/*

 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>

 * Copyright (c) 2023, Sam Atkins <atkinssj@serenityos.org>

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#include "BitmapFont.h"

#include "Emoji.h"

#include <AK/BuiltinWrappers.h>

#include <AK/Utf32View.h>

#include <AK/Utf8View.h>

#include <LibCore/File.h>

#include <LibCore/Resource.h>

#include <LibCore/System.h>

#include <LibGfx/Font/FontDatabase.h>

#include <LibGfx/Font/FontStyleMapping.h>

#include <LibGfx/Painter.h>

#include <string.h>

namespace Gfx {

struct [[gnu::packed]] FontFileHeader {

    char magic[4];

    u8 glyph_width;

    u8 glyph_height;

    u16 range_mask_size;

    u8 is_variable_width;

    u8 glyph_spacing;

    u8 baseline;

    u8 mean_line;

    u8 presentation_size;

    u16 weight;

    u8 slope;

    char name[32];

    char family[32];

};

static_assert(AssertSize<FontFileHeader, 80>());

static constexpr size_t s_max_glyph_count = 0x110000;

static constexpr size_t s_max_range_mask_size = s_max_glyph_count / (256 * 8);

}

template<>

class AK::Traits<Gfx::FontFileHeader> : public DefaultTraits<Gfx::FontFileHeader> {

public:

    static constexpr bool is_trivially_serializable() { return true; }

};

namespace Gfx {

NonnullRefPtr<Font> BitmapFont::clone() const

{

    return MUST(try_clone());

}

ErrorOr<NonnullRefPtr<Font>> BitmapFont::try_clone() const

{

    auto new_range_mask = TRY(Core::System::allocate(m_range_mask.size(), 1));

    m_range_mask.copy_to(new_range_mask);

    size_t bytes_per_glyph = sizeof(u32) * glyph_height();

    auto new_rows = TRY(Core::System::allocate(m_glyph_count, bytes_per_glyph));

    m_rows.copy_to(new_rows);

    auto new_widths = TRY(Core::System::allocate(m_glyph_count, 1));

    m_glyph_widths.copy_to(new_widths);

    return TRY(adopt_nonnull_ref_or_enomem(new (nothrow) BitmapFont(m_name, m_family, new_rows, new_widths, m_fixed_width, m_glyph_width, m_glyph_height, m_glyph_spacing, new_range_mask, m_baseline, m_mean_line, m_presentation_size, m_weight, m_slope, true)));

}

ErrorOr<NonnullRefPtr<BitmapFont>> BitmapFont::create(u8 glyph_height, u8 glyph_width, bool fixed, size_t glyph_count)

{

    glyph_count += 256 - (glyph_count % 256);

    glyph_count = min(glyph_count, s_max_glyph_count);

    size_t glyphs_per_range = 8 * 256;

    u16 range_mask_size = ceil_div(glyph_count, glyphs_per_range);

    auto new_range_mask = TRY(Core::System::allocate(range_mask_size, 1));

    for (size_t i = 0; i < glyph_count; i += 256) {

        new_range_mask[i / 256 / 8] |= 1 << (i / 256 % 8);

    }

    size_t bytes_per_glyph = sizeof(u32) * glyph_height;

    auto new_rows = TRY(Core::System::allocate(glyph_count, bytes_per_glyph));

    auto new_widths = TRY(Core::System::allocate(glyph_count, 1));

    return adopt_nonnull_ref_or_enomem(new (nothrow) BitmapFont("Untitled"_string, "Untitled"_string, new_rows, new_widths, fixed, glyph_width, glyph_height, 1, new_range_mask, 0, 0, 0, 400, 0, true));

