/**
 *  AutoResizeTextView.java
 *
 *  Author:
 *       Jarl Gullberg <jarl.gullberg@gmail.com>
 *       Sam Hocevar <sam@hocevar.net>
 *
 *  Copyright (c) 2016 Jarl Gullberg
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.nihlus.matjakt.ui.widgets;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.RectF;
import android.os.Build;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.SparseIntArray;
import android.util.TypedValue;
import android.widget.TextView;

// Suppressing all warnings for this class - it's not my code
@SuppressWarnings("ALL")
public class AutoResizeTextView extends TextView
{
    private static final int NO_LINE_LIMIT = -1;
    private final RectF mTextRect = new RectF();

    private RectF mAvailableSpaceRect;

    private SparseIntArray mTextCachedSizes;

    private TextPaint mPaint;

    private float mMaxTextSize;

    private float mSpacingMult = 1.0f;

    private float mSpacingAdd = 0.0f;

    private float mMinTextSize = 20;

    private int mWidthLimit;
    private int mMaxLines;
    private final SizeTester mSizeTester = new SizeTester()
    {
        @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
        @Override
        public int onTestSize(int suggestedSize, RectF availableSPace)
        {
            mPaint.setTextSize(suggestedSize);
            String text = getText().toString();
            boolean singleline = getMaxLines() == 1;
            if (singleline)
            {
                mTextRect.bottom = mPaint.getFontSpacing();
                mTextRect.right = mPaint.measureText(text);
            }
            else
            {
                StaticLayout layout = new StaticLayout(text, mPaint,
                        mWidthLimit, Alignment.ALIGN_NORMAL, mSpacingMult,
                        mSpacingAdd, true);
                // return early if we have more lines
                if (getMaxLines() != NO_LINE_LIMIT
                        && layout.getLineCount() > getMaxLines())
                {
                    return 1;
                }
                mTextRect.bottom = layout.getHeight();
                int maxWidth = -1;
                for (int i = 0; i < layout.getLineCount(); i++)
                {
                    if (maxWidth < layout.getLineWidth(i))
                    {
                        maxWidth = (int) layout.getLineWidth(i);
                    }
                }
                mTextRect.right = maxWidth;
            }

            mTextRect.offsetTo(0, 0);
            if (availableSPace.contains(mTextRect))
            {
                // may be too small, don't worry we will find the best match
                return -1;
            }
            else
            {
                // too big
                return 1;
            }
        }
    };
    private boolean mEnableSizeCache = true;
    private boolean mInitiallized;

    public AutoResizeTextView(Context context)
    {
        super(context);
        initialize();
    }

    public AutoResizeTextView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        initialize();
    }

    public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
        initialize();
    }

    private static int binarySearch(int start, int end, SizeTester sizeTester,
                                    RectF availableSpace)
    {
        int lastBest = start;
        int lo = start;
        int hi = end - 1;
        int mid = 0;
        while (lo <= hi)
        {
            mid = (lo + hi) >>> 1;
            int midValCmp = sizeTester.onTestSize(mid, availableSpace);
            if (midValCmp < 0)
            {
                lastBest = lo;
                lo = mid + 1;
            }
            else if (midValCmp > 0)
            {
                hi = mid - 1;
                lastBest = hi;
            }
            else
            {
                return mid;
            }
        }
        // make sure to return last best
        // this is what should always be returned
        return lastBest;

    }

    private void initialize()
    {
        mPaint = new TextPaint(getPaint());
        mMaxTextSize = getTextSize();
        mAvailableSpaceRect = new RectF();
        mTextCachedSizes = new SparseIntArray();
        if (mMaxLines == 0)
        {
            // no value was assigned during construction
            mMaxLines = NO_LINE_LIMIT;
        }
        mInitiallized = true;
    }

    @Override
    public void setText(final CharSequence text, BufferType type)
    {
        super.setText(text, type);
        adjustTextSize(text.toString());
    }

    @Override
    public void setTextSize(float size)
    {
        mMaxTextSize = size;
        mTextCachedSizes.clear();
        adjustTextSize(getText().toString());
    }

    public int getMaxLines()
    {
        return mMaxLines;
    }

    @Override
    public void setMaxLines(int maxlines)
    {
        super.setMaxLines(maxlines);
        mMaxLines = maxlines;
        reAdjust();
    }

