;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10 -*-
;;;; *************************************************************************
;;;; FILE IDENTIFICATION
;;;;
;;;; Name:          views.lisp
;;;; Purpose:       View methods for Hyperobjects
;;;; Programmer:    Kevin M. Rosenberg
;;;; Date Started:  Apr 2000
;;;;
;;;; $Id: views.lisp,v 1.44 2003/05/14 21:18:12 kevin Exp $
;;;;
;;;; This file is Copyright (c) 2000-2003 by Kevin M. Rosenberg
;;;; *************************************************************************
 
(in-package :hyperobject)

(eval-when (:compile-toplevel :execute)
  (declaim (optimize (speed 2) (safety 2) (compilation-speed 0) (debug 2))))


(defclass object-view ()
  ((object-class-name :initform nil :initarg :object-class-name
		      :accessor object-class-name
		 :documentation "Name of class of object to be viewed.")
   (object-class :initform nil :initarg :object-class
		 :accessor object-class
		 :documentation "Class of object to be viewed.")
   (slots :initform nil :initarg :slots :accessor slots
	  :documentation "List of effective slots for object to be viewed.")
   (name :initform nil :initarg :name :accessor name
	 :documentation "Name for this view.")
   (category :initform nil :initarg :category :accessor category
	     :documentation "Category for view. Helpful when want to find a view corresponding to a particular category.")
   (source-code :initform nil :initarg :source-code :accessor source-code 
		:documentation "Source code for generating view.")
   (country-language :initform :en :initarg :country-language
		     :documentation "Country's Language for this view.")
   ;;
   (file-start-str :type (or string null) :initform nil :initarg :file-start-str
		   :accessor file-start-str)
   (file-end-str :type (or string null) :initform nil :initarg :file-end-str
		 :accessor file-end-str)
   (list-start-str-or-func :type (or string function null) :initform nil
			   :initarg :list-start-str-or-func
		      :accessor list-start-str-or-func)
   (list-start-indent :initform nil :initarg :list-start-indent
		      :accessor list-start-indent)
   (list-end-str-or-func :type (or string function null) :initform nil
			 :initarg :list-end-str-or-func
		    :accessor list-end-str-or-func)
   (list-end-indent :initform nil :initarg :list-end-indent
		    :accessor list-end-indent)
   (obj-start-str-or-func :type (or string function null) :initform nil :initarg :obj-start-str-or-func
		     :accessor obj-start-str-or-func)
   (obj-start-indent :initform nil :initarg :obj-start-indent
		     :accessor obj-start-indent)
   (obj-end-str-or-func :type (or string function null) :initform nil :initarg :obj-end-str-or-func
		   :accessor obj-end-str-or-func)
   (obj-end-indent :initform nil :initarg :obj-end-indent
		   :accessor obj-end-indent)
   (obj-data-indent :initform nil :initarg :obj-data-indent
		    :accessor obj-data-indent)
   (obj-data-func :type (or function null) :initform nil
			:initarg :obj-data-func
			:accessor obj-data-func)
   (obj-data-print-code :type (or function null) :initform nil
		  :initarg :obj-data-print-code
		  :accessor obj-data-print-code)
   (obj-data-end-str :type (or string null) :initform nil
			:initarg :obj-data-end-str
			:accessor obj-data-end-str)
   (link-slots :type list :initform nil
	       :documentation "List of slot names that have hyperlinks"
	       :accessor link-slots)
   (link-page-name :type (or string null) :initform nil :initarg :link-page-name
		   :accessor link-page-name)
   (link-href-start :type (or string null) :initform nil :initarg :link-href-start
		    :accessor link-href-start)
   (link-href-end :type (or string null) :initform nil :initarg :link-href-end
		  :accessor link-href-end)
   (link-ampersand :type (or string null) :initform nil :initarg :link-ampersand
		   :accessor link-ampersand))
  (:default-initargs :link-page-name "disp-func1")
  (:documentation "View class for a hyperobject"))


