/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.micode.notes.ui;

import android.content.Context;
import android.graphics.Rect;
import android.text.Layout;
import android.text.Selection;
import android.text.Spanned;
import android.text.TextUtils;
import android.text.style.URLSpan;
import android.util.AttributeSet;
import android.util.Log;
import android.view.ContextMenu;
import android.view.KeyEvent;
import android.view.MenuItem;
import android.view.MenuItem.OnMenuItemClickListener;
import android.view.MotionEvent;
import android.widget.EditText;

import net.micode.notes.R;

import java.util.HashMap;
import java.util.Map;

/**
 * 自定义的可编辑文本视图，支持文本变化监听、删除和新增文本事件。
 */
public class NoteEditText extends EditText {
    private static final String TAG = "NoteEditText";
    private int mIndex; // 当前文本视图的索引
    private int mSelectionStartBeforeDelete; // 删除操作前的选择起始位置

    private static final String SCHEME_TEL = "tel:";
    private static final String SCHEME_HTTP = "http:";
    private static final String SCHEME_EMAIL = "mailto:";

    // URL方案与对应操作资源ID的映射
    private static final Map<String, Integer> sSchemaActionResMap = new HashMap<String, Integer>();

    static {
        sSchemaActionResMap.put(SCHEME_TEL, R.string.note_link_tel);
        sSchemaActionResMap.put(SCHEME_HTTP, R.string.note_link_web);
        sSchemaActionResMap.put(SCHEME_EMAIL, R.string.note_link_email);
    }

    /**
     * 文本视图变化监听接口。
     */
    public interface OnTextViewChangeListener {
        /**
         * 当按下删除键且文本为空时，删除当前文本视图。
         */
        void onEditTextDelete(int index, String text);

        /**
         * 当按下回车键时，新增一个文本视图。
         */
        void onEditTextEnter(int index, String text);

        /**
         * 当文本变化时，隐藏或显示项目选项。
         */
        void onTextChange(int index, boolean hasText);
    }

    private OnTextViewChangeListener mOnTextViewChangeListener;

    /**
     * 构造函数，初始化编辑文本视图。
     *
     * @param context 上下文对象
     */
    public NoteEditText(Context context) {
        super(context, null);
        mIndex = 0;
    }

    /**
     * 设置当前文本视图的索引。
     *
     * @param index 当前文本视图的索引
     */
    public void setIndex(int index) {
        mIndex = index;
    }

    /**
     * 设置文本视图变化监听器。
     *
     * @param listener 文本视图变化监听器
     */
    public void setOnTextViewChangeListener(OnTextViewChangeListener listener) {
        mOnTextViewChangeListener = listener;
    }

    /**
     * 构造函数，初始化编辑文本视图。
     *
     * @param context 上下文对象
     * @param attrs   属性集
     */
    public NoteEditText(Context context, AttributeSet attrs) {
        super(context, attrs, android.R.attr.editTextStyle);
    }

    /**
     * 构造函数，初始化编辑文本视图。
     *
     * @param context  上下文对象
     * @param attrs    属性集
     * @param defStyle 样式
     */
    public NoteEditText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    /**
     * 处理触摸事件，调整光标位置。
     */
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                // 计算触摸位置相对于文本的偏移量，并调整光标位置
                int x = (int) event.getX();
                int y = (int) event.getY();
                x -= getTotalPaddingLeft();
                y -= getTotalPaddingTop();
                x += getScrollX();
                y += getScrollY();

                Layout layout = getLayout();
                int line = layout.getLineForVertical(y);
                int off = layout.getOffsetForHorizontal(line, x);
                Selection.setSelection(getText(), off);
                break;
        }

        return super.onTouchEvent(event);
    }

    /**
     * 处理键盘按下事件。
     */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_ENTER:
                // 处理回车键事件，准备新增文本视图
                if (mOnTextViewChangeListener != null) {
                    return false;
                }
                break;
            case KeyEvent.KEYCODE_DEL:
                // 记录删除操作前的选择位置
                mSelectionStartBeforeDelete = getSelectionStart();
                break;
            default:
                break;
        }
        return super.onKeyDown(keyCode, event);
    }

    /**
     * 处理键盘弹起事件。
     */
    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_DEL:
                // 处理删除键事件，若为首个文本且非空，则删除当前文本
                if (mOnTextViewChangeListener != null) {
                    if (0 == mSelectionStartBeforeDelete && mIndex != 0) {
                        mOnTextViewChangeListener.onEditTextDelete(mIndex, getText().toString());
                        return true;
                    }
                } else {
                    Log.d(TAG, "OnTextViewChangeListener was not seted");
                }
                break;
            case KeyEvent.KEYCODE_ENTER:
                // 处理回车键事件，新增文本视图
                if (mOnTextViewChangeListener != null) {
                    int selectionStart = getSelectionStart();
                    String text = getText().subSequence(selectionStart, length()).toString();
                    setText(getText().subSequence(0, selectionStart));
                    mOnTextViewChangeListener.onEditTextEnter(mIndex + 1, text);
                } else {
                    Log.d(TAG, "OnTextViewChangeListener was not seted");
                }
                break;
            default:
                break;
        }
        return super.onKeyUp(keyCode, event);
    }

    /**
     * 当焦点变化时，通知文本变化情况。
     */
    @Override
    protected void onFocusChanged(boolean focused, int direction, Rect previouslyFocusedRect) {
        if (mOnTextViewChangeListener != null) {
            if (!focused && TextUtils.isEmpty(getText())) {
                mOnTextViewChangeListener.onTextChange(mIndex, false);
            } else {
                mOnTextViewChangeListener.onTextChange(mIndex, true);
            }
        }
        super.onFocusChanged(focused, direction, previouslyFocusedRect);
    }

    /**
     * 创建上下文菜单，支持点击URL跳转。
     */
    @Override
    protected void onCreateContextMenu(ContextMenu menu) {
        if (getText() instanceof Spanned) {
            int selStart = getSelectionStart();
            int selEnd = getSelectionEnd();

            int min = Math.min(selStart, selEnd);
            int max = Math.max(selStart, selEnd);

            final URLSpan[] urls = ((Spanned) getText()).getSpans(min, max, URLSpan.class);
            if (urls.length == 1) {
                int defaultResId = 0;
                for (String schema : sSchemaActionResMap.keySet()) {
                    if (urls[0].getURL().indexOf(schema) >= 0) {
                        defaultResId = sSchemaActionResMap.get(schema);
                        break;
                    }
                }

                if (defaultResId == 0) {
                    defaultResId = R.string.note_link_other;
                }

                menu.add(0, 0, 0, defaultResId).setOnMenuItemClickListener(
                        new OnMenuItemClickListener() {
                            public boolean onMenuItemClick(MenuItem item) {
                                // 跳转到URL指向的页面
                                urls[0].onClick(NoteEditText.this);
                                return true;
                            }
                        });
            }
        }
        super.onCreateContextMenu(menu);
    }
}