BBCodeToSpanTransformer

import android.content.Context;
import android.graphics.BlurMaskFilter;
import android.graphics.Color;
import android.graphics.EmbossMaskFilter;
import android.graphics.Typeface;
import android.net.Uri;
import android.text.Layout;
import android.text.style.AbsoluteSizeSpan;
import android.text.style.BackgroundColorSpan;
import android.text.style.ForegroundColorSpan;
import android.text.style.ImageSpan;
import android.text.style.QuoteSpan;
import android.text.style.RelativeSizeSpan;
import android.text.style.StrikethroughSpan;
import android.text.style.StyleSpan;
import android.text.style.TypefaceSpan;
import android.text.style.URLSpan;
import android.text.style.UnderlineSpan;
import android.text.style.AlignmentSpan;
import android.text.style.BulletSpan;
import android.text.style.MaskFilterSpan;
import android.text.style.SubscriptSpan;
import android.text.style.SuperscriptSpan;
import android.view.Gravity;

import com.binaryfork.spanny.Spanny;

import org.primeframework.transformer.domain.Document;
import org.primeframework.transformer.domain.Node;
import org.primeframework.transformer.domain.TagNode;
import org.primeframework.transformer.domain.TextNode;
import org.primeframework.transformer.service.TransformException;
import org.primeframework.transformer.service.TransformerSpanny;


/**
 * BBCode to Spanny Transformer For a downgraded version of https://github.com/inversoft/prime-transformer (Java 8 to Java 7)
 [bullet]First point[/bullet][BR]
[bullet]Second point[/bullet][BR]
[bullet=30]A[/bullet][BR]
[bullet=30]B[/bullet][BR]
[quote]Quote me if you can I'm writing so much text that I can be quoted for ages. Yes[/quote][BR]
[code]public method() static url variable + ; ... ++a - b = c;[/code][BR]
[blur]Blur this[/blur][BR]
[emboss][b]bold emboss this[/b][/emboss][BR]
[b][i]Bold italic[/i][/b][BR]
[s]strike[/s][BR]
[u]underline[/u][BR]
[style relsize=2.2]Bigger text[/style][BR]
32[superscript]2[/superscript] + x[BR]
[align=center]Align me if you can I'm writing so much text that I can be quoted for ages. Yes[/align][BR]
[align=opposite]Align me if you can I'm writing so much text that I can be quoted for ages. Yes[/align][BR]
[align=normal]Align me if you can I'm writing so much text that I can be quoted for ages. Yes[/align][BR]
[url=https://www.google.be]Google LINK[/url][BR]
[phone=+32466666666]0466666666[/phone]
 */
public class BBCodeToSpanTransformer implements TransformerSpanny {

    public static final String TAG_BOLD = "b";
    public static final String TAG_LABEL = "l";
    public static final String TAG_STRIKE = "s";
    public static final String TAG_ITALIC = "i";
    public static final String TAG_UNDERLINE = "u";
    public static final String TAG_URL = "url";
    public static final String TAG_PHONE = "phone";
    public static final String TAG_IMG = "img";
    public static final String TAG_CODE = "code";
    public static final String TAG_QUOTE = "quote";
    public static final String TAG_STYLE = "style";
    public static final String TAG_COLOR = "color";
    public static final String TAG_FONT_FAMILY = "font-family";

    public static final String TAG_BLUR = "blur";
    public static final String TAG_BULLET = "bullet";
    public static final String TAG_EMBOSS = "emboss";
    public static final String TAG_SUPERSCRIPT = "superscript";
    public static final String TAG_SUBSCRIPT = "subscript";
    public static final String TAG_FONT = "font";
    public static final String TAG_ALIGN = "align";

    public static final String ALIGN_CENTER = "center";
    public static final String ALIGN_NORMAL = "normal";
    public static final String ALIGN_OPPOSITE = "opposite";

    public static final String ATTR_BLUR = "blur";
    public static final String ATTR_EMBOSS = "emboss";
    public static final String ATTR_SUPERSCRIPT = "superscript";
    public static final String ATTR_SUBSCRIPT = "subscript";
    
    public static final String ATTR_COLOR = "color";
    public static final String ATTR_SIZE = "size";
    public static final String ATTR_ABS_SIZE = "abssize";
    public static final String ATTR_REL_SIZE = "relsize";
    public static final String ATTR_BG_COLOR = "bgcolor";
    public static final String ATTR_FG_COLOR = "fgcolor";
    public static final String ATTR_FONT_FAMILY = "font-family";

    private Context context;

    public BBCodeToSpanTransformer(Context context) {
        this.context = context;
    }

