/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2020 - Raw Material Software Limited

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 6 End-User License
   Agreement and JUCE Privacy Policy (both effective as of the 16th June 2020).

   End User License Agreement: www.juce.com/juce-6-licence
   Privacy Policy: www.juce.com/juce-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

namespace FontValues
{
    static float limitFontHeight (const float height) noexcept
    {
        return jlimit (0.1f, 10000.0f, height);
    }

    const float defaultFontHeight = 14.0f;
    float minimumHorizontalScale = 0.7f;
    String fallbackFont;
    String fallbackFontStyle;
}

using GetTypefaceForFont = Typeface::Ptr (*)(const Font&);
GetTypefaceForFont juce_getTypefaceForFont = nullptr;

float Font::getDefaultMinimumHorizontalScaleFactor() noexcept                { return FontValues::minimumHorizontalScale; }
void Font::setDefaultMinimumHorizontalScaleFactor (float newValue) noexcept  { FontValues::minimumHorizontalScale = newValue; }

//==============================================================================
class TypefaceCache  : private DeletedAtShutdown
{
public:
    TypefaceCache()
    {
        setSize (10);
    }

    ~TypefaceCache()
    {
        clearSingletonInstance();
    }

    JUCE_DECLARE_SINGLETON (TypefaceCache, false)

    void setSize (const int numToCache)
    {
        const ScopedWriteLock sl (lock);

        faces.clear();
        faces.insertMultiple (-1, CachedFace(), numToCache);
    }

    void clear()
    {
        const ScopedWriteLock sl (lock);

        setSize (faces.size());
        defaultFace = nullptr;
    }

    Typeface::Ptr findTypefaceFor (const Font& font)
    {
        const auto faceName = font.getTypefaceName();
        const auto faceStyle = font.getTypefaceStyle();

        jassert (faceName.isNotEmpty());

        {
            const ScopedReadLock slr (lock);

            for (int i = faces.size(); --i >= 0;)
            {
                CachedFace& face = faces.getReference(i);

                if (face.typefaceName == faceName
                     && face.typefaceStyle == faceStyle
                     && face.typeface != nullptr
                     && face.typeface->isSuitableForFont (font))
                {
                    face.lastUsageCount = ++counter;
                    return face.typeface;
                }
            }
        }

        const ScopedWriteLock slw (lock);
        int replaceIndex = 0;
        auto bestLastUsageCount = std::numeric_limits<size_t>::max();

        for (int i = faces.size(); --i >= 0;)
        {
            auto lu = faces.getReference(i).lastUsageCount;

            if (bestLastUsageCount > lu)
            {
                bestLastUsageCount = lu;
                replaceIndex = i;
            }
        }

        auto& face = faces.getReference (replaceIndex);
        face.typefaceName = faceName;
        face.typefaceStyle = faceStyle;
        face.lastUsageCount = ++counter;

        if (juce_getTypefaceForFont == nullptr)
            face.typeface = Font::getDefaultTypefaceForFont (font);
        else
            face.typeface = juce_getTypefaceForFont (font);

        jassert (face.typeface != nullptr); // the look and feel must return a typeface!

        if (defaultFace == nullptr && font == Font())
            defaultFace = face.typeface;

        return face.typeface;
    }

    Typeface::Ptr getDefaultFace() const noexcept
    {
        const ScopedReadLock slr (lock);
        return defaultFace;
    }

private:
    struct CachedFace
    {
        CachedFace() noexcept {}

        // Although it seems a bit wacky to store the name here, it's because it may be a
        // placeholder rather than a real one, e.g. "<Sans-Serif>" vs the actual typeface name.
        // Since the typeface itself doesn't know that it may have this alias, the name under
        // which it was fetched needs to be stored separately.
        String typefaceName, typefaceStyle;
        size_t lastUsageCount = 0;
        Typeface::Ptr typeface;
    };

    Typeface::Ptr defaultFace;
    ReadWriteLock lock;
    Array<CachedFace> faces;
    size_t counter = 0;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (TypefaceCache)
};

JUCE_IMPLEMENT_SINGLETON (TypefaceCache)

void Typeface::setTypefaceCacheSize (int numFontsToCache)
{
    TypefaceCache::getInstance()->setSize (numFontsToCache);
}

void (*clearOpenGLGlyphCache)() = nullptr;

void Typeface::clearTypefaceCache()
{
    TypefaceCache::getInstance()->clear();

