// SPDX-FileCopyrightText: 2019-2024 Connor McLaughlin <stenzek@gmail.com> and contributors.
// SPDX-License-Identifier: (GPL-3.0 OR CC-BY-NC-ND-4.0)

#include "bios.h"
#include "cpu_disasm.h"
#include "host.h"
#include "settings.h"

#include "common/assert.h"
#include "common/error.h"
#include "common/file_system.h"
#include "common/log.h"
#include "common/md5_digest.h"
#include "common/path.h"

#include <cerrno>

Log_SetChannel(BIOS);

namespace BIOS {
static const ImageInfo* GetInfoForHash(const std::span<u8> image, const ImageInfo::Hash& hash);
static void PatchBIOS(u8* image, u32 image_size, u32 address, u32 value, u32 mask = UINT32_C(0xFFFFFFFF));

static constexpr ImageInfo::Hash MakeHashFromString(const char str[])
{
  ImageInfo::Hash h{};
  for (int i = 0; str[i] != '\0'; i++)
  {
    u8 nibble = 0;
    char ch = str[i];
    if (ch >= '0' && ch <= '9')
      nibble = str[i] - '0';
    else if (ch >= 'a' && ch <= 'z')
      nibble = 0xA + (str[i] - 'a');
    else if (ch >= 'A' && ch <= 'Z')
      nibble = 0xA + (str[i] - 'A');

