/*
 * 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.
 */

/* $Id$ */

package org.apache.fop.fonts;

import java.awt.Rectangle;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.fop.apps.io.InternalResourceResolver;


/**
 * Abstract base class for custom fonts loaded from files, for example.
 */
public abstract class CustomFont extends Typeface
            implements FontDescriptor, MutableFont {

    /** Fallback thickness for underline and strikeout when not provided by the font. */
    private static final int DEFAULT_LINE_THICKNESS = 50;

    private URI fontFileURI;
    private String fontName;
    private String fullName;
    private Set<String> familyNames;
    private String fontSubName;
    private URI embedFileURI;
    private String embedResourceName;
    private final InternalResourceResolver resourceResolver;
    private EmbeddingMode embeddingMode = EmbeddingMode.AUTO;

    private int capHeight;
    private int xHeight;
    private int ascender;
    private int descender;
    private int[] fontBBox = {0, 0, 0, 0};
    private int flags = 4;
    private int weight; //0 means unknown weight
    private int stemV;
    private int italicAngle;
    private int missingWidth;
    private FontType fontType = FontType.TYPE1;
    private int firstChar;
    private int lastChar = 255;

    private int underlinePosition;

    private int underlineThickness;

    private int strikeoutPosition;

    private int strikeoutThickness;

    private Map<Integer, Map<Integer, Integer>> kerning;

    private boolean useKerning = true;
    /** the character map, mapping Unicode ranges to glyph indices. */
    protected List<CMapSegment> cmap = new ArrayList<CMapSegment>();
    private boolean useAdvanced = true;
    private boolean simulateStyle;
    protected List<SimpleSingleByteEncoding> additionalEncodings;
    protected Map<Character, SingleByteFont.UnencodedCharacter> unencodedCharacters;

    /**
     * @param resourceResolver the URI resource resolver for controlling file access
     */
    public CustomFont(InternalResourceResolver resourceResolver) {
        this.resourceResolver = resourceResolver;
    }


    /** {@inheritDoc} */
    public URI getFontURI() {
        return fontFileURI;
    }

    /** {@inheritDoc} */
    public String getFontName() {
        return fontName;
    }

    /** {@inheritDoc} */
    public String getEmbedFontName() {
        return getFontName();
    }

    /** {@inheritDoc} */
    public String getFullName() {
        return fullName;
    }

    /**
     * Returns the font family names.
     * @return the font family names (a Set of Strings)
     */
    public Set<String> getFamilyNames() {
        return Collections.unmodifiableSet(this.familyNames);
    }

    /**
     * Returns the font family name stripped of whitespace.
     * @return the stripped font family
     * @see FontUtil#stripWhiteSpace(String)
     */
    public String getStrippedFontName() {
        return FontUtil.stripWhiteSpace(getFontName());
    }

    /**
     * Returns font's subfamily name.
     * @return the font's subfamily name
     */
    public String getFontSubName() {
        return fontSubName;
    }

    /**
     * Returns an URI representing an embeddable font file.
     *
     * @return URI to an embeddable font file or null if not available.
     */
    public URI getEmbedFileURI() {
        return embedFileURI;
    }

    /**

     * Returns the embedding mode for this font.
     * @return embedding mode
     */
    public EmbeddingMode getEmbeddingMode() {
        return embeddingMode;
    }

    /**
     * Returns an {@link InputStream} representing an embeddable font file.
     *
     * @return {@link InputStream} for an embeddable font file
     * @throws IOException if embedFileName is not null but Source is not found
     */
    public InputStream getInputStream() throws IOException {
        return resourceResolver.getResource(embedFileURI);
    }

    /**
     * Returns the lookup name to an embeddable font file available as a
     * resource.
     * (todo) Remove this method, this should be done using a resource: URI.
     * @return the lookup name
     */
    public String getEmbedResourceName() {
        return embedResourceName;
    }

    /**
     * {@inheritDoc}
     */
    public int getAscender() {
        return ascender;
    }

    /**
     * {@inheritDoc}
     */
    public int getDescender() {
        return descender;
    }

