#!/usr/bin/env zsh

local idx="${@[(ei)--help]}"
local flags_end="${@[(ei)--]}"
if (( idx < flags_end )); then
	printf "Usage: $0 [--all] [REMOTE]..."
	return 0
fi

idx="${@[(ei)--all]}"
if (( idx < flags_end )); then
	# Replace --all flag with empty string. Will be replaced with
	# refs/remotes/ later so that all remotes are listed
	set -- "${@[1,$((idx-1))]}" "" "${@[$((idx+1)),-1]}"
fi

git for-each-ref --format='%(upstream),%(refname)' refs/heads "${@/#/refs/remotes/}" \
	| sort -d \
	| sed -Ez '
		s:(^|\n|,)refs/(heads|remotes/):\1:g
		s:(^|\n),([^/][^\n]*):\1\2,:g
		s:,/:,:g
		s:(^|\n)([^,]+),\n\2:\1\2:g
		s:(^|\n)([^/,]*)([^\n]*\n\2(,|/))*:\n,\n&:g
		s:\n,\n+$:\n:' \
	| { echo remote,local; cat; } \
	| sed -E 's:(.*),(.*):\2,\1:g; s:^,: ,:; s:,$:, :' \
	| column -ts, \
	| sed '2d; 1{p;s/./―/g}'