    @Override
    public void setSingleLine()
    {
        super.setSingleLine();
        mMaxLines = 1;
        reAdjust();
    }

    @Override
    public void setSingleLine(boolean singleLine)
    {
        super.setSingleLine(singleLine);
        if (singleLine)
        {
            mMaxLines = 1;
        }
        else
        {
            mMaxLines = NO_LINE_LIMIT;
        }
        reAdjust();
    }

    @Override
    public void setLines(int lines)
    {
        super.setLines(lines);
        mMaxLines = lines;
        reAdjust();
    }

    @Override
    public void setTextSize(int unit, float size)
    {
        Context c = getContext();
        Resources r;

        if (c == null)
        {
            r = Resources.getSystem();
        }
        else
        {
            r = c.getResources();
        }
        mMaxTextSize = TypedValue.applyDimension(unit, size,
                r.getDisplayMetrics());
        mTextCachedSizes.clear();
        adjustTextSize(getText().toString());
    }

    @Override
    public void setLineSpacing(float add, float mult)
    {
        super.setLineSpacing(add, mult);
        mSpacingMult = mult;
        mSpacingAdd = add;
    }

    /**
     * Set the lower text size limit and invalidate the view
     *
     * @param minTextSize The minimum text sixe in sp units.
     */
    public void setMinTextSize(float minTextSize)
    {
        mMinTextSize = minTextSize;
        reAdjust();
    }

    private void reAdjust()
    {
        adjustTextSize(getText().toString());
    }

    private void adjustTextSize(String string)
    {
        if (!mInitiallized)
        {
            return;
        }
        int startSize = (int) mMinTextSize;
        int heightLimit = getMeasuredHeight() - getCompoundPaddingBottom()
                - getCompoundPaddingTop();
        mWidthLimit = getMeasuredWidth() - getCompoundPaddingLeft()
                - getCompoundPaddingRight();
        mAvailableSpaceRect.right = mWidthLimit;
        mAvailableSpaceRect.bottom = heightLimit;
        super.setTextSize(
                TypedValue.COMPLEX_UNIT_PX,
                efficientTextSizeSearch(startSize, (int) mMaxTextSize,
                        mSizeTester, mAvailableSpaceRect));
    }

    /**
     * Enables or disables size caching, enabling it will improve performance
     * where you are animating a value inside TextView. This stores the font
     * size against getText().length() Be careful though while enabling it as 0
     * takes more space than 1 on some fonts and so on.
     *
     * @param enable enable font size caching
     */
    public void enableSizeCache(boolean enable)
    {
        mEnableSizeCache = enable;
        mTextCachedSizes.clear();
        adjustTextSize(getText().toString());
    }

    private int efficientTextSizeSearch(int start, int end,
                                        SizeTester sizeTester, RectF availableSpace)
    {
        if (!mEnableSizeCache)
        {
            return binarySearch(start, end, sizeTester, availableSpace);
        }
        String text = getText().toString();
        int key = text == null ? 0 : text.length();
        int size = mTextCachedSizes.get(key);
        if (size != 0)
        {
            return size;
        }
        size = binarySearch(start, end, sizeTester, availableSpace);
        mTextCachedSizes.put(key, size);
        return size;
    }

    @Override
    protected void onTextChanged(final CharSequence text, final int start,
                                 final int before, final int after)
    {
        super.onTextChanged(text, start, before, after);
        reAdjust();
    }

    @Override
    protected void onSizeChanged(int width, int height, int oldwidth,
                                 int oldheight)
    {
        mTextCachedSizes.clear();
        super.onSizeChanged(width, height, oldwidth, oldheight);
        if (width != oldwidth || height != oldheight)
        {
            reAdjust();
        }
    }

    private interface SizeTester
    {
        /**
         * @param suggestedSize  Size of text to be tested
         * @param availableSpace available space in which text must fit
         * @return an integer < 0 if after applying {@code suggestedSize} to
         * text, it takes less space than {@code availableSpace}, > 0
         * otherwise
         */
        int onTestSize(int suggestedSize, RectF availableSpace);
    }
}
