1 files changed, 210 insertions, 0 deletions
diff --git a/src/components/follow.js b/src/components/follow.js
new file mode 100644
index 0000000..4fe4c58
--- /dev/null
+++ b/src/components/follow.js
@@ -0,0 +1,210 @@
+import * as followActions from '../actions/follow';
+import messages from '../content/messages';
+import Hint from '../content/hint';
+import HintKeyProducer from '../content/hint-key-producer';
+
+const DEFAULT_HINT_CHARSET = 'abcdefghijklmnopqrstuvwxyz';
+
+const availableKey = (keyCode) => {
+  return (
+    KeyboardEvent.DOM_VK_0 <= keyCode && keyCode <= KeyboardEvent.DOM_VK_9 ||
+    KeyboardEvent.DOM_VK_A <= keyCode && keyCode <= KeyboardEvent.DOM_VK_Z
+  );
+};
+
+const isNumericKey = (code) => {
+  return KeyboardEvent.DOM_VK_0 <= code && code <= KeyboardEvent.DOM_VK_9;
+};
+
+const isAlphabeticKey = (code) => {
+  return KeyboardEvent.DOM_VK_A <= code && code <= KeyboardEvent.DOM_VK_Z;
+};
+
+const inWindow = (window, element) => {
+  let {
+    top, left, bottom, right
+  } = element.getBoundingClientRect();
+  return (
+    top >= 0 && left >= 0 &&
+    bottom <= (window.innerHeight || document.documentElement.clientHeight) &&
+    right <= (window.innerWidth || document.documentElement.clientWidth)
+  );
+};
+
+export default class FollowComponent {
+  constructor(wrapper, store) {
+    this.wrapper = wrapper;
+    this.store = store;
+    this.hintElements = {};
+    this.state = {};
+
+    let doc = wrapper.ownerDocument;
+    doc.addEventListener('keydown', this.onKeyDown.bind(this));
+  }
+
+  update() {
+    let prevState = this.state;
+    this.state = this.store.getState();
+    if (!prevState.enabled && this.state.enabled) {
+      this.create();
+    } else if (prevState.enabled && !this.state.enabled) {
+      this.remove();
+    } else if (JSON.stringify(prevState.keys) !==
+      JSON.stringify(this.state.keys)) {
+      this.updateHints();
+    }
+  }
+
+  onKeyDown(e) {
+    if (!this.state.enabled) {
+      return;
+    }
+
+    let { keyCode } = e;
+    switch (keyCode) {
+    case KeyboardEvent.DOM_VK_ENTER:
+    case KeyboardEvent.DOM_VK_RETURN:
+      this.activate(this.hintElements[
+        FollowComponent.codeChars(this.state.keys)].target);
+      return;
+    case KeyboardEvent.DOM_VK_ESCAPE:
+      this.store.dispatch(followActions.disable());
+      return;
+    case KeyboardEvent.DOM_VK_BACK_SPACE:
+    case KeyboardEvent.DOM_VK_DELETE:
+      this.store.dispatch(followActions.backspace());
+      break;
+    default:
+      if (availableKey(keyCode)) {
+        this.store.dispatch(followActions.keyPress(keyCode));
+      }
+      break;
+    }
+
+    e.stopPropagation();
+    e.preventDefault();
+  }
+
+  updateHints() {
+    let chars = FollowComponent.codeChars(this.state.keys);
+    let shown = Object.keys(this.hintElements).filter((key) => {
+      return key.startsWith(chars);
+    });
+    let hidden = Object.keys(this.hintElements).filter((key) => {
+      return !key.startsWith(chars);
+    });
+    if (shown.length === 0) {
+      this.remove();
+      return;
+    } else if (shown.length === 1) {
+      this.activate(this.hintElements[chars].target);
+      this.remove();
+    }
+
+    shown.forEach((key) => {
+      this.hintElements[key].show();
+    });
+    hidden.forEach((key) => {
+      this.hintElements[key].hide();
+    });
+  }
+
+  activate(element) {
+    switch (element.tagName.toLowerCase()) {
+    case 'a':
+      if (this.state.newTab) {
+        // getAttribute() to avoid to resolve absolute path
+        let href = element.getAttribute('href');
+
+        // eslint-disable-next-line no-script-url
+        if (!href || href === '#' || href.startsWith('javascript:')) {
+          return;
+        }
+        return browser.runtime.sendMessage({
+          type: messages.OPEN_URL,
+          url: element.href,
+          newTab: this.state.newTab,
+        });
+      }
+      if (element.href.startsWith('http://') ||
+        element.href.startsWith('https://') ||
+        element.href.startsWith('ftp://')) {
+        return browser.runtime.sendMessage({
+          type: messages.OPEN_URL,
+          url: element.href,
+          newTab: this.state.newTab,
+        });
+      }
+      return element.click();
+    case 'input':
+      switch (element.type) {
+      case 'file':
+      case 'checkbox':
+      case 'radio':
+      case 'submit':
+      case 'reset':
+      case 'button':
+      case 'image':
+      case 'color':
+        return element.click();
+      default:
+        return element.focus();
+      }
+    case 'textarea':
+      return element.focus();
+    case 'button':
+      return element.click();
+    }
+  }
+
+  create() {
+    let doc = this.wrapper.ownerDocument;
+    let elements = FollowComponent.getTargetElements(doc);
+    let producer = new HintKeyProducer(DEFAULT_HINT_CHARSET);
+    let hintElements = {};
+    Array.prototype.forEach.call(elements, (ele) => {
+      let keys = producer.produce();
+      let hint = new Hint(ele, keys);
+      hintElements[keys] = hint;
+    });
+    this.hintElements = hintElements;
+  }
+
+  remove() {
+    let hintElements = this.hintElements;
+    Object.keys(this.hintElements).forEach((key) => {
+      hintElements[key].remove();
+    });
+  }
+
+  static codeChars(codes) {
+    const CHARCODE_ZERO = '0'.charCodeAt(0);
+    const CHARCODE_A = 'a'.charCodeAt(0);
+
+    let chars = '';
+
+    for (let code of codes) {
+      if (isNumericKey(code)) {
+        chars += String.fromCharCode(
+          code - KeyboardEvent.DOM_VK_0 + CHARCODE_ZERO);
+      } else if (isAlphabeticKey(code)) {
+        chars += String.fromCharCode(
+          code - KeyboardEvent.DOM_VK_A + CHARCODE_A);
+      }
+    }
+    return chars;
+  }
+
+  static getTargetElements(doc) {
+    let all = doc.querySelectorAll('a,button,input,textarea');
+    let filtered = Array.prototype.filter.call(all, (element) => {
+      let style = window.getComputedStyle(element);
+      return style.display !== 'none' &&
+        style.visibility !== 'hidden' &&
+        element.type !== 'hidden' &&
+        element.offsetHeight > 0 &&
+        inWindow(window, element);
+    });
+    return filtered;
+  }
+}