(defun get-category-view (obj category &optional slots)
  "Find or make a category view for an object"
  (let ((obj-class (class-of obj)))
    (if (null category)
	(default-view obj-class)
	(aif (find category (views obj-class) :key #'category)
	     it
	     (let ((view
		    (make-instance 'object-view
				   :object-class-name (class-name obj-class)
				   :object-class obj-class
				   :category category
				   :slots slots)))
	       (push view (views obj-class))
	       view)))))
			     
;;;; *************************************************************************
;;;;  Metaclass Intialization
;;;; *************************************************************************

(defun finalize-views (cl)
  "Finalize all views that are given on a objects initialization"
  (unless (default-print-slots cl)
    (setf (default-print-slots cl)
	  (mapcar #'slot-definition-name (class-slots cl))))
  (let ((views '()))
    (dolist (view-def (views cl))
      (push (make-object-view cl view-def) views))
    (setf (views cl) (nreverse views)))
  (cond
    ((default-view cl)
     (setf (default-view cl) (make-object-view cl (default-view cl))))
    ((car (views cl))
     (setf (default-view cl) (make-object-view cl (car (views cl)))))
    (t
     (setf (default-view cl) (make-object-view cl :default)))))

(defun make-object-view (cl view-def)
  "Make an object view from a definition. Do nothing if a class is passed so that reinitialization will be a no-op"
  (cond
    ((typep view-def 'object-view)
     view-def)
    ((eq view-def :default)
     (let* ((name (class-name cl))
	    (view (make-instance 'object-view :name "automatic"
				 :object-class-name name
				 :object-class cl
				 :category :compact-text)))
       view))
    ((consp view-def)
     (eval `(make-instance ,view-def)))
    (t
     (error "Invalid parameter to make-object-view: ~S" view-def))))

(defmethod initialize-instance :after ((view object-view)
				       &rest initargs &key &allow-other-keys)
  (initialize-view (object-class view) view))
  
(defun initialize-view (obj-cl view)
  "Calculate all view slots for a hyperobject class"
  (cond
    ((category view)
     (initialize-view-by-category obj-cl view))
    ((source-code view)
     (initialize-view-by-source-code obj-cl view))
    (t
     (setf (category view) :compact-text)
     (initialize-view-by-category obj-cl view))))

(defun initialize-view-by-source-code (obj-cl view)
  "Initialize a view based upon a source code"
  (let ((source-code (source-code view)))
    (error "not implemented")
    )
  )

(defmacro write-simple (v s)
  `(typecase ,v
    (string
     (write-string ,v ,s))
    #+allegro
    (fixnum
     (excl::print-fixnum ,s 10 ,v)) 
    (symbol
     (write-string (symbol-name ,v) ,s))
    (t
     (write-string (write-to-string ,v) ,s))))

(defun write-ho-value (obj name type formatter cdata strm)
  (declare (ignorable type))
  (let* ((slot-data (slot-value obj name))
	 (fmt-data (if formatter
		       (funcall formatter slot-data)
		   slot-data))
	 (data (if cdata
		   (kmrcl:xml-cdata fmt-data)
		   fmt-data)))
    (write-simple data strm)))


(defun ppfc-html (title name type formatter cdata print-func)
  (vector-push-extend '(write-string "<span class=\"" s) print-func)
  (vector-push-extend `(write-string ,title s) print-func)
  (vector-push-extend '(write-string "\">" s) print-func)
  (vector-push-extend `(write-ho-value x ',name ',type ',formatter ,cdata s) print-func)
  (vector-push-extend '(write-string "</span>" s) print-func))

(defun ppfc-xml (tag name type formatter cdata print-func)
  (vector-push-extend '(write-char #\< s) print-func)
  (vector-push-extend `(write-string ,tag s) print-func)
  (vector-push-extend '(write-char #\> s) print-func)
  (vector-push-extend `(write-ho-value x ',name ',type ',formatter ,cdata s) print-func)
  (vector-push-extend '(write-string "</" s) print-func)
  (vector-push-extend `(write-string ,tag s) print-func)
  (vector-push-extend '(write-char #\> s) print-func))

