(in-package :cl-tty.backend)

(defclass simple-backend (backend)
  ((output-stream :initform *standard-output*
                  :initarg :output-stream
                  :accessor backend-output-stream)))

(defun make-simple-backend (&key output-stream)
  (make-instance 'simple-backend
    :output-stream (or output-stream *standard-output*)))

(defmethod initialize-backend ((b simple-backend))
  b)

(defmethod shutdown-backend ((b simple-backend))
  (values))

(defmethod backend-size ((b simple-backend))
  ;; Try ioctl, fall back to 80x24
  (values 80 24))

(defmethod backend-write ((b simple-backend) string)
  (let ((stream (backend-output-stream b)))
    (write-string string stream)
    (finish-output stream)
    (length string)))

(defmethod draw-text ((b simple-backend) x y string fg bg
                      &key bold italic underline reverse dim blink)
  (declare (ignore x y fg bg bold italic underline reverse dim blink))
  (backend-write b string))

(defun %simple-border-char (edge-style pos)
  "Return ASCII border character for EDGE-STYLE at POS.
POS is :top-left, :top-right, :bottom-left, :bottom-right,
:horizontal, or :vertical."
  (case pos
    ((:top-left :top-right :bottom-left :bottom-right) #\+)
    (:horizontal #\-)
    (:vertical #\|)))

(defmethod draw-border ((b simple-backend) x y width height
                        &key style fg bg title title-align)
  (declare (ignore style fg bg title title-align))
  (let ((h (%simple-border-char nil :horizontal))
        (v (%simple-border-char nil :vertical)))
    ;; Position cursor with newlines and spaces (no escape sequences)
    (dotimes (row y) (backend-write b (string #\Newline)))
    ;; Top edge
    (backend-write b (make-string x :initial-element #\space))
    (backend-write b (make-string width :initial-element h))
    ;; Sides
    (loop for i from 1 below (1- height)
          do (backend-write b (string #\Newline))
             (backend-write b (make-string x :initial-element #\space))
             (backend-write b (string v))
             (backend-write b (make-string (- width 2) :initial-element #\space))
             (backend-write b (string v)))
    ;; Bottom edge
    (backend-write b (string #\Newline))
    (backend-write b (make-string x :initial-element #\space))
    (backend-write b (make-string width :initial-element h))))

(defmethod draw-rect ((b simple-backend) x y width height
                      &key bg)
  (declare (ignore x y width height bg))
  ;; On simple backend, background fill is a no-op
  (values))

(defmethod draw-link ((b simple-backend) x y string url
                      &key fg bg)
  (declare (ignore url fg bg))
  (draw-text b x y string nil nil))

(defmethod draw-ellipsis ((b simple-backend) x y width
                          &key fg bg)
  (declare (ignore x y width fg bg))
  (backend-write b "..."))