#lang scheme/base
(require scheme/class
         ffi/unsafe/atomic
         "syntax.rkt"
         "../unsafe/pango.rkt"
         "../unsafe/cairo.rkt"
         "font-syms.rkt"
         "font-dir.rkt"
         "local.rkt"
         "xp.rkt")

(provide font%
         font-list% the-font-list
         make-font
         family-symbol? style-symbol? weight-symbol? smoothing-symbol?
         get-pango-attrs
         get-face-list
         (protect-out substitute-fonts?
                      install-alternate-face))

(define-local-member-name 
  get-pango-attrs)

(define underlined-attrs (let ([l (pango_attr_list_new)])
                           (pango_attr_list_insert l (pango_attr_underline_new
                                                      PANGO_UNDERLINE_SINGLE))
                           l))
(define fallback-attrs (and xp? 
			    (let ([l (pango_attr_list_new)])
			      (pango_attr_list_insert l (pango_attr_fallback_new #f))
			      l)))

(define (size? v) (and (exact-positive-integer? v)
                       (v . <= . 1024)))

(define-local-member-name s-set-table-key)

(define font-descs (make-weak-hash))
(define ps-font-descs (make-weak-hash))
(define keys (make-weak-hash))

(define-syntax-rule (atomically e)
  (begin (start-atomic) (begin0 e (end-atomic))))

(define substitute-fonts? (memq (system-type) '(macosx windows)))
(define substitute-mapping (make-hasheq))

(define (install-alternate-face ch layout font desc attrs context)
  (or
   (for/or ([face (in-list 
                   (let ([v (hash-ref substitute-mapping (char->integer ch) #f)])
                     (cond
                      [(string? v) 
                       ;; found previously
                       (list v)]
                      [v 
                       ;; failed to find previously
                       null]
                      [else
                       ;; Hack: prefer Lucida Grande
                       (cons "Lucida Grande" (get-face-list))])))])
     (let ([desc (send (make-object font%
                                    (send font get-point-size)
                                    face
                                    (send font get-family)
                                    (send font get-style)
                                    (send font get-weight)
                                    (send font get-underlined)
                                    (send font get-smoothing)
                                    (send font get-size-in-pixels))
                       get-pango)])
       (and desc
            (let ([attrs (send font get-pango-attrs)])
              (pango_layout_set_font_description layout desc)
              (when attrs (pango_layout_set_attributes layout attrs))
              (and (zero? (pango_layout_get_unknown_glyphs_count layout))
                   (begin
                     (hash-set! substitute-mapping (char->integer ch) face)
                     #t))))))
   (begin
     (hash-set! substitute-mapping (char->integer ch) #t)
     ;; put old desc & attrs back
     (pango_layout_set_font_description layout desc)
     (when attrs (pango_layout_set_attributes layout attrs)))))

(define (has-screen-glyph? c font desc for-label?)
  (let* ([s (cairo_image_surface_create CAIRO_FORMAT_ARGB32 1 1)]
         [cr (cairo_create s)]
         [context (pango_cairo_create_context cr)]
         [layout (pango_layout_new context)]
	 ;; Under Windows XP, there's no font 
	 ;; fallback/substitution in control labels:
	 [no-subs? (and xp? for-label?)])
    (pango_layout_set_font_description layout desc)
    (pango_layout_set_text layout (string c))
    (when no-subs?
      (pango_layout_set_attributes layout fallback-attrs))
    (pango_cairo_update_layout cr layout)
    (begin0
     (or (zero? (pango_layout_get_unknown_glyphs_count layout))
         (and substitute-fonts?
	      (not no-subs?)
              (install-alternate-face c layout font desc #f context)
              (zero? (pango_layout_get_unknown_glyphs_count layout))))
     (g_object_unref layout)
     (g_object_unref context)
     (cairo_destroy cr)
     (cairo_surface_destroy s))))

(defclass font% object%

  (define table-key #f)
  (define/public (s-set-table-key k) (set! table-key k))

  (define cached-desc #f)
  (define ps-cached-desc #f)
  
  (define/public (get-pango)
    (create-desc #f 
                 cached-desc
                 font-descs
                 (lambda (d) (set! cached-desc d))))

  (define/public (get-ps-pango)
    (create-desc #t
                 ps-cached-desc
                 ps-font-descs
                 (lambda (d) (set! ps-cached-desc d))))

  (define/private (create-desc ps? cached-desc font-descs install!)
    (or cached-desc
        (let ([desc (atomically (hash-ref font-descs key #f))])
          (and desc
               (install! desc)
               desc))
        (let* ([desc (pango_font_description_new)])
          (pango_font_description_set_family desc 
                                             (if ps?
                                                 (send the-font-name-directory
                                                       get-post-script-name
                                                       id
                                                       weight
                                                       style)
                                                 (send the-font-name-directory
                                                       get-screen-name
                                                       id
                                                       weight
                                                       style)))
          (pango_font_description_set_style desc (case style
                                                   [(normal) PANGO_STYLE_NORMAL]
                                                   [(italic) PANGO_STYLE_ITALIC]
                                                   [(slant) PANGO_STYLE_OBLIQUE]))
          (pango_font_description_set_weight desc (case weight
                                                    [(normal) PANGO_WEIGHT_MEDIUM]
                                                    [(light) PANGO_WEIGHT_LIGHT]
                                                    [(bold) PANGO_WEIGHT_BOLD]))
          (if size-in-pixels?
              (pango_font_description_set_absolute_size desc (* size PANGO_SCALE))
              (pango_font_description_set_size desc (inexact->exact (floor (* size PANGO_SCALE)))))
          (install! desc)
          (atomically (hash-set! font-descs key desc))
          desc)))

  (define/public (get-pango-attrs)
    (if underlined?
        underlined-attrs
        #f))

  (define face #f)
  (def/public (get-face) face)

  (define family 'default)
  (def/public (get-family) family)

  (define size 12)
  (def/public (get-point-size) size)

  (define size-in-pixels? #f)
  (def/public (get-size-in-pixels) size-in-pixels?)

