$(document).ready( function() {
  // Lookup for UI components
  var cas_server_selection = $('#cas_server_selection');
  var select_server = $('#select_server');

  var div_cas_config = $('#cas_config');
  var ul_cas_config = div_cas_config.find('ul').first();

  var div_user_info = $('#user_info');
  var div_warnings = $('#warnings');

  var div_cas_logs = $('#cas_logs');
  var pre_cas_logs = div_cas_logs.find('pre').first();

  var login_btn = $('#login_btn');
  var caslogout_btn = $('#caslogout_btn');
  var locallogout_btn = $('#locallogout_btn');
  var truncatelog_btn = $('#truncatelog_btn');

  // Configure CAS servers selection (from API return)
  var configure_cas_server_selection = function(cas_servers, selected) {
    select_server.html('');
    if (!cas_servers || Object.keys(cas_servers).length <= 1) {
      cas_server_selection.css('display', 'none');
      return true;
    }
    for (var cas_host in cas_servers) {
      var option = $('<option value="'+cas_host+'">'+cas_host+'</option>');
      if (cas_host == selected)
        option.attr('selected', 'selected');
      select_server.append(option);
    }
    cas_server_selection.css('display', 'block');
  };

  // Show CAS configuration (from API return)
  var show_cas_config = function(cas_config) {
    ul_cas_config.html('');
    if (!cas_config) {
      div_cas_config.css('display', 'none');
      return true;
    }
    for (var key in cas_config) {
      var li = $('<li><strong>'+key+':</strong> <em>'+cas_config[key]+'</em></li>');
      ul_cas_config.append(li);
    }
    div_cas_config.css('display', 'block');
  };

  // Show warning messages (from API return)
  var show_warnings = function(warnings) {
    div_warnings.html('<h2>Warning messages</h2>');
    if (!warnings.length) {
      div_warnings.css('display', 'none');
      return true;
    }
    var ul = $('<ul>');
    $(warnings).each(function(idx, warning) {
      var li = $('<li>'+warning+'</li>');
      ul.append(li);
    });
    div_warnings.append(ul);
    div_warnings.css('display', 'block');
  };

  // Show phpCAS logs
  var show_cas_logs = function(logs) {
    pre_cas_logs.html('');
    if (!logs) {
      div_cas_logs.css('display', 'none');
      return true;
    }
    pre_cas_logs.html(logs);
    div_cas_logs.css('display', 'block');
  };

  // Show user information
  var show_user_info = function(username, attributes) {
    div_user_info.html('<h2>Connected user information</h2>');
    div_user_info.css('display', 'block');
    if (!username) {
      div_user_info.append('<p>Not connected</p>');
      return true;
    }
    var p_username = $('<p><strong>Username:</strong> <em>'+username+'</em></p>');
    div_user_info.append(p_username);

    div_user_info.append('<h3>Attributes</h3>');
    var ul = $('<ul>');
    if (attributes) {
      for (var attr in attributes) {
        var li = $('<li><strong>'+attr+':</strong> <em>'+attributes[attr]+':</em></li>');
        ul.append(li);
      }
    }
    else {
      ul.append($('<li>No attribute.</li>'));
    }
    div_user_info.append(ul);

  };

  // Handle API AJAX call return
  var handle_ajax_return = function(data) {
    configure_cas_server_selection(data.cas_servers, data.cas_server);
    show_warnings(data.warnings);
    show_cas_logs(data.logs);
    show_cas_config(data.config);
    show_user_info(data.user, data.attributes);
  };

  // Handle API AJAX call fail
  var handle_ajax_fail = function(jqXHR, textStatus, errorThrown) {
    alert('An error occurred during AJAX request: '+textStatus);
  };

  // Make an API AJAX call
  var make_ajax_call = function(action, data, callback) {
    if (!data) data = {};
    data['do'] = action;
    $.ajax(
      {type: "GET", url: 'index.php', data: data}
    ).done(function(data) {
      handle_ajax_return(data);
      if (callback) callback(data);
    }).fail(handle_ajax_fail);
  };

  // On select server change, make API call to change current server
  select_server.on('change', function(event) {
    make_ajax_call('change_server', {'server': select_server.val()});
  });

  // On local logout button click, make API call to trigger it
  locallogout_btn.on('click', function(event) {
    make_ajax_call('locallogout');
  });

  // On CAS logout button click, make API call to trigger it
  caslogout_btn.on('click', function(event) {
    make_ajax_call('logout', {}, function(data) {
      if (data.data && data.data.logout_url)
        window.location = data.data.logout_url;
    });
  });

  // On login button click, make API call to trigger it
  login_btn.on('click', function(event) {
    make_ajax_call('login', {}, function(data) {
      if (data.data && data.data.login_url)
        window.location = data.data.login_url;
    });
  });

  // On truncate log button click, make API call to trigger it
  if (truncatelog_btn) {
    truncatelog_btn.on('click', function(event) {
      make_ajax_call('truncatelog');
    });
  }

  // Check if CAS ticket is present in current URL
  var check_ticket_is_present = new RegExp('[\?&]ticket=([^&]+)');
  var ticket_data = check_ticket_is_present.exec(window.location);

  // If CAS ticket present, make API call to validate it
  if (ticket_data) {
    make_ajax_call('validate_ticket', {'ticket': ticket_data[1]}, function(data) {
      // If ticket is valid, clean current URI
      if (data.success)
        window.location = 'index.php';
    });
  }
  else {
    // if not CAS ticket present, make API call to get current status
    make_ajax_call('status');
  }
});