    h[i / 2] |= nibble << (((i & 1) ^ 1) * 4);
  }
  return h;
}

// clang-format off
static constexpr const ImageInfo s_image_info_by_hash[] = {
  {"SCPH-1000, DTL-H1000 (v1.0)", ConsoleRegion::NTSC_J, MakeHashFromString("239665b1a3dade1b5a52c06338011044"), true},
  {"SCPH-1001, 5003, DTL-H1201, H3001 (v2.2 12-04-95 A)", ConsoleRegion::NTSC_U, MakeHashFromString("924e392ed05558ffdb115408c263dccf"), true},
  {"SCPH-1002, DTL-H1002 (v2.0 05-10-95 E)", ConsoleRegion::PAL, MakeHashFromString("54847e693405ffeb0359c6287434cbef"), true},
  {"SCPH-1002, DTL-H1102 (v2.1 07-17-95 E)", ConsoleRegion::PAL, MakeHashFromString("417b34706319da7cf001e76e40136c23"), true},
  {"SCPH-1002, DTL-H1202, H3002 (v2.2 12-04-95 E)", ConsoleRegion::PAL, MakeHashFromString("e2110b8a2b97a8e0b857a45d32f7e187"), true},
  {"DTL-H1100 (v2.2 03-06-96 D)", ConsoleRegion::NTSC_J, MakeHashFromString("ca5cfc321f916756e3f0effbfaeba13b"), true},
  {"SCPH-3000, DTL-H1000H (v1.1 01-22-95)", ConsoleRegion::NTSC_J, MakeHashFromString("849515939161e62f6b866f6853006780"), true},
  {"SCPH-1001, DTL-H1001 (v2.0 05-07-95 A)", ConsoleRegion::NTSC_U, MakeHashFromString("dc2b9bf8da62ec93e868cfd29f0d067d"), true},
  {"SCPH-3500 (v2.1 07-17-95 J)", ConsoleRegion::NTSC_J, MakeHashFromString("cba733ceeff5aef5c32254f1d617fa62"), true},
  {"SCPH-1001, DTL-H1101 (v2.1 07-17-95 A)", ConsoleRegion::NTSC_U, MakeHashFromString("da27e8b6dab242d8f91a9b25d80c63b8"), true},
  {"SCPH-5000, DTL-H1200, H3000 (v2.2 12-04-95 J)", ConsoleRegion::NTSC_J, MakeHashFromString("57a06303dfa9cf9351222dfcbb4a29d9"), true},
  {"SCPH-5500 (v3.0 09-09-96 J)", ConsoleRegion::NTSC_J, MakeHashFromString("8dd7d5296a650fac7319bce665a6a53c"), true},
  {"SCPH-5501, 5503, 7003 (v3.0 11-18-96 A)", ConsoleRegion::NTSC_U, MakeHashFromString("490f666e1afb15b7362b406ed1cea246"), true},
  {"SCPH-5502, 5552 (v3.0 01-06-97 E)", ConsoleRegion::PAL, MakeHashFromString("32736f17079d0b2b7024407c39bd3050"), true},
  {"SCPH-7000, 7500, 9000 (v4.0 08-18-97 J)", ConsoleRegion::NTSC_J, MakeHashFromString("8e4c14f567745eff2f0408c8129f72a6"), true},
  {"SCPH-7000W (v4.1 11-14-97 A)", ConsoleRegion::NTSC_J, MakeHashFromString("b84be139db3ee6cbd075630aa20a6553"), true},
  {"SCPH-7001, 7501, 7503, 9001, 9003, 9903 (v4.1 12-16-97 A)", ConsoleRegion::NTSC_U, MakeHashFromString("1e68c231d0896b7eadcad1d7d8e76129"), true},
  {"SCPH-7002, 7502, 9002 (v4.1 12-16-97 E)", ConsoleRegion::PAL, MakeHashFromString("b9d9a0286c33dc6b7237bb13cd46fdee"), true},
  {"SCPH-100 (v4.3 03-11-00 J)", ConsoleRegion::NTSC_J, MakeHashFromString("8abc1b549a4a80954addc48ef02c4521"), true},
  {"SCPH-101 (v4.4 03-24-00 A)", ConsoleRegion::NTSC_U, MakeHashFromString("9a09ab7e49b422c007e6d54d7c49b965"), true},
  {"SCPH-101 (v4.5 05-25-00 A)", ConsoleRegion::NTSC_U, MakeHashFromString("6e3735ff4c7dc899ee98981385f6f3d0"), true},
  {"SCPH-102 (v4.4 03-24-00 E)", ConsoleRegion::PAL, MakeHashFromString("b10f5e0e3d9eb60e5159690680b1e774"), true},
  {"SCPH-102 (v4.5 05-25-00 E)", ConsoleRegion::PAL, MakeHashFromString("de93caec13d1a141a40a79f5c86168d6"), true},
  {"SCPH-1000R (v4.5 05-25-00 J)", ConsoleRegion::NTSC_J, MakeHashFromString("476d68a94ccec3b9c8303bbd1daf2810"), true},
  {"PS2, SCPH-18000 (v5.0 10-27-00 J)", ConsoleRegion::NTSC_J, MakeHashFromString("d8f485717a5237285e4d7c5f881b7f32"), true},
  {"PS2, SCPH-30003 (v5.0 09-02-00 E)", ConsoleRegion::PAL, MakeHashFromString("71f50ef4f4e17c163c78908e16244f7d"), true},
