// ================================================================================
// ==      This file is a part of Turbo Badger. (C) 2011-2014, Emil Segerås      ==
// ==                     See tb_core.h for more information.                    ==
// ================================================================================

#include "tb_font_renderer.h"
#include "tb_renderer.h"
#include "tb_system.h"
#include <math.h>

namespace tb {

// ================================================================================================

static void blurGlyph(unsigned char* src, int srcw, int srch, int srcStride, unsigned char* dst, int dstw, int dsth, int dstStride, float* temp, float* kernel, int kernelRadius)
{
    for (int y = 0; y < srch; y++)
    {
        for (int x = 0; x < dstw; x++)
        {
            float val = 0;
            for (int k_ofs = -kernelRadius; k_ofs <= kernelRadius; k_ofs++)
            {
                if (x - kernelRadius + k_ofs >= 0 && x - kernelRadius + k_ofs < srcw)
                    val += src[y * srcStride + x - kernelRadius + k_ofs] * kernel[k_ofs + kernelRadius];
            }
            temp[y * dstw + x] = val;
        }
    }
    for (int y = 0; y < dsth; y++)
    {
        for (int x = 0; x < dstw; x++)
        {
            float val = 0;
            for (int k_ofs = -kernelRadius; k_ofs <= kernelRadius; k_ofs++)
            {
                if (y - kernelRadius + k_ofs >= 0 && y - kernelRadius + k_ofs < srch)
                    val += temp[(y - kernelRadius + k_ofs) * dstw + x] * kernel[k_ofs + kernelRadius];
            }
            dst[y * dstStride + x] = (unsigned char)(val + 0.5f);
        }
    }
}

// ================================================================================================

TBFontEffect::TBFontEffect()
    : m_blur_radius(0)
    , m_tempBuffer(nullptr)
    , m_kernel(nullptr)
{
}

TBFontEffect::~TBFontEffect()
{
    delete [] m_tempBuffer;
    delete [] m_kernel;
}

void TBFontEffect::SetBlurRadius(int blur_radius)
{
    assert(blur_radius >= 0);
    if (m_blur_radius == blur_radius)
        return;
    m_blur_radius = blur_radius;
    if (m_blur_radius > 0)
    {
        delete [] m_kernel;
        m_kernel = new float[m_blur_radius * 2 + 1];
        if (!m_kernel)
        {
            m_blur_radius = 0;
            return;
        }
        float stdDevSq2 = (float)m_blur_radius / 2.f;
        stdDevSq2 = 2.f * stdDevSq2 * stdDevSq2;
        float scale = 1.f / sqrt(3.1415f * stdDevSq2);
        float sum = 0;
        for (int k = 0; k < 2 * m_blur_radius + 1; k++)
        {
            float x = (float)(k - m_blur_radius);
            float kval = scale * exp(-(x * x / stdDevSq2));
            m_kernel[k] = kval;
            sum += kval;
        }
        for (int k = 0; k < 2 * m_blur_radius + 1; k++)
            m_kernel[k] /= sum;
    }
}

TBFontGlyphData *TBFontEffect::Render(TBGlyphMetrics *metrics, const TBFontGlyphData *src)
{
    TBFontGlyphData *effect_glyph_data = nullptr;
    if (m_blur_radius > 0 && src->data8)
    {
        // Create a new TBFontGlyphData for the blurred glyph
        effect_glyph_data = new TBFontGlyphData;
        if (!effect_glyph_data)
            return nullptr;
        effect_glyph_data->w = src->w + m_blur_radius * 2;
        effect_glyph_data->h = src->h + m_blur_radius * 2;
        effect_glyph_data->stride = effect_glyph_data->w;
        effect_glyph_data->data8 = new unsigned char[effect_glyph_data->w * effect_glyph_data->h];

        // Reserve memory needed for blurring.
        if (!effect_glyph_data->data8 ||
                !m_blur_temp.Reserve(effect_glyph_data->w * effect_glyph_data->h * sizeof(float)))
        {
            delete effect_glyph_data;
            return nullptr;
        }

        // Blur!
        blurGlyph(src->data8, src->w, src->h, src->stride,
                  effect_glyph_data->data8, effect_glyph_data->w, effect_glyph_data->h, effect_glyph_data->w,
                  (float *)m_blur_temp.GetData(), m_kernel, m_blur_radius);

        // Adjust glyph position to compensate for larger size.
        metrics->x -= m_blur_radius;
        metrics->y -= m_blur_radius;
    }
    return effect_glyph_data;
}

// == TBFontGlyph =================================================================================

TBFontGlyph::TBFontGlyph(const TBID &hash_id, UCS4 cp)
    : hash_id(hash_id)
    , cp(cp)
    , frag(nullptr)
    , has_rgb(false)
{
}