}

ErrorOr<NonnullRefPtr<BitmapFont>> BitmapFont::unmasked_character_set() const

{

    auto new_range_mask = TRY(Core::System::allocate(s_max_range_mask_size, 1));

    constexpr u8 max_bits { 0b1111'1111 };

    memset(new_range_mask.data(), max_bits, s_max_range_mask_size);

    size_t bytes_per_glyph = sizeof(u32) * glyph_height();

    auto new_rows = TRY(Core::System::allocate(s_max_glyph_count, bytes_per_glyph));

    auto new_widths = TRY(Core::System::allocate(s_max_glyph_count, 1));

    for (size_t code_point = 0; code_point < s_max_glyph_count; ++code_point) {

        auto index = glyph_index(code_point);

        if (index.has_value()) {

            new_widths[code_point] = m_glyph_widths[index.value()];

            memcpy(&new_rows[code_point * bytes_per_glyph], &m_rows[index.value() * bytes_per_glyph], bytes_per_glyph);

        }

    }

    return adopt_nonnull_ref_or_enomem(new (nothrow) BitmapFont(m_name, m_family, new_rows, new_widths, m_fixed_width, m_glyph_width, m_glyph_height, m_glyph_spacing, new_range_mask, m_baseline, m_mean_line, m_presentation_size, m_weight, m_slope, true));

}

ErrorOr<NonnullRefPtr<BitmapFont>> BitmapFont::masked_character_set() const

{

    auto new_range_mask = TRY(Core::System::allocate(s_max_range_mask_size, 1));

    u16 new_range_mask_size { 0 };

    for (size_t i = 0; i < m_glyph_count; ++i) {

        if (m_glyph_widths[i] > 0) {

            new_range_mask[i / 256 / 8] |= 1 << (i / 256 % 8);

            if (i / 256 / 8 + 1 > new_range_mask_size)

                new_range_mask_size = i / 256 / 8 + 1;

        }

    }

    size_t new_glyph_count { 0 };

    for (size_t i = 0; i < new_range_mask_size; ++i) {

        new_glyph_count += 256 * popcount(new_range_mask[i]);

    }

    size_t bytes_per_glyph = sizeof(u32) * m_glyph_height;

    auto new_rows = TRY(Core::System::allocate(new_glyph_count, bytes_per_glyph));

    auto new_widths = TRY(Core::System::allocate(new_glyph_count, 1));

    for (size_t i = 0, j = 0; i < m_glyph_count; ++i) {

        if (!(new_range_mask[i / 256 / 8] & 1 << (i / 256 % 8))) {

            j++;

            i += 255;

            continue;

        }

        new_widths[i - j * 256] = m_glyph_widths[i];

        memcpy(&new_rows[(i - j * 256) * bytes_per_glyph], &m_rows[i * bytes_per_glyph], bytes_per_glyph);

    }

    // Now that we're done working with the range-mask memory, reduce its reported size down to what it should be.

    new_range_mask = { new_range_mask.data(), new_range_mask_size };

    return adopt_nonnull_ref_or_enomem(new (nothrow) BitmapFont(m_name, m_family, new_rows, new_widths, m_fixed_width, m_glyph_width, m_glyph_height, m_glyph_spacing, new_range_mask, m_baseline, m_mean_line, m_presentation_size, m_weight, m_slope, true));

}

BitmapFont::BitmapFont(String name, String family, Bytes rows, Span<u8> widths, bool is_fixed_width, u8 glyph_width, u8 glyph_height, u8 glyph_spacing, Bytes range_mask, u8 baseline, u8 mean_line, u8 presentation_size, u16 weight, u8 slope, bool owns_arrays)

    : m_name(move(name))

    , m_family(move(family))

    , m_range_mask(range_mask)

    , m_rows(rows)

    , m_glyph_widths(widths)

    , m_glyph_width(glyph_width)

    , m_glyph_height(glyph_height)

    , m_min_glyph_width(glyph_width)

    , m_max_glyph_width(glyph_width)

    , m_glyph_spacing(glyph_spacing)

    , m_baseline(baseline)

    , m_mean_line(mean_line)

    , m_presentation_size(presentation_size)

    , m_weight(weight)

    , m_slope(slope)

    , m_fixed_width(is_fixed_width)