(defun ppfc-html-labels (label name type formatter cdata print-func)
  (vector-push-extend '(write-string "<span class=\"label\">" s) print-func)
  (vector-push-extend `(write-string ,label s) print-func)
  (vector-push-extend '(write-string "</span> " s) print-func)
  (ppfc-html label name type formatter cdata print-func))

(defun ppfc-xhtml-labels (label tag name type formatter cdata print-func)
  (vector-push-extend '(write-string "<span class=\"label\">" s) print-func)
  (vector-push-extend `(write-string ,label s) print-func)
  (vector-push-extend '(write-string "</span> " s) print-func)
  (ppfc-html tag name type formatter cdata print-func))

(defun ppfc-xml-labels (label tag name type formatter cdata print-func)
  (vector-push-extend '(write-string "<label>" s) print-func)
  (vector-push-extend `(write-string ,label s) print-func)
  (vector-push-extend '(write-string "</label> " s) print-func)
  (ppfc-xml tag name type formatter cdata print-func))

(defun ppfc-html-link (name type formatter cdata nlink print-func)
  (declare (fixnum nlink))
  (vector-push-extend '(write-char #\< s) print-func)
  (vector-push-extend `(write-string (nth ,(+ nlink nlink) links) s) print-func) 
  (vector-push-extend '(write-char #\> s) print-func)
  (vector-push-extend `(write-ho-value x ',name ',type ',formatter ,cdata s) print-func)
  (vector-push-extend '(write-string "</" s) print-func)
  (vector-push-extend `(write-string (nth ,(+ nlink nlink 1) links) s) print-func) 
  (vector-push-extend '(write-char #\> s) print-func))

(defun ppfc-html-link-labels (label name type formatter cdata nlink print-func)
  (vector-push-extend '(write-string "<label>" s) print-func)
  (vector-push-extend `(write-string ,label s) print-func)
  (vector-push-extend '(write-string "</label> " s) print-func)
  (ppfc-html-link name type formatter cdata nlink print-func))

(defun push-print-fun-code (category slot nlink print-func)
  (let* ((formatter (esd-print-formatter slot))
	 (name (slot-definition-name slot))
	 (namestr-lower (string-downcase (symbol-name name)))
	 (xml-namestr (escape-xml-string namestr-lower))
	 (xml-tag (escape-xml-string namestr-lower))
	 (type (slot-value slot 'type))
	 (cdata (not (null
		      (and (in category :xml :xhtml :xml-link :xhtml-link
			       :xml-labels :ie-xml-labels
			       :xhtml-link-labels :xml-link-labels :ie-xml-link
			       :ie-xml-link-labels)
			   (or formatter
			       (lisp-type-is-a-string type))))))
	 (hyperlink (esd-hyperlink slot)))
    
    (case category
      (:compact-text
       (vector-push-extend
	`(write-ho-value x ',name ',type ',formatter ,cdata s) print-func))
      (:compact-text-labels
       (vector-push-extend `(write-string ,namestr-lower s) print-func)
       (vector-push-extend '(write-char #\space s) print-func)
       (vector-push-extend
	`(write-ho-value x ',name ',type ',formatter ,cdata s) print-func))
      ((or :html :xhtml)
       (ppfc-html namestr-lower name type formatter cdata print-func))
      (:xml
       (ppfc-xml xml-tag name type formatter cdata print-func))
      (:html-labels
       (ppfc-html-labels namestr-lower name type formatter cdata print-func))
      (:xhtml-labels
       (ppfc-xhtml-labels xml-namestr namestr-lower name type formatter cdata print-func))
      (:xml-labels
       (ppfc-xml-labels xml-namestr xml-tag name type formatter cdata print-func))
      ((or :html-link :xhtml-link)
       (if hyperlink
	   (ppfc-html-link name type formatter cdata nlink print-func)
	   (ppfc-html namestr-lower name type formatter cdata print-func)))
      ((or :xml-link :ie-xml-link)
       (if hyperlink
	   (ppfc-html-link name type formatter cdata nlink print-func)
	   (ppfc-xml xml-tag name type formatter cdata print-func)))
      (:html-link-labels
       (if hyperlink
	   (ppfc-html-link-labels namestr-lower name type formatter cdata nlink
				  print-func)
	   (ppfc-html-labels namestr-lower name type formatter cdata print-func)))
      (:xhtml-link-labels
       (if hyperlink
	   (ppfc-html-link-labels xml-namestr name type formatter cdata nlink
				  print-func)
	   (ppfc-xhtml-labels xml-tag namestr-lower name type formatter cdata
			      print-func)))
      ((or :xml-link-labels :ie-xml-link-labels)
       (if hyperlink
	   (ppfc-html-link-labels xml-namestr name type formatter cdata nlink
				  print-func)
	   (ppfc-xml-labels xml-tag namestr-lower name type formatter cdata
			    print-func))))))


