var RedirectHttp = {
<% configs.each do |(key, value)| %>
  <%= key %>: <%= value.to_json %>,
<% end %>
  
  // Generates a redirection input with the specified value.  Inputs
  // have names like '<%= prefix %>[key]' to prevent collisions and
  // facilitate parsing server-side.
  redirect_input: function(key, value) {
    var input = document.createElement("input"); 
    input.setAttribute("id", '<%= prefix %>[' + key + ']');
    input.setAttribute("name", '<%= prefix %>[' + key + ']');
    input.setAttribute("type", 'hidden');
    input.setAttribute("value", value);
    return input;
  },
  
  // Redirect the form, adds the redirection inputs, and then submits the
  // form, if submit is true or undefined.  After submit, the redirection
  // inputs are removed from the form.
  redirect_form: function(form, submit) {
    if(typeof submit == 'undefined') { submit = true };
    
    if(submit) {
      
      // form.submit() raises an error if an input is named submit
      // (note you're hosed if the input is not type=submit)
      var submit_inputs = [];
      var inputs = document.getElementsByTagName('input');
      for(i=0; i<inputs.length; i++) {
        var input = inputs[i];
        if(input.getAttribute('type') == 'submit' && input.getAttribute('name') == 'submit') {
          input.setAttribute('name', '<%= prefix %>submit');
          submit_inputs.push(input);
        }
      }
      
      // set redirection inputs
      var original_action = form.getAttribute('<%= prefix %>original_action');
      var redirect_inputs = [
<% configs.each do |(key, value)| %>
        RedirectHttp.redirect_input('<%= key %>', RedirectHttp.<%= key %>),
<% end %>
        RedirectHttp.redirect_input('original_action', original_action)
      ];
      form.setAttribute('action', '<%= redirect_action %>');
      for(i=0; i<redirect_inputs.length; i++) { form.appendChild(redirect_inputs[i]); }
      
      form.submit();
      
      // reset redirection inputs
      form.setAttribute('action', original_action);
      for(i=0; i<redirect_inputs.length; i++) { form.removeChild(redirect_inputs[i]); }
      
      if(RedirectHttp.submit_request) {
        this.revert();
        form.submit();
      };
      
      // reset the submit inputs
      for(i=0; i<submit_inputs.length; i++) {
        var input = submit_inputs[i];
        input.setAttribute('name', 'submit');
      }
    };
  },
  
  // Sumbits the redirected link with redirection parameters in the query
  // string, if submit is true or undefined.
  redirect_link: function(link, submit) {
    if(typeof submit == 'undefined') { submit = true };
    
    if(submit) {
      var original_href = link.getAttribute('<%= prefix %>original_href');
      redirect_params = [
<% configs.each do |(key, value)| %>
        escape('<%= prefix %>[<%= key %>]') + "=" + escape(RedirectHttp.<%= key %>),
<% end %>
        '<%= prefix %>[original_action]=' + escape(original_href)
      ];
      location.href = '<%= redirect_action %>?' + redirect_params.join("&").replace(/%20/g, "+");
      
      if(RedirectHttp.submit_request) {
        this.revert();
        location.href = link.getAttribute("href");
      };
    };
  },
  
  // Wraps the current onX event so that it may be called without interfering
  // with the redirection (ie wrapper).  Note events are not called again
  // when a form is submitted or a redirection is performed by the wrapper.
  wrap: function(current, wrapper) {
    return "try {" +
    "  var <%= prefix %>result = function(<%= prefix %>this) { " + 
        current.replace(/(\W)this(?=\W)/g, "$1<%= prefix %>this") +
    "  }(this);" + 
    "  RedirectHttp." + wrapper + "(this, <%= prefix %>result);" +
    "} catch(ex) {" +
      "alert('Error during redirection: ' + ex.message + '\\nOriginal onsubmit: " + current.replace(/'/g, "\\'") + "');" +
    "}; return false;"
  },
  
  // Redirects forms and links to '<%= redirect_action %>'
  redirect: function() {    
    try {
      
      // redirect forms to the redirect_action
      var forms = document.getElementsByTagName('form');
      for(i=0; i<forms.length; i++) {
        var form = forms[i];
        
        // do not redirect forms related to <%= prefix %>
        if(form.getAttribute("class") != "<%= prefix %>form") {
          
          // store the original action
          form.setAttribute("<%= prefix %>original_action",  form.getAttribute('action'));
          
          // redirect onSubmit
          var current_on_submit = '';
          if(form.hasAttribute("onSubmit")) current_on_submit = form.getAttribute("onSubmit");
          var on_submit = RedirectHttp.wrap(current_on_submit, 'redirect_form');
        
          form.setAttribute("onSubmit", on_submit);
          form.setAttribute("<%= prefix %>original_callback", current_on_submit);
        }
      }
      
      // redirect links to the redirect_action
      var links = document.getElementsByTagName('a');
      for(i=0; i<links.length; i++) {
        var link = links[i];
        
        // do not redirect links related to <%= prefix %>
        if(link.getAttribute("class") != "<%= prefix %>link") {
          
          // store the original href
          link.setAttribute("<%= prefix %>original_href", link.getAttribute("href"));
        
          // redirect onClick
          var current_on_click = '';
          if(link.hasAttribute("onClick")) current_on_click = link.getAttribute("onClick");
          var on_click = RedirectHttp.wrap(current_on_click, 'redirect_link');
        
          link.setAttribute("onClick", on_click);
          link.setAttribute("<%= prefix %>original_callback", current_on_click);
        };
      }
      
    } catch(ex) {
      alert_error(ex);
    }
  },
  
  // Reverts redirection and removes the redirection div
  revert: function() {
    try {
      
      // redirect forms back to original actions
      var forms = document.getElementsByTagName('form');
      for(i=0; i<forms.length; i++) {
        var form = forms[i];
      
        // check in case the form was not redirected
        if(form.hasAttribute('<%= prefix %>original_action')) {
          form.setAttribute('action', form.getAttribute('<%= prefix %>original_action'));
          form.removeAttribute('<%= prefix %>original_action');
          
          form.setAttribute('onSubmit', form.getAttribute('<%= prefix %>original_callback'));
          form.removeAttribute('<%= prefix %>original_callback');
        }
      }
      
      // redirect links back to original hrefs
      var links = document.getElementsByTagName('a');
      for(i=0; i<links.length; i++) {
        var link = links[i];
        
        // check in case the link was not redirected
        if(link.hasAttribute('<%= prefix %>original_href')) {
          link.setAttribute('href', link.getAttribute('<%= prefix %>original_href'));
          link.removeAttribute('<%= prefix %>original_href');
          
          link.setAttribute('onClick', link.getAttribute('<%= prefix %>original_callback'));
          link.removeAttribute('<%= prefix %>original_callback');
        }
      }
      
    } catch(ex) {
      alert_error(ex);
    }
    
    // remove self
    var redirect_http = document.getElementById("<%= prefix %>")
    if(redirect_http) document.body.removeChild(redirect_http);
  },
  
  // Alerts errors due to RedirectHttp
  alert_error: function(ex) {
    alert("Redirect HTTP Error: " + ex.message + "\n\n The webpage may have been corrupted; be sure to refresh.");
  }
};