/*
 * 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.Spannable;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.TextUtils;
import android.text.style.StyleSpan;
import android.text.style.URLSpan;
import android.text.style.UnderlineSpan;
import android.text.style.ForegroundColorSpan;
import android.graphics.Typeface;
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;

/**
 * 自定义笔记编辑文本框
 * <p>
 * 该类继承自EditText，用于小米便签应用中的笔记编辑，支持链接识别、键盘事件处理
 * 和文本视图变化监听等功能
 * </p>
 */
public class NoteEditText extends EditText {
    /**
     * 日志标签
     */
    private static final String TAG = "NoteEditText";
    
    /**
     * 当前编辑框的索引
     */
    private int mIndex;
    
    /**
     * 删除操作前的选择起始位置
     */
    private int mSelectionStartBeforeDelete;

    /**
     * 电话链接协议
     */
    private static final String SCHEME_TEL = "tel:" ;
    
    /**
     * HTTP链接协议
     */
    private static final String SCHEME_HTTP = "http:" ;
    
    /**
     * 邮件链接协议
     */
    private static final String SCHEME_EMAIL = "mailto:" ;

    /**
     * 链接协议与资源ID的映射表
     */
    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);
    }

    /**
     * 文本视图变化监听器接口
     * <p>
     * 由{@link NoteEditActivity}调用，用于处理编辑框的删除或添加
     * </p>
     */
    public interface OnTextViewChangeListener {
        /**
         * 当按下{@link KeyEvent#KEYCODE_DEL}且文本为空时，删除当前编辑框
         */
        void onEditTextDelete(int index, String text);

        /**
         * 当按下{@link KeyEvent#KEYCODE_ENTER}时，在当前编辑框后添加新的编辑框
         */
        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);
    }

    /**
     * 文本视图变化监听器实例
     */
    private OnTextViewChangeListener mOnTextViewChangeListener;

    /**
     * 构造函数，创建笔记编辑文本框
     * @param context 上下文对象
     */
    public NoteEditText(Context context) {
        super(context, null);
        mIndex = 0;
    }

    /**
     * 设置编辑框索引
     * @param index 编辑框索引
     */
    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，创建笔记编辑文本框
     * @param context 上下文对象
     * @param attrs 属性集合
     */
    public NoteEditText(Context context, AttributeSet attrs) {
        super(context, attrs, android.R.attr.editTextStyle);
    }

    /**
     * 构造函数，创建笔记编辑文本框
     * @param context 上下文对象
     * @param attrs 属性集合
     * @param defStyle 默认样式
     */
    public NoteEditText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        // TODO Auto-generated constructor stub
    }

    /**
     * 处理触摸事件
     * <p>
     * 当用户点击编辑框时，将光标定位到点击位置
     * </p>
     * @param event 触摸事件
     * @return 事件是否被处理
     */
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:

                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);
    }

    /**
     * 处理按键按下事件
     * <p>
     * 监听回车键和删除键的按下事件
     * </p>
     * @param keyCode 按键代码
     * @param event 按键事件
     * @return 事件是否被处理
     */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_ENTER:
                if (mOnTextViewChangeListener != null) {
                    return false;
                }
                break;
            case KeyEvent.KEYCODE_DEL:
                mSelectionStartBeforeDelete = getSelectionStart();
                break;
            default:
                break;
        }
        return super.onKeyDown(keyCode, event);
    }

    /**
     * 处理按键释放事件
     * <p>
     * 监听删除键和回车键的释放事件，实现编辑框的删除和添加功能
     * </p>
     * @param keyCode 按键代码
     * @param event 按键事件
     * @return 事件是否被处理
     */
    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        switch(keyCode) {
            case KeyEvent.KEYCODE_DEL:
                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:
                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);
    }

    /**
     * 处理焦点变化事件
     * <p>
     * 当编辑框失去焦点且文本为空时，通知监听器隐藏项目选项
     * 当编辑框获得焦点或文本不为空时，通知监听器显示项目选项
     * </p>
     * @param focused 是否获得焦点
     * @param direction 焦点变化方向
     * @param previouslyFocusedRect 之前焦点所在的矩形区域
     */
    @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
     * <p>
     * 当选中的文本包含链接时，创建相应的链接操作菜单
     * </p>
     * @param menu 上下文菜单
     */
    @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) {
                                // goto a new intent
                                urls[0].onClick(NoteEditText.this);
                                return true;
                            }
                        });
            }
        }
        super.onCreateContextMenu(menu);
    }

    /**
     * 应用粗体格式到选中文本
     */
    public void applyBold() {
        applyStyle(Typeface.BOLD);
    }

    /**
     * 应用斜体格式到选中文本
     */
    public void applyItalic() {
        applyStyle(Typeface.ITALIC);
    }

    /**
     * 应用下划线格式到选中文本
     */
    public void applyUnderline() {
        SpannableStringBuilder ssb = new SpannableStringBuilder(getText());
        int start = getSelectionStart();
        int end = getSelectionEnd();
        
        if (start != end) {
            // 检查是否已存在下划线样式
            UnderlineSpan[] existingUnderlines = ssb.getSpans(start, end, UnderlineSpan.class);
            if (existingUnderlines.length > 0) {
                // 移除下划线
                for (UnderlineSpan span : existingUnderlines) {
                    ssb.removeSpan(span);
                }
            } else {
                // 添加下划线
                ssb.setSpan(new UnderlineSpan(), start, end, Spannable.SPAN_EXCLUSIVE_INCLUSIVE);
            }
            setText(ssb);
            setSelection(start, end);
        }
    }
    
    /**
     * 应用指定颜色到选中文本
     * @param color 要应用的颜色值
     */
    public void applyTextColor(int color) {
        SpannableStringBuilder ssb = new SpannableStringBuilder(getText());
        int start = getSelectionStart();
        int end = getSelectionEnd();
        
        if (start != end) {
            // 移除已有的文字颜色
            ForegroundColorSpan[] existingSpans = ssb.getSpans(start, end, ForegroundColorSpan.class);
            for (ForegroundColorSpan span : existingSpans) {
                ssb.removeSpan(span);
            }
            
            // 添加新的文字颜色
            ssb.setSpan(new ForegroundColorSpan(color), start, end, Spannable.SPAN_EXCLUSIVE_INCLUSIVE);
            
            setText(ssb);
            setSelection(start, end);
        }
    }

    /**
     * 应用字体样式到选中文本
     */
    private void applyStyle(int style) {
        SpannableStringBuilder ssb = new SpannableStringBuilder(getText());
        int start = getSelectionStart();
        int end = getSelectionEnd();
        
        if (start != end) {
            // 获取当前选中文本的所有样式
            StyleSpan[] existingSpans = ssb.getSpans(start, end, StyleSpan.class);
            
            // 计算当前选中文本的总样式
            int currentStyle = Typeface.NORMAL;
            if (existingSpans.length > 0) {
                // 如果有样式，取第一个样式（假设所有样式一致）
                currentStyle = existingSpans[0].getStyle();
            }
            
            // 计算新的字体样式
            int newStyle;
            if ((currentStyle & style) != 0) {
                // 移除该样式
                newStyle = currentStyle & ~style;
            } else {
                // 添加该样式
                newStyle = currentStyle | style;
            }
            
            // 移除旧的样式
            for (StyleSpan span : existingSpans) {
                ssb.removeSpan(span);
            }
            
            // 添加新的样式
            ssb.setSpan(new StyleSpan(newStyle), start, end, Spannable.SPAN_EXCLUSIVE_INCLUSIVE);
            setText(ssb);
            setSelection(start, end);
        }
    }
}