/* ====================================================================
   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You 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 org.apache.poi.sl.draw;

import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.font.FontRenderContext;
import java.awt.font.LineBreakMeasurer;
import java.awt.font.TextAttribute;
import java.awt.font.TextLayout;
import java.awt.geom.Rectangle2D;
import java.io.InvalidObjectException;
import java.text.AttributedCharacterIterator;
import java.text.AttributedCharacterIterator.Attribute;
import java.text.AttributedString;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.poi.sl.usermodel.AutoNumberingScheme;
import org.apache.poi.sl.usermodel.Hyperlink;
import org.apache.poi.sl.usermodel.Insets2D;
import org.apache.poi.sl.usermodel.PaintStyle;
import org.apache.poi.sl.usermodel.PlaceableShape;
import org.apache.poi.sl.usermodel.ShapeContainer;
import org.apache.poi.sl.usermodel.Sheet;
import org.apache.poi.sl.usermodel.TextParagraph;
import org.apache.poi.sl.usermodel.TextParagraph.BulletStyle;
import org.apache.poi.sl.usermodel.TextParagraph.TextAlign;
import org.apache.poi.sl.usermodel.TextRun;
import org.apache.poi.sl.usermodel.TextRun.TextCap;
import org.apache.poi.sl.usermodel.TextShape;
import org.apache.poi.sl.usermodel.TextShape.TextDirection;
import org.apache.poi.util.StringUtil;
import org.apache.poi.util.Units;


public class DrawTextParagraph implements Drawable {
    /** Keys for passing hyperlinks to the graphics context */
    public static final XlinkAttribute HYPERLINK_HREF = new XlinkAttribute("href");
    public static final XlinkAttribute HYPERLINK_LABEL = new XlinkAttribute("label");

    protected TextParagraph<?,?,?> paragraph;
    double x, y;
    protected List<DrawTextFragment> lines = new ArrayList<DrawTextFragment>();
    protected String rawText;
    protected DrawTextFragment bullet;
    protected int autoNbrIdx;

    /**
     * the highest line in this paragraph. Used for line spacing.
     */
    protected double maxLineHeight;

    /**
     * Defines an attribute used for storing the hyperlink associated with
     * some renderable text.
     */
    private static class XlinkAttribute extends Attribute {

        XlinkAttribute(String name) {
            super(name);
        }

        /**
         * Resolves instances being deserialized to the predefined constants.
         */
        protected Object readResolve() throws InvalidObjectException {
            if (HYPERLINK_HREF.getName().equals(getName())) {
                return HYPERLINK_HREF;
            }
            if (HYPERLINK_LABEL.getName().equals(getName())) {
                return HYPERLINK_LABEL;
            }
            throw new InvalidObjectException("unknown attribute name");
        }
    }


    public DrawTextParagraph(TextParagraph<?,?,?> paragraph) {
        this.paragraph = paragraph;
    }

    public void setPosition(double x, double y) {
        // TODO: replace it, by applyTransform????
        this.x = x;
        this.y = y;
    }

    public double getY() {
        return y;
    }

    /**
     * Sets the auto numbering index of the handled paragraph
     * @param index the auto numbering index
     */
    public void setAutoNumberingIdx(int index) {
        autoNbrIdx = index;
    }

    public void draw(Graphics2D graphics){
        if (lines.isEmpty()) return;

        double penY = y;

        boolean firstLine = true;
        int indentLevel = paragraph.getIndentLevel();
        Double leftMargin = paragraph.getLeftMargin();
        if (leftMargin == null) {
            // if the marL attribute is omitted, then a value of 347663 is implied
            leftMargin = Units.toPoints(347663L*indentLevel);
        }
        Double indent = paragraph.getIndent();
        if (indent == null) {
            indent = Units.toPoints(347663L*indentLevel);
        }
        if (isHSLF()) {
            // special handling for HSLF
            indent -= leftMargin;
        }

//        Double rightMargin = paragraph.getRightMargin();
//        if (rightMargin == null) {
//            rightMargin = 0d;
//        }

