#!/bin/bash

#V0.2

#Requires:
#If you will be creating ~/.config , requires known_hosts_merge
#If you will be creating ~/.config , requires known2config
#If you will be pushing out key(s) to remote servers, requires quick-ssh-keyinstall
#Requires standard ssh tools: ssh , ssh-add , ssh-keygen , ssh-agent
#Requires standard posix/unix/linux command line tools.


Status () {
	echo "== $@"
}


cd >/dev/null

if [ ! -e .ssh ]; then
	mkdir .ssh
fi

chmod 700 ~ ~/.ssh/

cd .ssh

KeysAvailable=''
#For each of the 3 supported keypair types, we need the public keyfile
#and either the private key on disk or the private key loaded into ssh-agent.

Status 'Checking for existing keys.'
if [ -s id_dsa.pub ]; then
	if [ -s id_dsa ] || ssh-add -l 2>/dev/null | grep -q 'id_dsa'; then
		Status 'DSA keypair found, good'
		KeysAvailable="$KeysAvailable DSA"
	else
		Status 'Public key id_dsa.pub found, but no private key available.  Exiting; check with the helpdesk.'
		exit 1
	fi
fi

if [ -s id_ecdsa.pub ]; then
	if [ -s id_ecdsa ] || ssh-add -l 2>/dev/null | grep -q 'id_ecdsa'; then
		Status 'ECDSA keypair found, good'
		KeysAvailable="$KeysAvailable ECDSA"
	else
		Status 'Public key id_ecdsa.pub found, but no private key available.  Exiting; check with the helpdesk.'
		exit 1
	fi
fi

if [ -s id_rsa.pub ]; then
	if [ -s id_rsa.pub ] || ssh-add -l 2>/dev/null | grep -q 'id_rsa'; then
		Status 'RSA keypair found, good'
		KeysAvailable="$KeysAvailable RSA"
	else
		Status 'Public key id_rsa.pub found, but no private key available.  Exiting; check with the helpdesk.'
		exit 1
	fi
fi

if [ -z "$KeysAvailable" ]; then
	Status 'No ssh keypairs located, will create keypair'
	Status 'You will need to enter a long passhrase twice; remember this.'
	ssh-keygen -b 2048 -t rsa -f ~/.ssh/id_rsa
	if [ ! -s id_rsa -o ! -s id_rsa.pub ]; then
		Status 'Keys do not appear to have been successfully created;'
		Status 'please check with the helpdesk.  Exiting.'
		exit 1.
	fi
fi

if [ "`ssh-add -l`" = 'The agent has no identities.' ]; then
	Status 'About to load the ssh key(s) into the agent; please enter passphrase(s).'
	ssh-add
fi

if [ "`ssh-add -l`" = 'The agent has no identities.' ]; then
	Status 'The attempt to load ssh key(s) failed.  Please check with the helpdesk.  Exiting.'
	exit 1
fi

echo 'Do you have an ssh gateway (a host to which you ssh, then from there ssh to your other ssh servers)?'
echo 'If so, enter it here, if not or you are not sure, just press enter.'
read Gateway

if [ ! -s ~/.ssh/config ]; then
	#No config file; offer to generate one from known_hosts if that exists.
	Status 'Creating ~/.ssh/config file'
	if [ -s ~/.ssh/known_hosts ]; then
		if [ -n "$Gateway" ]; then
			cat ~/.ssh/known_hosts | known_hosts_merge | known2config -p "$Gateway" >~/.ssh/config
		else
			cat ~/.ssh/known_hosts | known_hosts_merge | known2config >~/.ssh/config
		fi
	fi
else
	if [ -s ~/.ssh/known_hosts ]; then
		Status 'You appear to have a ~/.ssh/config file already.  I will create a ~/.ssh/config.addme file with potentially new hosts that you can choose to merge into your existing ~/.ssh/config file if needed.'
		if [ -n "$Gateway" ]; then
			cat ~/.ssh/known_hosts | known_hosts_merge | known2config -p "$Gateway" >~/.ssh/config.addme
		else
			cat ~/.ssh/known_hosts | known_hosts_merge | known2config >~/.ssh/config.addme
		fi
		echo 'If you would like to merge the contents of ~/.ssh/config.addme into ~/.ssh/config , this would be a good time to do so, as the next step offers to install your ssh keys onto all servers in ~/.ssh/config .  Either way, press enter when you are done with any merging steps.'
		read Junk
	fi
fi

chmod go-w ~/.ssh/config

Status 'Would you like your key(s) installed on each of the hosts in'
Status 'your ~/.ssh/config that do not already have at least one key (Y/N)?'
Status 'You will need to enter the password for each one once.'
read Answer
case "$Answer" in
[Yy]*)
	quick-ssh-keyinstall `cat ~/.ssh/config | grep '^Host[[:space:]][[:space:]]*' | grep -v '^Host[[:space:]][[:space:]]*\*' | sed -e 's/^Host[[:space:]][[:space:]]*//' | sed -e 's/[[:space:]].*//'  | sort -u`
	;;
esac


Status 'Done.  Remember to run   ssh-add   once after each reboot to load your keys.'