(defun view-has-links-p (view)
  (in (category view) :html-link :xhtml-link :xml-link :ie-xml-link
      :html-link-labels :xhtml-link-labels :xml-link-labels
      :ie-xml-link-labels))

(defun initialize-view-by-category (obj-cl view)
  "Initialize a view based upon a preset category"
  (unless (in (category view) :compact-text :compact-text-labels
	      :html :html-labels :html-link-labels
	      :xhtml :xhtml-labels :xhtml-link-labels
	      :xhtml-link :html-link
	      :xml :xml-labels :xml-link :ie-xml-link
	      :xml-link-labels :ie-xml-link-labels)
    (error "Unknown view category ~A" (category view)))
  
  (unless (slots view) (setf (slots view) (default-print-slots obj-cl)))

  (let ((links '())
	(print-func (make-array 10 :fill-pointer 0 :adjustable t)))

    (do* ((slots (slots view) (cdr slots))
	  (slot-name (car slots) (car slots))
	  (slot (find-slot-by-name obj-cl slot-name)
		(find-slot-by-name obj-cl slot-name)))
	 ((null slots))
      (unless slot
	(error "Slot ~A is not found in class ~S" slot-name obj-cl))
      
      (push-print-fun-code (category view) slot (length links) print-func)
      (when (> (length slots) 1)
	(vector-push-extend '(write-char #\space s) print-func))

      (when (and (view-has-links-p view) (esd-hyperlink slot))
	(push (slot-definition-name slot) links)))

    (when (plusp (length print-func))
      (setf (obj-data-print-code view) `(lambda (x s links)
					 (declare (ignorable links))
					 ,@(map 'list #'identity print-func)))
      (setf (obj-data-func view)
	    (compile nil (eval (obj-data-print-code view)))))
    
    (setf (link-slots view) (nreverse links)))

  (finalize-view-by-category view)
  view)

(defun finalize-view-by-category (view)
  (case (category view)
    ((or :compact-text :compact-text-labels)
     (initialize-text-view view))
    ((or :html :xhtml :html-labels :xhtml-labels)
     (initialize-html-view view))
    ((or :xml :xml-labels)
     (initialize-xml-view view))
    ((or :html-link :html-link-labels)
     (initialize-html-view view)
     (setf (link-href-start view) "a href=")
     (setf (link-href-end view) "a")
     (setf (link-ampersand view) "&"))
    ((or :xhtml-link :xhtml-link-labels)
     (initialize-html-view view)
     (setf (link-href-start view) "a href=")
     (setf (link-href-end view) "a")
     (setf (link-ampersand view) "&amp;"))
    ((or :xml-link :xml-link-labels)
     (initialize-xml-view view)
     (setf (link-href-start view)
	   "xmllink xlink:type=\"simple\" xlink:href=")
     (setf (link-href-end view) "xmllink")
     (setf (link-ampersand view) "&amp;"))
    ((or :ie-xml-link :ie-xml-link-labels)
     (initialize-xml-view view)
     (setf (link-href-start view) "html:a href=")
     (setf (link-href-end view) "html:a")
     (setf (link-ampersand view) "&amp;"))))