    , m_owns_arrays(owns_arrays)

{

    update_x_height();

    for (size_t i = 0, index = 0; i < m_range_mask.size(); ++i) {

        for (size_t j = 0; j < 8; ++j) {

            if (m_range_mask[i] & (1 << j)) {

                m_glyph_count += 256;

                m_range_indices.append(index++);

            } else {

                m_range_indices.append({});

            }

        }

    }

    if (!m_fixed_width) {

        u8 maximum = 0;

        u8 minimum = 255;

        for (size_t i = 0; i < m_glyph_count; ++i) {

            minimum = min(minimum, m_glyph_widths[i]);

            maximum = max(maximum, m_glyph_widths[i]);

        }

        m_min_glyph_width = minimum;

        m_max_glyph_width = max(maximum, m_glyph_width);

    }

}

BitmapFont::~BitmapFont()

{

    if (m_owns_arrays) {

        free(m_glyph_widths.data());

        free(m_rows.data());

        free(m_range_mask.data());

    }

}

ErrorOr<NonnullRefPtr<BitmapFont>> BitmapFont::try_load_from_stream(FixedMemoryStream& stream)

{

    auto& header = *TRY(stream.read_in_place<FontFileHeader const>());

    if (memcmp(header.magic, "!Fnt", 4))

        return Error::from_string_literal("Gfx::BitmapFont::load_from_memory: Incompatible header");

    if (header.name[sizeof(header.name) - 1] != '\0')

        return Error::from_string_literal("Gfx::BitmapFont::load_from_memory: Nonnull-terminated name");

    if (header.family[sizeof(header.family) - 1] != '\0')

        return Error::from_string_literal("Gfx::BitmapFont::load_from_memory: Nonnull-terminated family");

    size_t bytes_per_glyph = sizeof(u32) * header.glyph_height;

    size_t glyph_count { 0 };

    // FIXME: These ReadonlyFoo -> Foo casts are awkward, and only needed because BitmapFont is

    //        sometimes editable and sometimes not. Splitting it into editable/non-editable classes

    //        would make this a lot cleaner.

    ReadonlyBytes readonly_range_mask = TRY(stream.read_in_place<u8 const>(header.range_mask_size));

    Bytes range_mask { const_cast<u8*>(readonly_range_mask.data()), readonly_range_mask.size() };

    for (size_t i = 0; i < header.range_mask_size; ++i)

        glyph_count += 256 * popcount(range_mask[i]);

    ReadonlyBytes readonly_rows = TRY(stream.read_in_place<u8 const>(glyph_count * bytes_per_glyph));

    Bytes rows { const_cast<u8*>(readonly_rows.data()), readonly_rows.size() };

    ReadonlySpan<u8> readonly_widths = TRY(stream.read_in_place<u8 const>(glyph_count));

    Span<u8> widths { const_cast<u8*>(readonly_widths.data()), readonly_widths.size() };

    if (!stream.is_eof())

        return Error::from_string_literal("Gfx::BitmapFont::load_from_memory: Trailing data in file");

    auto name = TRY(String::from_utf8(ReadonlyBytes { header.name, strlen(header.name) }));

    auto family = TRY(String::from_utf8(ReadonlyBytes { header.family, strlen(header.family) }));

    auto font = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) BitmapFont(move(name), move(family), rows, widths, !header.is_variable_width, header.glyph_width, header.glyph_height, header.glyph_spacing, range_mask, header.baseline, header.mean_line, header.presentation_size, header.weight, header.slope)));

    return font;

}

ErrorOr<NonnullRefPtr<BitmapFont>> BitmapFont::try_load_from_resource(NonnullRefPtr<Core::Resource> resource)

{

    auto stream = resource->stream();

    auto font = TRY(try_load_from_stream(stream));

    font->m_owned_data = move(resource);

    return font;

}

ErrorOr<NonnullRefPtr<BitmapFont>> BitmapFont::try_load_from_mapped_file(NonnullOwnPtr<Core::MappedFile> mapped_file)

