clwars/combat.lisp

;;; Combat systems implemented here

(defvar *combat-menu-options-display* "
Actions:
1 | Attack | a
2 | Regen. Shields | r
3 | Overcharge Gun | o
4 | Attempt to flee | f
")

;; Combat options:
;; Attack (with specific weapon)
;; Regen shields
;; - (add value to rep-shield-val at cost of overcharing
;; - (overcharing can cause warp field to go into low-power)
;; - (overcharging can cause hull damage)
;; Overcharge gun at cost of overcharing reactor
;; Attempt to flee into the warp
;; - (requires full power / overcharged reactor)
;; - (can also cause reactor to go low power, which removes ability to regen/overcharge)

(defun combat-loop (sector)
  "The main loop responsbile for resolving combat situations"
  (let ((combat-state T))
    (loop
      while combat-state
      do (progn
	   (format T *combat-menu-options-display*)
	   (let ((top-level-selection (prompt-read "Enter a selection: ")))
	     (case (read-from-string top-level-selection)
	       (1 (progn ;; There is a way to collapse this progn into a single
		         ;; function call, but it's arguably a lot less readable
		    (let* ((weapon (weapon-select-menu (player-ship-obj sector)))
			   (attack-result (player-ship-attack
					   (player-ship-obj sector)
					   (first (enemy-ships sector))
					   weapon)))
		      (if attack-result
			  (progn
			    (setf (enemy-ships sector) (delete attack-result (enemy-ships sector)))
			    (format T "Your opponent has been vanquished!~%")
			    (top-level-game-menu))))))))))))
		

;; Select weapon
;; Determine if hit (% chance?)
;; If hit resolve shield
;; -- IF Shields down (ie shield damage causes target shield value to be 0)
;; -- Apply hull damage
;; ELSE
;; -- Decrement shield value per value of shield dmg

(defun weapon-select-menu (player-ship-obj)
  (let ((weapon-list (loop for weapon in (weapons player-ship-obj)
			   for i from 0
			   collect (list i
					 (name weapon)
					 (shield-dmg weapon)
					 (hull-dmg weapon)
					 (ammo-cost weapon)))))
    (format T "~%Available Ammo: ~A~%~%" (ammo (inventory player-ship-obj)))
    (format T "Available Weapons: ~%")
    (format-table T weapon-list :column-label '("Number" "Name" "Shield Damage" "Hull Damage" "Ammo Cost"))
    (let ((selection (prompt-read "Select a weapon to via the number column: ")))
      (format t "Selection was number: ~A and weapon name: ~A~%~%"
	      selection
	      (second (nth (parse-integer selection) weapon-list)))
      (return-from weapon-select-menu (nth (parse-integer selection) (weapons player-ship-obj))))))


(defun calculate-shield-damage (attacker-obj target-obj attacker-weapon)
  "Given a target and a weapon, return a value that the
   targets shield value should now be set as"
  (let ((new-shield-value (- (rep-shield-val target-obj) (shield-dmg attacker-weapon))))
    (setf (ammo (inventory attacker-obj)) (- (ammo (inventory attacker-obj)) (ammo-cost attacker-weapon)))
    (if (>= 0 new-shield-value)
	(return-from calculate-shield-damage 0)
	(return-from calculate-shield-damage new-shield-value))))

(defun calculate-hull-damage (attacker-obj target-obj attacker-weapon)
  "Given a target and a weapon, return a value that the
   targets hull value should now be set as"
  (let ((new-hull-value (- (armor-val target-obj) (hull-dmg attacker-weapon))))
    (setf (ammo (inventory attacker-obj)) (- (ammo (inventory attacker-obj)) (ammo-cost attacker-weapon)))
    (if (>= 0 new-hull-value)
	(return-from calculate-hull-damage 0)
	(return-from calculate-hull-damage new-hull-value))))

(defun player-ship-attack (player-ship-obj target-obj attacker-weapon)
  "Given a target and the attackers chosen weapon resolve the combat by
   calculating shield/hull damage and resolving resources. If the target
   is reduced to 0 hull points, return the target-obj and end combat"
  (if (> (ammo-cost attacker-weapon) (ammo (inventory player-ship-obj)))
      (progn
	(format T "You don't have enough ammo to fire your ~A gun!~%" (name attacker-weapon))
	(return-from player-ship-attack NIL)))
  (let ((calculated-shield-damage (calculate-shield-damage player-ship-obj target-obj attacker-weapon))
	(calculated-hull-damage (calculate-hull-damage player-ship-obj target-obj attacker-weapon)))
    (setf (rep-shield-val target-obj) calculated-shield-damage) ;; Resolve shield hit
    (format T "You hit their repulsor shields for ~A !~%" (shield-dmg attacker-weapon))
    (if (= 0 calculated-shield-damage)
	(progn
	  (setf (armor-val target-obj) calculated-hull-damage)
	  (format T "You hit their hull for ~A !~%" (hull-dmg attacker-weapon))))
    (if (= 0 calculated-hull-damage)
	(progn
	  (format T "Their hulls been breached! You've won the exchange!~%")
	  (return-from player-ship-attack target-obj))
	NIL)))

(defun display-weapons (player-ship-obj)
  "Given player ship, display weapons and associated attributes"
  (let* ((weapons (weapons player-ship-obj))
	 (weapon-list (loop for weapon in weapons
			    collect (list (name weapon)
					  (shield-dmg weapon)
					  (hull-dmg weapon)
					  (ammo-cost weapon)))))
    (format T "~%WEAPON DETAILS~%")
    (format-table T weapon-list :column-label '("Name" "Shield Damage" "Hull Damage" "Ammo Cost"))))