/*  GRAPHITE2 LICENSING

    Copyright 2010, SIL International
    All rights reserved.

    This library is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published
    by the Free Software Foundation; either version 2.1 of License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should also have received a copy of the GNU Lesser General Public
    License along with this library in the file named "LICENSE".
    If not, write to the Free Software Foundation, 51 Franklin Street,
    Suite 500, Boston, MA 02110-1335, USA or visit their web page on the
    internet at http://www.fsf.org/licenses/lgpl.html.
*/
#include <cassert>
#include <cstdlib>
#include <cstdint>
#include <fstream>
#include <iostream>
#include <map>
#include <memory>
#include <string>
#include <vector>

#include <graphite2/Font.h>

#include "inc/Endian.h"
#include "inc/Face.h"
#include "inc/FeatureMap.h"
#include "inc/TtfUtil.h"

using namespace graphite2;


class face_handle : public gr_face_ops
{
public:
  using table_t = std::pair<void const *, size_t>;
  static const table_t no_table;


private:
  std::vector<uint8_t> _ttf;
  void const *    _table_dir;
  void const *    _header_tbl;
  mutable std::map<const TtfUtil::Tag, table_t> _tables;

  static
  decltype(_ttf) buffer_from_file(std::string const & backing_font_path) {
    std::ifstream f(backing_font_path, std::ifstream::binary);
    decltype(_ttf) result(size_t(f.seekg(0, std::ios::end).tellg()));
    f.seekg(0, std::ios::beg);

    result.assign(std::istreambuf_iterator<char>(f),
                  std::istreambuf_iterator<char>());
    return result;
  }

public:
  face_handle() noexcept
  : gr_face_ops({sizeof(gr_face_ops), get_table_fn, nullptr}),
    _table_dir(nullptr), _header_tbl(nullptr) {}

  face_handle(std::string const & backing_font_path)
  : gr_face_ops({sizeof(gr_face_ops), get_table_fn, nullptr}),
    _ttf(buffer_from_file(backing_font_path)),
    _table_dir(nullptr),
    _header_tbl(nullptr)
  {
    size_t tbl_offset, tbl_len;

    // Get the header
    if (!TtfUtil::GetHeaderInfo(tbl_offset, tbl_len)
        || tbl_len > _ttf.size()
        || tbl_offset > _ttf.size() - tbl_len
        || !TtfUtil::CheckHeader(_header_tbl = _ttf.data() + tbl_offset))
      throw std::runtime_error(backing_font_path + ": invalid font.");

      // Get the table directory
    if (!TtfUtil::GetTableDirInfo(_header_tbl, tbl_offset, tbl_len)
        || tbl_len > _ttf.size()
        || tbl_offset > _ttf.size() - tbl_len)
      throw std::runtime_error(backing_font_path + ": invalid font");
    _table_dir = _ttf.data() + tbl_offset;
  }

  inline
  void replace_table(TtfUtil::Tag name, void const * data, size_t len) noexcept
  {
    _tables[name] = {data, len};
  }

  table_t const & operator [] (TtfUtil::Tag name) const noexcept
  {
    assert(_header_tbl);
    assert(_table_dir);
    auto & table = _tables[name];

    if (!table.first)
    {
      size_t tbl_offset, tbl_len;
      if (TtfUtil::GetTableInfo(name, _header_tbl, _table_dir,
            tbl_offset, tbl_len))
          table = {_ttf.data() + tbl_offset, tbl_len};
    }

    return table;
  }

private:
  static const void * get_table_fn(const void *afh, unsigned int name,
                                  size_t *len) {
    assert(afh != nullptr);

    face_handle const & fh = *static_cast<decltype(&fh)>(afh);
    auto & t = fh[name];
    *len = t.second;
    return t.first;
  }
};
const face_handle::table_t face_handle::no_table = {0,0};


#pragma pack(push, 1)

template<typename T> class _be
{
	T _v;

public:
  _be(const T & t) noexcept               {_v = be::swap<T>(t);}
  constexpr operator T () const noexcept  {return be::swap<T>(_v); }
};

struct FeatHeader
{
    _be<gr_uint16> m_major;
    _be<gr_uint16> m_minor;
    _be<gr_uint16> m_numFeat;
    _be<gr_uint16> m_reserved1;
    _be<gr_uint32> m_reserved2;
};

struct FeatDefn
{
    _be<gr_uint32> m_featId;
    _be<gr_uint16> m_numFeatSettings;
    _be<gr_uint16> m_reserved1;
    _be<gr_uint32> m_settingsOffset;
    _be<gr_uint16> m_flags;
    _be<gr_uint16> m_label;
};

