#lang scheme/base
(require "private/provide-structs.ss"
         scheme/serialize
         scheme/contract)

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

(define-struct collect-info (fp ht ext-ht parts tags gen-prefix relatives parents))
(define-struct resolve-info (ci delays undef searches))

(define (part-collected-info part ri)
  (hash-ref (collect-info-parts (resolve-info-ci ri))
            part))

(define (collect-put! ci key val)
  (let ([ht (collect-info-ht ci)])
    (let ([old-val (hash-ref ht key #f)])
      (when old-val
        (fprintf (current-error-port)
                 "WARNING: collected information for key multiple times: ~e; values: ~e ~e\n"
                 key old-val val))
    (hash-set! ht key val))))

(define (resolve-get/where part ri key)
  (let ([key (tag-key key ri)])
    (let ([v (hash-ref (if part
                         (collected-info-info (part-collected-info part ri))
                         (collect-info-ht (resolve-info-ci ri)))
                       key
                       #f)])
      (cond
        [v (values v #f)]
        [part (resolve-get/where
               (collected-info-parent (part-collected-info part ri))
               ri key)]
        [else
         (values (hash-ref (collect-info-ext-ht (resolve-info-ci ri)) key #f)
                 #t)]))))

(define (resolve-get/ext? part ri key)
  (let-values ([(v ext?) (resolve-get/where part ri key)])
    (when ext?
      (hash-set! (resolve-info-undef ri) (tag-key key ri) #t))
    (values v ext?)))

(define (resolve-get part ri key)
  (let-values ([(v ext?) (resolve-get/ext? part ri key)])
    v))

(define (resolve-get/tentative part ri key)
  (let-values ([(v ext?) (resolve-get/where part ri key)])
    v))

(define (resolve-search search-key part ri key)
  (let ([s-ht (hash-ref (resolve-info-searches ri)
                        search-key
                        (lambda ()
                          (let ([s-ht (make-hash)])
                            (hash-set! (resolve-info-searches ri)
                                       search-key s-ht)
                            s-ht)))])
    (hash-set! s-ht key #t))
  (resolve-get part ri key))

(define (resolve-get-keys part ri key-pred)
  (let ([l null])
    (hash-for-each
     (collected-info-info (part-collected-info part ri))
     (lambda (k v) (when (key-pred k) (set! l (cons k l)))))
    l))

(provide (struct-out collect-info)
         (struct-out resolve-info))

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

(provide tag?)
(define (tag? s)
  (and (pair? s)
       (symbol? (car s))
       (pair? (cdr s))
       (or (string? (cadr s))
           (generated-tag? (cadr s))
           (and (pair? (cadr s))
                (list? (cadr s))))
       (null? (cddr s))))

(provide block?)
(define (block? p)
  (or (paragraph? p)
      (table? p)
      (itemization? p)
      (nested-flow? p)
      (compound-paragraph? p)
      (delayed-block? p)
      (traverse-block? p)))

(define content-symbols
  #hasheq([nbsp . #t]
          [mdash . #t]
          [ndash . #t]
          [ldquo . #t]
          [rdquo . #t]
          [rsquo . #t]
          [prime . #t]
          [rarr . #t]
          [larr . #t]
          [alpha . #t]
          [infin . #t]
          [lang . #t]
          [rang . #t]))

(provide content?)
(define (content? v) 
  (or (string? v)
      (element? v)
      (and (list? v) (andmap content? v))
      (delayed-element? v)
      (traverse-element? v)
      (part-relative-element? v)
      (multiarg-element? v)
      (hash-ref content-symbols v #f)))

(provide element-style?)
(define (element-style? s)
  (or (style? s) (not s) (string? s) (symbol? s)))

(define (string-without-newline? s)
  (and (string? s)
       (not (regexp-match? #rx"\n" s))))