#+ignore
(defun initialize-view-by-category (obj-cl view)
  "Initialize a view based upon a preset category"
  (let ((fmtstr nil)
	(first-field t)
	(value-func '())
	(links '())
	(category (category view)))

    (unless (in category :compact-text :compact-text-labels
		:html :html-labels :html-link-labels
		:xhtml :xhtml-labels :xhtml-link-labels
		:xml :xml-labels :xml-link :ie-xml-link
		:xml-link-labels :ie-xml-link-labels)
      (error "Unknown view category ~A" category))
    
    (unless (slots view)
      (setf (slots view) (default-print-slots obj-cl)))
    (dolist (slot-name (slots view))
      (let ((slot (find-slot-by-name obj-cl slot-name)))
	(unless slot
	  (error "Slot ~A is not found in class ~S" slot-name obj-cl))
	(let* ((name (slot-definition-name slot))
	       (namestr-lower (string-downcase (symbol-name name)))
	       (xml-namestr (escape-xml-string namestr-lower))
	       (xml-tag (escape-xml-string namestr-lower))
	       (type (slot-value slot 'type))
	       (print-formatter (esd-print-formatter slot)))

	  (cond
	    (first-field
	     (setq fmtstr "")
	     (setq first-field nil))
	    (t
	     (string-append fmtstr " ")))

	  (let ((value-fmt
		 (case type
		   ((or :integer :fixnum)
		    "~d")
		   (:boolean
		    "~a")
		   (otherwise
		    "~a"))))
	    (case category
	      (:compact-text
	       (string-append fmtstr value-fmt))
	      (:compact-text-labels
	       (string-append fmtstr namestr-lower " " value-fmt))
	      ((or :html :xhtml)
	       (string-append fmtstr (concatenate 'string "<span class=\"" namestr-lower "\">" value-fmt "</span>")))
	      (:xml
	       (string-append fmtstr (concatenate 'string "<" namestr-lower ">" value-fmt "</" namestr-lower ">")))
	      (:html-labels
	       (string-append fmtstr (concatenate 'string "<span class=\"label\">" namestr-lower "</span> <span class=\"" namestr-lower "\">" value-fmt "</span>")))
	      (:xhtml-labels
	       (string-append fmtstr (concatenate 'string "<span class=\"label\">" xml-namestr "</span> <span class=\"" namestr-lower "\">" value-fmt "</span>")))
	      (:xml-labels
	       (string-append fmtstr (concatenate 'string "<label>" xml-namestr "</label> <" xml-tag ">" value-fmt "</" xml-tag ">")))
	      ((or :html-link :xhtml-link)
	       (push name links)
	       (if (esd-hyperlink slot)
		   (string-append fmtstr "<~~a>" value-fmt "</~~a>")
		   (string-append fmtstr (concatenate 'string "<span class=\"" namestr-lower "\">" value-fmt "</span>"))))
	      ((or :xml-link :ie-xml-link)
	       (push name links)
	       (if (esd-hyperlink slot)
		   (string-append fmtstr "<~~a>" value-fmt "</~~a>")
		   (string-append fmtstr (concatenate 'string "<" xml-tag ">" value-fmt "</" xml-tag ">"))))
	      (:html-link-labels
	       (push name links)
	       (if (esd-hyperlink slot)
		   (string-append fmtstr "<span class=\"label\">" namestr-lower "</span> <~~a>" value-fmt "</~~a>")
		   (string-append fmtstr (concatenate 'string "<span class=\"label\">" namestr-lower "</span> <span class=\"" namestr-lower "\">" value-fmt "</span>"))))
	      (:xhtml-link-labels
	       (push name links)
	       (if (esd-hyperlink slot)
		   (string-append fmtstr "<span class=\"label\">" xml-namestr "</span> <~~a>" value-fmt "</~~a>")
		   (string-append fmtstr (concatenate 'string "<span class=\"label\">" xml-namestr "</span> <span class=\"" namestr-lower "\">" value-fmt "</span>"))))
	      ((or :xml-link-labels :ie-xml-link-labels)
	       (push name links)
	       (if (esd-hyperlink slot)
		   (string-append fmtstr "<label>" xml-namestr "</label> <~~a>" value-fmt "</~~a>")
		   (string-append fmtstr (concatenate 'string "<label>" xml-namestr "</label> <" xml-tag ">" value-fmt "</" xml-tag ">")))))
	    ) ;; let value-fmt
	    