        //The vertical line spacing
        Double spacing = paragraph.getLineSpacing();
        if (spacing == null) spacing = 100d;

        for(DrawTextFragment line : lines){
            double penX;

            if(firstLine) {
                if (!isEmptyParagraph()) {
                    // TODO: find out character style for empty, but bulleted/numbered lines
                    bullet = getBullet(graphics, line.getAttributedString().getIterator());
                }

                if (bullet != null){
                    bullet.setPosition(x+leftMargin+indent, penY);
                    bullet.draw(graphics);
                    // don't let text overlay the bullet and advance by the bullet width
                    double bulletWidth = bullet.getLayout().getAdvance() + 1;
                    penX = x + Math.max(leftMargin, leftMargin+indent+bulletWidth);
                } else {
                    penX = x + leftMargin;
                }
            } else {
                penX = x + leftMargin;
            }

            Rectangle2D anchor = DrawShape.getAnchor(graphics, paragraph.getParentShape());
            // Insets are already applied on DrawTextShape.drawContent
            // but (outer) anchor need to be adjusted
            Insets2D insets = paragraph.getParentShape().getInsets();
            double leftInset = insets.left;
            double rightInset = insets.right;

            TextAlign ta = paragraph.getTextAlign();
            if (ta == null) ta = TextAlign.LEFT;
            switch (ta) {
                case CENTER:
                    penX += (anchor.getWidth() - line.getWidth() - leftInset - rightInset - leftMargin) / 2;
                    break;
                case RIGHT:
                    penX += (anchor.getWidth() - line.getWidth() - leftInset - rightInset);
                    break;
                default:
                    break;
            }

            line.setPosition(penX, penY);
            line.draw(graphics);

            if(spacing > 0) {
                // If linespacing >= 0, then linespacing is a percentage of normal line height.
                penY += spacing*0.01* line.getHeight();
            } else {
                // negative value means absolute spacing in points
                penY += -spacing;
            }

            firstLine = false;
        }

        y = penY - y;
    }

    public float getFirstLineHeight() {
        return (lines.isEmpty()) ? 0 : lines.get(0).getHeight();
    }

    public float getLastLineHeight() {
        return (lines.isEmpty()) ? 0 : lines.get(lines.size()-1).getHeight();
    }

    public boolean isEmptyParagraph() {
        return (lines.isEmpty() || rawText.trim().isEmpty());
    }

    public void applyTransform(Graphics2D graphics) {
    }

    public void drawContent(Graphics2D graphics) {
    }

    /**
     * break text into lines, each representing a line of text that fits in the wrapping width
     *
     * @param graphics The drawing context for computing text-lengths.
     */
    protected void breakText(Graphics2D graphics){
        lines.clear();

        DrawFactory fact = DrawFactory.getInstance(graphics);
        StringBuilder text = new StringBuilder();
        AttributedString at = getAttributedString(graphics, text);
        boolean emptyParagraph = ("".equals(text.toString().trim()));

        AttributedCharacterIterator it = at.getIterator();
        LineBreakMeasurer measurer = new LineBreakMeasurer(it, graphics.getFontRenderContext());
        for (;;) {
            int startIndex = measurer.getPosition();

            double wrappingWidth = getWrappingWidth(lines.size() == 0, graphics) + 1; // add a pixel to compensate rounding errors
            // shape width can be smaller that the sum of insets (this was proved by a test file)
            if(wrappingWidth < 0) wrappingWidth = 1;

            int nextBreak = text.indexOf("\n", startIndex + 1);
            if (nextBreak == -1) nextBreak = it.getEndIndex();

            TextLayout layout = measurer.nextLayout((float)wrappingWidth, nextBreak, true);
            if (layout == null) {
                 // layout can be null if the entire word at the current position
                 // does not fit within the wrapping width. Try with requireNextWord=false.
                 layout = measurer.nextLayout((float)wrappingWidth, nextBreak, false);
            }

            if(layout == null) {
                // exit if can't break any more
                break;
            }

            int endIndex = measurer.getPosition();
            // skip over new line breaks (we paint 'clear' text runs not starting or ending with \n)
            if(endIndex < it.getEndIndex() && text.charAt(endIndex) == '\n'){
                measurer.setPosition(endIndex + 1);
            }