(provide-structs
 [part ([tag-prefix (or/c false/c string?)]
        [tags (listof tag?)]
        [title-content (or/c false/c content?)]
        [style style?]
        [to-collect list?]
        [blocks (listof block?)]
        [parts (listof part?)])]
 [paragraph ([style style?]
             [content content?])]
 [table ([style style?]
         [blockss (listof (listof (or/c block? (one-of/c 'cont))))])]
 [delayed-block ([resolve (any/c part? resolve-info? . -> . block?)])]
 [itemization ([style style?]
               [blockss (listof (listof block?))])]
 [nested-flow ([style style?]
               [blocks (listof block?)])]
 [compound-paragraph ([style style?]
                      [blocks (listof block?)])]

 [element ([style element-style?]
           [content content?])]
 [(toc-element element) ([toc-content content?])]
 [(target-element element) ([tag tag?])]
 [(toc-target-element target-element) ()]
 [(page-target-element target-element) ()]
 [(redirect-target-element target-element) ([alt-path path-string?]
                                            [alt-anchor string?])]
 [(link-element element) ([tag tag?])]
 [(index-element element) ([tag tag?]
                           [plain-seq (and/c pair? (listof string-without-newline?))]
                           [entry-seq (listof content?)]
                           [desc any/c])]
 [(image-element element) ([path (or/c path-string?
                                       (cons/c (one-of/c 'collects)
                                               (listof bytes?)))]
                           [suffixes (listof #rx"^[.]")]
                           [scale real?])]
 [multiarg-element ([style element-style?]
                    [contents (listof content?)])]

 [style ([name (or/c string? symbol? #f)]
         [properties list?])]
 ;; properties:
 [document-version ([text (or/c string? false/c)])]
 [target-url ([addr path-string?])]
 [color-property ([color (or/c string? (list/c byte? byte? byte?))])]
 [background-color-property ([color (or/c string? (list/c byte? byte? byte?))])]

 [table-columns ([styles (listof style?)])]
 [table-cells ([styless (listof (listof style?))])]

 [collected-info ([number (listof (or/c false/c integer?))]
                  [parent (or/c false/c part?)]
                  [info any/c])])

(provide plain)
(define plain (make-style #f null))

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

;; Traverse block has special serialization support:
(define-struct traverse-block (traverse)
  #:property
  prop:serializable
  (make-serialize-info
   (lambda (d)
     (let ([ri (current-serialize-resolve-info)])
       (unless ri
         (error 'serialize-traverse-block
                "current-serialize-resolve-info not set"))
       (vector (traverse-block-block d ri))))
   #'deserialize-traverse-block
   #f
   (or (current-load-relative-directory) (current-directory))))

(define block-traverse-procedure/c
  (recursive-contract
   ((symbol? any/c . -> . any/c)
    (symbol? any/c . -> . any)
    . -> . (or/c block-traverse-procedure/c
                 block?))))

(provide block-traverse-procedure/c)
(provide/contract
 (struct traverse-block ([traverse block-traverse-procedure/c])))

(provide deserialize-traverse-block)
(define deserialize-traverse-block
  (make-deserialize-info values values))

(define (traverse-block-block b i)
  (cond
   [(collect-info? i)
    (let ([p (hash-ref (collect-info-fp i) b #f)])
      (if (block? p)
          p
          (error 'traverse-block-block
                 "no block computed for traverse-block: ~e"
                 b)))]
   [(resolve-info? i)
    (traverse-block-block b (resolve-info-ci i))]))

(provide/contract
 [traverse-block-block (traverse-block?
                        (or/c resolve-info? collect-info?)
                        . -> . block?)])

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

;; Traverse element has special serialization support:
(define-struct traverse-element (traverse)
  #:property
  prop:serializable
  (make-serialize-info
   (lambda (d)
     (let ([ri (current-serialize-resolve-info)])
       (unless ri
         (error 'serialize-traverse-block
                "current-serialize-resolve-info not set"))
       (vector (traverse-element-content d ri))))
   #'deserialize-traverse-element
   #f
   (or (current-load-relative-directory) (current-directory))))

(define element-traverse-procedure/c
  (recursive-contract
   ((symbol? any/c . -> . any/c)
    (symbol? any/c . -> . any)
    . -> . (or/c element-traverse-procedure/c
                 content?))))