    RenderingHelpers::SoftwareRendererSavedState::clearGlyphCache();

    if (clearOpenGLGlyphCache != nullptr)
        clearOpenGLGlyphCache();
}

//==============================================================================
class Font::SharedFontInternal  : public ReferenceCountedObject
{
public:
    SharedFontInternal() noexcept
        : typeface (TypefaceCache::getInstance()->getDefaultFace()),
          typefaceName (Font::getDefaultSansSerifFontName()),
          typefaceStyle (Font::getDefaultStyle()),
          height (FontValues::defaultFontHeight)
    {
    }

    SharedFontInternal (int styleFlags, float fontHeight) noexcept
        : typefaceName (Font::getDefaultSansSerifFontName()),
          typefaceStyle (FontStyleHelpers::getStyleName (styleFlags)),
          height (fontHeight),
          underline ((styleFlags & underlined) != 0)
    {
        if (styleFlags == plain)
            typeface = TypefaceCache::getInstance()->getDefaultFace();
    }

    SharedFontInternal (const String& name, int styleFlags, float fontHeight) noexcept
        : typefaceName (name),
          typefaceStyle (FontStyleHelpers::getStyleName (styleFlags)),
          height (fontHeight),
          underline ((styleFlags & underlined) != 0)
    {
        if (styleFlags == plain && typefaceName.isEmpty())
            typeface = TypefaceCache::getInstance()->getDefaultFace();
    }

    SharedFontInternal (const String& name, const String& style, float fontHeight) noexcept
        : typefaceName (name), typefaceStyle (style), height (fontHeight)
    {
        if (typefaceName.isEmpty())
            typefaceName = Font::getDefaultSansSerifFontName();
    }

    explicit SharedFontInternal (const Typeface::Ptr& face) noexcept
        : typeface (face),
          typefaceName (face->getName()),
          typefaceStyle (face->getStyle()),
          height (FontValues::defaultFontHeight)
    {
        jassert (typefaceName.isNotEmpty());
    }

    SharedFontInternal (const SharedFontInternal& other) noexcept
        : ReferenceCountedObject(),
          typeface (other.typeface),
          typefaceName (other.typefaceName),
          typefaceStyle (other.typefaceStyle),
          height (other.height),
          horizontalScale (other.horizontalScale),
          kerning (other.kerning),
          ascent (other.ascent),
          underline (other.underline)
    {
    }

    bool operator== (const SharedFontInternal& other) const noexcept
    {
        return height == other.height
                && underline == other.underline
                && horizontalScale == other.horizontalScale
                && kerning == other.kerning
                && typefaceName == other.typefaceName
                && typefaceStyle == other.typefaceStyle;
    }

    /*  The typeface and ascent data members may be read/set from multiple threads
        simultaneously, e.g. in the case that two Font instances reference the same
        SharedFontInternal and call getTypefacePtr() simultaneously.

        We lock in functions that modify the typeface or ascent in order to
        ensure thread safety.
    */

    Typeface::Ptr getTypefacePtr (const Font& f)
    {
        const ScopedLock lock (mutex);

        if (typeface == nullptr)
        {
            typeface = TypefaceCache::getInstance()->findTypefaceFor (f);
            jassert (typeface != nullptr);
        }

        return typeface;
    }

    void checkTypefaceSuitability (const Font& f)
    {
        const ScopedLock lock (mutex);

        if (typeface != nullptr && ! typeface->isSuitableForFont (f))
            typeface = nullptr;
    }

    float getAscent (const Font& f)
    {
        const ScopedLock lock (mutex);

        if (ascent == 0.0f)
            ascent = getTypefacePtr (f)->getAscent();

        return height * ascent;
    }

    /*  We do not need to lock in these functions, as it's guaranteed
        that these data members can only change if there is a single Font
        instance referencing the shared state.
    */

    String getTypefaceName() const          { return typefaceName; }
    String getTypefaceStyle() const         { return typefaceStyle; }
    float getHeight() const                 { return height; }
    float getHorizontalScale() const        { return horizontalScale; }
    float getKerning() const                { return kerning; }
    bool getUnderline() const               { return underline; }