  {"PS2, DTL-H10000 (v5.0 01/17/00 T)", ConsoleRegion::Auto, MakeHashFromString("32f2e4d5ff5ee11072a6bc45530f5765"), true},
  {"PS2, SCPH-10000 (v5.0 01/17/00 T)", ConsoleRegion::Auto, MakeHashFromString("acf4730ceb38ac9d8c7d8e21f2614600"), true},
  {"PS2, DTL-H10000 (v5.0 02/17/00 T)", ConsoleRegion::Auto, MakeHashFromString("acf9968c8f596d2b15f42272082513d1"), true},
  {"PS2, SCPH-10000/SCPH-15000 (v5.0 02/17/00 T)", ConsoleRegion::Auto, MakeHashFromString("b1459d7446c69e3e97e6ace3ae23dd1c"), true},
  {"PS2, DTL-H10000 (v5.0 02/24/00 T)", ConsoleRegion::Auto, MakeHashFromString("d3f1853a16c2ec18f3cd1ae655213308"), true},
  {"PS2, DTL-H30001 (v5.0 07/27/00 A)", ConsoleRegion::NTSC_U, MakeHashFromString("63e6fd9b3c72e0d7b920e80cf76645cd"), true},
  {"PS2, SCPH-30001 (v5.0 07/27/00 A)", ConsoleRegion::NTSC_U, MakeHashFromString("a20c97c02210f16678ca3010127caf36"), true},
  {"PS2, SCPH-30001 (v5.0 09/02/00 A)", ConsoleRegion::NTSC_U, MakeHashFromString("8db2fbbac7413bf3e7154c1e0715e565"), true},
  {"PS2, DTL-H30002 (v5.0 09/02/00 E)", ConsoleRegion::PAL, MakeHashFromString("91c87cb2f2eb6ce529a2360f80ce2457"), true},
  {"PS2, DTL-H30102 (v5.0 09/02/00 E)", ConsoleRegion::PAL, MakeHashFromString("3016b3dd42148a67e2c048595ca4d7ce"), true},
  {"PS2, SCPH-30002/SCPH-30003/SCPH-30004 (v5.0 09/02/00 E)", ConsoleRegion::PAL, MakeHashFromString("b7fa11e87d51752a98b38e3e691cbf17"), true},
  {"PS2, SCPH-18000 (GH-003) (v5.0 10/27/00 J)", ConsoleRegion::NTSC_J, MakeHashFromString("f63bc530bd7ad7c026fcd6f7bd0d9525"), true},
  {"PS2, SCPH-18000 (GH-008) (v5.0 10/27/00 J)", ConsoleRegion::NTSC_J, MakeHashFromString("cee06bd68c333fc5768244eae77e4495"), true},
  {"PS2, DTL-H30101 (v5.0 12/28/00 A)", ConsoleRegion::NTSC_U, MakeHashFromString("0bf988e9c7aaa4c051805b0fa6eb3387"), true},
  {"PS2, SCPH-30001/SCPH-35001 (v5.0 12/28/00 A)", ConsoleRegion::NTSC_U, MakeHashFromString("8accc3c49ac45f5ae2c5db0adc854633"), true},
  {"PS2, DTL-H30102 (v5.0 12/28/00 E)", ConsoleRegion::PAL, MakeHashFromString("6f9a6feb749f0533aaae2cc45090b0ed"), true},
  {"PS2, SCPH-30002/SCPH-30003/SCPH-30004/SCHP-35002/SCPH-35003/SCPH-35004 (v5.0 12/28/00 E)", ConsoleRegion::PAL, MakeHashFromString("838544f12de9b0abc90811279ee223c8"), true},
  {"PS2, DTL-H30000 (v5.0 01/18/01 J)", ConsoleRegion::NTSC_J, MakeHashFromString("bb6bbc850458fff08af30e969ffd0175"), true},
  {"PS2, SCPH-30000/SCPH-35000 (v5.0 01/18/01 J)", ConsoleRegion::NTSC_J, MakeHashFromString("815ac991d8bc3b364696bead3457de7d"), true},
  {"PS2, SCPH-30001R (v5.0 04/27/01 A)", ConsoleRegion::NTSC_U, MakeHashFromString("b107b5710042abe887c0f6175f6e94bb"), true},
  {"PS2, SCPH-30000 (v5.0 04/27/01 J)", ConsoleRegion::NTSC_J, MakeHashFromString("ab55cceea548303c22c72570cfd4dd71"), true},
  {"PS2, SCPH-30001R (v5.0 07/04/01 A)", ConsoleRegion::NTSC_U, MakeHashFromString("18bcaadb9ff74ed3add26cdf709fff2e"), true},
  {"PS2, SCPH-30002R/SCPH-30003R/SCPH-30004R (v5.0 07/04/01 E)", ConsoleRegion::PAL, MakeHashFromString("491209dd815ceee9de02dbbc408c06d6"), true},
  {"PS2, SCPH-30001R (v5.0 10/04/01 A)", ConsoleRegion::NTSC_U, MakeHashFromString("7200a03d51cacc4c14fcdfdbc4898431"), true},
  {"PS2, SCPH-30002R/SCPH-30003R/SCPH-30004R (v5.0 10/04/01 E)", ConsoleRegion::PAL, MakeHashFromString("8359638e857c8bc18c3c18ac17d9cc3c"), true},
  {"PS2, SCPH-30005R/SCPH-30006R/SCPH-30007R (v5.0 07/30/01 J)", ConsoleRegion::NTSC_J, MakeHashFromString("352d2ff9b3f68be7e6fa7e6dd8389346"), true},
  {"PS2, SCPH-39001 (v5.0 02/07/02 A)", ConsoleRegion::NTSC_U, MakeHashFromString("d5ce2c7d119f563ce04bc04dbc3a323e"), true},
