Channeled Divine Health

You bring forth a sphere of pure healing energy. You pour divine power into it, slowly building the energy it holds, until it is ready to mend an ally's wounds. This spell allows you to heal an ally, or damage an undead creature, at a range greater than touch. When you cast this spell, you channel energy into it. You can choose how long to spend casting this spell. If you cast this spell as a swift action, it has a range of touch, and you heal a single touched creature of 1d8 points of damage. An undead creature you touch takes this amount of damage instead of being healed. If you cast this spell as a standard action, it has a range of close, and you heal a single creature within range of damage equal to 1d8 points + your caster level (maximum +10). An undead creature you designate within range takes this amount of damage instead of being healed. If you cast this spell as a full-round casting this spell, it has a range of medium, and you heal a single creature within range of damage equal to 2d8 points + your caster level (maximum +15). An undead creature you designate within range takes this amount of damage instead of being healed. If you spend 2 full rounds casting this spell, it has a range of long, and you heal a single creature within range of damage equal to 4d8 points + your caster level (maximum +20). An undead creature you designate within range takes this amount of damage instead of being healed. You do not need to declare ahead of time how long you want to spend casting the spell. When you begin casting this spell, you decide that you are finished casting after the appropriate time has passed.