# ip(8) completion for fish

# The difficulty here is that ip allows abbreviating options, so we need to complete "ip a" like "ip address", but not "ip m" like "ip mroute"
# Also the manpage and even the grammar it accepts is utter shite (options can only be before commands, some things are only in the BNF, others only in the text)
# It also quite likes the word "dev", even though it needs it less than the BNF specifies

set -l ip_commands link address addrlabel route rule neigh ntable tunnel tuntap maddr mroute mrule monitor xfrm netns l2tp tcp_metrics
set -l ip_addr a ad add addr addre addres address
set -l ip_link l li lin link
set -l ip_all_commands $ip_commands $ip_addr $ip_link

function __fish_ip_commandwords
	set -l skip 0
	set -l cmd (commandline -opc)
	# HACK: Handle and/or/not specially because they have hardcoded completion behavior
	# that doesn't remove them from the commandline
	if contains -- $cmd[1] and or not
		set -e cmd[1]
	end
	# Remove the first word because it's "ip" or an alias for it
	set -e cmd[1]
	set -l have_command 0
	for word in $cmd
		switch $word
			# Normalize the commands to their full form - `ip a` is `ip address`
			# This can't be just an unambiguity check because there's also `ip addrlabel`
			case a ad add addr addre addres address
				# "addr add" is a thing, so we can only echo "address" if it's actually the command
				if test $have_command = 0
					set have_command 1
					echo address
				else
					echo $word
				end
			case l li lin link
				if test $have_command = 0
					set have_command 1
					echo link
				else
					echo $word
				end
			case "addrl*"
				if test $have_command = 0
					set have_command 1
					echo addrlabel
				else
					echo $word
				end
			case r ro rou rout route
				if test $have_command = 0
					set have_command 1
					echo route
				else
					echo $word
				end
			case "ru*"
				if test $have_command = 0
					set have_command 1
					echo rule
				else
					echo $word
				end
			case n ne nei neig neigh
				if test $have_command = 0
					set have_command 1
					echo neigh
				else
					echo $word
				end
			case nt
				if test $have_command = 0
					set have_command 1
					echo ntable
				else
					echo $word
				end
			case t tu tun tunn tunne tunnel
				if test $have_command = 0
					set have_command 1
					echo tunnel
				else
					echo $word
				end
			case "tunt*"
				if test $have_command = 0
					set have_command 1
					echo tuntap
				else
					echo $word
				end
			case m ma mad madd maddr maddre maddres maddress
				if test $have_command = 0
					set have_command 1
					echo maddress
				else
					echo $word
				end
			case mr "mro*"
				if test $have_command = 0
					set have_command 1
					echo mroute
				else
					echo $word
				end
			case "mru*"
				if test $have_command = 0
					set have_command 1
					echo mrule
				else
					echo $word
				end
			case "mo*"
				if test $have_command = 0
					set have_command 1
					echo monitor
				else
					echo $word
				end
			case "x*"
				if test $have_command = 0
					set have_command 1
					echo xfrm
				else
					echo $word
				end
			case "net*"
				if test $have_command = 0
					set have_command 1
					echo netns
				else
					echo $word
				end
			case "l*"
				if test $have_command = 0
					set have_command 1
					echo l2tp
				else
					echo $word
				end
			case "tc*"
				if test $have_command = 0
					set have_command 1
					echo tcp_metrics
				else
					echo $word
				end
			case "to*"
				if test $have_command = 0
					set have_command 1
					echo token
				else
					echo $word
				end
			case '-n' '-netns' '--netns'
				if test $have_command = 0
					set skip 1
				else
					echo $word
				end
			case '-*'
				test $have_command = 0; and continue
				echo $word
			case '*'
				if test $skip = 1
					set skip 0
					continue
				end
				echo $word
		end
	end
	# Print an empty line if the current token is empty, so we know that the one before it is finished
	# TODO: For some reason it is necessary to always print the current token - why doesn't the above loop catch it?
	set -l token (commandline -ct)
	echo $token
end

function __fish_ip_device
	ip -o link show | while read a b c
		printf '%s\t%s\n' (string replace ':' '' -- $b) "Device"
	end
end

function __fish_ip_scope
	if test -r /etc/iproute2/rt_scopes
		string replace -r '#.*' '' < /etc/iproute2/rt_scopes \
		| string match -v '^\s*$' \
		| string replace -r '(\S+)\s*(\S+)' '$1\t$2\n$2\t$1' \
		| string match -rv '^(global|link|host).*' # Ignore scopes with better descriptions
	end
	# Predefined scopes
	printf '%s\t%s\n' global "Address is globally valid" \
	link "Address is link-local, only valid on this device" \
	host "Address is only valid on this host"
end