(provide/contract
 (struct traverse-element ([traverse element-traverse-procedure/c])))

(provide deserialize-traverse-element)
(define deserialize-traverse-element
  (make-deserialize-info values values))

(define (traverse-element-content e i)
  (cond
   [(collect-info? i)
    (let ([c (hash-ref (collect-info-fp i) e #f)])
      (if (content? c)
          c
          (error 'traverse-block-block
                 "no block computed for traverse-block: ~e"
                 e)))]
   [(resolve-info? i)
    (traverse-element-content e (resolve-info-ci i))]))

(provide element-traverse-procedure/c)
(provide/contract
 [traverse-element-content (traverse-element?
                            (or/c resolve-info? collect-info?)
                            . -> . content?)])

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

;; Delayed element has special serialization support:
(define-struct delayed-element (resolve sizer plain)
  #:property
  prop:serializable
  (make-serialize-info
   (lambda (d)
     (let ([ri (current-serialize-resolve-info)])
       (unless ri
         (error 'serialize-delayed-element
                "current-serialize-resolve-info not set"))
       (with-handlers ([exn:fail:contract?
                        (lambda (exn)
                          (error 'serialize-delayed-element
                                 "serialization failed (wrong resolve info? delayed element never rendered?); ~a"
                                 (exn-message exn)))])
         (vector (delayed-element-content d ri)))))
   #'deserialize-delayed-element
   #f
   (or (current-load-relative-directory) (current-directory))))

(provide/contract
 (struct delayed-element ([resolve (any/c part? resolve-info? . -> . list?)]
                          [sizer (-> any)]
                          [plain (-> any)])))

(provide deserialize-delayed-element)
(define deserialize-delayed-element
  (make-deserialize-info values values))

(provide delayed-element-content)
(define (delayed-element-content e ri)
  (hash-ref (resolve-info-delays ri) e))

(provide delayed-block-blocks)
(define (delayed-block-blocks p ri)
  (hash-ref (resolve-info-delays ri) p))

(provide current-serialize-resolve-info)
(define current-serialize-resolve-info (make-parameter #f))

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

;; part-relative element has special serialization support:
(define-struct part-relative-element (collect sizer plain)
  #:property
  prop:serializable
  (make-serialize-info
   (lambda (d)
     (let ([ri (current-serialize-resolve-info)])
       (unless ri
         (error 'serialize-part-relative-element
                "current-serialize-resolve-info not set"))
       (with-handlers ([exn:fail:contract?
                        (lambda (exn)
                          (error 'serialize-part-relative-element
                                 "serialization failed (wrong resolve info? part-relative element never rendered?); ~a"
                                 (exn-message exn)))])
         (vector
          (part-relative-element-content d ri)))))
   #'deserialize-part-relative-element
   #f
   (or (current-load-relative-directory) (current-directory))))

(provide/contract
 (struct part-relative-element ([collect (collect-info? . -> . list?)]
                                [sizer (-> any)]
                                [plain (-> any)])))

(provide deserialize-part-relative-element)
(define deserialize-part-relative-element
  (make-deserialize-info values values))

(provide part-relative-element-content)
(define (part-relative-element-content e ci/ri)
  (hash-ref (collect-info-relatives
             (if (resolve-info? ci/ri) (resolve-info-ci ci/ri) ci/ri))
            e))

(provide collect-info-parents)