    @Override
    public Spanny transform(
            Document document,
            boolean transform)
            throws TransformException {

        return recurse(document, transform);
    }

    protected Spanny recurse(
            Node node,
            boolean transform)
            throws TransformException {
        Spanny spanny = new Spanny();

        if (node instanceof TextNode) {
            TextNode textNode = (TextNode) node;
            String text = textNode.getBody();

            spanny.append(text);
        } else if (node instanceof Document) {
            Document document = (Document) node;
            for (Node child : document.children) {
                spanny.append(recurse(child, transform));
            }
        } else if (node instanceof TagNode) {
            TagNode tagNode = (TagNode) node;
            String tagName = tagNode.getName().toLowerCase();

            if (transform) {
                // Transform the children first
                Spanny childBuild = new Spanny();
                for (Node child : tagNode.children) {
                    childBuild.append(recurse(child, transform));
                }

                transformToSpanny(spanny, tagName, tagNode, childBuild);

            } else {
                spanny.append(tagNode.getRawString());
            }
        } else {
            throw new TransformException("Invalid node class [" + node.getClass() + "]");
        }

        return spanny;
    }

    protected void transformToSpanny(
            final Spanny spanny,
            final String tagName,
            final TagNode tagNode,
            CharSequence body) {
        boolean tagUnknown = false;
        String attribute = tagNode.attribute;

        Object span = null;
        String url;

        switch (tagName) {
            case TAG_LABEL:
                body = "\n" + body + "\n";
                span = new StyleSpan(Typeface.BOLD);
                break;

            case TAG_BOLD:
                span = new StyleSpan(Typeface.BOLD);
                break;

            case TAG_ITALIC:
                span = new StyleSpan(Typeface.ITALIC);
                break;

            case TAG_UNDERLINE:
                span = new UnderlineSpan();
                break;

            case TAG_PHONE:
                url = attribute == null || attribute.isEmpty() ? "tel:" + body : "tel:" + attribute;
                span = new URLSpan(url);
                break;

            case TAG_URL:
                url = attribute == null || attribute.isEmpty() ? body.toString() : attribute;
                span = new URLSpan(url);
                break;

            case TAG_STRIKE:
                span = new StrikethroughSpan();
                break;

            case TAG_IMG:
                url = attribute == null || attribute.isEmpty() ? body.toString() : attribute;
                if (!canProcess(url)) {
                    return;
                }
                span = new ImageSpan(context, Uri.parse(processUrl(url)));
                break;

            case TAG_CODE:
                span = new QuoteSpan();
                break;

            case TAG_QUOTE:
                span = new QuoteSpan();
                break;

            case TAG_FONT_FAMILY:
                if (attribute != null && !attribute.isEmpty()) {
                    span = new TypefaceSpan(attribute);
                }
                break;

            case TAG_STYLE:
                if (!tagNode.attributes.isEmpty()) {
                    Object[] spans = new Object[tagNode.attributes.size()];
                    int i = 0;
                    for (String attrName : tagNode.attributes.keySet()) {
                        span = createStyleSpan(attrName, tagNode.attributes.get(attrName));
                        if (span == null) {
                            continue;
                        }
                        spans[i] = span;
                        i++;
                    }
                    spanny.append(body, spans);
                } else {
                    styleSingleAttributeBehavior(spanny, tagName, tagNode, body);
                }
                break;

            case TAG_COLOR:
                span = new ForegroundColorSpan(Color.parseColor(attribute));
                break;