// == TBFontGlyphCache ============================================================================

TBFontGlyphCache::TBFontGlyphCache()
{
    // Only use one map for the font face. The glyph cache will start forgetting
    // glyphs that haven't been used for a while if the map gets full.
    m_frag_manager.SetNumMapsLimit(1);
    m_frag_manager.SetDefaultMapSize(TB_GLYPH_CACHE_WIDTH, TB_GLYPH_CACHE_HEIGHT);

    g_renderer->AddListener(this);
}

TBFontGlyphCache::~TBFontGlyphCache()
{
    g_renderer->RemoveListener(this);
}

TBFontGlyph *TBFontGlyphCache::GetGlyph(const TBID &hash_id, UCS4 cp)
{
    if (TBFontGlyph *glyph = m_glyphs.Get(hash_id))
    {
        // Move the glyph to the end of m_all_rendered_glyphs so we maintain LRU (oldest first)
        if (m_all_rendered_glyphs.ContainsLink(glyph))
        {
            m_all_rendered_glyphs.Remove(glyph);
            m_all_rendered_glyphs.AddLast(glyph);
        }
        return glyph;
    }
    return nullptr;
}

TBFontGlyph *TBFontGlyphCache::CreateAndCacheGlyph(const TBID &hash_id, UCS4 cp)
{
    assert(!GetGlyph(hash_id, cp));
    TBFontGlyph *glyph = new TBFontGlyph(hash_id, cp);
    if (glyph && m_glyphs.Add(glyph->hash_id, glyph))
        return glyph;
    delete glyph;
    return nullptr;
}

TBBitmapFragment *TBFontGlyphCache::CreateFragment(TBFontGlyph *glyph, int w, int h, int stride, uint32 *data)
{
    assert(GetGlyph(glyph->hash_id, glyph->cp));
    // Don't bother if the requested glyph is too large.
    if (w > TB_GLYPH_CACHE_WIDTH || h > TB_GLYPH_CACHE_HEIGHT)
        return nullptr;

    bool try_drop_largest = true;
    bool dropped_large_enough_glyph = false;
    do
    {
        // Attempt creating a fragment for the rendered glyph data
        if (TBBitmapFragment *frag = m_frag_manager.CreateNewFragment(glyph->hash_id, false, w, h, stride, data))
        {
            glyph->frag = frag;
            m_all_rendered_glyphs.AddLast(glyph);
            return frag;
        }
        // Drop the oldest glyph that's large enough to free up the space we need.
        if (try_drop_largest)
        {
            const int check_limit = 20;
            int check_count = 0;
            for (TBFontGlyph *oldest = m_all_rendered_glyphs.GetFirst(); oldest && check_count < check_limit; oldest = oldest->GetNext())
            {
                if (oldest->frag->Width() >= w && oldest->frag->GetAllocatedHeight() >= h)
                {
                    DropGlyphFragment(oldest);
                    dropped_large_enough_glyph = true;
                    break;
                }
                check_count++;
            }
            try_drop_largest = false;
        }
        // We had no large enough glyph so just drop the oldest one. We will likely
        // spin around the loop, fail and drop again a few times before we succeed.
        if (!dropped_large_enough_glyph)
        {
            if (TBFontGlyph *oldest = m_all_rendered_glyphs.GetFirst())
                DropGlyphFragment(oldest);
            else
                break;
        }
    } while (true);
    return nullptr;
}

void TBFontGlyphCache::DropGlyphFragment(TBFontGlyph *glyph)
{
    assert(glyph->frag);
    m_frag_manager.FreeFragment(glyph->frag);
    glyph->frag = nullptr;
    m_all_rendered_glyphs.Remove(glyph);
}

#ifdef TB_RUNTIME_DEBUG_INFO
void TBFontGlyphCache::Debug()
{
    m_frag_manager.Debug();
}
#endif // TB_RUNTIME_DEBUG_INFO

void TBFontGlyphCache::OnContextLost()
{
    m_frag_manager.DeleteBitmaps();
}

void TBFontGlyphCache::OnContextRestored()
{
    // No need to do anything. The bitmaps will be created when drawing.
}

// ================================================================================================

TBFontFace::TBFontFace(TBFontGlyphCache *glyph_cache, TBFontRenderer *renderer, const TBFontDescription &font_desc)
    : m_glyph_cache(glyph_cache), m_font_renderer(renderer), m_font_desc(font_desc), m_bgFont(nullptr), m_bgX(0), m_bgY(0)
{
    if (m_font_renderer)
        m_metrics = m_font_renderer->GetMetrics();
    else
    {
        // Invent some metrics for the test font
        int size = m_font_desc.GetSize();
        m_metrics.ascent = size - size / 4;
        m_metrics.descent = size / 4;
        m_metrics.height = size;
    }
}

