#include "System.hh"

#include <stdint.h>

#include <phosg/Strings.hh>
#include <stdexcept>
#include <string>
#include <vector>

using namespace std;
using namespace phosg;

namespace ResourceDASM {

static const vector<uint16_t> default_const_words({
    // clang-format off
    // 00
    0x0000, 0x0008, 0x4EBA, 0x206E, 0x4E75, 0x000C, 0x0004, 0x7000,
    0x0010, 0x0002, 0x486E, 0xFFFC, 0x6000, 0x0001, 0x48E7, 0x2F2E,
    // 10
    0x4E56, 0x0006, 0x4E5E, 0x2F00, 0x6100, 0xFFF8, 0x2F0B, 0xFFFF,
    0x0014, 0x000A, 0x0018, 0x205F, 0x000E, 0x2050, 0x3F3C, 0xFFF4,
    // 20
    0x4CEE, 0x302E, 0x6700, 0x4CDF, 0x266E, 0x0012, 0x001C, 0x4267,
    0xFFF0, 0x303C, 0x2F0C, 0x0003, 0x4ED0, 0x0020, 0x7001, 0x0016,
    // 30
    0x2D40, 0x48C0, 0x2078, 0x7200, 0x588F, 0x6600, 0x4FEF, 0x42A7,
    0x6706, 0xFFFA, 0x558F, 0x286E, 0x3F00, 0xFFFE, 0x2F3C, 0x6704,
    // 40
    0x598F, 0x206B, 0x0024, 0x201F, 0x41FA, 0x81E1, 0x6604, 0x6708,
    0x001A, 0x4EB9, 0x508F, 0x202E, 0x0007, 0x4EB0, 0xFFF2, 0x3D40,
    // 50
    0x001E, 0x2068, 0x6606, 0xFFF6, 0x4EF9, 0x0800, 0x0C40, 0x3D7C,
    0xFFEC, 0x0005, 0x203C, 0xFFE8, 0xDEFC, 0x4A2E, 0x0030, 0x0028,
    // 60
    0x2F08, 0x200B, 0x6002, 0x426E, 0x2D48, 0x2053, 0x2040, 0x1800,
    0x6004, 0x41EE, 0x2F28, 0x2F01, 0x670A, 0x4840, 0x2007, 0x6608,
    // 70
    0x0118, 0x2F07, 0x3028, 0x3F2E, 0x302B, 0x226E, 0x2F2B, 0x002C,
    0x670C, 0x225F, 0x6006, 0x00FF, 0x3007, 0xFFEE, 0x5340, 0x0040,
    // 80
    0xFFE4, 0x4A40, 0x660A, 0x000F, 0x4EAD, 0x70FF, 0x22D8, 0x486B,
    0x0022, 0x204B, 0x670E, 0x4AAE, 0x4E90, 0xFFE0, 0xFFC0, 0x002A,
    // 90
    0x2740, 0x6702, 0x51C8, 0x02B6, 0x487A, 0x2278, 0xB06E, 0xFFE6,
    0x0009, 0x322E, 0x3E00, 0x4841, 0xFFEA, 0x43EE, 0x4E71, 0x7400,
    // A0
    0x2F2C, 0x206C, 0x003C, 0x0026, 0x0050, 0x1880, 0x301F, 0x2200,
    0x660C, 0xFFDA, 0x0038, 0x6602, 0x302C, 0x200C, 0x2D6E, 0x4240,
    // B0
    0xFFE2, 0xA9F0, 0xFF00, 0x377C, 0xE580, 0xFFDC, 0x4868, 0x594F,
    0x0034, 0x3E1F, 0x6008, 0x2F06, 0xFFDE, 0x600A, 0x7002, 0x0032,
    // C0
    0xFFCC, 0x0080, 0x2251, 0x101F, 0x317C, 0xA029, 0xFFD8, 0x5240,
    0x0100, 0x6710, 0xA023, 0xFFCE, 0xFFD4, 0x2006, 0x4878, 0x002E,
    // D0
    0x504F, 0x43FA, 0x6712, 0x7600, 0x41E8, 0x4A6E, 0x20D9, 0x005A,
    0x7FFF, 0x51CA, 0x005C, 0x2E00, 0x0240, 0x48C7, 0x6714, 0x0C80,
    // E0
    0x2E9F, 0xFFD6, 0x8000, 0x1000, 0x4842, 0x4A6B, 0xFFD2, 0x0048,
    0x4A47, 0x4ED1, 0x206F, 0x0041, 0x600C, 0x2A78, 0x422E, 0x3200,
    // F0
    0x6574, 0x6716, 0x0044, 0x486D, 0x2008, 0x486C, 0x0B7C, 0x2640,
    0x0400, 0x0068, 0x206D, 0x000D, 0x2A40, 0x000B, 0x003E, 0x0220,
    // clang-format on
});

string decompress_system2(
    const CompressedResourceHeader& header,
    const void* source,
    size_t size) {
  StringReader r(source, size);
  StringWriter w;
  w.str().reserve(header.decompressed_size);

  vector<uint16_t> custom_const_words;
  const vector<uint16_t>* const_words;
  if (header.version.v9.param2 & 1) {
    // The original implementation copies the const words into the decompressor
    // itself! They probably did this because the table could be shorter than
    // 0x100 entries, so the remainder of it defaults to zeroes... but they
    // don't clear the remainder of the table after copying it, nor do they
    // clear the table after decompression is done, so it seems that a resource
    // could technically refer to parts of a previous one's const words table,
    // depending on the order in which they were decompressed. We don't support
    // such behavior here, of course.
    size_t num_const_words = header.version.v9.param1 + 1;
    while (custom_const_words.size() < num_const_words) {
      custom_const_words.emplace_back(r.get_u16b());
    }
    const_words = &custom_const_words;
  } else {
    const_words = &default_const_words;
  }

  if (header.version.v9.param2 & 2) {
    // Result is not composed entirely of const words. There's a bitstream
    // specifying for each word whether it's a const word or not, as well as the
    // const word indexes and raw data for non-const words.
    uint8_t source_types = 0;
    while (w.str().size() < (header.decompressed_size >> 1)) {
      if ((w.str().size() & 15) == 0) {
        source_types = r.get_u8();
      }
      if (source_types & 0x80) {
        w.put_u16b(const_words->at(r.get_u8()));
      } else {
        w.put_u8(r.get_u8());
        w.put_u8(r.get_u8());
      }
      source_types <<= 1;
    }

  } else {
    // Result is composed entirely of const words.
    while (w.str().size() < (header.decompressed_size >> 1)) {
      w.put_u16b(const_words->at(r.get_u8()));
    }
  }

  if (header.decompressed_size & 1) {
    w.put_u8(r.get_u8());
  }

  return w.str();
}

} // namespace ResourceDASM