struct FeatSetting
{
    _be<gr_int16>	m_value;
    _be<gr_uint16>	m_label;
};

struct FeatTableTestA
{
    FeatHeader  m_header;
    FeatDefn    m_defs[1];
    FeatSetting m_settings[2];
};
#pragma pack(pop)

const FeatTableTestA testDataA = {
    { 2, 0, 1, 0, 0},
    {{0x41424344, 2, 0, sizeof(FeatHeader) + sizeof(FeatDefn), 0, 1}},
    {{0,10},{1,11}}
};

struct FeatTableTestB
{
    FeatHeader  m_header;
    FeatDefn    m_defs[2];
    FeatSetting m_settings[4];
};

const FeatTableTestB testDataB = {
    { 2, 0, 2, 0, 0},
    {{0x41424344, 2, 0, sizeof(FeatHeader) + 2 * sizeof(FeatDefn), 0, 1},
     {0x41424345, 2, 0, sizeof(FeatHeader) + 2 * sizeof(FeatDefn) + 2 * sizeof(FeatSetting), 0, 2}},
    {{0,10},{1,11},{0,12},{1,13}}
};
const FeatTableTestB testDataBunsorted = {
    { 2, 0, 2, 0, 0},
    {{0x41424345, 2, 0, sizeof(FeatHeader) + 2 * sizeof(FeatDefn) + 2 * sizeof(FeatSetting), 0, 2},
     {0x41424344, 2, 0, sizeof(FeatHeader) + 2 * sizeof(FeatDefn), 0, 1}},
    {{0,10},{1,11},{0,12},{1,13}}
};

struct FeatTableTestC
{
    FeatHeader m_header;
    FeatDefn m_defs[3];
    FeatSetting m_settings[7];
};

const FeatTableTestC testDataCunsorted = {
    { 2, 0, 3, 0, 0},
    {{0x41424343, 3, 0, sizeof(FeatHeader) + 3 * sizeof(FeatDefn) + 4 * sizeof(FeatSetting), 0, 1},
     {0x41424345, 2, 0, sizeof(FeatHeader) + 3 * sizeof(FeatDefn) + 2 * sizeof(FeatSetting), 0, 3},
     {0x41424344, 2, 0, sizeof(FeatHeader) + 3 * sizeof(FeatDefn), 0, 2}},
    {{0,10},{1,11},{0,12},{1,13},{0,14},{1,15},{2,16}}
};

struct FeatTableTestD
{
    FeatHeader m_header;
    FeatDefn m_defs[4];
    FeatSetting m_settings[9];
};

const FeatTableTestD testDataDunsorted = {
    { 2, 0, 4, 0, 0},
    {{400, 3, 0, sizeof(FeatHeader) + 4 * sizeof(FeatDefn) + 4 * sizeof(FeatSetting), 0, 1},
     {100, 2, 0, sizeof(FeatHeader) + 4 * sizeof(FeatDefn) + 2 * sizeof(FeatSetting), 0, 3},
     {300, 2, 0, sizeof(FeatHeader) + 4 * sizeof(FeatDefn), 0, 2},
     {200, 2, 0, sizeof(FeatHeader) + 4 * sizeof(FeatDefn) + 7 * sizeof(FeatSetting), 0, 2}
    },
    {{0,10},{1,11},{0,12},{10,13},{0,14},{1,15},{2,16},{2,17},{4,18}}
};

struct FeatTableTestE
{
    FeatHeader m_header;
    FeatDefn m_defs[5];
    FeatSetting m_settings[11];
};
const FeatTableTestE testDataE = {
    { 2, 0, 5, 0, 0},
    {{400, 3, 0, sizeof(FeatHeader) + 5 * sizeof(FeatDefn) + 4 * sizeof(FeatSetting), 0, 1},
     {100, 2, 0, sizeof(FeatHeader) + 5 * sizeof(FeatDefn) + 2 * sizeof(FeatSetting), 0, 3},
     {500, 2, 0, sizeof(FeatHeader) + 5 * sizeof(FeatDefn) + 9 * sizeof(FeatSetting), 0, 3},
     {300, 2, 0, sizeof(FeatHeader) + 5 * sizeof(FeatDefn), 0, 2},
     {200, 2, 0, sizeof(FeatHeader) + 5 * sizeof(FeatDefn) + 7 * sizeof(FeatSetting), 0, 2}
    },
    {{0,10},{1,11},{0,12},{10,13},{0,14},{1,15},{2,16},{2,17},{4,18},{1,19},{2,20}}
};