TBFontFace::~TBFontFace()
{
    // It would be nice to drop all glyphs we have live for this font face.
    // Now they only die when they get old and kicked out of the cache.
    // We currently don't drop any font faces either though (except on shutdown)
    delete m_font_renderer;
}

void TBFontFace::SetBackgroundFont(TBFontFace *font, const TBColor &col, int xofs, int yofs)
{
    m_bgFont = font;
    m_bgX = xofs;
    m_bgY = yofs;
    m_bgColor = col;
}

bool TBFontFace::RenderGlyphs(const char *glyph_str, int glyph_str_len)
{
    if (!m_font_renderer)
        return true; // This is the test font

    if (glyph_str_len == TB_ALL_TO_TERMINATION)
        glyph_str_len = strlen(glyph_str);

    bool has_all_glyphs = true;
    int i = 0;
    while (glyph_str[i] && i < glyph_str_len)
    {
        UCS4 cp = utf8::decode_next(glyph_str, &i, glyph_str_len);
        if (!GetGlyph(cp, true))
            has_all_glyphs = false;
    }
    return has_all_glyphs;
}

TBFontGlyph *TBFontFace::CreateAndCacheGlyph(UCS4 cp)
{
    if (!m_font_renderer)
        return nullptr; // This is the test font

    // Create the new glyph
    TBFontGlyph *glyph = m_glyph_cache->CreateAndCacheGlyph(GetHashId(cp), cp);
    if (glyph)
        m_font_renderer->GetGlyphMetrics(&glyph->metrics, cp);
    return glyph;
}

void TBFontFace::RenderGlyph(TBFontGlyph *glyph)
{
    assert(!glyph->frag);
    TBFontGlyphData glyph_data;
    if (m_font_renderer->RenderGlyph(&glyph_data, glyph->cp))
    {
        TBFontGlyphData *effect_glyph_data = m_effect.Render(&glyph->metrics, &glyph_data);
        TBFontGlyphData *result_glyph_data = effect_glyph_data ? effect_glyph_data : &glyph_data;

        // The glyph data may be in uint8 format, which we have to convert since we always
        // create fragments (and TBBitmap) in 32bit format.
        uint32 *glyph_dsta_src = result_glyph_data->data32;
        if (!glyph_dsta_src && result_glyph_data->data8)
        {
            if (m_temp_buffer.Reserve(result_glyph_data->w * result_glyph_data->h * sizeof(uint32)))
            {
                glyph_dsta_src = (uint32 *) m_temp_buffer.GetData();
                for (int y = 0; y < result_glyph_data->h; y++)
                    for (int x = 0; x < result_glyph_data->w; x++)
                    {
#ifdef TB_PREMULTIPLIED_ALPHA
                        uint8 opacity = result_glyph_data->data8[x + y * result_glyph_data->stride];
                        glyph_dsta_src[x + y * result_glyph_data->w] = TBColor(opacity, opacity, opacity, opacity);
#else
                        glyph_dsta_src[x + y * result_glyph_data->w] = TBColor(255, 255, 255, result_glyph_data->data8[x + y * result_glyph_data->stride]);
#endif
                    }
            }
        }

        // Finally, the glyph data is ready and we can create a bitmap fragment.
        if (glyph_dsta_src)
        {
            glyph->has_rgb = result_glyph_data->rgb;
            m_glyph_cache->CreateFragment(glyph, result_glyph_data->w, result_glyph_data->h,
                                          result_glyph_data->stride, glyph_dsta_src);
        }

        delete effect_glyph_data;
    }
#ifdef TB_RUNTIME_DEBUG_INFO
    //char glyph_str[9];
    //int len = utf8::encode(cp, glyph_str);
    //glyph_str[len] = 0;
    //TBStr info;
    //info.SetFormatted("Created glyph %d (\"%s\"). Cache contains %d glyphs (%d%% full) using %d bitmaps.\n", cp, glyph_str, m_all_glyphs.CountLinks(), m_frag_manager.GetUseRatio(), m_frag_manager.GetNumMaps());
    //TBDebugOut(info);
#endif
}

TBID TBFontFace::GetHashId(UCS4 cp) const
{
    return cp * 31 + m_font_desc.GetFontFaceID();
}

