({
						"[Path=\\string~/.local/share/fonts/",
						",UprightFeatures = {FontIndex=13}",
						",BoldFeatures    = {FontIndex=28}",
						"]{SourceHanSerif.ttc}",
						"\\newCJKfontfamily[Path=\\string~/.local/share/fonts/",
						"  ,UprightFeatures = {FontIndex=28}",
						"  ,BoldFeatures    = {FontIndex=38}",
						"]\\secondaryfont{Source Han Sans TC}",
						"\\newcommand*{\\sfont}[1]{{\\secondaryfont #1}}",
					}),
					t({
						"[Path=\\string~/.local/share/fonts/",
						",UprightFeatures = {FontIndex=28}",
						",BoldFeatures    = {FontIndex=38}",
						"]{SourceHanSans.ttc}",
						"\\newCJKfontfamily[Path=\\string~/.local/share/fonts/",
						",UprightFeatures = {FontIndex=13}",
						",BoldFeatures    = {FontIndex=28}",
						"]\\secondaryfont{Source Han Serif TC}",
						"\\newcommand*{\\sfont}[1]{{\\secondaryfont #1}}",
					}),
				}),
				i(3, "% Sender Address"),
				i(2, "% Reciever Address"),
			}
		),
		{ condition = line_begin } -- set condition in the `opts` table
	),
}