	  (let ((func (if print-formatter
		  `(,print-formatter (slot-value x (quote ,name)))
		  `(slot-value x (quote ,name)))))
	    (when (and (in category :xml :xhtml :xml-link :xhtml-link
			   :xml-labels :ie-xml-labels
			   :xhtml-link-labels :xml-link-labels :ie-xml-link
			   :ie-xml-link-labels)
		       (or print-formatter
			   (lisp-type-is-a-string type)))
	      (setq func `(kmrcl:xml-cdata ,func)))
	    (push func value-func))
	  )))
	  
    (when value-func
      (setq value-func
	    (compile nil (eval `(lambda (x) (values ,@(nreverse value-func)))))))

    (setf (obj-data-fmtstr view) fmtstr)
    (setf (obj-data-value-func view) value-func)
    (setf (link-slots view) (nreverse links))
    
    (case category
      ((or :compact-text :compact-text-labels)
       (initialize-text-view view))
      ((or :html :xhtml :html-labels :xhtml-labels)
       (initialize-html-view view))
      ((or :xml :xml-labels)
       (initialize-xml-view view))
      ((or :html-link :html-link-labels)
       (initialize-html-view view)
       (setf (link-href-start view) "a href=")
       (setf (link-href-end view) "a")
       (setf (link-ampersand view) "&"))
      ((or :xhtml-link :xhtml-link-labels)
       (initialize-html-view view)
       (setf (link-href-start view) "a href=")
       (setf (link-href-end view) "a")
       (setf (link-ampersand view) "&amp;"))
      ((or :xml-link :xml-link-labels)
       (initialize-xml-view view)
       (setf (link-href-start view)
	     "xmllink xlink:type=\"simple\" xlink:href=")
       (setf (link-href-end view) "xmllink")
       (setf (link-ampersand view) "&amp;"))
      ((or :ie-xml-link :ie-xml-link-labels)
       (initialize-xml-view view)
       (setf (link-href-start view) "html:a href=")
       (setf (link-href-end view) "html:a")
       (setf (link-ampersand view) "&amp;"))))
  view)


;;;; *************************************************************************
;;;;  View Data Format Section
;;;; *************************************************************************

(defun class-name-of (obj)
  (string-downcase (class-name (class-of obj))))

(defvar +newline-string+ (format nil "~%"))

(defun write-user-name-maybe-plural (obj nitems strm)
  (write-string
   (if (> nitems 1)
       (hyperobject-class-user-name-plural obj)
       (hyperobject-class-user-name obj))
   strm))

(defun initialize-text-view (view)
  (setf (list-start-str-or-func view)
	(compile nil
		 (eval '(lambda (obj nitems strm)
			 (write-user-name-maybe-plural obj nitems strm)
			 (write-char #\: strm)
			 (write-char #\Newline strm)))))
  (setf (list-start-indent view) t)
  (setf (obj-data-indent view) t)
  (setf (obj-data-end-str view) +newline-string+))

(defun html-list-start-func (obj nitems strm)
  (write-string "<p><b>" strm)
  (write-user-name-maybe-plural obj nitems strm)
  (write-string ":</b></p><div class=\"" strm)
  (write-string (class-name-of obj) strm)
  (write-string "\"><ul>" strm)
  (write-char #\newline strm))