  {"PS2, SCPH-39002/SCPH-39003/SCPH-39004 (v5.0 03/19/02 E)", ConsoleRegion::PAL, MakeHashFromString("0d2228e6fd4fb639c9c39d077a9ec10c"), true},
  {"PS2, SCPH-37000/SCPH-39000 (v5.0 04/26/02 J)", ConsoleRegion::NTSC_J, MakeHashFromString("72da56fccb8fcd77bba16d1b6f479914"), true},
  {"PS2, SCPH-39008 (v5.0 04/26/02 E)", ConsoleRegion::PAL, MakeHashFromString("5b1f47fbeb277c6be2fccdd6344ff2fd"), true},
  {"PS2, SCPH-39005/SCPH-39006/SCPH-39007 (v5.0 04/26/02 J)", ConsoleRegion::NTSC_J, MakeHashFromString("315a4003535dfda689752cb25f24785c"), true},
  {"PS2, DTL-H50000 (v5.0 02/06/03 J)", ConsoleRegion::NTSC_J, MakeHashFromString("54ecde087258557e2ddb5c3ddb004028"), true},
  {"PS2, SCPH-50000/SCPH-55000 (v5.0 02/06/03 J)", ConsoleRegion::NTSC_J, MakeHashFromString("312ad4816c232a9606e56f946bc0678a"), true},
  {"PS2, DTL-H50002 (v5.0 02/27/03 E)", ConsoleRegion::PAL, MakeHashFromString("666018ffec65c5c7e04796081295c6c7"), true},
  {"PS2, SCPH-50002/SCPH-50003/SCPH-50004 (v5.0 02/27/03 E)", ConsoleRegion::PAL, MakeHashFromString("6e69920fa6eef8522a1d688a11e41bc6"), true},
  {"PS2, DTL-H50001 (v5.0 03/25/03 A)", ConsoleRegion::NTSC_U, MakeHashFromString("eb960de68f0c0f7f9fa083e9f79d0360"), true},
  {"PS2, SCPH-50001 (v5.0 03/25/03 A)", ConsoleRegion::NTSC_U, MakeHashFromString("8aa12ce243210128c5074552d3b86251"), true},
  {"PS2, DTL-H50009 (v5.0 02/24/03 J)", ConsoleRegion::NTSC_J, MakeHashFromString("240d4c5ddd4b54069bdc4a3cd2faf99d"), true},
  {"PS2, DESR-5000/DESR-5100/DESR-7000/DESR-7100 (v5.0 10/28/03 J)", ConsoleRegion::NTSC_J, MakeHashFromString("1c6cd089e6c83da618fbf2a081eb4888"), true},
  {"PS2, SCPH-55000 (v5.0 06/23/03 J)", ConsoleRegion::NTSC_J, MakeHashFromString("463d87789c555a4a7604e97d7db545d1"), true},
  {"PS2, DTL-H50001 (v5.0 06/23/03 A)", ConsoleRegion::NTSC_U, MakeHashFromString("ab9d49ad40ae49f19856ad187777b1b3"), true},
  {"PS2, SCPH-50001/SCPH-50010 (v5.0 06/23/03 A)", ConsoleRegion::NTSC_U, MakeHashFromString("35461cecaa51712b300b2d6798825048"), true},
  {"PS2, SCPH-50002/SCPH-50003/SCPH-50004 (v5.0 06/23/03 E)", ConsoleRegion::PAL, MakeHashFromString("bd6415094e1ce9e05daabe85de807666"), true},
  {"PS2, SCPH-50006/SCPH-50007 (v5.0 06/23/03 J)", ConsoleRegion::NTSC_J, MakeHashFromString("2e70ad008d4ec8549aada8002fdf42fb"), true},
  {"PS2, SCPH-50005 (v5.0 06/23/03 J)", ConsoleRegion::NTSC_J, MakeHashFromString("50d5b97b57d8c9b6534adcb46c2027d4"), true},
  {"PS2, SCPH-50008 (v5.0 06/23/03 E)", ConsoleRegion::PAL, MakeHashFromString("b53d51edc7fc086685e31b811dc32aad"), true},
  {"PS2, SCPH-50009 (v5.0 06/23/03 J)", ConsoleRegion::NTSC_J, MakeHashFromString("1b6e631b536247756287b916f9396872"), true},
  {"PS2, SCPH-50000 (v5.0 08/22/03 J)", ConsoleRegion::NTSC_J, MakeHashFromString("00da1b177096cfd2532c8fa22b43e667"), true},
  {"PS2, SCPH-50004 (v5.0 08/22/03 E)", ConsoleRegion::PAL, MakeHashFromString("afde410bd026c16be605a1ae4bd651fd"), true},
  {"PS2, SCPH-50011 (v5.0 03/29/04 A)", ConsoleRegion::NTSC_U, MakeHashFromString("81f4336c1de607dd0865011c0447052e"), true},
  {"PS2, SCPH-70000 (v5.0 06/14/04 J)", ConsoleRegion::NTSC_J, MakeHashFromString("0eee5d1c779aa50e94edd168b4ebf42e"), true},
  {"PS2, SCPH-70001/SCPH-70011/SCPH-70012 (v5.0 06/14/04 A)", ConsoleRegion::NTSC_U, MakeHashFromString("d333558cc14561c1fdc334c75d5f37b7"), true},
  {"PS2, SCPH-70002/SCPH-70003/SCPH-70004/SCPH-70008 (v5.0 06/14/04 E)", ConsoleRegion::PAL, MakeHashFromString("dc752f160044f2ed5fc1f4964db2a095"), true},