    /*  This shared state may be shared between two or more Font instances that are being
        read/modified from multiple threads.
        Before modifying a shared instance you *must* call dupeInternalIfShared to
        ensure that only one Font instance is pointing to the SharedFontInternal instance
        during the modification.
    */

    void setTypeface (Typeface::Ptr x)
    {
        jassert (getReferenceCount() == 1);
        typeface = std::move (x);
    }

    void setTypefaceName (String x)
    {
        jassert (getReferenceCount() == 1);
        typefaceName = std::move (x);
    }

    void setTypefaceStyle (String x)
    {
        jassert (getReferenceCount() == 1);
        typefaceStyle = std::move (x);
    }

    void setHeight (float x)
    {
        jassert (getReferenceCount() == 1);
        height = x;
    }

    void setHorizontalScale (float x)
    {
        jassert (getReferenceCount() == 1);
        horizontalScale = x;
    }

    void setKerning (float x)
    {
        jassert (getReferenceCount() == 1);
        kerning = x;
    }

    void setAscent (float x)
    {
        jassert (getReferenceCount() == 1);
        ascent = x;
    }

    void setUnderline (bool x)
    {
        jassert (getReferenceCount() == 1);
        underline = x;
    }

private:
    Typeface::Ptr typeface;
    String typefaceName, typefaceStyle;
    float height = 0.0f, horizontalScale = 1.0f, kerning = 0.0f, ascent = 0.0f;
    bool underline = false;

    CriticalSection mutex;
};

//==============================================================================
Font::Font()                                : font (new SharedFontInternal()) {}
Font::Font (const Typeface::Ptr& typeface)  : font (new SharedFontInternal (typeface)) {}
Font::Font (const Font& other) noexcept     : font (other.font) {}

Font::Font (float fontHeight, int styleFlags)
    : font (new SharedFontInternal (styleFlags, FontValues::limitFontHeight (fontHeight)))
{
}

Font::Font (const String& typefaceName, float fontHeight, int styleFlags)
    : font (new SharedFontInternal (typefaceName, styleFlags, FontValues::limitFontHeight (fontHeight)))
{
}

Font::Font (const String& typefaceName, const String& typefaceStyle, float fontHeight)
    : font (new SharedFontInternal (typefaceName, typefaceStyle, FontValues::limitFontHeight (fontHeight)))
{
}

Font& Font::operator= (const Font& other) noexcept
{
    font = other.font;
    return *this;
}

Font::Font (Font&& other) noexcept
    : font (std::move (other.font))
{
}

Font& Font::operator= (Font&& other) noexcept
{
    font = std::move (other.font);
    return *this;
}

Font::~Font() noexcept = default;

bool Font::operator== (const Font& other) const noexcept
{
    return font == other.font
            || *font == *other.font;
}

bool Font::operator!= (const Font& other) const noexcept
{
    return ! operator== (other);
}

void Font::dupeInternalIfShared()
{
    if (font->getReferenceCount() > 1)
        font = *new SharedFontInternal (*font);
}

void Font::checkTypefaceSuitability()
{
    font->checkTypefaceSuitability (*this);
}

//==============================================================================
struct FontPlaceholderNames
{
    String sans    { "<Sans-Serif>" },
           serif   { "<Serif>" },
           mono    { "<Monospaced>" },
           regular { "<Regular>" };
};

static const FontPlaceholderNames& getFontPlaceholderNames()
{
    static FontPlaceholderNames names;
    return names;
}

#if JUCE_MSVC
// This is a workaround for the lack of thread-safety in MSVC's handling of function-local
// statics - if multiple threads all try to create the first Font object at the same time,
// it can cause a race-condition in creating these placeholder strings.
struct FontNamePreloader { FontNamePreloader() { getFontPlaceholderNames(); } };
static FontNamePreloader fnp;
#endif

const String& Font::getDefaultSansSerifFontName()       { return getFontPlaceholderNames().sans; }
const String& Font::getDefaultSerifFontName()           { return getFontPlaceholderNames().serif; }
const String& Font::getDefaultMonospacedFontName()      { return getFontPlaceholderNames().mono; }
const String& Font::getDefaultStyle()                   { return getFontPlaceholderNames().regular; }

String Font::getTypefaceName() const noexcept           { return font->getTypefaceName(); }
String Font::getTypefaceStyle() const noexcept          { return font->getTypefaceStyle(); }

void Font::setTypefaceName (const String& faceName)
{
    if (faceName != font->getTypefaceName())
    {
        jassert (faceName.isNotEmpty());

        dupeInternalIfShared();
        font->setTypefaceName (faceName);
        font->setTypeface (nullptr);
        font->setAscent (0);
    }
}

void Font::setTypefaceStyle (const String& typefaceStyle)
{
    if (typefaceStyle != font->getTypefaceStyle())
    {
        dupeInternalIfShared();
        font->setTypefaceStyle (typefaceStyle);
        font->setTypeface (nullptr);
        font->setAscent (0);
    }
}