(defun initialize-html-view (view)
  (initialize-text-view view)
  (setf (file-start-str view) (format nil "<html><body>~%"))
  (setf (file-end-str view) (format nil "</body><html>~%"))
  (setf (list-start-indent view) t)
  (setf (list-start-str-or-func view) #'html-list-start-func)
  (setf (list-end-str-or-func view) (format nil "</ul></div>~%"))
  (setf (list-end-indent view) t)
  (setf (obj-start-indent view) t)
  (setf (obj-start-str-or-func view) "<li>")
  (setf (obj-end-indent view)  t)
  (setf (obj-end-str-or-func view)  (format nil "</li>~%"))
  (setf (obj-data-indent view) nil))

(defun initialize-xhtml-view (view)
  (initialize-text-view view)
  (setf (file-start-str view) (format nil "<html><body>~%"))
  (setf (file-end-str view) (format nil "</body><html>~%"))
  (setf (list-start-indent view) t)
  (setf (list-start-str-or-func view) #'html-list-start-func)
  (setf (list-end-str-or-func view) (format nil "</ul></div>~%"))
  (setf (list-end-indent view) t)
  (setf (obj-start-indent view) t)
  (setf (obj-start-str-or-func view) "<li>")
  (setf (obj-end-indent view)  t)
  (setf (obj-end-str-or-func view) (format nil "</li>~%"))
  (setf (obj-data-indent view) nil))

(defun xmlformat-list-end-func (x strm)
  (write-string "</" strm)
  (write-string (class-name-of x) strm)
  (write-string "list" strm)
  (write-string ">" strm)
  (write-char #\newline strm))

(defun xmlformat-list-start-func (x nitems strm)
  (write-char #\< strm)
  (write-string (class-name-of x) strm)
  (write-string "list><title>" strm)
  (write-user-name-maybe-plural x nitems strm)
  (write-string ":</title>" strm)
  (write-char #\newline strm))

(defun initialize-xml-view (view)
  (initialize-text-view view)
  (setf (file-start-str view) "") ; (std-xml-header)
  (setf (list-start-indent view)  t)
  (setf (list-start-str-or-func view) #'xmlformat-list-start-func)
  (setf (list-end-indent view) t)
  (setf (list-end-str-or-func view) #'xmlformat-list-end-func)
  (setf (obj-start-str-or-func view) (format nil "<~(~a~)>" (object-class-name view)))
  (setf (obj-start-indent view) t)
  (setf (obj-end-str-or-func view) (format nil "</~(~a~)>~%" (object-class-name view)))
  (setf (obj-end-indent view) nil)
  (setf (obj-data-indent view) nil))


;;; File Start and Ends

(defun fmt-file-start (view strm)
  (awhen (file-start-str view)
	 (write-string it strm)))

(defun fmt-file-end (view strm)
  (awhen (file-end-str view)
	 (write-string it strm)))

;;; List Start and Ends

(defun fmt-list-start (obj view strm indent num-items)
  (when (list-start-indent view)
    (indent-spaces indent strm))
  (awhen (list-start-str-or-func view)
	 (if (stringp it)
	     (write-string it strm)
	     (funcall it obj num-items strm))))

(defun fmt-list-end (obj view strm indent num-items)
  (declare (ignore num-items))
  (when (list-end-indent view)
      (indent-spaces indent strm))
  (awhen (list-end-str-or-func view)
	 (if (stringp it)
	     (write-string it strm)
	     (funcall it obj strm))))

;;; Object Start and Ends

(defun fmt-obj-start (obj view strm indent)
  (when (obj-start-indent view)
    (indent-spaces indent strm))
  (awhen (obj-start-str-or-func view)
	 (if (stringp it)
	     (write-string it strm)
	     (funcall it obj strm))))

(defun fmt-obj-end (obj view strm indent)
  (when (obj-end-indent view)
    (indent-spaces indent strm))
  (awhen (obj-end-str-or-func view)
	 (if (stringp it)
	     (write-string it strm)
	     (funcall it obj strm))))
  