  {"PS2, SCPH-70002 (v5.0 06/14/04 E)", ConsoleRegion::PAL, MakeHashFromString("7ebb4fc5eab6f79a27d76ac9aad392b2"), true},
  {"PS2, DTL-H70002 (v5.0 06/14/04 E)", ConsoleRegion::PAL, MakeHashFromString("63ead1d74893bf7f36880af81f68a82d"), true},
  {"PS2, SCPH-70005/SCPH-70006/SCPH-70007 (v5.0 06/14/04 J)", ConsoleRegion::NTSC_J, MakeHashFromString("3e3e030c0f600442fa05b94f87a1e238"), true},
  {"PS2, DESR-5500/DESR-5700/DESR-7500/DESR-7700 (v5.0 09/17/04 J)", ConsoleRegion::NTSC_J, MakeHashFromString("1ad977bb539fc9448a08ab276a836bbc"), true},
  {"PS2, DTL-H75000 (v5.0 06/20/05 J)", ConsoleRegion::NTSC_J, MakeHashFromString("bf0078ba5e19d57eae18047407f3b6e5"), true},
  {"PS2, SCPH-75000 (v5.0 06/20/05 J)", ConsoleRegion::NTSC_J, MakeHashFromString("eb4f40fcf4911ede39c1bbfe91e7a89a"), true},
  {"PS2, DTL-H75000A (v5.0 06/20/05 A)", ConsoleRegion::NTSC_U, MakeHashFromString("9959ad7a8685cad66206e7752ca23f8b"), true},
  {"PS2, SCPH-75001/SCPH-75010 (v5.0 06/20/05 A)", ConsoleRegion::NTSC_U, MakeHashFromString("929a14baca1776b00869f983aa6e14d2"), true},
  {"PS2, SCPH-75002/SCPH-75003/SCPH-75004/SCPH-75008 (v5.0 06/20/05 E)", ConsoleRegion::PAL, MakeHashFromString("573f7d4a430c32b3cc0fd0c41e104bbd"), true},
  {"PS2, SCPH-75006 (v5.0 06/20/05 J)", ConsoleRegion::NTSC_J, MakeHashFromString("df63a604e8bff5b0599bd1a6c2721bd0"), true},
  {"PS2, SCPH-77000 (v5.0 02/10/06 J)", ConsoleRegion::NTSC_J, MakeHashFromString("5b1ba4bb914406fae75ab8e38901684d"), true},
  {"PS2, SCPH-77001/SCPH-77010 (v5.0 02/10/06 A)", ConsoleRegion::NTSC_U, MakeHashFromString("cb801b7920a7d536ba07b6534d2433ca"), true},
  {"PS2, SCPH-77002/SCPH-77003/SCPH-77004/SCPH-77008 (v5.0 02/10/06 E)", ConsoleRegion::PAL, MakeHashFromString("af60e6d1a939019d55e5b330d24b1c25"), true},
  {"PS2, SCPH-77006/SCPH-77007 (v5.0 02/10/06 J)", ConsoleRegion::NTSC_J, MakeHashFromString("549a66d0c698635ca9fa3ab012da7129"), true},
  {"PS2, DTL-H90000 (v5.0 09/05/06 J)", ConsoleRegion::NTSC_J, MakeHashFromString("5e2014472c88f74f7547d8c2c60eca45"), true},
  {"PS2, SCPH-79000/SCPH-90000 (v5.0 09/05/06 J)", ConsoleRegion::NTSC_J, MakeHashFromString("5de9d0d730ff1e7ad122806335332524"), true},
  {"PS2, DTL-H90000 (v5.0 09/05/06 A)", ConsoleRegion::NTSC_U, MakeHashFromString("21fe4cad111f7dc0f9af29477057f88d"), true},
  {"PS2, SCPH-79001/SCPH-79010/SCPH-90001 (v5.0 09/05/06 A)", ConsoleRegion::NTSC_U, MakeHashFromString("40c11c063b3b9409aa5e4058e984e30c"), true},
  {"PS2, SCPH-79002/SCPH-79003/SCPH-79004/SCPH-79008/SCPH-90002/SCPH-90003/SCPH-90004 (v5.0 09/05/06 E)", ConsoleRegion::PAL, MakeHashFromString("80bbb237a6af9c611df43b16b930b683"), true},
  {"PS2, SCPH-79006/SCPH-79007/SCPH-90006/SCPH-90007 (v5.0 09/05/06 J)", ConsoleRegion::NTSC_J, MakeHashFromString("c37bce95d32b2be480f87dd32704e664"), true},
  {"PS2, SCPH-90000 (v5.0 02/20/08 J)", ConsoleRegion::NTSC_J, MakeHashFromString("80ac46fa7e77b8ab4366e86948e54f83"), true},
  {"PS2, SCPH-90001/SCPH-90010 (v5.0 02/20/08 A)", ConsoleRegion::NTSC_U, MakeHashFromString("21038400dc633070a78ad53090c53017"), true},
  {"PS2, SCPH-90002/SCPH-90003/SCPH-90004/SCPH-90008 (v5.0 02/20/08 E)", ConsoleRegion::PAL, MakeHashFromString("dc69f0643a3030aaa4797501b483d6c4"), true},
  {"PS2, SCPH-90005/SCPH-90006/SCPH-90007 (v5.0 02/20/08 J)", ConsoleRegion::NTSC_J, MakeHashFromString("30d56e79d89fbddf10938fa67fe3f34e"), true},
  {"PS2, KDL-22PX300 (v5.0 04/15/10 E)", ConsoleRegion::PAL, MakeHashFromString("93ea3bcee4252627919175ff1b16a1d9"), true},
};
// clang-format on