{

    auto font = TRY(try_load_from_stream(*mapped_file));

    font->m_owned_data = move(mapped_file);

    return font;

}

NonnullRefPtr<BitmapFont> BitmapFont::load_from_uri(StringView uri)

{

    return MUST(try_load_from_uri(uri));

}

ErrorOr<NonnullRefPtr<BitmapFont>> BitmapFont::try_load_from_uri(StringView uri)

{

    return try_load_from_resource(TRY(Core::Resource::load_from_uri(uri)));

}

ErrorOr<void> BitmapFont::write_to_file(ByteString const& path)

{

    auto stream = TRY(Core::File::open(path, Core::File::OpenMode::Write));

    TRY(write_to_file(move(stream)));

    return {};

}

ErrorOr<void> BitmapFont::write_to_file(NonnullOwnPtr<Core::File> file)

{

    FontFileHeader header;

    memset(&header, 0, sizeof(FontFileHeader));

    memcpy(header.magic, "!Fnt", 4);

    header.glyph_width = m_glyph_width;

    header.glyph_height = m_glyph_height;

    header.range_mask_size = m_range_mask.size();

    header.baseline = m_baseline;

    header.mean_line = m_mean_line;

    header.is_variable_width = !m_fixed_width;

    header.glyph_spacing = m_glyph_spacing;

    header.presentation_size = m_presentation_size;

    header.weight = m_weight;

    header.slope = m_slope;

    memcpy(header.name, m_name.bytes().data(), min(m_name.bytes().size(), sizeof(header.name) - 1));

    memcpy(header.family, m_family.bytes().data(), min(m_family.bytes().size(), sizeof(header.family) - 1));

    TRY(file->write_until_depleted({ &header, sizeof(header) }));

    TRY(file->write_until_depleted(m_range_mask));

    TRY(file->write_until_depleted(m_rows));

    TRY(file->write_until_depleted(m_glyph_widths));

    return {};

}

Optional<Glyph> BitmapFont::glyph(u32 code_point) const

{

    auto maybe_index = glyph_index(code_point);

    if (!maybe_index.has_value())

        return {};

    auto index = maybe_index.release_value();

    auto width = m_glyph_widths[index];

    auto glyph_byte_count = m_glyph_height * GlyphBitmap::bytes_per_row();

    return Glyph(

        GlyphBitmap(m_rows.slice(index * glyph_byte_count, glyph_byte_count), { width, m_glyph_height }),

        0,

        width,

        m_glyph_height);

}

Glyph BitmapFont::raw_glyph(u32 code_point) const

{

    auto width = m_glyph_widths[code_point];

    auto glyph_byte_count = m_glyph_height * GlyphBitmap::bytes_per_row();

    return Glyph(

        GlyphBitmap(m_rows.slice(code_point * glyph_byte_count, glyph_byte_count), { width, m_glyph_height }),

        0,

        width,

        m_glyph_height);

}

Optional<size_t> BitmapFont::glyph_index(u32 code_point) const

{

    auto index = code_point / 256;

    if (index >= m_range_indices.size())

        return {};

    if (!m_range_indices[index].has_value())

        return {};

    return m_range_indices[index].value() * 256 + code_point % 256;

}

bool BitmapFont::contains_glyph(u32 code_point) const

{

    auto index = glyph_index(code_point);

    return index.has_value() && m_glyph_widths[index.value()] > 0;

}

float BitmapFont::glyph_width(u32 code_point) const

{

    if (is_ascii(code_point) && !is_ascii_printable(code_point))

        return 0;

    auto index = glyph_index(code_point);

    return m_fixed_width || !index.has_value() ? m_glyph_width : m_glyph_widths[index.value()];

}

template<typename CodePointIterator>

static float glyph_or_emoji_width_impl(BitmapFont const& font, CodePointIterator& it)