            TextAlign hAlign = paragraph.getTextAlign();
            if(hAlign == TextAlign.JUSTIFY || hAlign == TextAlign.JUSTIFY_LOW) {
                layout = layout.getJustifiedLayout((float)wrappingWidth);
            }

            AttributedString str = (emptyParagraph)
                ? null // we will not paint empty paragraphs
                : new AttributedString(it, startIndex, endIndex);
            DrawTextFragment line = fact.getTextFragment(layout, str);
            lines.add(line);

            maxLineHeight = Math.max(maxLineHeight, line.getHeight());

            if(endIndex == it.getEndIndex()) break;
        }

        rawText = text.toString();
    }

    protected DrawTextFragment getBullet(Graphics2D graphics, AttributedCharacterIterator firstLineAttr) {
        BulletStyle bulletStyle = paragraph.getBulletStyle();
        if (bulletStyle == null) return null;

        String buCharacter;
        AutoNumberingScheme ans = bulletStyle.getAutoNumberingScheme();
        if (ans != null) {
            buCharacter = ans.format(autoNbrIdx);
        } else {
            buCharacter = bulletStyle.getBulletCharacter();
        }
        if (buCharacter == null) return null;

        String buFont = bulletStyle.getBulletFont();
        if (buFont == null) buFont = paragraph.getDefaultFontFamily();
        assert(buFont != null);

        PlaceableShape<?,?> ps = getParagraphShape();
        PaintStyle fgPaintStyle = bulletStyle.getBulletFontColor();
        Paint fgPaint;
        if (fgPaintStyle == null) {
            fgPaint = (Paint)firstLineAttr.getAttribute(TextAttribute.FOREGROUND);
        } else {
            fgPaint = new DrawPaint(ps).getPaint(graphics, fgPaintStyle);
        }

        float fontSize = (Float)firstLineAttr.getAttribute(TextAttribute.SIZE);
        Double buSz = bulletStyle.getBulletFontSize();
        if (buSz == null) buSz = 100d;
        if (buSz > 0) fontSize *= buSz* 0.01;
        else fontSize = (float)-buSz;


        AttributedString str = new AttributedString(mapFontCharset(buCharacter,buFont));
        str.addAttribute(TextAttribute.FOREGROUND, fgPaint);
        str.addAttribute(TextAttribute.FAMILY, buFont);
        str.addAttribute(TextAttribute.SIZE, fontSize);

        TextLayout layout = new TextLayout(str.getIterator(), graphics.getFontRenderContext());
        DrawFactory fact = DrawFactory.getInstance(graphics);
        return fact.getTextFragment(layout, str);
    }

    protected String getRenderableText(TextRun tr) {
        StringBuilder buf = new StringBuilder();
        TextCap cap = tr.getTextCap();
        String tabs = null;
        for (char c : tr.getRawText().toCharArray()) {
            switch (c) {
                case '\t':
                    if (tabs == null) {
                        tabs = tab2space(tr);
                    }
                    buf.append(tabs);
                    break;
                case '\u000b':
                    buf.append('\n');
                    break;
                default:
                    switch (cap) {
                        case ALL: c = Character.toUpperCase(c); break;
                        case SMALL: c = Character.toLowerCase(c); break;
                        case NONE: break;
                    }

                    buf.append(c);
                    break;
            }
        }

        return buf.toString();
    }

    /**
     * Replace a tab with the effective number of white spaces.
     */
    private String tab2space(TextRun tr) {
        AttributedString string = new AttributedString(" ");
        String fontFamily = tr.getFontFamily();
        if (fontFamily == null) fontFamily = "Lucida Sans";
        string.addAttribute(TextAttribute.FAMILY, fontFamily);