TBFontGlyph *TBFontFace::GetGlyph(UCS4 cp, bool render_if_needed)
{
    TBFontGlyph *glyph = m_glyph_cache->GetGlyph(GetHashId(cp), cp);
    if (!glyph)
        glyph = CreateAndCacheGlyph(cp);
    if (glyph && !glyph->frag && render_if_needed)
        RenderGlyph(glyph);
    return glyph;
}

void TBFontFace::DrawString(int x, int y, const TBColor &color, const char *str, int len)
{
    if (m_bgFont)
        m_bgFont->DrawString(x+m_bgX, y+m_bgY, m_bgColor, str, len);

    if (m_font_renderer)
        g_renderer->BeginBatchHint(TBRenderer::BATCH_HINT_DRAW_BITMAP_FRAGMENT);

    int i = 0;
    while (str[i] && i < len)
    {
        UCS4 cp = utf8::decode_next(str, &i, len);
        if (cp == 0xFFFF)
            continue;
        if (TBFontGlyph *glyph = GetGlyph(cp, true))
        {
            if (glyph->frag)
            {
                TBRect dst_rect(x + glyph->metrics.x, y + glyph->metrics.y + GetAscent(), glyph->frag->Width(), glyph->frag->Height());
                TBRect src_rect(0, 0, glyph->frag->Width(), glyph->frag->Height());
                if (glyph->has_rgb)
                    g_renderer->DrawBitmap(dst_rect, src_rect, glyph->frag);
                else
                    g_renderer->DrawBitmapColored(dst_rect, src_rect, color, glyph->frag);
            }
            x += glyph->metrics.advance;
        }
        else if (!m_font_renderer) // This is the test font. Use same glyph width as height and draw square.
        {
            g_renderer->DrawRect(TBRect(x, y, m_metrics.height / 3, m_metrics.height), color);
            x += m_metrics.height / 3 + 1;
        }
    }

    if (m_font_renderer)
        g_renderer->EndBatchHint();
}

int TBFontFace::GetStringWidth(const char *str, int len)
{
    int width = 0;
    int i = 0;
    while (str[i] && i < len)
    {
        UCS4 cp = utf8::decode_next(str, &i, len);
        if (cp == 0xFFFF)
            continue;
        if (!m_font_renderer) // This is the test font. Use same glyph width as height.
            width += m_metrics.height / 3 + 1;
        else if (TBFontGlyph *glyph = GetGlyph(cp, false))
            width += glyph->metrics.advance;
    }
    return width;
}

#ifdef TB_RUNTIME_DEBUG_INFO
void TBFontFace::Debug()
{
    m_glyph_cache->Debug();
}
#endif // TB_RUNTIME_DEBUG_INFO

// == TBFontManager ===============================================================================

TBFontManager::TBFontManager()
{
    // Add the test dummy font with empty name (Equals to ID 0)
    AddFontInfo("-test-font-dummy-", "");
    m_test_font_desc.SetSize(16);
    CreateFontFace(m_test_font_desc);

    // Use the test dummy font as default by default
    m_default_font_desc = m_test_font_desc;
}

TBFontManager::~TBFontManager()
{
}

TBFontInfo *TBFontManager::AddFontInfo(const char *filename, const char *name)
{
    if (TBFontInfo *fi = new TBFontInfo(filename, name))
    {
        if (m_font_info.Add(fi->GetID(), fi))
            return fi;
        delete fi;
    }
    return nullptr;
}

TBFontInfo *TBFontManager::GetFontInfo(const TBID &id) const
{
    return m_font_info.Get(id);
}

bool TBFontManager::HasFontFace(const TBFontDescription &font_desc) const
{
    return m_fonts.Get(font_desc.GetFontFaceID()) ? true : false;
}

TBFontFace *TBFontManager::GetFontFace(const TBFontDescription &font_desc)
{
    if (TBFontFace *font = m_fonts.Get(font_desc.GetFontFaceID()))
        return font;
    if (TBFontFace *font = m_fonts.Get(GetDefaultFontDescription().GetFontFaceID()))
        return font;
    return m_fonts.Get(m_test_font_desc.GetFontFaceID());
}

TBFontFace *TBFontManager::CreateFontFace(const TBFontDescription &font_desc)
{
    assert(!HasFontFace(font_desc)); // There is already a font added with this description!

    TBFontInfo *fi = GetFontInfo(font_desc.GetID());
    if (!fi)
        return nullptr;

    if (fi->GetID() == 0) // Is this the test dummy font
    {
        if (TBFontFace *font = new TBFontFace(&m_glyph_cache, nullptr, font_desc))
        {
            if (m_fonts.Add(font_desc.GetFontFaceID(), font))
                return font;
            delete font;
        }
        return nullptr;
    }

    // Iterate through font renderers until we find one capable of creating a font for this file.
    for (TBFontRenderer *fr = m_font_renderers.GetFirst(); fr; fr = fr->GetNext())
    {
        if (TBFontFace *font = fr->Create(this, fi->GetFilename(), font_desc))
        {
            if (m_fonts.Add(font_desc.GetFontFaceID(), font))
                return font;
            delete font;
        }
    }
    return nullptr;
}

}; // namespace tb