// OpenBIOS is separate, because there's no fixed hash for it. So just in case something collides with a hash of zero...
// which would be unlikely.
static constexpr const BIOS::ImageInfo s_openbios_info = {"OpenBIOS", ConsoleRegion::Auto, {}, false};
static constexpr const char s_openbios_signature[] = {'O', 'p', 'e', 'n', 'B', 'I', 'O', 'S'};
static constexpr u32 s_openbios_signature_offset = 0x78;

} // namespace BIOS

TinyString BIOS::ImageInfo::GetHashString(const BIOS::ImageInfo::Hash& hash)
{
  return TinyString::from_format(
    "{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}", hash[0],
    hash[1], hash[2], hash[3], hash[4], hash[5], hash[6], hash[7], hash[8], hash[9], hash[10], hash[11], hash[12],
    hash[13], hash[14], hash[15]);
}

std::optional<BIOS::Image> BIOS::LoadImageFromFile(const char* filename, Error* error)
{
  std::optional<BIOS::Image> ret;

  auto fp = FileSystem::OpenManagedCFile(filename, "rb", error);
  if (!fp)
  {
    Error::AddPrefixFmt(error, "Failed to open BIOS '{}': ", Path::GetFileName(filename));
    return ret;
  }

  const u64 size = static_cast<u64>(FileSystem::FSize64(fp.get()));
  if (size != BIOS_SIZE && size != BIOS_SIZE_PS2 && size != BIOS_SIZE_PS3)
  {
    Error::SetStringFmt(error, "BIOS image '{}' size mismatch, expecting either {} or {} bytes but got {} bytes",
                        Path::GetFileName(filename), static_cast<unsigned>(BIOS_SIZE),
                        static_cast<unsigned>(BIOS_SIZE_PS2), size);
    return ret;
  }

  // We want to hash the whole file. That means reading the whole thing in, if it's a larger BIOS (PS2).
  std::optional<std::vector<u8>> data = FileSystem::ReadBinaryFile(fp.get(), error);
  if (!data.has_value() || data->size() < BIOS_SIZE)
    return ret;

  ret = BIOS::Image();
  ret->hash = MD5Digest::HashData(data.value());

  // But only copy the first 512KB, since that's all that's mapped.
  ret->data = std::move(data.value());
  ret->data.resize(BIOS_SIZE);
  ret->info = GetInfoForHash(ret->data, ret->hash);

