#!/usr/bin/env bash
# bollux: a bash gemini client
# Author: Case Duckworth
# License: MIT
# Version: 0.1

# Program information
PRGN="${0##*/}"
VRSN=0.1
# State
REDIRECTS=0

bollux_usage() {
	cat <<END
$PRGN (v. $VRSN): a bash gemini client
usage:
	$PRGN [-h]
	$PRGN [-q] [-v] [URL]
flags:
	-h	show this help and exit
	-q	be quiet: log no messages
	-v	verbose: log more messages
parameters:
	URL	the URL to start in
		If not provided, the user will be prompted.
END
}

run() {
	log debug "$@"
	"$@"
}

die() {
	ec="$1"
	shift
	log error "$*"
	exit "$ec"
}

trim() { sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//'; }

log() {
	[[ "$BOLLUX_LOGLEVEL" == QUIET ]] && return
	case "$1" in
	d* | D*) # debug
		[[ "$BOLLUX_LOGLEVEL" == DEBUG ]] || return
		fmt=34
		;;
	e* | E*) # error
		fmt=31
		;;
	*) fmt=1 ;;
	esac
	shift
	printf >&2 '\e[%sm%s:\e[0m\t%s\n' "$fmt" "$PRGN" "$*"
}

# main entry point
bollux() {
	run bollux_args "$@"
	run bollux_config

	if [[ ! "${BOLLUX_URL:+isset}" ]]; then
		run prompt GO BOLLUX_URL
	fi

	run blastoff "$BOLLUX_URL"
}

bollux_args() {
	while getopts :hvq OPT; do
		case "$OPT" in
		h)
			bollux_usage
			exit
			;;
		v) BOLLUX_LOGLEVEL=DEBUG ;;
		q) BOLLUX_LOGLEVEL=QUIET ;;
		:) die 1 "Option -$OPTARG requires an argument" ;;
		*) die 1 "Unknown option: -$OPTARG" ;;
		esac
	done
	shift $((OPTIND - 1))
	if (($# == 1)); then
		BOLLUX_URL="$1"
	fi
}

bollux_config() {
	: "${BOLLUX_CONFIG:=${XDG_CONFIG_DIR:-$HOME/.config}/bollux/config}"

	if [ -f "$BOLLUX_CONFIG" ]; then
		# shellcheck disable=1090
		. "$BOLLUX_CONFIG"
	else
		log debug "Can't load config file '$BOLLUX_CONFIG'."
	fi

	: "${BOLLUX_DOWNDIR:=.}"                   # where to save downloads
	: "${BOLLUX_LOGLEVEL:=3}"                  # log level
	: "${BOLLUX_MAXREDIR:=5}"                  # max redirects
	: "${BOLLUX_PORT:=1965}"                   # port number
	: "${BOLLUX_PROTO:=gemini}"                # default protocol
	: "${BOLLUX_LESSKEY:=/tmp/bollux-lesskey}" # where to store binds
	: "${BOLLUX_PAGESRC:=/tmp/bollux-src}"     # where to save the page source
	: "${BOLLUX_URL:=}"                        # start url
}

prompt() {
	prompt="$1"
	shift
	read </dev/tty -e -r -p "$prompt> " "$@"
}

blastoff() { # load a url
	local well_formed=true
	if [[ "$1" == "-u" ]]; then
		well_formed=false
		shift
	fi
	URL="$1"

	if $well_formed && [[ "$1" != "$BOLLUX_URL" ]]; then
		URL="$(run munge_url "$1" "$BOLLUX_URL")"
	fi
	[[ "$URL" != *://* ]] && URL="$BOLLUX_PROTO://$URL"
	URL="$(trim <<<"$URL")"

	server="${URL#*://}"
	server="${server%%/*}"

	run request_url "$server" "$BOLLUX_PORT" "$URL" |
		run handle_response "$URL"
}

munge_url() {
	local -A new old u
	eval "$(split_url new <<<"$1")"
	for k in "${!new[@]}"; do log d "new[$k]=${new[$k]}"; done
	eval "$(split_url old <<<"$2")"
	for k in "${!old[@]}"; do log d "old[$k]=${old[$k]}"; done