        Double fs = tr.getFontSize();
        if (fs == null) fs = 12d;
        string.addAttribute(TextAttribute.SIZE, fs.floatValue());

        TextLayout l = new TextLayout(string.getIterator(), new FontRenderContext(null, true, true));
        double wspace = l.getAdvance();

        Double tabSz = paragraph.getDefaultTabSize();
        if (tabSz == null) tabSz = wspace*4;

        int numSpaces = (int)Math.ceil(tabSz / wspace);
        StringBuilder buf = new StringBuilder();
        for(int i = 0; i < numSpaces; i++) {
            buf.append(' ');
        }
        return buf.toString();
    }


    /**
     * Returns wrapping width to break lines in this paragraph
     *
     * @param firstLine whether the first line is breaking
     *
     * @return  wrapping width in points
     */
    protected double getWrappingWidth(boolean firstLine, Graphics2D graphics){
        TextShape<?,?> ts = paragraph.getParentShape();

        // internal margins for the text box
        Insets2D insets = ts.getInsets();
        double leftInset = insets.left;
        double rightInset = insets.right;

        int indentLevel = paragraph.getIndentLevel();
        if (indentLevel == -1) {
            // default to 0, if indentLevel is not set
            indentLevel = 0;
        }
        Double leftMargin = paragraph.getLeftMargin();
        if (leftMargin == null) {
            // if the marL attribute is omitted, then a value of 347663 is implied
            leftMargin = Units.toPoints(347663L*(indentLevel+1));
        }
        Double indent = paragraph.getIndent();
        if (indent == null) {
            indent = Units.toPoints(347663L*indentLevel);
        }
        Double rightMargin = paragraph.getRightMargin();
        if (rightMargin == null) {
            rightMargin = 0d;
        }

        Rectangle2D anchor = DrawShape.getAnchor(graphics, ts);
        TextDirection textDir = ts.getTextDirection();
        double width;
        if (!ts.getWordWrap()) {
            Dimension pageDim = ts.getSheet().getSlideShow().getPageSize();
            // if wordWrap == false then we return the advance to the (right) border of the sheet
            switch (textDir) {
                default:
                    width = pageDim.getWidth() - anchor.getX();
                    break;
                case VERTICAL:
                    width = pageDim.getHeight() - anchor.getX();
                    break;
                case VERTICAL_270:
                    width = anchor.getX();
                    break;
            }
        } else {
            switch (textDir) {
                default:
                    width = anchor.getWidth() - leftInset - rightInset - leftMargin - rightMargin;
                    break;
                case VERTICAL:
                case VERTICAL_270:
                    width = anchor.getHeight() - leftInset - rightInset - leftMargin - rightMargin;
                    break;
            }
            if (firstLine && !isHSLF()) {
                if (bullet != null){
                    if (indent > 0) width -= indent;
                } else {
                    if (indent > 0) width -= indent; // first line indentation
                    else if (indent < 0) { // hanging indentation: the first line start at the left margin
                        width += leftMargin;
                    }
                }
            }
        }

        return width;
    }

    private static class AttributedStringData {
        Attribute attribute;
        Object value;
        int beginIndex, endIndex;
        AttributedStringData(Attribute attribute, Object value, int beginIndex, int endIndex) {
            this.attribute = attribute;
            this.value = value;
            this.beginIndex = beginIndex;
            this.endIndex = endIndex;
        }
    }

    /**
     * Helper method for paint style relative to bounds, e.g. gradient paint
     */
    @SuppressWarnings("rawtypes")
    private PlaceableShape<?,?> getParagraphShape() {
        return new PlaceableShape(){
            public ShapeContainer<?,?> getParent() { return null; }
            public Rectangle2D getAnchor() { return paragraph.getParentShape().getAnchor(); }
            public void setAnchor(Rectangle2D anchor) {}
            public double getRotation() { return 0; }
            public void setRotation(double theta) {}
            public void setFlipHorizontal(boolean flip) {}
            public void setFlipVertical(boolean flip) {}
            public boolean getFlipHorizontal() { return false; }
            public boolean getFlipVertical() { return false; }
            public Sheet<?,?> getSheet() { return paragraph.getParentShape().getSheet(); }
        };
    }

    protected AttributedString getAttributedString(Graphics2D graphics, StringBuilder text){
        List<AttributedStringData> attList = new ArrayList<AttributedStringData>();
        if (text == null) text = new StringBuilder();