  DEV_LOG("Hash for BIOS '{}': {}", FileSystem::GetDisplayNameFromPath(filename), ImageInfo::GetHashString(ret->hash));
  return ret;
}

const BIOS::ImageInfo* BIOS::GetInfoForHash(const std::span<u8> image, const ImageInfo::Hash& hash)
{
  // check for openbios
  if (image.size() >= (s_openbios_signature_offset + std::size(s_openbios_signature)) &&
      std::memcmp(&image[s_openbios_signature_offset], s_openbios_signature, std::size(s_openbios_signature)) == 0)
  {
    return &s_openbios_info;
  }

  for (const ImageInfo& ii : s_image_info_by_hash)
  {
    if (ii.hash == hash)
      return &ii;
  }

  WARNING_LOG("Unknown BIOS hash: {}", ImageInfo::GetHashString(hash));
  return nullptr;
}

bool BIOS::IsValidBIOSForRegion(ConsoleRegion console_region, ConsoleRegion bios_region)
{
  return (console_region == ConsoleRegion::Auto || bios_region == ConsoleRegion::Auto || bios_region == console_region);
}

void BIOS::PatchBIOS(u8* image, u32 image_size, u32 address, u32 value, u32 mask /*= UINT32_C(0xFFFFFFFF)*/)
{
  const u32 phys_address = address & UINT32_C(0x1FFFFFFF);
  const u32 offset = phys_address - BIOS_BASE;
  Assert(phys_address >= BIOS_BASE && (offset + sizeof(u32)) <= image_size);

  u32 existing_value;
  std::memcpy(&existing_value, &image[offset], sizeof(existing_value));
  u32 new_value = (existing_value & ~mask) | value;
  std::memcpy(&image[offset], &new_value, sizeof(new_value));

  SmallString old_disasm, new_disasm;
  CPU::DisassembleInstruction(&old_disasm, address, existing_value);
  CPU::DisassembleInstruction(&new_disasm, address, new_value);
  DEV_LOG("BIOS-Patch 0x{:08X} (+0x{:X}): 0x{:08X} {} -> {:08X} {}", address, offset, existing_value, old_disasm,
          new_value, new_disasm);
}

bool BIOS::PatchBIOSFastBoot(u8* image, u32 image_size)
{
  // Replace the shell entry point with a return back to the bootstrap.
  INFO_LOG("Patching BIOS to skip intro");
  PatchBIOS(image, image_size, 0x1FC18000, 0x3C011F80); // lui at, 1f80
  PatchBIOS(image, image_size, 0x1FC18004, 0x3C0A0300); // lui t2, 0300h
  PatchBIOS(image, image_size, 0x1FC18008, 0xAC2A1814); // sw zero, 1814h(at)        ; turn the display on
  PatchBIOS(image, image_size, 0x1FC1800C, 0x03E00008); // jr ra
  PatchBIOS(image, image_size, 0x1FC18010, 0x00000000); // nop
  return true;
}

bool BIOS::IsValidPSExeHeader(const PSEXEHeader& header, size_t file_size)
{
  static constexpr char expected_id[] = {'P', 'S', '-', 'X', ' ', 'E', 'X', 'E'};
  if (file_size < sizeof(expected_id) || std::memcmp(header.id, expected_id, sizeof(expected_id)) != 0)
    return false;

  if ((header.file_size + sizeof(PSEXEHeader)) > file_size)
  {
    WARNING_LOG("Incorrect file size in PS-EXE header: {} bytes should not be greater than {} bytes", header.file_size,
                file_size - sizeof(PSEXEHeader));
  }

  return true;
}

DiscRegion BIOS::GetPSExeDiscRegion(const PSEXEHeader& header)
{
  static constexpr char ntsc_u_id[] = "Sony Computer Entertainment Inc. for North America area";
  static constexpr char ntsc_j_id[] = "Sony Computer Entertainment Inc. for Japan area";
  static constexpr char pal_id[] = "Sony Computer Entertainment Inc. for Europe area";

  if (std::memcmp(header.marker, ntsc_u_id, sizeof(ntsc_u_id) - 1) == 0)
    return DiscRegion::NTSC_U;
  else if (std::memcmp(header.marker, ntsc_j_id, sizeof(ntsc_j_id) - 1) == 0)
    return DiscRegion::NTSC_J;
  else if (std::memcmp(header.marker, pal_id, sizeof(pal_id) - 1) == 0)
    return DiscRegion::PAL;
  else
    return DiscRegion::Other;
}