  (define smoothing 'default)
  (def/public (get-smoothing) smoothing)
  
  (define style 'normal)
  (def/public (get-style) style)

  (define underlined? #f)
  (def/public (get-underlined) underlined?)

  (define weight 'normal)
  (def/public (get-weight) weight)

  (def/public (get-font-id) id)
  (def/public (get-font-key) key)

  (def/public (screen-glyph-exists? [char? c]
                                    [any? [for-label? #f]])
    (has-screen-glyph? c this (get-pango) for-label?))

  (init-rest args)
  (super-new)
  (case-args 
   args
   [() (void)]
   [([size? _size]
     [family-symbol? _family]
     [style-symbol? [_style 'normal]]
     [weight-symbol? [_weight 'normal]]
     [any? [_underlined? #f]]
     [smoothing-symbol? [_smoothing 'default]]
     [any? [_size-in-pixels? #f]])
    (set! size _size)
    (set! family _family)
    (set! style _style)
    (set! weight _weight)
    (set! underlined? _underlined?)
    (set! smoothing _smoothing)
    (set! size-in-pixels? _size-in-pixels?)]
   [([size? _size]
     [(make-or-false string?) _face]
     [family-symbol? _family]
     [style-symbol? [_style 'normal]]
     [weight-symbol? [_weight 'normal]]
     [any? [_underlined? #f]]
     [smoothing-symbol? [_smoothing 'default]]
     [any? [_size-in-pixels? #f]])
    (set! size _size)
    (set! face (and _face (string->immutable-string _face)))
    (set! family _family)
    (set! style _style)
    (set! weight _weight)
    (set! underlined? _underlined?)
    (set! smoothing _smoothing)
    (set! size-in-pixels? _size-in-pixels?)]
   (init-name 'font%))

  (define id 
    (if face
        (send the-font-name-directory find-or-create-font-id face family)
        (send the-font-name-directory find-family-default-font-id family)))
  (define key
    (let ([key (vector id size style weight underlined? smoothing size-in-pixels?)])
      (let ([old-key (atomically (hash-ref keys key #f))])
        (if old-key
            (weak-box-value old-key)
            (begin
              (atomically (hash-set! keys key (make-weak-box key)))
              key))))))

;; ----------------------------------------

(defclass font-list% object%
  (define fonts (make-weak-hash))
  (super-new)
  (define/public (find-or-create-font . args)
    (let ([key
           (case-args 
            args
            [([size? size]
              [family-symbol? family]
              [style-symbol? [style 'normal]]
              [weight-symbol? [weight 'normal]]
              [any? [underlined? #f]]
              [smoothing-symbol? [smoothing 'default]]
              [any? [size-in-pixels? #f]])
             (vector size family style weight underlined? smoothing size-in-pixels?)]
            [([size? size]
              [(make-or-false string?) face]
              [family-symbol? family]
              [style-symbol? [style 'normal]]
              [weight-symbol? [weight 'normal]]
              [any? [underlined? #f]]
              [smoothing-symbol? [smoothing 'default]]
              [any? [size-in-pixels? #f]])
             (vector size (and face (string->immutable-string face)) family
                     style weight underlined? smoothing size-in-pixels?)]
            (method-name 'find-or-create-font font-list%))])
      (atomically
       (let ([e (hash-ref fonts key #f)])
         (or (and e
                  (ephemeron-value e))
             (let* ([f (apply make-object font% (vector->list key))]
                    [e (make-ephemeron key f)])
               (send f s-set-table-key key)
               (hash-set! fonts key e)
               f)))))))

(define the-font-list (new font-list%))

(define (get-face-list [mode 'all])
  (sort
   (map pango_font_family_get_name
	(let ([fams (pango_font_map_list_families
		     (pango_cairo_font_map_get_default))])
	  (if (eq? mode 'mono)
	      (filter pango_font_family_is_monospace fams)
	      fams)))
   string<?))

(define (make-font #:size [size 12]
                   #:face [face #f]
                   #:family [family 'default]
                   #:style [style 'normal]
                   #:weight [weight 'normal]
                   #:underlined? [underlined? #f]
                   #:smoothing [smoothing 'default]
                   #:size-in-pixels? [size-in-pixels? #f])
  (unless (size? size) (raise-type-error 'make-font "exact integer in [1, 1024]" size))
  (unless (or (not face) (string? face)) (raise-type-error 'make-font "string or #f" face))
  (unless (family-symbol? family) (raise-type-error 'make-font "family-symbol" family))
  (unless (style-symbol? style) (raise-type-error 'make-font "style-symbol" style))
  (unless (weight-symbol? weight) (raise-type-error 'make-font "weight-symbol" weight))
  (unless (smoothing-symbol? smoothing) (raise-type-error 'make-font "smoothing-symbol" smoothing))
  (make-object font% size face family style weight underlined? smoothing size-in-pixels?))
