#!/bin/sh

guess_content_type() {
	ext="${ref%"~"}"
	case "${ext##*.}" in
		appcache|manifest)	content_type=text/cache-manifest                  ;;
		atom             )	content_type=application/atom+xml                 ;;
		bat              )	content_type=application/x-msdownload             ;;
		coffee           )	content_type=text/coffeescript                    ;;
		css              )	content_type=text/css                             ;;
		csv              )	content_type=text/csv                             ;;
		eot              )	content_type=application/vnd.ms-fontobject        ;;
		geojson          )	content_type=application/vnd.geo+json             ;;
		hbs|handlebars   )	content_type=text/x-handlebars-template           ;;
		htc              )	content_type=text/x-component                     ;;
		htm|html         )	content_type=text/html                            ;;
		ics              )	content_type=text/calendar                        ;;
		jscad            )	content_type=application/javascript               ;;
		json             )	content_type=application/json                     ;;
		jsonld           )	content_type=application/ld+json                  ;;
		kml              )	content_type=application/vnd.google-earth.kml+xml ;;
		# md|markdown      )	content_type=text/markdown                        ;;
		mjs|js           )	content_type=application/javascript               ;;
		mhtml            )	content_type=multipart/related                    ;;
		n3               )	content_type=text/n3                              ;;
		nt               )	content_type=application/n-triples                ;;
		otf              )	content_type=font/otf                             ;;
		owl|rdf          )	content_type=application/rdf+xml                  ;;
		pdf              )	content_type=application/pdf                      ;;
		rss              )	content_type=application/rss+xml                  ;;
		shex|shexc       )	content_type=text/shex                            ;;
		svg              )	content_type=image/svg+xml                        ;;
		swf              )	content_type=application/x-shockwave-flash        ;;
		stl              )	content_type=model/stl                            ;;
		tt[cf]           )	content_type=application/x-font-ttf               ;;
		ttl              )	content_type=text/turtle                          ;;
		vcard            )	content_type=text/vcard                           ;;
		vcf              )	content_type=text/x-vcard                         ;;
		vtt              )	content_type=text/vtt                             ;;
		woff             )	content_type=application/font-woff                ;;
		woff2            )	content_type=application/font-woff2               ;;
		xht|xhtml        )	content_type=application/xhtml+xml                ;;
		xml              )	content_type=text/xml                             ;;
		txt              )	content_type=text/plain                           ;;
		xsl|xsd          )	content_type=application/xml                      ;;
		xslt             )	content_type=application/xslt+xml                 ;;
		yaml|yml         )	content_type=text/yaml                            ;;
		wasm             )	content_type=application/wasm                     ;;
		rpm|[ds]rpm      )	content_type=application/x-redhat-package-manager ;;
		*                )	content_type=text/plain                           ;;
	esac
	case "${ext##*.}" in
		bat|eot|htc|kml|nt|otf|pdf|svg|swf|ttc|ttf|woff|woff2|wasm|rpm|[ds]rpm)                                             ;;
		*                                                                     ) content_type="$content_type; charset=utf-8" ;;
	esac
}


cd /var/cache/nginx/ra.ws.co.ls.cgi || exit
tmpf="$(mktemp -t 'ra.ws.co.ls-XXXXXXXX')"
trap 'rm -f "$tmpf"' EXIT INT

dir="${DOCUMENT_URI%/blob/*}"
if ! [ -d ".$dir.git" ]; then
	{ mkdir -p ".$dir.git" && git clone --depth 1 --filter=blob:none --bare "https://git.sr.ht$dir" ".$dir.git"; } > "$tmpf" 2>&1 || {
		printf '%s\n' 'Status: 500 Internal Server Error' 'Content-Type: text/plain; charset=utf-8' ''
		cat "$tmpf"
		exit
	}
fi
cd ".$dir.git" || exit


if [ $(( $(date -r .ls-remote +%s 2>/dev/null) + 600 )) -lt $(date +%s) ]; then
	git ls-remote --symref > new.ls-remote
	cmp -s .ls-remote new.ls-remote 2>/dev/null; cmpfail=$?
	mv new.ls-remote .ls-remote

	if [ $cmpfail -ne 0 ]; then
		while IFS='	' read -r val ref; do
			{ [ "$ref" = HEAD ] && [ "${val#"ref:"}" != "$val" ]; } && echo "$val" > HEAD
			{ [ "${ref%"^{}"}" = "$ref" ] && [ "$ref" != HEAD ]; } && echo "$ref:$ref"
		done < .ls-remote | git fetch --stdin --no-write-fetch-head origin >&2
	fi
fi


echo "${DOCUMENT_URI#*/blob/}" | gawk '{
	slashes=$0
	gsub(/[^/]*/, "", slashes)
	for(i = 1; i <= length(slashes); ++i)
		print gensub(/\//, ":", i, $0)
}' | {
	while read -r ref; do
		git show "$ref" > "$tmpf" && {
			guess_content_type
			printf '%s\n' 'Status: 200 OK'                                                      \
			              "Content-Type: $content_type"                                         \
			              'Cache-Control: max-age=86400, public'                                \
			              "ETag: \"$(git rev-parse "$ref" 2>/dev/null || echo "$ref"):${ref#*:}\"" \
			              ''
			exec cat "$tmpf"
		}
	done

	printf '%s\n' 'Status: 400 Bad Request' 'Content-Type: text/plain; charset=utf-8' ''
	exec cat "$tmpf"
}