;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10; Package: modlisp -*-
;;;; *************************************************************************
;;;; FILE IDENTIFICATION
;;;;
;;;; Name:          utils.lisp
;;;; Purpose:       Utility functions for modlisp package
;;;; Programmer:    Kevin M. Rosenberg
;;;; Date Started:  Dec 2002
;;;;
;;;; $Id$
;;;; *************************************************************************

(in-package #:modlisp)

(defun format->string (fmt)
  (case fmt
    (:html "text/html")
    (:xml "text/xml")
    (:text "text/plain")
    (otherwise fmt)))

(defun format-string (fmt headers)
 `(("Content-Type" .
    ,(format->string fmt))
   . ,headers))

(defmacro write-response ((&key headers len (status "200 OK")) &body body)
  (let ((result (gensym "RES-")))
   `(progn
      (write-header-line "Status" ,status)
      (dolist (hdr ,headers)
        (write-header-line (car hdr) (cdr hdr)))
    ,@(and len
        `((write-header-line "Content-Length" ,len)
          (write-header-line "Keep-Socket" "1")
          (write-header-line "Connection" "Keep-Alive")))
      (write-string "end" *modlisp-socket*)
      (write-char #\NewLine *modlisp-socket*)
      (let ((,result (progn ,@body)))
        (,(if len 'force-output 'finish-output)  *modlisp-socket*)
        (setq *close-modlisp-socket* ,(not len))
        ,result))))

(defmacro with-ml-page ((&key (format :html) (precompute t) headers)
                        &body body)
  (if precompute
    `(output-ml-page ,format (with-output-to-string (*modlisp-socket*) ,@body) :headers ,headers)
    `(write-response (:headers (format-string ,format ,headers)) ,@body)))

(defun redirect-to-location (url)
  (write-response (:status "307 Temporary Redirect" :headers `(("Location" . ,url)))))

(defmacro output-ml-page (format html &key headers)
  (let ((str (gensym "STR-")))
   `(let ((,str ,html))
      (write-response (:len (format nil "~d" (length ,str))
                       :headers (format-string ,format ,headers))
        (write-string ,str *modlisp-socket*)))))

(defun output-html-page (str &key headers)
  (output-ml-page :html str :headers headers))

(defun output-xml-page (str &key headers)
  (output-ml-page :xml str :headers headers))

;; Utility functions for library users

(defun query-to-alist (posted-string &key (keyword t))
  "Converts a posted string to an assoc list of keyword names and values,
\"a=1&bc=demo\" => ((:a . \"1\") (:bc . \"demo\"))"
  (when posted-string
    (let ((alist '()))
      (dolist (name=val (kmrcl:delimited-string-to-list posted-string #\&)
               (nreverse alist))
        (let ((name-val-list (kmrcl:delimited-string-to-list name=val #\=)))
          (if (= 2 (length name-val-list))
            (destructuring-bind (name val) name-val-list
              (push (cons (if keyword
                              (kmrcl:ensure-keyword name)
                            name)
                          (kmrcl:decode-uri-query-string val))
                    alist))
            (cmsg-c :debug "Invalid number of #\= in ~S" name-val-list)))))))