function __fish_complete_ip
	set -l cmd (__fish_ip_commandwords)
	set -l count (count $cmd)
	switch "$cmd[1]"
		case address
			# We're still _on_ the second word, which is the subcommand
			if not set -q cmd[3]
				printf '%s\t%s\n' add "Add new protocol address" \
				delete "Delete protocol address" \
				show "Look at protocol addresses" \
				flush "Flush protocol addresses"
			else
				switch $cmd[2]
					# Change and replace are undocumented (apart from mentions in the BNF)
					case add change replace
						switch $count
							case 3
								# __fish_ip_complete_ip
							case '*'
								switch $cmd[-2]
									case dev
										__fish_ip_device
									case scope
										__fish_ip_scope
									# TODO: Figure out how to complete these
									case label
										# Prefix
									case local peer broadcast
										# Address
									case valid_lft preferred_lft
										# Lifetime
									case '*'
										printf '%s\t%s\n' forever "Keep address valid forever" \
										home "(Ipv6 only) Designate address as home adress" \
										nodad "(Ipv6 only) Don't perform duplicate address detection" \
										dev "Add address to specified device" \
										scope "Set scope of address" \
										label "Tag address with label"
								end
						end
					case delete
						switch $count
							case 3
								ip -o addr show | while read a b c d e
									echo $d
								end
							case 4
								# A dev argument is mandatory, but contrary to the BNF, other things (like "scope") are also valid here
								# And yes, unlike e.g. show, this _needs_ the "dev" before the device
								# Otherwise it barfs and says "??? prefix is expected"
								# Anyway, try to steer the user towards supplying a device
								echo dev
							case 5
								switch $cmd[-2]
									case dev
										ip -o addr show | string match "*$cmd[3]*" | while read a b c
											echo $b
										end
								# TODO: Moar
						end
					case show save flush # These take the same args
						switch $cmd[-2]
							case dev
								__fish_ip_device
							case scope
								__fish_ip_scope
							case to
								# Prefix
							case label
								# Label-pattern
							case '*'
								printf '%s\t%s\n' up "Only active devices" \
								dev "Limit to a certain device" \
								scope "Limit scope" \
								to "Limit prefix" \
								label "Limit by label" \
								dynamic "(Ipv6 only) Limit to dynamic addresses" \
								permanent "(Ipv6 only) Limit to permanent addresses"
								__fish_ip_device
								# TODO: Moar
						end
					end
				end
			end
		case link
			if not set -q cmd[3]
				printf '%s\t%s\n' add "Add virtual link" \
				delete "Delete virtual link" \
				set "Change device attributes" \
				show "Display device attributes" \
				help "Display help"
			else
				# TODO: Add moar
				switch $cmd[2]
					case add
						switch $cmd[-2]
							case link
								__fish_ip_device
							case name
							case type
								printf '%s\t%s\n' \
								macvtap "Virtual interface based on link layer address (MAC) and TAP." \
								vcan "Virtual Controller Area Network interface" \
								veth "Virtual ethernet interface" \
								vlan "802.1q tagged virtual LAN interface" \
								vxlan "Virtual eXtended LAN" \
								ip6tnl "Virtual tunnel interface IPv4|IPv6 over IPv6" \
								ipip "Virtual tunnel interface IPv4 over IPv4" \
								sit "Virtual tunnel interface IPv6 over IPv4" \
								gre "Virtual tunnel interface GRE over IPv4" \
								gretap "Virtual L2 tunnel interface GRE over IPv4" \
								ip6gre "Virtual tunnel interface GRE over IPv6" \
								ip6gretap "Virtual L2 tunnel interface GRE over IPv6" \
								vti "Virtual tunnel interface" \
								nlmon "Netlink monitoring device" \
								ipvlan "Interface for L3 (IPv6/IPv4) based VLANs" \
								lowpan "Interface for 6LoWPAN (IPv6) over IEEE 802.15.4 / Bluetooth" \
								geneve "GEneric NEtwork Virtualization Encapsulation"
						end
					case delete
					case set
					case show
					case help
				end
			end
	end
end
			
complete -f -c ip
complete -f -c ip -a '(__fish_complete_ip)'
complete -f -c ip -n "not __fish_seen_subcommand_from $ip_all_commands" -a "$ip_commands"
# Yes, ip only takes options before "objects"
complete -c ip -s b -l batch -d "Read commands from file or stdin" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -l force -d "Don't terminate on errors in batch mode" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -s V -l Version -d "Print the version" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s s -l stats -d "Output more information" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s d -l details -d "Output more detailed information" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s l -l loops -d "Specify maximum number of loops for 'ip addr flush'" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s f -l family -d "The protocol family to use" -a "inet inet6 bridge ipx dnet link any" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s 4 -d "Short for --family inet" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s 6 -d "Short for --family inet6" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s B -d "Short for --family bridge" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s D -d "Short for --family decnet" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s I -d "Short for --family ipx" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s O -d "Short for --family link" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s o -l oneline -d "Output on one line" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s r -l resolve -d "Resolve names and print them instead of addresses" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s n -l net -l netns -d "Use specified network namespace" -n "not __fish_seen_subcommand_from $ip_commands"
complete -c ip -f -s a -l all -d "Execute command for all objects" -n "not __fish_seen_subcommand_from $ip_commands"