;;;; Ru*** roLeplay Playground virtual tabletop
;;;; Copyright (C) 2022  Zull
;;;;
;;;; This program is free software: you can redistribute it and/or modify
;;;; it under the terms of the GNU General Public License as published by
;;;; the Free Software Foundation, either version 3 of the License, or
;;;; (at your option) any later version.
;;;;
;;;; This program is distributed in the hope that it will be useful,
;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;;; GNU General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU General Public License
;;;; along with this program.  If not, see <https://www.gnu.org/licenses/>.

(in-package :rulp.graphics)

(defparameter +grid-span+ 50)
(defparameter +is-grid-letters+ t)
(defparameter +is-grid+ t)


; these two functions can be edited when different grids will be added
(defun position-actor-to-view (a)
  (* a +grid-span+))
(defun position-view-to-actor (a)
  (floor (/ a +grid-span+)))

(defparameter +letters-list+
  '("A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M"
    "N" "O" "P" "Q" "R" "S" "T" "U" "V" "W" "X" "Y" "Z"))

;; this function cycle throughout the letters
(defun letter-cycle (n)
  (nth (mod n (length +letters-list+)) +letters-list+))

(defun toggle-grid ()
  (if +is-grid+
      (setf +is-grid+ nil)
      (setf +is-grid+ t)))

;; NOTE: horrible
(defun toggle-grid-letters ()
  (if +is-grid-letters+
      (setf +is-grid-letters+ nil)
      (setf +is-grid-letters+ t)))

;; FIXME: the function doesn't consider *viewpoint-zoom*
(defmacro grid-render (renderer &optional (x 0) (y 0) (w 100) (h 100))
  "renderize a grid in where required"
  `(let ((neg-x (* ,x -1))
         (neg-y (* ,y -1))
         (plane-x (x *plane*))
         (plane-y (y *plane*))
         (x-iterations (/ (- ,w ,x) *plane-grid*))
         (y-iterations (/ (- ,h ,y) *plane-grid*)))
    (progn
      ;; (sdl2:set-render-draw-color ,renderer ,red ,green ,blue 255)
      (loop :for i :from (ceiling (/ neg-x *plane-grid*)) :to x-iterations
            :do
               (sdl2:render-draw-line ,renderer
                                      (+ (* i *plane-grid*) plane-x)
                                      (+ plane-y neg-y)
                                      (+ (* i *plane-grid*) plane-x)
                                      (+ ,h plane-y neg-y))
            )
      (loop :for j :from (ceiling (/ neg-y *plane-grid*)) :to y-iterations
            :do
               (sdl2:render-draw-line ,renderer
                                      (+ plane-x neg-x)
                                      (+ (* j *plane-grid*) plane-y)
                                      (+ plane-x ,w neg-x)
                                      (+ (* j *plane-grid*) plane-y))
            ))
    (sdl2:set-render-draw-color ,renderer 0 0 0 255)
     ))

(defmacro indexes-render (renderer &optional (x 0) (y 0) (w 0) (h 0))
  `(let ((neg-x (* ,x -1))
         (neg-y (* ,y -1))
         (x-offset (x *plane*))
         (y-offset (y *plane*))
         (x-iterations (/ (- ,w ,x) *plane-grid*))
         (y-iterations (/ (- ,h ,y) *plane-grid*)))
     (loop :for k :from (floor (/ neg-x *plane-grid*)) :to x-iterations
           :do (loop :for l :from (floor (/ neg-y *plane-grid*)) :to y-iterations
                     :do (tr-write (coordinate-to-grid-index (cons l (+ k 1)))
                                   (+ x-offset (* k *plane-grid*))
                                   (+ y-offset (* l *plane-grid*))
                                   (floor (/ *plane-grid* 3))
                                   (floor (/ *plane-grid* 3))
                                   ,renderer)))
     ;; (sdl2:set-render-draw-color ,renderer 0 255 0 100) ; remember to uncomment both
     ;; (sdl2:render-fill-rect ,renderer (sdl2:make-rect ,x ,y ,w ,h)) ; test for x y w and h
     ))

;;; BUG: the coordinates given to the macros are incorrect. The render-fill-rect test
;;; proven that the coordinates are not faithful of the view point visual. These
;;; coordinate must be adjusted so the (now commented) render-fill-rect line will
;;; always fill all the screen