(in-package :cl-tui.box)

(defclass box ()
  ((layout-node :initform (make-layout-node) :accessor box-layout-node
     :initarg :layout-node)
   (border-style :initform :single :initarg :border-style
     :accessor box-border-style)
   (title :initform nil :initarg :title :accessor box-title)
   (title-align :initform :left :initarg :title-align
     :accessor box-title-align)
   (fg :initform nil :initarg :fg :accessor box-fg)
   (bg :initform nil :initarg :bg :accessor box-bg)))

(defun make-box (&key (border-style :single) title
                  (title-align :left) fg bg
                  width height)
  (make-instance 'box
    :border-style border-style
    :title title
    :title-align title-align
    :fg fg
    :bg bg
    :layout-node (make-layout-node
                   :width width
                   :height height
                   :direction :column)))

(defun render-box (box backend)
  "Render BOX at its computed layout position using BACKEND."
  (let ((ln (box-layout-node box))
        (bs (box-border-style box))
        (title (box-title box))
        (fg (box-fg box))
        (bg (box-bg box)))
    (let ((x (layout-node-x ln))
          (y (layout-node-y ln))
          (w (layout-node-width ln))
          (h (layout-node-height ln)))
      (when (or (zerop w) (zerop h) (< w 2) (< h 2))
        (return-from render-box (values)))
      (when bg
        (draw-rect backend x y w h :bg bg))
      (when bs
        (draw-border backend x y w h :style bs :fg fg :bg bg))
      (when title
        (let* ((content-w (- w 4))
               (tx (+ x 2))
               (ty (+ y (if bs 1 0)))
               (ta (box-title-align box))
               (display (subseq title 0 (min (length title) content-w))))
          (case ta
            (:center (draw-text backend (+ x (ceiling (- w (length display)) 2)) ty display fg bg))
            (:right (draw-text backend (+ x (- w (length display) 2)) ty display fg bg))
            (t (draw-text backend tx ty display fg bg))))))))