        PlaceableShape<?,?> ps = getParagraphShape();

        DrawFontManager fontHandler = (DrawFontManager)graphics.getRenderingHint(Drawable.FONT_HANDLER);
        @SuppressWarnings("unchecked")
        Map<String,String> fontMap = (Map<String,String>)graphics.getRenderingHint(Drawable.FONT_MAP);
        @SuppressWarnings("unchecked")
        Map<String,String> fallbackMap = (Map<String,String>)graphics.getRenderingHint(Drawable.FONT_FALLBACK);

        for (TextRun run : paragraph){
            String runText = getRenderableText(run);
            // skip empty runs
            if (runText.isEmpty()) continue;

            // user can pass an custom object to convert fonts
            String mappedFont = run.getFontFamily();
            String fallbackFont = Font.SANS_SERIF;

            if (mappedFont == null) {
                mappedFont = paragraph.getDefaultFontFamily();
            }
            if (mappedFont == null) {
                mappedFont = Font.SANS_SERIF;
            }            
            if (fontHandler != null) {
                String font = fontHandler.getRendererableFont(mappedFont, run.getPitchAndFamily());
                if (font != null) {
                    mappedFont = font;
                }
                font = fontHandler.getFallbackFont(mappedFont, run.getPitchAndFamily());
                if (font != null) {
                    fallbackFont = font;
                }
            } else {
                if (fontMap != null) {
                    if (fontMap.containsKey(mappedFont)) {
                        mappedFont = fontMap.get(mappedFont);
                    } else if (fontMap.containsKey("*")) {
                        mappedFont = fontMap.get("*");
                    }
                }
                if (fallbackMap != null) {
                    if (fallbackMap.containsKey(mappedFont)) {
                        fallbackFont = fallbackMap.get(mappedFont);
                    } else if (fallbackMap.containsKey("*")) {
                        fallbackFont = fallbackMap.get("*");
                    }
                }
            }
            
            runText = mapFontCharset(runText,mappedFont);
            int beginIndex = text.length();
            text.append(runText);
            int endIndex = text.length();

            attList.add(new AttributedStringData(TextAttribute.FAMILY, mappedFont, beginIndex, endIndex));

            PaintStyle fgPaintStyle = run.getFontColor();
            Paint fgPaint = new DrawPaint(ps).getPaint(graphics, fgPaintStyle);
            attList.add(new AttributedStringData(TextAttribute.FOREGROUND, fgPaint, beginIndex, endIndex));

            Double fontSz = run.getFontSize();
            if (fontSz == null) {
                fontSz = paragraph.getDefaultFontSize();
            }
            attList.add(new AttributedStringData(TextAttribute.SIZE, fontSz.floatValue(), beginIndex, endIndex));

            if(run.isBold()) {
                attList.add(new AttributedStringData(TextAttribute.WEIGHT, TextAttribute.WEIGHT_BOLD, beginIndex, endIndex));
            }
            if(run.isItalic()) {
                attList.add(new AttributedStringData(TextAttribute.POSTURE, TextAttribute.POSTURE_OBLIQUE, beginIndex, endIndex));
            }
            if(run.isUnderlined()) {
                attList.add(new AttributedStringData(TextAttribute.UNDERLINE, TextAttribute.UNDERLINE_ON, beginIndex, endIndex));
                attList.add(new AttributedStringData(TextAttribute.INPUT_METHOD_UNDERLINE, TextAttribute.UNDERLINE_LOW_TWO_PIXEL, beginIndex, endIndex));
            }
            if(run.isStrikethrough()) {
                attList.add(new AttributedStringData(TextAttribute.STRIKETHROUGH, TextAttribute.STRIKETHROUGH_ON, beginIndex, endIndex));
            }
            if(run.isSubscript()) {
                attList.add(new AttributedStringData(TextAttribute.SUPERSCRIPT, TextAttribute.SUPERSCRIPT_SUB, beginIndex, endIndex));
            }
            if(run.isSuperscript()) {
                attList.add(new AttributedStringData(TextAttribute.SUPERSCRIPT, TextAttribute.SUPERSCRIPT_SUPER, beginIndex, endIndex));
            }
            