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

;; Delayed index entry also has special serialization support.
;; It uses the same delay -> value table as delayed-element
(define-struct delayed-index-desc (resolve)
  #:mutable
  #:property
  prop:serializable 
  (make-serialize-info
   (lambda (d)
     (let ([ri (current-serialize-resolve-info)])
       (unless ri
         (error 'serialize-delayed-index-desc
                "current-serialize-resolve-info not set"))
       (with-handlers ([exn:fail:contract?
                        (lambda (exn)
                          (error 'serialize-index-desc
                                 "serialization failed (wrong resolve info?); ~a"
                                 (exn-message exn)))])
         (vector
          (delayed-element-content d ri)))))
   #'deserialize-delayed-index-desc
   #f
   (or (current-load-relative-directory) (current-directory))))

(provide/contract
 (struct delayed-index-desc ([resolve (any/c part? resolve-info? . -> . any)])))

(provide deserialize-delayed-index-desc)
(define deserialize-delayed-index-desc
  (make-deserialize-info values values))

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

(define-struct (collect-element element) (collect)
  #:mutable
  #:property
  prop:serializable
  (make-serialize-info
   (lambda (d)
     (vector (make-element
              (element-style d)
              (element-content d))))
   #'deserialize-collect-element
   #f
   (or (current-load-relative-directory) (current-directory))))

(provide deserialize-collect-element)
(define deserialize-collect-element
  (make-deserialize-info values values))

(provide/contract
 [struct collect-element ([style element-style?]
                          [content content?]
                          [collect (collect-info? . -> . any)])])

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

(define-struct (render-element element) (render)
  #:property
  prop:serializable
  (make-serialize-info
   (lambda (d)
     (vector (make-element
              (element-style d)
              (element-content d))))
   #'deserialize-render-element
   #f
   (or (current-load-relative-directory) (current-directory))))

(provide deserialize-render-element)
(define deserialize-render-element
  (make-deserialize-info values values))

(provide/contract
 [struct render-element ([style element-style?]
                         [content content?]
                         [render (any/c part? resolve-info? . -> . any)])])

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

(define-struct generated-tag ()
  #:property
  prop:serializable
  (make-serialize-info
   (lambda (g)
     (let ([ri (current-serialize-resolve-info)])
       (unless ri
         (error 'serialize-generated-tag
                "current-serialize-resolve-info not set"))
       (let ([t (hash-ref (collect-info-tags (resolve-info-ci ri)) g #f)])
         (if t
           (vector t)
           (error 'serialize-generated-tag
                  "serialization failed (wrong resolve info?)")))))
   #'deserialize-generated-tag
   #f
   (or (current-load-relative-directory) (current-directory))))

(provide (struct-out generated-tag))

(provide deserialize-generated-tag)
(define deserialize-generated-tag
  (make-deserialize-info values values))

(provide generate-tag tag-key
         current-tag-prefixes
         add-current-tag-prefix)

(define (generate-tag tg ci)
  (if (generated-tag? (cadr tg))
      (let ([t (cadr tg)])
        (list (car tg)
              (let ([tags (collect-info-tags ci)])
                (or (hash-ref tags t #f)
                    (let ([key (list* 'gentag
                                      (hash-count tags)
                                      (collect-info-gen-prefix ci))])
                      (hash-set! tags t key)
                      key)))))
      tg))

(define (tag-key tg ri)
  (if (generated-tag? (cadr tg))
      (list (car tg)
            (hash-ref (collect-info-tags (resolve-info-ci ri)) (cadr tg)))
      tg))

(define current-tag-prefixes (make-parameter null))
(define (add-current-tag-prefix t)
  (let ([l (current-tag-prefixes)])
    (if (null? l)
        t
        (cons (car t) (append l (cdr t))))))

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

(provide content->string
         strip-aux)