	u['scheme']="${new['scheme']:-${old['scheme']:-}}"
	u['authority']="${new['authority']:-${old['authority']:-}}"
	# XXX this whole path thing is wack
	if [[ "${new['path']+isset}" ]]; then
		log d 'new path set'
		if [[ "${new['path']}" == /* ]]; then
			log d 'new path == /*'
			u['path']="${new['path']}"
		elif [[ "${new['authority']}" == "${old['authority']}" || ! "${new['authority']+isset}" ]]; then
			p="${old['path']:-}/${new['path']}"
			log d "$p ( $(normalize_path <<<"$p") )"
			u['path']="$(normalize_path <<<"$p")"
		else
			log d 'u path = new path'
			u['path']="${new['path']}"
		fi
	elif [[ "${new['query']+isset}" || "${new['fragment']+isset}" ]]; then
		log d 'u path = old path'
		u['path']="${old['path']}"
	else
		u['path']="/"
	fi
	u['query']="${new['query']:-}"
	u['fragment']="${new['fragment']:-}"
	for k in "${!u[@]}"; do log d "u[$k]=${u[$k]}"; done

	run printf '%s%s%s%s%s\n' \
		"${u['scheme']}" "${u['authority']}" "${u['path']}" \
		"${u['query']}" "${u['fragment']}"
}

normalize_path() {
	gawk '{
	split($0, path, /\//)
	for (c in path) {
		if (path[c] == "" || path[c] == ".") {
			continue
		}
		if (path[c] == "..") {
			sub(/[^\/]+$/, "", ret)
			continue
		}
		if (! ret || match(ret, /\/$/)) {
			slash = ""
		} else {
			slash = "/"
		}
		ret = ret slash path[c]
	}
	print (ret ~ /^\// ? "" : "/") ret
	}'
}

split_url() {
	gawk -vvar="$1" '{
	if (match($0, /^[A-Za-z]+:/)) {
		arr["scheme"] = substr($0, RSTART, RLENGTH)
		$0 = substr($0, RLENGTH + 1)
	}
	if (match($0, /^\/\/[^\/?#]+?/) || (match($0, /^[^\/?#]+?/) && scheme)) {
	arr["authority"] = substr($0, RSTART, RLENGTH)
		$0 = substr($0, RLENGTH + 1)
	}
	if (match($0, /^\/?[^?#]+/)) {
		arr["path"] = substr($0, RSTART, RLENGTH)
		$0 = substr($0, RLENGTH + 1)
	}
	if (match($0, /^\?[^#]+/)) {
		arr["query"] = substr($0, RSTART, RLENGTH)
		$0 = substr($0, RLENGTH + 1)
	}
	if (match($0, /^#.*/)) {
		arr["fragment"] = substr($0, RSTART, RLENGTH)
		$0 = substr($0, RLENGTH + 1)
	}
	for (part in arr) {
		sub(/[[:space:]]+$/, "", arr[part])
		printf var "[\"%s\"]=\"%s\"\n", part, arr[part]
	}
	}'
}

request_url() {
	local server="$1"
	local port="$2"
	local url="$3"

	ssl_cmd=(openssl s_client -crlf -quiet -connect "$server:$port")
	ssl_cmd+=(-servername "$server") # SNI
	run "${ssl_cmd[@]}" <<<"$url" 2>/dev/null
}

handle_response() {
	local url="$1" code meta

	while read -r -d $'\r' hdr; do
		code="$(gawk '{print $1}' <<<"$hdr")"
		meta="$(
			gawk '{for(i=2;i<=NF;i++)printf "%s ",$i;printf "\n"}' <<<"$hdr"
		)"
		break
	done

	log x "[$code] $meta"

	case "$code" in
	1*)
		REDIRECTS=0
		BOLLUX_URL="$URL"
		run prompt "$meta" QUERY
		run blastoff "?$QUERY"
		;;
	2*)
		REDIRECTS=0
		BOLLUX_URL="$URL"
		run display "$meta"
		;;
	3*)
		((REDIRECTS += 1))
		if ((REDIRECTS > BOLLUX_MAXREDIR)); then
			die $((100 + code)) "Too many redirects!"
		fi
		BOLLUX_URL="$URL"
		run blastoff "$meta"
		;;
	4*)
		REDIRECTS=0
		die "$((100 + code))" "$code"
		;;
	5*)
		REDIRECTS=0
		die "$((100 + code))" "$code"
		;;
	6*)
		REDIRECTS=0
		die "$((100 + code))" "$code"
		;;
	*) die "$((100 + code)) Unknown response code: $code." ;;
	esac
}

display() {
	case "$1" in
	*\;*)
		mime="$(cut -d\; -f1 <<<"$1" | trim)"
		charset="$(cut -d\; -f2 <<<"$1" | trim)"
		;;
	*) mime="$(trim <<<"$1")" ;;
	esac

