var availableCommands    = {};
var keyToCommandRegistry = {};

function addCommand(command, description, isBackgroundCommand) {
  if (availableCommands[command])
  {
    console.log(command, "is already defined! Check commands.js for duplicates.");
    return;
  }

  availableCommands[command] = { description: description, isBackgroundCommand: isBackgroundCommand };
}

function mapKeyToCommand(key, command) {
  if (!availableCommands[command])
  {
    console.log(command, "doesn't exist!");
    return;
  }

  keyToCommandRegistry[key] = { command: command, isBackgroundCommand: availableCommands[command].isBackgroundCommand };
}

function unmapKey(key) { delete keyToCommandRegistry[key]; }

function parseCustomKeyMappings(customKeyMappings) {
  lines = customKeyMappings.split("\n");

  for (var i = 0; i < lines.length; i++) {
    if (lines[i][0] == "\"" || lines[i][0] == "#") { continue }
    split_line = lines[i].split(" "); // TODO(ilya): Support all whitespace.
    if (split_line.length < 2) { continue }

    var lineCommand = split_line[0];
    var key         = split_line[1];

    if (lineCommand == "map") {
      if (split_line.length != 3) { continue }

      var vimiumCommand = split_line[2];

      if (!availableCommands[vimiumCommand]) { continue }

      console.log("Mapping", key, "to", vimiumCommand);
      mapKeyToCommand(key, vimiumCommand);
    }
    else if (lineCommand == "unmap") {
      console.log("Unmapping", key);
      unmapKey(key);
    }
  }
}

// Navigating the current page:
addCommand('showHelp',            'Show help.',  true);
addCommand('scrollDown',          'Scroll down.');
addCommand('scrollUp',            'Scroll up.');
addCommand('scrollLeft',          'Scroll left.');
addCommand('scrollRight',         'Scroll right.');
addCommand('scrollToTop',         'Scroll to the top of the page.');
addCommand('scrollToBottom',      'Scroll to the bottom of the page.');
addCommand('scrollPageDown',      'Scroll a page up.');
addCommand('scrollPageUp',        'Scroll a page down.');
addCommand('scrollFullPageDown',  'Scroll a full page down.');
addCommand('scrollFullPageUp',    'Scroll a full page up.');

addCommand('reload',              'Reload the page.');
addCommand('toggleViewSource',    'View page source.');
addCommand('zoomIn',              'Zoom in.');
addCommand('zoomOut',             'Zoom out.');
addCommand('copyCurrentUrl',      'Copy the current URL to the clipboard.');

addCommand('enterInsertMode',     'Enter insert mode.');

addCommand('activateLinkHintsMode',               'Enter link hints mode to open links in current tab.');
addCommand('activateLinkHintsModeToOpenInNewTab', 'Enter link hints mode to open links in new tab.');

addCommand('enterFindMode',        'Enter find mode.');
addCommand('performFind',          'Cycle forward to the next find match.');
addCommand('performBackwardsFind', 'Cycle backward to the previous find match.');

// Navigating your history:
addCommand('goBack',              'Go back in history.');
addCommand('goForward',           'Go forward in history.');

// Manipulating tabs:
addCommand('nextTab',             'Go one tab right.',  true);
addCommand('previousTab',         'Go one tab left.',   true);
addCommand('createTab',           'Create new tab.',    true);
addCommand('removeTab',           'Close current tab.', true);
addCommand('restoreTab',          "Restore closed tab.", true);


// An ordered listing of all available commands, grouped by type. This is the order they will
// be shown in the help page.
var commandGroups = {
  pageNavigation:
    ["scrollDown", "scrollUp", "scrollLeft", "scrollRight",
     "scrollToTop", "scrollToBottom", "scrollPageDown", "scrollPageUp", "scrollFullPageDown",
     "reload", "toggleViewSource", "zoomIn", "zoomOut", "copyCurrentUrl",
     "enterInsertMode", "activateLinkHintsMode", "activateLinkHintsModeToOpenInNewTab",
     "enterFindMode", "performFind", "performBackwardsFind"],
  historyNavigation:
    ["goBack", "goForward"],
  tabManipulation:
    ["nextTab", "previousTab", "createTab", "removeTab", "restoreTab"]
};

mapKeyToCommand('?', 'showHelp');
mapKeyToCommand('j', 'scrollDown');
mapKeyToCommand('k', 'scrollUp');
mapKeyToCommand('h', 'scrollLeft');
mapKeyToCommand('l', 'scrollRight');
mapKeyToCommand('gg', 'scrollToTop');
mapKeyToCommand('G', 'scrollToBottom');
mapKeyToCommand('<c-e>', 'scrollDown');
mapKeyToCommand('<c-y>', 'scrollUp');
mapKeyToCommand('<c-d>', 'scrollPageDown');
mapKeyToCommand('<c-u>', 'scrollPageUp');
mapKeyToCommand('<c-f>', 'scrollFullPageDown');
mapKeyToCommand('<c-b>', 'scrollFullPageUp');
mapKeyToCommand('r', 'reload');
mapKeyToCommand('gf', 'toggleViewSource');

mapKeyToCommand('i', 'enterInsertMode');

mapKeyToCommand('ba', 'goBack');
mapKeyToCommand('H', 'goBack');
mapKeyToCommand('fw', 'goForward');
mapKeyToCommand('fo', 'goForward');
mapKeyToCommand('L', 'goForward');

mapKeyToCommand('zi', 'zoomIn');
mapKeyToCommand('zo', 'zoomOut');

mapKeyToCommand('f', 'activateLinkHintsMode');
mapKeyToCommand('F', 'activateLinkHintsModeToOpenInNewTab');

mapKeyToCommand('/', 'enterFindMode');
mapKeyToCommand('n', 'performFind');
mapKeyToCommand('N', 'performBackwardsFind');

mapKeyToCommand('yy', 'copyCurrentUrl');

mapKeyToCommand('K', 'nextTab');
mapKeyToCommand('J', 'previousTab');
mapKeyToCommand('gt', 'nextTab');
mapKeyToCommand('gT', 'previousTab');

mapKeyToCommand('t', 'createTab');
mapKeyToCommand('d', 'removeTab');
mapKeyToCommand('u', 'restoreTab');