Font Font::withTypefaceStyle (const String& newStyle) const
{
    Font f (*this);
    f.setTypefaceStyle (newStyle);
    return f;
}

StringArray Font::getAvailableStyles() const
{
    return findAllTypefaceStyles (getTypefacePtr()->getName());
}

Typeface::Ptr Font::getTypefacePtr() const
{
    return font->getTypefacePtr (*this);
}

Typeface* Font::getTypeface() const
{
    return getTypefacePtr().get();
}

//==============================================================================
const String& Font::getFallbackFontName()
{
    return FontValues::fallbackFont;
}

void Font::setFallbackFontName (const String& name)
{
    FontValues::fallbackFont = name;

   #if JUCE_MAC || JUCE_IOS
    jassertfalse; // Note that use of a fallback font isn't currently implemented in OSX..
   #endif
}

const String& Font::getFallbackFontStyle()
{
    return FontValues::fallbackFontStyle;
}

void Font::setFallbackFontStyle (const String& style)
{
    FontValues::fallbackFontStyle = style;

   #if JUCE_MAC || JUCE_IOS
    jassertfalse; // Note that use of a fallback font isn't currently implemented in OSX..
   #endif
}

//==============================================================================
Font Font::withHeight (const float newHeight) const
{
    Font f (*this);
    f.setHeight (newHeight);
    return f;
}

float Font::getHeightToPointsFactor() const
{
    return getTypefacePtr()->getHeightToPointsFactor();
}

Font Font::withPointHeight (float heightInPoints) const
{
    Font f (*this);
    f.setHeight (heightInPoints / getHeightToPointsFactor());
    return f;
}

void Font::setHeight (float newHeight)
{
    newHeight = FontValues::limitFontHeight (newHeight);

    if (font->getHeight() != newHeight)
    {
        dupeInternalIfShared();
        font->setHeight (newHeight);
        checkTypefaceSuitability();
    }
}

void Font::setHeightWithoutChangingWidth (float newHeight)
{
    newHeight = FontValues::limitFontHeight (newHeight);

    if (font->getHeight() != newHeight)
    {
        dupeInternalIfShared();
        font->setHorizontalScale (font->getHorizontalScale() * (font->getHeight() / newHeight));
        font->setHeight (newHeight);
        checkTypefaceSuitability();
    }
}

int Font::getStyleFlags() const noexcept
{
    int styleFlags = font->getUnderline() ? underlined : plain;

    if (isBold())    styleFlags |= bold;
    if (isItalic())  styleFlags |= italic;

    return styleFlags;
}

Font Font::withStyle (const int newFlags) const
{
    Font f (*this);
    f.setStyleFlags (newFlags);
    return f;
}

void Font::setStyleFlags (const int newFlags)
{
    if (getStyleFlags() != newFlags)
    {
        dupeInternalIfShared();
        font->setTypeface (nullptr);
        font->setTypefaceStyle (FontStyleHelpers::getStyleName (newFlags));
        font->setUnderline ((newFlags & underlined) != 0);
        font->setAscent (0);
    }
}

void Font::setSizeAndStyle (float newHeight,
                            const int newStyleFlags,
                            const float newHorizontalScale,
                            const float newKerningAmount)
{
    newHeight = FontValues::limitFontHeight (newHeight);

    if (font->getHeight() != newHeight
         || font->getHorizontalScale() != newHorizontalScale
         || font->getKerning() != newKerningAmount)
    {
        dupeInternalIfShared();
        font->setHeight (newHeight);
        font->setHorizontalScale (newHorizontalScale);
        font->setKerning (newKerningAmount);
        checkTypefaceSuitability();
    }

    setStyleFlags (newStyleFlags);
}

void Font::setSizeAndStyle (float newHeight,
                            const String& newStyle,
                            const float newHorizontalScale,
                            const float newKerningAmount)
{
    newHeight = FontValues::limitFontHeight (newHeight);

    if (font->getHeight() != newHeight
         || font->getHorizontalScale() != newHorizontalScale
         || font->getKerning() != newKerningAmount)
    {
        dupeInternalIfShared();
        font->setHeight (newHeight);
        font->setHorizontalScale (newHorizontalScale);
        font->setKerning (newKerningAmount);
        checkTypefaceSuitability();
    }

    setTypefaceStyle (newStyle);
}

Font Font::withHorizontalScale (const float newHorizontalScale) const
{
    Font f (*this);
    f.setHorizontalScale (newHorizontalScale);
    return f;
}

void Font::setHorizontalScale (const float scaleFactor)
{
    dupeInternalIfShared();
    font->setHorizontalScale (scaleFactor);
    checkTypefaceSuitability();
}

float Font::getHorizontalScale() const noexcept
{
    return font->getHorizontalScale();
}

float Font::getExtraKerningFactor() const noexcept
{
    return font->getKerning();
}