    /**
     * {@inheritDoc}
     */
    public int getCapHeight() {
        return capHeight;
    }

    /**
     * {@inheritDoc}
     */
    public int getAscender(int size) {
        return size * ascender;
    }

    /**
     * {@inheritDoc}
     */
    public int getDescender(int size) {
        return size * descender;
    }

    /**
     * {@inheritDoc}
     */
    public int getCapHeight(int size) {
        return size * capHeight;
    }

    /**
     * {@inheritDoc}
     */
    public int getXHeight(int size) {
        return size * xHeight;
    }

    /**
     * {@inheritDoc}
     */
    public int[] getFontBBox() {
        return fontBBox;
    }

    /** {@inheritDoc} */
    public int getFlags() {
        return flags;
    }

    /** {@inheritDoc} */
    public boolean isSymbolicFont() {
        return ((getFlags() & 4) != 0) || "ZapfDingbatsEncoding".equals(getEncodingName());
        //Note: The check for ZapfDingbats is necessary as the PFM does not reliably indicate
        //if a font is symbolic.
    }

    /**
     * Returns the font weight (100, 200...800, 900). This value may be different from the
     * one that was actually used to register the font.
     * @return the font weight (or 0 if the font weight is unknown)
     */
    public int getWeight() {
        return this.weight;
    }

    /**
     * {@inheritDoc}
     */
    public int getStemV() {
        return stemV;
    }

    /**
     * {@inheritDoc}
     */
    public int getItalicAngle() {
        return italicAngle;
    }

    /**
     * Returns the width to be used when no width is available.
     * @return a character width
     */
    public int getMissingWidth() {
        return missingWidth;
    }

    /**
     * {@inheritDoc}
     */
    public FontType getFontType() {
        return fontType;
    }

    /**
     * Returns the index of the first character defined in this font.
     * @return the index of the first character
     */
    public int getFirstChar() {
        return firstChar;
    }

    /**
     * Returns the index of the last character defined in this font.
     * @return the index of the last character
     */
    public int getLastChar() {
        return lastChar;
    }

    /**
     * Used to determine if kerning is enabled.
     * @return True if kerning is enabled.
     */
    public boolean isKerningEnabled() {
        return useKerning;
    }

    /**
     * {@inheritDoc}
     */
    public final boolean hasKerningInfo() {
        return (isKerningEnabled() && (kerning != null) && !kerning.isEmpty());
    }

    /**
     * {@inheritDoc}
     */
    public final Map<Integer, Map<Integer, Integer>> getKerningInfo() {
        if (hasKerningInfo()) {
            return kerning;
        } else {
            return Collections.emptyMap();
        }
    }

    /**
     * Used to determine if advanced typographic features are enabled.
     * By default, this is false, but may be overridden by subclasses.
     * @return true if enabled.
     */
    public boolean isAdvancedEnabled() {
        return useAdvanced;
    }

    /* ---- MutableFont interface ---- */

    /** {@inheritDoc} */
    public void setFontURI(URI uri) {
        this.fontFileURI = uri;
    }

    /** {@inheritDoc} */
    public void setFontName(String name) {
        this.fontName = name;
    }

    /** {@inheritDoc} */
    public void setFullName(String name) {
        this.fullName = name;
    }

    /** {@inheritDoc} */
    public void setFamilyNames(Set<String> names) {
        this.familyNames = new HashSet<String>(names);
    }

    /**
     * Sets the font's subfamily name.
     * @param subFamilyName the subfamily name of the font
     */
    public void setFontSubFamilyName(String subFamilyName) {
        this.fontSubName = subFamilyName;
    }

    /**
     * {@inheritDoc}
     */
    public void setEmbedURI(URI path) {
        this.embedFileURI = path;
    }

    /**
     * {@inheritDoc}
     */
    public void setEmbedResourceName(String name) {
        this.embedResourceName = name;
    }

    /**
     * {@inheritDoc}
     */
    public void setEmbeddingMode(EmbeddingMode embeddingMode) {
        this.embeddingMode = embeddingMode;
    }

