(define-module (pastebin httpserver))

(use-modules (web request)

             (web response)

             (web uri)

             (sxml simple)

             (pastebin data)

             (rnrs bytevectors)

             (ice-9 textual-ports)

             (ice-9 binary-ports)

             (ice-9 regex)

             (ice-9 match)

             (srfi srfi-1))

(export make-pastebin-handler)

(define (read-parts reqbody boundary)

  (define b2 (string-append "(\r\n)?--" boundary))

  (let A ((start 0) (parts '()))

    (let ((sm (string-match b2 reqbody start)))

      (if sm

          ;; +2 => CRLF

          (A (+ 2 (match:end sm 0))

             (cons (substring reqbody start (match:start sm 0)) parts))

          (cdr (reverse parts))))))

(define (get-new-pin str pin)

  (let ((crlfi (string-contains str "\r\n" pin)))

    (if crlfi crlfi (string-length str))))

(define (parse-part partstr)

  (let A ((headers '()) (pin 0))

    (let* ((newpin (get-new-pin partstr pin))

           (line (substring partstr pin newpin)))

      (if (string-null? line)

          (cons (reverse headers) (substring partstr (+ 2 newpin)))

          (A (cons line headers) (+ 2 newpin))))))

(define (get-content-dispo-name-from-headers headers)

  (let ((fl (find (lambda (line) (string-prefix-ci? "content-disposition: " line)) headers)))

    (if fl

        (let ((sm (string-match "name=(.*)" fl)))

          (if sm (string-trim-both (match:substring sm 1) #\") ""))

        "")))

(define (read-multipart-form-data reqbody boundary)

  (define parts (read-parts reqbody boundary))

  (map

   (lambda (part)

     (let ((pp (parse-part part)))

       (cons (get-content-dispo-name-from-headers (car pp)) (cdr pp))))

   parts))

(define (templatize title body)

  `(html (head

          (title ,title)

          (meta (@ (name "viewport") (content "width=device-width, initial-scale=1"))))

         (body ,@body)))

(define (make-raw-link-pb-entry pb-id)

  `(a (@ (href ,(format #f "/raw/~a" pb-id))) "raw"))

(define (make-pastebin-handler data-path)

  (lambda (request request-body)

    (if (eq? (request-method request) 'POST)

        (let* ((headers (request-headers request))

               (content-type-all (assq-ref headers 'content-type))

               (content-type (if content-type-all (car content-type-all) #f))

               (boundary (if (eq? content-type 'multipart/form-data)

                             (assq-ref (cdr content-type-all) 'boundary) #f))

               (reqbody-string (utf8->string request-body)))

          (if boundary

              (let ((form-data (read-multipart-form-data reqbody-string boundary)))

                (call-with-dir-as-pb-data

                 data-path

                 (lambda (pb-data)

                   (pb-data-new-entry pb-data

                                      (assoc-ref form-data "text"))))))))

    ;; match raw file

    (match (split-and-decode-uri-path (uri-path (request-uri request)))

      (("raw" pb-id)

       (values (build-response

                #:code 200

                #:headers `((content-type . (text/plain))))

               (lambda (port)

                 (call-with-input-file

                     ;; the file name

                     (call-with-dir-as-pb-data data-path

                                               (lambda (p) (pb-get-file-path p pb-id)))

                   ;; the input port

                   (lambda (inport)

                     (let A ((inport' inport))

                       (let ((bv (get-bytevector-n inport' 4096)))

                         (if (not (eof-object? bv))

                             (begin

                               (put-bytevector port bv)

                               (A inport'))))))))))

      ;; match everything else

      (_

       (values (build-response

                #:code 200

                #:headers `((content-type . (text/html))))

               (lambda (port)

                 (let* ((top5 (call-with-dir-as-pb-data

                               data-path

                               (lambda (pb-data) (pb-data-get-top pb-data 5))))

                        (sxml (templatize

                               "pastebin"

                               `((form (@ (method "post") (enctype "multipart/form-data"))

                                       (textarea (@ (name "text")) "") (input (@ (type "submit"))))

                                 (table (@ (border 1)) (tr (th "id") (th "text") (th ""))

                                        ,(map (lambda (entry)

                                                `(tr (td ,(pb-entry-id entry))

                                                     (td ,(pb-entry-text entry))

                                                     (td ,(make-raw-link-pb-entry (pb-entry-id entry)))))

                                              top5))))))

                   (display "<!DOCTYPE html>\n" port)

                   (sxml->xml sxml port))))))))