#!/bin/sh
 # -*- tcl -*- \
 exec tclsh8.3 $0 ${1+"$@"}
 
 package require Tcl 8.3
 
 if {![catch { package require nstcl-html }] &&
     ![catch { package require nstcl-http }]} {
     namespace import nstcl::*
 } else {
     package require http
 
     proc ns_geturl {url} {
         set conn [http::geturl $url]
         set html [http::data $conn]
         http::cleanup $conn
         return $html
     }
 
     proc ns_urlencode {string} {
         set allowed_chars  {[a-zA-Z0-9]}
         set encoded_string ""
      
         foreach char [split $string ""] {
             if {[string match $allowed_chars $char]} {
                 append encoded_string $char
             } else {
                 scan $char %c ascii
                 append encoded_string %[format %02x $ascii]
             }
         }
      
         return $encoded_string
     }
 
     proc util_httppost {url formvars} {
         set conn [http::geturl $url -query $formvars]
         set html [http::data $conn]
         http::cleanup $conn
         return $html
     }
 }
 
 
 proc environment {default args} {
     foreach arg $args {
         if {[info exists ::env($arg)] && [string length $::env($arg)]} {
             return $::env($arg)
         }
     }
     return $default
 }
 
 
 proc editor {} {
     if {$::tcl_platform(platform) == "unix"} {
         set default vi
     } else {
         set default notepad
     }
     return [environment $default EDITOR Editor editor]
 }
 
 
 proc temp_directory {} {
     return [environment [pwd] TEMP Temp temp TMP Tmp tmp TEMPDIR Tempdir]
 }
 
 
 proc abort {reason} {
     puts stderr $reason
     exit 1
 }
 
  
 proc editfile {file} {
     global tcl_platform
 
     if {$tcl_platform(platform) == "unix"} {
         package require Expect
         log_user 0
         spawn [editor] $file
         interact
     } else {
         exec [editor] $file
     }
 }
 
    
 proc main {page} {
     set wiki https://wiki.tcl-lang.org
     set url  $wiki/[ns_urlencode $page]
 
     # Fetch the wiki page
     if {[catch { ns_geturl $url } html]} {
         abort "Error retrieveing $url: $html"
     }
     
     # find the edit URL
     if {![regexp {Edit <a href="((\d+)@)">} $html => edit page_num]} {
         abort "$url is not an editable page"
     }
     
     # Retrieve the edit page <form>
     if {[catch { ns_geturl https://wiki.tcl-lang.org/$edit } html]} {
         abort "Error fetching https://wiki.tcl-lang.org/$edit: $html"
     }
 
     set vars [list]
     
     # Figure out where the form is supposed to POST results to
     if {![regexp -nocase -- {form\s+[^<]*action="([^"]+)"} $html => action]} {
         abort "Couldn't figure out where to POST the edit to"
     }
     
     # normalize the action URL if it's not an absolute link
     switch -regexp -- $action {
         {(?i)^http} {}
         {^/*}       { set action https://wiki.tcl-lang.org$action }
         default     { set action https://wiki.tcl-lang.org/$action }
     }
     
     
     # Snag the existing content so we can edit it
     if {![regexp {(?i)(<textarea[^>]+>)([^<]*)<} $html => textarea content]} {
         abort "Couldn't find any editable content"
     }
     
     # Figure out what formvar we're supposed to pass the contents back as
     if {![regexp {(?i)name=['"]?([^'"\s]+)['"]} $textarea => textvar]} {
         abort "Couldn't figure out the name of the <textarea>"
     }
     
     # find and propagate all (hidden) form variables/defaults
     foreach input [regexp -inline -all -- {(?i)<input\s+[^>]+>} $html] {
         if {[regexp -nocase -- {name=['"]?([^'"\s]+)} $input => name]} {
             if {![regexp {(?i)value=['"]([^'"]+)['"]} $input => value]} {
                 set value ""
             }
 
             lappend vars [ns_urlencode $name]=[ns_urlencode $value]
         }
     }
 
 
     # unescape HTML entities     
     set content [string map [list "&amp;"   & \
                                   "&lt;"    < \
                                   "&gt;"    > \
                                   "&quot;" \"] $content]
     
     # compute the name of the temporary file to use
     set tmpfile [file join [temp_directory] wiki-$page_num.tmp]
      
     # file shouldn't exist ...
     if {[file exists $tmpfile]} {
         abort "Another edit already in progress? $tmpfile already exists"
     }
     
     # save existing wiki content to the temporary file
     if {[catch {
         set fp [open $tmpfile w]
         puts -nonewline $fp $content
         close $fp
     } problem]} {
         catch { file delete -force $tmpfile }
         abort "Error writing $tmpfile ($problem)"
     }
     
     # edit the file
     if {[catch { editfile $tmpfile } problem]} {
         catch { file delete -force $tmpfile }
         abort "Error occured trying to start the editor: $problem"
     }
     
     # read 
     if {[catch {
         set fp [open $tmpfile]
         set new_content [read $fp]
         close $fp
         file delete -force $tmpfile
     } problem]} {
         catch { file delete -force $tmpfile }
         abort "Error reading edited content: $problem"
     }
      
     # were there ANY changes at all?
     if {[string equal $content $new_content]} {
         # don't barf if stdout is closed
         catch { puts "No changes were made" }
         exit 0
     }
     
     lappend vars $textvar=[ns_urlencode $new_content]
 
     # POST the edited version
     if {[catch { util_httppost $action [join $vars &] } html]} {
         abort "Error uploading changes: $html"
     }
 
     switch -regexp -- $html {
         {Page saved\.\.\.} { set result "Wiki updated" }
         {Edit conflict}    { set result "Wiki NOT updated due to edit conflict" }
         default { 
             set result "Warning!: Not sure if the Wiki was updated or not..." 
         }
     }
 
     # don't barf if stdout is closed
     catch { puts $result }
 }
 
 
 if {[llength $argv] != 1} {
     abort "usage: wiki-edit page"
 } else {
     main [lindex $argv 0]
 }

     # find and propagate all (hidden) form variables/defaults
     foreach input [regexp -inline -all -- {(?i)<input\s+[^>]+>} $html] {
         if {[regexp -nocase -- {name=['"]?([^'"\s]+)} $input => name]} {
             if {![regexp {(?i)value=['"]([^'"]+)['"]} $input => value]} {
                 set value ""
             }
             ### hier mehrmals action='...', daher folgender HACK:
               if {"$name" == "Action" && "$value" == "Cancel"} {
               } else {
                  lappend vars [ns_urlencode $name]=[ns_urlencode $value]
               }
         }
     }