            case TAG_BLUR:
                span = makeBlur();
                break;
            case TAG_BULLET:
                if (tagNode.attribute != null && !tagNode.attribute.isEmpty()) {
                    try {
                        span = new BulletSpan(Integer.valueOf(tagNode.attribute));
                    } catch (NumberFormatException ex) {
                        span = new BulletSpan();
                    }
                } else {
                    span = new BulletSpan();
                }
                break;
            case TAG_ALIGN:
                Layout.Alignment alignment = Layout.Alignment.ALIGN_CENTER;
                if (tagNode.attribute != null) {
                    switch (tagNode.attribute) {
                        case ALIGN_CENTER:
                            alignment = Layout.Alignment.ALIGN_CENTER;
                            break;
                        case ALIGN_NORMAL:
                            alignment = Layout.Alignment.ALIGN_NORMAL;
                            break;
                        case ALIGN_OPPOSITE:
                            alignment = Layout.Alignment.ALIGN_OPPOSITE;
                            break;
                        default:
                            alignment = Layout.Alignment.ALIGN_CENTER;
                    }
                }
                span = new AlignmentSpan.Standard(alignment);
                break;
            case TAG_EMBOSS:
                span = makeEmboss();
                break;

            case TAG_SUPERSCRIPT:
                span = new SuperscriptSpan();
                break;
            case TAG_SUBSCRIPT:
                span = new SubscriptSpan();
                break;

            case TAG_FONT:
                if (tagNode.attribute != null && !tagNode.attribute.isEmpty()) {
                    try {
                        Typeface font = Typeface.createFromAsset(getContext().getAssets(), tagNode.attribute);
                        if (font != null) {
                            span = new CustomTypefaceSpan(font);
                        }
                    } catch (Exception e) {
                        //Do nothing
                    }
                }
                break;
                
            default:
                tagUnknown = true;

        }
        if (tagNode.attributes.isEmpty() && !tagUnknown) {
            spanny.append(body, span);
        }
    }

    /**
     * Intended to be available for a child class to change the default behavior
     *
     * @param spanny
     * @param tagName
     * @param tagNode
     * @param body
     */
    protected void styleSingleAttributeBehavior(
            final Spanny spanny,
            final String tagName,
            final TagNode tagNode,
            CharSequence body) {

    }

    protected Object createStyleSpan(
            final String attrName,
            final String attrValue) {
        switch (attrName) {

            case ATTR_COLOR:
            case ATTR_FG_COLOR:
                return new ForegroundColorSpan(Color.parseColor(attrValue));

            case ATTR_BG_COLOR:
                return new BackgroundColorSpan(Color.parseColor(attrValue));

            case ATTR_SIZE:
            case ATTR_ABS_SIZE:
                return new AbsoluteSizeSpan(Integer.parseInt(attrValue), true);

            case ATTR_REL_SIZE:
                return new RelativeSizeSpan(Float.parseFloat(attrValue));

            case ATTR_FONT_FAMILY:
                return new TypefaceSpan(attrValue);

                            case ATTR_BLUR:
                return makeBlur();

            case ATTR_EMBOSS:
                return makeEmboss();

            case ATTR_SUPERSCRIPT:
                return new SuperscriptSpan();

            case ATTR_SUBSCRIPT:
                return new SubscriptSpan();
                
            default:
                return null;
        }
    }

    private Object makeBlur() {
        return new MaskFilterSpan(new BlurMaskFilter(
                getContext().getResources().getDisplayMetrics().density * 2, BlurMaskFilter.Blur.NORMAL));
    }

    private Object makeEmboss() {
        return new MaskFilterSpan(new EmbossMaskFilter(new float[] { 1, 1, 1 }, 0.4f, 6, 3.5f));
    }
    
    /**
     * Intended to be available for a child class to change the default behavior
     * By default this transformer does not support network calls as they need to be done outside the main thread
     *
     * @param url
     * @return
     */
    protected boolean canProcess(final String url) {
        return !url.startsWith("http");
    }

    /**
     * Intended to be available for a child class to change the default behavior
     * By default this transformer does not support network calls as they need to be done outside the main thread
     *
     * @param url
     * @return
     */
    protected String processUrl(final String url) {
        return url;
    }
}