    /**
     * {@inheritDoc}
     */
    public void setCapHeight(int capHeight) {
        this.capHeight = capHeight;
    }

    /**
     * Returns the XHeight value of the font.
     * @param xHeight the XHeight value
     */
    public void setXHeight(int xHeight) {
        this.xHeight = xHeight;
    }

    /**
     * {@inheritDoc}
     */
    public void setAscender(int ascender) {
        this.ascender = ascender;
    }

    /**
     * {@inheritDoc}
     */
    public void setDescender(int descender) {
        this.descender = descender;
    }

    /**
     * {@inheritDoc}
     */
    public void setFontBBox(int[] bbox) {
        this.fontBBox = bbox;
    }

    /**
     * {@inheritDoc}
     */
    public void setFlags(int flags) {
        this.flags = flags;
    }

    /**
     * Sets the font weight. Valid values are 100, 200...800, 900.
     * @param weight the font weight
     */
    public void setWeight(int weight) {
        weight = (weight / 100) * 100;
        weight = Math.max(100, weight);
        weight = Math.min(900, weight);
        this.weight = weight;
    }

    /**
     * {@inheritDoc}
     */
    public void setStemV(int stemV) {
        this.stemV = stemV;
    }

    /**
     * {@inheritDoc}
     */
    public void setItalicAngle(int italicAngle) {
        this.italicAngle = italicAngle;
    }

    /**
     * {@inheritDoc}
     */
    public void setMissingWidth(int width) {
        this.missingWidth = width;
    }

    /**
     * {@inheritDoc}
     */
    public void setFontType(FontType fontType) {
        this.fontType = fontType;
    }

    /**
     * {@inheritDoc}
     */
    public void setFirstChar(int index) {
        this.firstChar = index;
    }

    /**
     * {@inheritDoc}
     */
    public void setLastChar(int index) {
        this.lastChar = index;
    }

    /**
     * {@inheritDoc}
     */
    public void setKerningEnabled(boolean enabled) {
        this.useKerning = enabled;
    }

    /**
     * {@inheritDoc}
     */
    public void setAdvancedEnabled(boolean enabled) {
        this.useAdvanced = enabled;
    }

    /**
     * {@inheritDoc}
     */
    public void setSimulateStyle(boolean enabled) {
        this.simulateStyle = enabled;
    }

    public boolean getSimulateStyle() {
        return this.simulateStyle;
    }

    /** {@inheritDoc} */
    public void putKerningEntry(Integer key, Map<Integer, Integer> value) {
        if (kerning == null) {
            kerning = new HashMap<Integer, Map<Integer, Integer>>();
        }
        this.kerning.put(key, value);
    }

    /**
     * Replaces the existing kerning map with a new one.
     * @param kerningMap the kerning map (the integers are
     *                          character codes)
     */
    public void replaceKerningMap(Map<Integer, Map<Integer, Integer>> kerningMap) {
        if (kerningMap == null) {
            this.kerning = Collections.emptyMap();
        } else {
            this.kerning = kerningMap;
        }
    }

    /**
     * Sets the character map for this font. It maps all available Unicode characters
     * to their glyph indices inside the font.
     * @param cmap the character map
     */
    public void setCMap(CMapSegment[] cmap) {
        this.cmap.clear();
        Collections.addAll(this.cmap, cmap);
    }

    /**
     * Returns the character map for this font. It maps all available Unicode characters
     * to their glyph indices inside the font.
     * @return the character map
     */
    public CMapSegment[] getCMap() {
        return cmap.toArray(new CMapSegment[cmap.size()]);
    }

    public int getUnderlinePosition(int size) {
        return (underlinePosition == 0)
                ? getDescender(size) / 2
                : size * underlinePosition;
    }

    public void setUnderlinePosition(int underlinePosition) {
        this.underlinePosition = underlinePosition;
    }

    public int getUnderlineThickness(int size) {
        return size * ((underlineThickness == 0) ? DEFAULT_LINE_THICKNESS : underlineThickness);
    }

    public void setUnderlineThickness(int underlineThickness) {
        this.underlineThickness = underlineThickness;
    }

