3 files changed, 79 insertions, 54 deletions

diff --git a/src/console/components/console.jsx b/src/console/components/console.jsx
index 23c93e3..7994f78 100644
--- a/src/console/components/console.jsx
+++ b/src/console/components/console.jsx
@@ -6,6 +6,8 @@ import Completion from './console/completion';
 import Message from './console/message';
 import * as consoleActions from '../../console/actions/console';
 
+const COMPLETION_MAX_ITEMS = 33;
+
 class ConsoleComponent extends Component {
   onBlur() {
     if (this.props.mode === 'command' || this.props.mode === 'find') {
@@ -105,7 +107,11 @@ class ConsoleComponent extends Component {
     case 'command':
     case 'find':
       return <div className='vimvixen-console-command-wrapper'>
-        <Completion />
+        <Completion
+          size={COMPLETION_MAX_ITEMS}
+          completions={this.props.completions}
+          select={this.props.select}
+        />
         <Input
           ref={(c) => { this.input = c; }}
           mode={this.props.mode}
diff --git a/src/console/components/console/completion.jsx b/src/console/components/console/completion.jsx
index c60543b..d836cec 100644
--- a/src/console/components/console/completion.jsx
+++ b/src/console/components/console/completion.jsx
@@ -1,5 +1,4 @@
 import { Component, h } from 'preact';
-import { connect } from 'preact-redux';
 
 const CompletionTitle = (props) => {
   return <li className='vimvixen-console-completion-title' >{props.title}</li>;
@@ -25,25 +24,60 @@ const CompletionItem = (props) => {
 
 
 class CompletionComponent extends Component {
+  constructor() {
+    super();
+    this.state = { viewOffset: 0, select: -1 };
+  }
+
+  static getDerivedStateFromProps(nextProps, prevState) {
+    if (prevState.select === nextProps.select) {
+      return null;
+    }
+
+    let viewSelect = (() => {
+      let index = 0;
+      for (let i = 0; i < nextProps.completions.length; ++i) {
+        ++index;
+        let g = nextProps.completions[i];
+        if (nextProps.select + i + 1 < index + g.items.length) {
+          return nextProps.select + i + 1;
+        }
+        index += g.items.length;
+      }
+    })();
+
+    let viewOffset = 0;
+    if (nextProps.select < 0) {
+      viewOffset = 0;
+    } else if (prevState.select < nextProps.select) {
+      viewOffset = Math.max(prevState.viewOffset,
+        viewSelect - nextProps.size + 1);
+    } else if (prevState.select > nextProps.select) {
+      viewOffset = Math.min(prevState.viewOffset, viewSelect);
+    }
+    return { viewOffset, select: nextProps.select };
+  }
+
   render() {
     let eles = [];
-    for (let i = 0; i < this.props.completions.length; ++i) {
-      let group = this.props.completions[i];
+    let index = 0;
+
+    for (let group of this.props.completions) {
       eles.push(<CompletionTitle title={ group.name }/>);
-      for (let j = 0; j < group.items.length; ++j) {
-        let item = group.items[j];
-        let selected =
-          i === this.props.groupSelection &&
-          j === this.props.itemSelection;
+      for (let item of group.items) {
         eles.push(<CompletionItem
           icon={item.icon}
           caption={item.caption}
           url={item.url}
-          highlight={selected}
+          highlight={index === this.props.select}
         / >);
+        ++index;
       }
     }
 
+    let viewOffset = this.state.viewOffset;
+    eles = eles.slice(viewOffset, viewOffset + this.props.size);
+
     return (
       <ul className='vimvixen-console-completion'>
         { eles }
@@ -52,5 +86,4 @@ class CompletionComponent extends Component {
   }
 }
 
-const mapStateToProps = state => state;
-export default connect(mapStateToProps)(CompletionComponent);
+export default CompletionComponent;
diff --git a/src/console/reducers/index.js b/src/console/reducers/index.js
index 7dcad17..614a72f 100644
--- a/src/console/reducers/index.js
+++ b/src/console/reducers/index.js
@@ -6,52 +6,43 @@ const defaultState = {
   consoleText: '',
   completionSource: '',
   completions: [],
-  groupSelection: -1,
-  itemSelection: -1,
+  select: -1,
+  viewIndex: 0,
 };
 
 const nextSelection = (state) => {
   if (state.completions.length === 0) {
-    return [-1, -1];
+    return -1;
   }
-  if (state.groupSelection < 0) {
-    return [0, 0];
+  if (state.select < 0) {
+    return 0;
   }
 
-  let group = state.completions[state.groupSelection];
-  if (state.groupSelection + 1 >= state.completions.length &&
-    state.itemSelection + 1 >= group.items.length) {
-    return [-1, -1];
+  let length = state.completions
+    .map(g => g.items.length)
+    .reduce((x, y) => x + y);
+  if (state.select + 1 < length) {
+    return state.select + 1;
   }
-  if (state.itemSelection + 1 >= group.items.length) {
-    return [state.groupSelection + 1, 0];
-  }
-  return [state.groupSelection, state.itemSelection + 1];
+  return -1;
 };
 
 const prevSelection = (state) => {
-  if (state.groupSelection < 0) {
-    return [
-      state.completions.length - 1,
-      state.completions[state.completions.length - 1].items.length - 1
-    ];
-  }
-  if (state.groupSelection === 0 && state.itemSelection === 0) {
-    return [-1, -1];
-  } else if (state.itemSelection === 0) {
-    return [
-      state.groupSelection - 1,
-      state.completions[state.groupSelection - 1].items.length - 1
-    ];
+  let length = state.completions
+    .map(g => g.items.length)
+    .reduce((x, y) => x + y);
+  if (state.select < 0) {
+    return length - 1;
   }
-  return [state.groupSelection, state.itemSelection - 1];
+  return state.select - 1;
 };
 
-const nextConsoleText = (completions, group, item, defaults) => {
-  if (group < 0 || item < 0) {
+const nextConsoleText = (completions, select, defaults) => {
+  if (select < 0) {
     return defaults;
   }
-  return completions[group].items[item].content;
+  let items = completions.map(g => g.items).reduce((g1, g2) => g1.concat(g2));
+  return items[select].content;
 };
 
 // eslint-disable-next-line max-lines-per-function
@@ -90,25 +81,20 @@ export default function reducer(state = defaultState, action = {}) {
     return { ...state,
       completions: action.completions,
       completionSource: action.completionSource,
-      groupSelection: -1,
-      itemSelection: -1, };
+      select: -1 };
   case actions.CONSOLE_COMPLETION_NEXT: {
-    let next = nextSelection(state);
+    let select = nextSelection(state);
     return { ...state,
-      groupSelection: next[0],
-      itemSelection: next[1],
+      select: select,
       consoleText: nextConsoleText(
-        state.completions, next[0], next[1],
-        state.completionSource), };
+        state.completions, select, state.completionSource) };
   }
   case actions.CONSOLE_COMPLETION_PREV: {
-    let next = prevSelection(state);
+    let select = prevSelection(state);
     return { ...state,
-      groupSelection: next[0],
-      itemSelection: next[1],
+      select: select,
       consoleText: nextConsoleText(
-        state.completions, next[0], next[1],
-        state.completionSource), };
+        state.completions, select, state.completionSource) };
   }
   default:
     return state;