{

    if (auto const* emoji = Emoji::emoji_for_code_point_iterator(it))

        return font.pixel_size() * emoji->width() / emoji->height();

    if (font.is_fixed_width())

        return font.glyph_fixed_width();

    return font.glyph_width(*it);

}

Unexecuted instantiation: BitmapFont.cpp:float Gfx::glyph_or_emoji_width_impl<AK::Utf8CodePointIterator>(Gfx::BitmapFont const&, AK::Utf8CodePointIterator&)

Unexecuted instantiation: BitmapFont.cpp:float Gfx::glyph_or_emoji_width_impl<AK::Utf32CodePointIterator>(Gfx::BitmapFont const&, AK::Utf32CodePointIterator&)

float BitmapFont::glyph_or_emoji_width(Utf8CodePointIterator& it) const

{

    return glyph_or_emoji_width_impl(*this, it);

}

float BitmapFont::glyph_or_emoji_width(Utf32CodePointIterator& it) const

{

    return glyph_or_emoji_width_impl(*this, it);

}

int BitmapFont::width_rounded_up(StringView view) const

{

    return static_cast<int>(ceilf(width(view)));

}

float BitmapFont::width(StringView view) const { return unicode_view_width(Utf8View(view)); }

float BitmapFont::width(Utf8View const& view) const { return unicode_view_width(view); }

float BitmapFont::width(Utf32View const& view) const { return unicode_view_width(view); }

template<typename T>

ALWAYS_INLINE int BitmapFont::unicode_view_width(T const& view) const

{

    if (view.is_empty())

        return 0;

    bool first = true;

    int width = 0;

    int longest_width = 0;

    for (auto it = view.begin(); it != view.end(); ++it) {

        auto code_point = *it;

        if (code_point == '\n' || code_point == '\r') {

            first = true;

            longest_width = max(width, longest_width);

            width = 0;

            continue;

        }

        if (!first)

            width += glyph_spacing();

        first = false;

        width += glyph_or_emoji_width(it);

    }

    longest_width = max(width, longest_width);

    return longest_width;

}

Unexecuted instantiation: int Gfx::BitmapFont::unicode_view_width<AK::Utf8View>(AK::Utf8View const&) const

Unexecuted instantiation: int Gfx::BitmapFont::unicode_view_width<AK::Utf32View>(AK::Utf32View const&) const

String BitmapFont::qualified_name() const

{

    return MUST(String::formatted("{} {} {} {}", family(), presentation_size(), weight(), slope()));

}

String BitmapFont::variant() const

{

    StringBuilder builder;

    builder.append(weight_to_name(weight()));

    if (slope() != 0) {

        if (builder.string_view() == "Regular"sv)

            builder.clear();

        else

            builder.append(' ');

        builder.append(slope_to_name(slope()));

    }

    return MUST(builder.to_string());

}

NonnullRefPtr<Font> BitmapFont::with_size(float point_size) const

{

    auto scaled_font = Gfx::FontDatabase::the().get(family(), point_size, weight(), width(), slope(), AllowInexactSizeMatch::Yes);

    VERIFY(scaled_font); // The inexact lookup should, at the very least, return `this` font.

    return *scaled_font;

}

Font const& Font::bold_variant() const

{

    if (m_bold_variant)

        return *m_bold_variant;

    m_bold_variant = Gfx::FontDatabase::the().get(family(), presentation_size(), 700, Gfx::FontWidth::Normal, 0);

    if (!m_bold_variant)

        m_bold_variant = this;

    return *m_bold_variant;

}

FontPixelMetrics BitmapFont::pixel_metrics() const

{

    return FontPixelMetrics {

        .size = (float)pixel_size(),

        .x_height = (float)x_height(),

        .advance_of_ascii_zero = (float)glyph_width('0'),

        .glyph_spacing = (float)glyph_spacing(),

        .ascent = (float)m_baseline,

        .descent = (float)(m_glyph_height - m_baseline),

        .line_gap = Gfx::Painter::LINE_SPACING,

    };

}

}