    public int getStrikeoutPosition(int size) {
        return (strikeoutPosition == 0)
                ? getXHeight(size) / 2
                : size * strikeoutPosition;
    }

    public void setStrikeoutPosition(int strikeoutPosition) {
        this.strikeoutPosition = strikeoutPosition;
    }

    public int getStrikeoutThickness(int size) {
        return (strikeoutThickness == 0) ? getUnderlineThickness(size) : size * strikeoutThickness;
    }

    public void setStrikeoutThickness(int strikeoutThickness) {
        this.strikeoutThickness = strikeoutThickness;
    }

    /**
     * Returns a Map of used Glyphs.
     * @return Map Map of used Glyphs
     */
    public abstract Map<Integer, Integer> getUsedGlyphs();

    /**
     * Returns the character from it's original glyph index in the font
     * @param glyphIndex The original index of the character
     * @return The character
     */
    public abstract char getUnicodeFromGID(int glyphIndex);

    /**
     * Indicates whether the encoding has additional encodings besides the primary encoding.
     * @return true if there are additional encodings.
     */
    public boolean hasAdditionalEncodings() {
        return (this.additionalEncodings != null) && (this.additionalEncodings.size() > 0);
    }

    /**
     * Returns the number of additional encodings this single-byte font maintains.
     * @return the number of additional encodings
     */
    public int getAdditionalEncodingCount() {
        if (hasAdditionalEncodings()) {
            return this.additionalEncodings.size();
        } else {
            return 0;
        }
    }

    /**
     * Returns an additional encoding.
     * @param index the index of the additional encoding
     * @return the additional encoding
     * @throws IndexOutOfBoundsException if the index is out of bounds
     */
    public SimpleSingleByteEncoding getAdditionalEncoding(int index)
            throws IndexOutOfBoundsException {
        if (hasAdditionalEncodings()) {
            return this.additionalEncodings.get(index);
        } else {
            throw new IndexOutOfBoundsException("No additional encodings available");
        }
    }

    /**
     * Adds an unencoded character (one that is not supported by the primary encoding).
     * @param ch the named character
     * @param width the width of the character
     */
    public void addUnencodedCharacter(NamedCharacter ch, int width, Rectangle bbox) {
        if (this.unencodedCharacters == null) {
            this.unencodedCharacters = new HashMap<Character, SingleByteFont.UnencodedCharacter>();
        }
        if (ch.hasSingleUnicodeValue()) {
            SingleByteFont.UnencodedCharacter uc = new SingleByteFont.UnencodedCharacter(ch, width, bbox);
            this.unencodedCharacters.put(ch.getSingleUnicodeValue(), uc);
        } else {
            //Cannot deal with unicode sequences, so ignore this character
        }
    }

    /**
     * Adds a character to additional encodings
     * @param ch character to map
     */
    protected char mapUnencodedChar(char ch) {
        if (this.unencodedCharacters != null) {
            SingleByteFont.UnencodedCharacter unencoded = this.unencodedCharacters.get(ch);
            if (unencoded != null) {
                if (this.additionalEncodings == null) {
                    this.additionalEncodings = new ArrayList<SimpleSingleByteEncoding>();
                }
                SimpleSingleByteEncoding encoding = null;
                char mappedStart = 0;
                int additionalsCount = this.additionalEncodings.size();
                for (int i = 0; i < additionalsCount; i++) {
                    mappedStart += 256;
                    encoding = getAdditionalEncoding(i);
                    char alt = encoding.mapChar(ch);
                    if (alt != 0) {
                        return (char)(mappedStart + alt);
                    }
                }
                if (encoding != null && encoding.isFull()) {
                    encoding = null;
                }
                if (encoding == null) {
                    encoding = new SimpleSingleByteEncoding(
                            getFontName() + "EncodingSupp" + (additionalsCount + 1));
                    this.additionalEncodings.add(encoding);
                    mappedStart += 256;
                }
                return (char)(mappedStart + encoding.addCharacter(unencoded.getCharacter()));
            }
        }
        return 0;
    }
}