const FeatTableTestE testBadOffset = {
    { 2, 0, 5, 0, 0},
    {{400, 3, 0, sizeof(FeatHeader) + 5 * sizeof(FeatDefn) + 4 * sizeof(FeatSetting), 0, 1},
     {100, 2, 0, sizeof(FeatHeader) + 5 * sizeof(FeatDefn) + 2 * sizeof(FeatSetting), 0, 3},
     {500, 2, 0, sizeof(FeatHeader) + 5 * sizeof(FeatDefn) + 9 * sizeof(FeatSetting), 0, 3},
     {300, 2, 0, sizeof(FeatHeader) + 5 * sizeof(FeatDefn), 0, 2},
     {200, 2, 0, sizeof(FeatHeader) + 5 * sizeof(FeatDefn) + 10 * sizeof(FeatSetting), 0, 2}
    },
    {{0,10},{1,11},{0,12},{10,13},{0,14},{1,15},{2,16},{2,17},{4,18},{1,19},{2,20}}
};

template <typename T>
inline
void testAssert(const char * msg, const T b)
{
    if (!b)
    {
        fprintf(stderr, msg, b);
        exit(1);
    }
}

template <typename T, typename R>
inline
void testAssertEqual(const char * msg, const T a, const R b)
{
    if (a != T(b))
    {
        fprintf(stderr, msg, a, T(b));
        exit(1);
    }
}


face_handle dummyFace;
using face_ptr = std::unique_ptr<gr_face, decltype(&gr_face_destroy)>;

template <class T> void testFeatTable(T const & table, std::string const & testName)
{
    FeatureMap testFeatureMap;
    dummyFace.replace_table(TtfUtil::Tag::Feat, &table, sizeof(T));
    face_ptr face(gr_make_face_with_ops(&dummyFace, &dummyFace, 0),
                  gr_face_destroy);
    if (!face)
      throw std::runtime_error("failed to load font");

    testAssert("readFeats", testFeatureMap.readFeats(*face));

    std::cerr << testName << std::endl;
    testAssertEqual("test num features %hu,%hu\n",
                    testFeatureMap.numFeats(),
                    table.m_header.m_numFeat);

    for (size_t i = 0; i < sizeof(table.m_defs) / sizeof(FeatDefn); i++)
    {
        const FeatureRef * ref = testFeatureMap.findFeatureRef(table.m_defs[i].m_featId);
        testAssert("test feat\n", ref);
        testAssertEqual("test feat settings %hu %hu\n", ref->getNumSettings(), table.m_defs[i].m_numFeatSettings);
        testAssertEqual("test feat label %hu %hu\n", ref->getNameId(), table.m_defs[i].m_label);
        size_t settingsIndex = (table.m_defs[i].m_settingsOffset - sizeof(FeatHeader)
            - (sizeof(FeatDefn) * table.m_header.m_numFeat)) / sizeof(FeatSetting);
        for (uint16_t j = 0; j < table.m_defs[i].m_numFeatSettings; j++)
        {
            testAssertEqual("setting label %hu %hu\n", ref->getSettingName(j),
                       table.m_settings[settingsIndex+j].m_label);
        }
    }
}


int main(int argc, char * argv[])
{
  try
  {
    if (argc != 2)
      throw std::length_error("not enough arguments: need a backing font");

    dummyFace = face_handle(argv[1]);
    testFeatTable<FeatTableTestA>(testDataA, "A\n");
    testFeatTable<FeatTableTestB>(testDataB, "B\n");
    testFeatTable<FeatTableTestB>(testDataBunsorted, "Bu\n");
    testFeatTable<FeatTableTestC>(testDataCunsorted, "C\n");
    testFeatTable<FeatTableTestD>(testDataDunsorted, "D\n");
    testFeatTable<FeatTableTestE>(testDataE, "E\n");

    // test a bad settings offset stradling the end of the table
    FeatureMap testFeatureMap;
    dummyFace.replace_table(TtfUtil::Tag::Feat, &testBadOffset, sizeof testBadOffset);
    face_ptr face(gr_make_face_with_ops(&dummyFace, &dummyFace, 0),
                  gr_face_destroy);
		testAssert("fail gracefully on bad table", !face);
  }
  catch (std::exception & e)
  {
    std::cerr << argv[0] << ": " << e.what() << std::endl;
    return 1;
  }

  return 0;
}