Font Font::withExtraKerningFactor (const float extraKerning) const
{
    Font f (*this);
    f.setExtraKerningFactor (extraKerning);
    return f;
}

void Font::setExtraKerningFactor (const float extraKerning)
{
    dupeInternalIfShared();
    font->setKerning (extraKerning);
    checkTypefaceSuitability();
}

Font Font::boldened() const                 { return withStyle (getStyleFlags() | bold); }
Font Font::italicised() const               { return withStyle (getStyleFlags() | italic); }

bool Font::isBold() const noexcept          { return FontStyleHelpers::isBold   (font->getTypefaceStyle()); }
bool Font::isItalic() const noexcept        { return FontStyleHelpers::isItalic (font->getTypefaceStyle()); }
bool Font::isUnderlined() const noexcept    { return font->getUnderline(); }

void Font::setBold (const bool shouldBeBold)
{
    auto flags = getStyleFlags();
    setStyleFlags (shouldBeBold ? (flags | bold)
                                : (flags & ~bold));
}

void Font::setItalic (const bool shouldBeItalic)
{
    auto flags = getStyleFlags();
    setStyleFlags (shouldBeItalic ? (flags | italic)
                                  : (flags & ~italic));
}

void Font::setUnderline (const bool shouldBeUnderlined)
{
    dupeInternalIfShared();
    font->setUnderline (shouldBeUnderlined);
    checkTypefaceSuitability();
}

float Font::getAscent() const
{
    return font->getAscent (*this);
}

float Font::getHeight() const noexcept      { return font->getHeight(); }
float Font::getDescent() const              { return font->getHeight() - getAscent(); }

float Font::getHeightInPoints() const       { return getHeight()  * getHeightToPointsFactor(); }
float Font::getAscentInPoints() const       { return getAscent()  * getHeightToPointsFactor(); }
float Font::getDescentInPoints() const      { return getDescent() * getHeightToPointsFactor(); }

int Font::getStringWidth (const String& text) const
{
    return (int) std::ceil (getStringWidthFloat (text));
}

float Font::getStringWidthFloat (const String& text) const
{
    auto w = getTypefacePtr()->getStringWidth (text);

    if (font->getKerning() != 0.0f)
        w += font->getKerning() * (float) text.length();

    return w * font->getHeight() * font->getHorizontalScale();
}

void Font::getGlyphPositions (const String& text, Array<int>& glyphs, Array<float>& xOffsets) const
{
    getTypefacePtr()->getGlyphPositions (text, glyphs, xOffsets);

    if (auto num = xOffsets.size())
    {
        auto scale = font->getHeight() * font->getHorizontalScale();
        auto* x = xOffsets.getRawDataPointer();

        if (font->getKerning() != 0.0f)
        {
            for (int i = 0; i < num; ++i)
                x[i] = (x[i] + (float) i * font->getKerning()) * scale;
        }
        else
        {
            for (int i = 0; i < num; ++i)
                x[i] *= scale;
        }
    }
}

void Font::findFonts (Array<Font>& destArray)
{
    for (auto& name : findAllTypefaceNames())
    {
        auto styles = findAllTypefaceStyles (name);

        String style ("Regular");

        if (! styles.contains (style, true))
            style = styles[0];

        destArray.add (Font (name, style, FontValues::defaultFontHeight));
    }
}

//==============================================================================
String Font::toString() const
{
    String s;

    if (getTypefaceName() != getDefaultSansSerifFontName())
        s << getTypefaceName() << "; ";

    s << String (getHeight(), 1);

    if (getTypefaceStyle() != getDefaultStyle())
        s << ' ' << getTypefaceStyle();

    return s;
}

Font Font::fromString (const String& fontDescription)
{
    const int separator = fontDescription.indexOfChar (';');
    String name;

    if (separator > 0)
        name = fontDescription.substring (0, separator).trim();

    if (name.isEmpty())
        name = getDefaultSansSerifFontName();

    String sizeAndStyle (fontDescription.substring (separator + 1).trimStart());

    float height = sizeAndStyle.getFloatValue();
    if (height <= 0)
        height = 10.0f;

    const String style (sizeAndStyle.fromFirstOccurrenceOf (" ", false, false));

    return Font (name, style, height);
}

} // namespace juce