            Hyperlink<?,?> hl = run.getHyperlink();
            if (hl != null) {
                attList.add(new AttributedStringData(HYPERLINK_HREF, hl.getAddress(), beginIndex, endIndex));
                attList.add(new AttributedStringData(HYPERLINK_LABEL, hl.getLabel(), beginIndex, endIndex));
            }
            
            int style = (run.isBold() ? Font.BOLD : 0) | (run.isItalic() ? Font.ITALIC : 0);
            Font f = new Font(mappedFont, style, (int)Math.rint(fontSz));
            
            // check for unsupported characters and add a fallback font for these
            char textChr[] = runText.toCharArray();
            int nextEnd = f.canDisplayUpTo(textChr, 0, textChr.length);
            int last = nextEnd;
            boolean isNextValid = (nextEnd == 0);
            while ( nextEnd != -1 && nextEnd <= textChr.length ) {
                if (isNextValid) {
                    nextEnd = f.canDisplayUpTo(textChr, nextEnd, textChr.length);
                    isNextValid = false;
                } else {
                    if (nextEnd >= textChr.length || f.canDisplay(Character.codePointAt(textChr, nextEnd, textChr.length)) ) {
                        attList.add(new AttributedStringData(TextAttribute.FAMILY, fallbackFont, beginIndex+last, beginIndex+Math.min(nextEnd,textChr.length)));
                        if (nextEnd >= textChr.length) {
                            break;
                        }
                        last = nextEnd;
                        isNextValid = true;
                    } else {
                        boolean isHS = Character.isHighSurrogate(textChr[nextEnd]);
                        nextEnd+=(isHS?2:1);
                    }
                }
            } 
        }

        // ensure that the paragraph contains at least one character
        // We need this trick to correctly measure text
        if (text.length() == 0) {
            Double fontSz = paragraph.getDefaultFontSize();
            text.append(" ");
            attList.add(new AttributedStringData(TextAttribute.SIZE, fontSz.floatValue(), 0, 1));
        }

        AttributedString string = new AttributedString(text.toString());
        for (AttributedStringData asd : attList) {
            string.addAttribute(asd.attribute, asd.value, asd.beginIndex, asd.endIndex);
        }

        return string;
    }

    protected boolean isHSLF() {
        return paragraph.getClass().getName().contains("HSLF");
    }

    /**
     * Map text charset depending on font family.
     * Currently this only maps for wingdings font (into unicode private use area)
     *
     * @param text the raw text
     * @param fontFamily the font family
     * @return AttributedString with mapped codepoints
     *
     * @see <a href="http://stackoverflow.com/questions/8692095">Drawing exotic fonts in a java applet</a>
     * @see StringUtil#mapMsCodepointString(String)
     */
    protected String mapFontCharset(String text, String fontFamily) {
        // TODO: find a real charset mapping solution instead of hard coding for Wingdings
        String attStr = text;
        if ("Wingdings".equalsIgnoreCase(fontFamily)) {
            // wingdings doesn't contain high-surrogates, so chars are ok
            boolean changed = false;
            char chrs[] = attStr.toCharArray();
            for (int i=0; i<chrs.length; i++) {
                // only change valid chars
                if ((0x20 <= chrs[i] && chrs[i] <= 0x7f) ||
                    (0xa0 <= chrs[i] && chrs[i] <= 0xff)) {
                    chrs[i] |= 0xf000;
                    changed = true;
                }
            }

            if (changed) {
                attStr = new String(chrs);
            }
        }
        return attStr;
    }
}