(define content->string
  (case-lambda
    [(c)
     (cond
       [(element? c) (content->string (element-content c))]
       [(multiarg-element? c) (content->string (multiarg-element-contents c))]
       [(list? c) (apply string-append (map content->string c))]
       [(part-relative-element? c) (content->string ((part-relative-element-plain c)))]
       [(delayed-element? c) (content->string ((delayed-element-plain c)))]
       [(string? c) c]
       [else (case c
               [(mdash) "---"]
               [(ndash) "--"]
               [(ldquo rdquo) "\""]
               [(rsquo) "'"]
               [(rarr) "->"]
               [(lang) "<"]
               [(rang) ">"]
               [else (format "~s" c)])])]
    [(c renderer sec ri)
     (cond
       [(and (link-element? c)
             (null? (element-content c)))
        (let ([dest (resolve-get sec ri (link-element-tag c))])
          ;; FIXME: this is specific to renderer
          (if dest
            (content->string (strip-aux
                              (if (pair? dest) (cadr dest) (vector-ref dest 1)))
                             renderer sec ri)
            "???"))]
       [(element? c) (content->string (element-content c) renderer sec ri)]
       [(multiarg-element? c) (content->string (multiarg-element-contents c) renderer sec ri)]
       [(list? c) (apply string-append
                         (map(lambda (e) (content->string e renderer sec ri))
                             c))]
       [(delayed-element? c)
        (content->string (delayed-element-content c ri) renderer sec ri)]
       [(part-relative-element? c)
        (content->string (part-relative-element-content c ri) renderer sec ri)]
       [else (content->string c)])]))

(define (aux-element? e)
  (and (element? e)
       (let ([s (element-style e)])
         (and (style? e)
              (memq 'aux (style-properties s))))))

(define (strip-aux content)
  (cond
    [(null? content) null]
    [(aux-element? content) null]
    [(list? content) (map strip-aux content)]
    [else content]))

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

(provide block-width
         content-width)

(define (content-width s)
  (cond
    [(string? s) (string-length s)]
    [(list? s) (for/fold ([v 0]) ([s (in-list s)]) (+ v (content-width s)))]
    [(element? s) (content-width (element-content s))]
    [(multiarg-element? s) (content-width (multiarg-element-contents s))]
    [(delayed-element? s) (content-width ((delayed-element-sizer s)))]
    [(part-relative-element? s) (content-width ((part-relative-element-sizer s)))]
    [else 1]))

(define (paragraph-width s)
  (content-width (paragraph-content s)))

(define (flow-width f)
  (apply max 0 (map block-width f)))

(define (block-width p)
  (cond
    [(paragraph? p) (paragraph-width p)]
    [(table? p) (table-width p)]
    [(itemization? p) (itemization-width p)]
    [(nested-flow? p) (nested-flow-width p)]
    [(compound-paragraph? p) (compound-paragraph-width p)]
    [(delayed-block? p) 1]
    [(eq? p 'cont) 0]))

(define (table-width p)
  (let ([blocks (table-blockss p)])
    (if (null? blocks)
      0
      (let loop ([blocks blocks])
        (if (null? (car blocks))
          0
          (+ (apply max 0 (map block-width (map car blocks)))
             (loop (map cdr blocks))))))))

(define (itemization-width p)
  (apply max 0 (map flow-width (itemization-blockss p))))

(define (nested-flow-width p)
  (+ 4 (apply max 0 (map block-width (nested-flow-blocks p)))))

(define (compound-paragraph-width p)
  (apply max 0 (map block-width (compound-paragraph-blocks p))))

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

(define (info-key? l)
  (and (pair? l)
       (symbol? (car l))
       (pair? (cdr l))))

(provide info-key?)
(provide/contract
 [part-collected-info (part? resolve-info? . -> . collected-info?)]
 [collect-put! (collect-info? info-key?  any/c . -> . any)]
 [resolve-get ((or/c part? false/c) resolve-info? info-key? . -> . any)]
 [resolve-get/tentative ((or/c part? false/c) resolve-info? info-key? . -> . any)]
 [resolve-get/ext? ((or/c part? false/c) resolve-info? info-key? . -> . any)]
 [resolve-search (any/c (or/c part? false/c) resolve-info? info-key? . -> . any)]
 [resolve-get-keys ((or/c part? false/c) resolve-info? (info-key? . -> . any/c) . -> . any/c)])