;;; Object Data 


(defun make-link-start (view fieldfunc fieldvalue refvars)
  (with-output-to-string (s)
    (write-string (link-href-start view) s)
    (write-char #\" s)
    (write-string (make-url (link-page-name view)) s)
    (write-string "?func=" s)
    (write-simple fieldfunc s)
    (write-string (link-ampersand view) s)
    (write-string "key=" s)
    (write-simple fieldvalue s)
    (dolist (var refvars)
      (write-string (link-ampersand view) s)
      (write-simple (car var) s)
      (write-char #\= s)
      (write-simple (cdr var) s))
    (write-char #\" s)))
  
(defun make-link-end (obj view fieldname)
  (declare (ignore obj fieldname))
  (link-href-end view))

(defun fmt-obj-data (obj view strm indent refvars)
  (when (obj-data-indent view)
    (indent-spaces indent strm))
  (if (link-slots view)
      (fmt-obj-data-with-link obj view strm refvars)
      (fmt-obj-data-plain obj view strm))
  (awhen (obj-data-end-str view)
	 (write-string it strm)))

(defun fmt-obj-data-plain (obj view strm)
  (awhen (obj-data-func view)
	 (funcall it obj strm nil)))

(defun fmt-obj-data-with-link (obj view strm refvars)
  (let ((refvalues '()))
    ;; make list of hyperlink link fields for printing to refstr template
    (dolist (name (link-slots view))
      (awhen (find name (hyperobject-class-hyperlinks obj) :key #'name)
	     (push (make-link-start view (lookup it) (slot-value obj name)
				    (append (link-parameters it) refvars))
		   refvalues)
	     (push (make-link-end obj view name) refvalues)))
    (funcall (obj-data-func view) obj strm (nreverse refvalues))))

(defun obj-data (obj view)
  "Returns the objects data as a string. Used by common-graphics outline function"
  (with-output-to-string (s) (fmt-obj-data-plain obj view s)))

;;; Display method for objects


(defun load-all-subobjects (objs)
  "Load all subobjects if they have not already been loaded."
  (dolist (obj (mklist objs))
    (dolist (subobj (hyperobject-class-subobjects obj))
      (awhen (slot-value obj (name-slot subobj))
	     (load-all-subobjects it))))
  objs)

(defun view-hyperobject (objs view category strm &optional (indent 0) filter
			 subobjects refvars)
  "Display a single or list of hyperobject-class instances and their subobjects"
  (declare (fixnum indent))
  (let-when (objlist (mklist objs))
    (let ((nobjs (length objlist))
	  (*print-pretty* nil)
	  (*print-circle* nil)
	  (*print-escape* nil)
	  (*print-readably* nil)
	  (*print-length* nil)
	  (*print-level* nil))
      (fmt-list-start (car objlist) view strm indent nobjs)
      (dolist (obj objlist)
        (unless (and filter (not (funcall filter obj)))
          (fmt-obj-start obj view strm indent)
          (fmt-obj-data obj view strm (1+ indent) refvars)
          (when (and subobjects (hyperobject-class-subobjects obj))
	    (dolist (subobj (hyperobject-class-subobjects obj))
	      (aif (slot-value obj (name-slot subobj))
		   (view-hyperobject it (get-category-view (car (mklist it)) category)
				     category strm (1+ indent) filter
				     subobjects	refvars))))
	  (fmt-obj-end obj view strm indent)))
      (fmt-list-end (car objlist) view strm indent nobjs)))
  objs)


(defun view (objs &key (stream *standard-output*) category view
	     filter subobjects refvars file-wrapper)
  "EXPORTED Function: prints hyperobject-class objects. Simplies call to view-hyperobject"
  (let-when (objlist (mklist objs))
    (when category
      (setq view (get-category-view (car objlist) category)))
    (unless view
      (setq view (default-view (class-of (car objlist)))))
    (when file-wrapper
      (fmt-file-start view stream))
    (view-hyperobject objlist view category stream 0 filter subobjects refvars)
    (when file-wrapper
      (fmt-file-end view stream)))
  objs)


;;; Misc formatting

(defun fmt-comma-integer (i)
  (format nil "~:d" i))