	[[ -z "$mime" ]] && mime="text/gemini"
	if [[ -z "$charset" ]]; then
		charset="utf-8"
	else
		charset="${charset#charset=}"
	fi

	log debug "mime=$mime; charset=$charset"

	case "$mime" in
	text/*)
		less_cmd=(less -R)
		{
			[[ -r "$BOLLUX_LESSKEY" ]] || mklesskey "$BOLLUX_LESSKEY"
		} && less_cmd+=(-k "$BOLLUX_LESSKEY")
		less_cmd+=(
			-Pm'bollux$'
			-PM'o\:open, g\:goto, r\:refresh$'
			-M
		)

		submime="${mime#*/}"
		if declare -F | grep -q "$submime"; then
			log d "typeset_$submime"
			{
				normalize_crlf |
					run "typeset_$submime" |
					tee "$BOLLUX_PAGESRC" |
					run "${less_cmd[@]}"
			} || run handle_keypress "$?"
		else
			log "cat"
			{
				normalize_crlf |
					tee "$BOLLUX_PAGESRC" |
					run "${less_cmd[@]}"
			} || run handle_keypress "$?"
		fi
		;;
	*) run download "$BOLLUX_URL" ;;
	esac
}

mklesskey() {
	lesskey -o "$1" - <<-END
		#command
		o quit 0 # 48 open a link
		g quit 1 # 49 goto a url
		[ quit 2 # 50 back
		] quit 3 # 51 forward
		r quit 4 # 52 re-request / download
	END
}

normalize_crlf() {
	gawk 'BEGIN{RS="\n\n"}{gsub(/\r\n?/,"\n");print;print ""}'
}

typeset_gemini() {
	gawk '
	BEGIN { pre = 0 }
	/^###/ { sub(/^#+[[:space:]]*/, ""); 
		printf "### \033[3m%s\033[0m\n", $0
	next }
	/^##/  { sub(/^#+[[:space:]]*/, ""); 
		printf "##  \033[1m%s\033[0m\n", $0
	next }
	/^#/   { sub(/^#+[[:space:]]*/, ""); 
		printf "#   \033[1;4m%s\033[0m\n", $0
	next }
	/^=>/  { 
		sub(/=>[[:space:]]*/, "")
		url = $1; desc = ""
		for (w=2;w<=NF;w++) 
			desc = desc (desc?" ":"") $w
		printf "=>  \033[1m[%02d]\033[0m \033[4m%s\033[0m\t\033[36m%s\033[0m\n", 
			(++ln), desc, url
	next }
	/```/  { pre = !pre; next }
	pre { printf "``` %s\n", $0; next }
	# /^\*/  { sub(/\*[[:space:]]*/, ""); }
	{ sub(/^/, " "); print }
	'
}

handle_keypress() {
	case "$1" in
	48) # o - open a link -- show a menu of links on the page
		run select_url "$BOLLUX_PAGESRC"
		;;
	49) # g - goto a url -- input a new url
		prompt GO URL
		run blastoff -u "$URL"
		;;
	50) # [ - back in the history
		run history_back
		;;
	51) # ] - forward in the history
		run history_forward
		;;
	52) # r - re-request the current resource
		run blastoff "$BOLLUX_URL"
		;;
	*) # 53-57 -- still available for binding
		;;
	esac
}

select_url() {
	run mapfile -t < <(extract_links <"$1")
	select u in "${MAPFILE[@]}"; do
		run blastoff "$(gawk '{print $1}' <<<"$u")" && break
	done </dev/tty
}

extract_links() {
	gawk -F$'\t' '/^=>/ {
		gsub("\033\\[[^m]*m", "")
		sub(/=>[[:space:]]*\[[0-9]+\][[:space:]]*/,"")
		if ($2) 
			printf "%s (\033[34m%s\033[0m)\n", $2, $1
		else
			printf "%s\n", $1
	}'
}

download() {
	tn="$(mktemp)"
	log x "Downloading: '$BOLLUX_URL' => '$tn'..."
	dd status=progress >"$tn"
	fn="$BOLLUX_DOWNDIR/${BOLLUX_URL##*/}"
	if [[ -f "$fn" ]]; then
		log x "Saved '$tn'."
	elif mv "$tn" "$fn"; then
		log x "Saved '$fn'."
	else
		log error "Error saving '$fn': downloaded to '$tn'."
	fi
}

history_back() { log error "Not implemented."; }
history_forward() { log error "Not implemented."; }

if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
	run bollux "$@"
else
	BOLLUX_LOGLEVEL=DEBUG
fi