std::optional<BIOS::Image> BIOS::GetBIOSImage(ConsoleRegion region, Error* error)
{
  std::string bios_name;
  switch (region)
  {
    case ConsoleRegion::NTSC_J:
      bios_name = Host::GetStringSettingValue("BIOS", "PathNTSCJ", "");
      break;

    case ConsoleRegion::PAL:
      bios_name = Host::GetStringSettingValue("BIOS", "PathPAL", "");
      break;

    case ConsoleRegion::NTSC_U:
    default:
      bios_name = Host::GetStringSettingValue("BIOS", "PathNTSCU", "");
      break;
  }

  std::optional<Image> image;

  if (bios_name.empty())
  {
    // auto-detect
    image = FindBIOSImageInDirectory(region, EmuFolders::Bios.c_str(), error);
  }
  else
  {
    // try the configured path
    image = LoadImageFromFile(Path::Combine(EmuFolders::Bios, bios_name).c_str(), error);
  }

  // verify region
  if (image.has_value() && (!image->info || !IsValidBIOSForRegion(region, image->info->region)))
  {
    WARNING_LOG("BIOS region {} does not match requested region {}. This may cause issues.",
                image->info ? Settings::GetConsoleRegionName(image->info->region) : "UNKNOWN",
                Settings::GetConsoleRegionName(region));
  }

  return image;
}

std::optional<BIOS::Image> BIOS::FindBIOSImageInDirectory(ConsoleRegion region, const char* directory, Error* error)
{
  INFO_LOG("Searching for a {} BIOS in '{}'...", Settings::GetConsoleRegionName(region), directory);

  FileSystem::FindResultsArray results;
  FileSystem::FindFiles(
    directory, "*", FILESYSTEM_FIND_FILES | FILESYSTEM_FIND_HIDDEN_FILES | FILESYSTEM_FIND_RELATIVE_PATHS, &results);

  std::string fallback_path;
  std::optional<Image> fallback_image;

  for (const FILESYSTEM_FIND_DATA& fd : results)
  {
    if (fd.Size != BIOS_SIZE && fd.Size != BIOS_SIZE_PS2 && fd.Size != BIOS_SIZE_PS3)
    {
      WARNING_LOG("Skipping '{}': incorrect size", fd.FileName.c_str());
      continue;
    }

    std::string full_path(Path::Combine(directory, fd.FileName));
    std::optional<Image> found_image = LoadImageFromFile(full_path.c_str(), nullptr);
    if (!found_image)
      continue;

    if (found_image->info && IsValidBIOSForRegion(region, found_image->info->region))
    {
      INFO_LOG("Using BIOS '{}': {}", fd.FileName.c_str(), found_image->info->description);
      fallback_image = std::move(found_image);
      return fallback_image;
    }

    // don't let an unknown bios take precedence over a known one
    if (fallback_image.has_value() && (fallback_image->info || !found_image->info))
      continue;

    fallback_path = std::move(full_path);
    fallback_image = std::move(found_image);
  }

  if (!fallback_image.has_value())
  {
#ifndef __ANDROID__
    Error::SetStringFmt(
      error,
      TRANSLATE_FS("System", "No BIOS image found for {} region.\n\nDuckStation requires a PS1 or PS2 BIOS in order to "
                             "run.\n\nFor legal reasons, you *must* obtain a BIOS from an actual PS1 unit that you own "
                             "(borrowing doesn't count).\n\nOnce dumped, this BIOS image should be placed in the bios "
                             "folder within the data directory (Tools Menu -> Open Data Directory)."),
      Settings::GetConsoleRegionName(region));
#else
    Error::SetStringFmt(error, TRANSLATE_FS("System", "No BIOS image found for {} region."),
                        Settings::GetConsoleRegionName(region));
#endif
    return fallback_image;
  }

  if (!fallback_image->info)
  {
    WARNING_LOG("Using unknown BIOS '{}'. This may crash.", Path::GetFileName(fallback_path));
  }
  else
  {
    WARNING_LOG("Falling back to possibly-incompatible image '{}': {}", Path::GetFileName(fallback_path),
                fallback_image->info->description);
  }

  return fallback_image;
}

std::vector<std::pair<std::string, const BIOS::ImageInfo*>> BIOS::FindBIOSImagesInDirectory(const char* directory)
{
  std::vector<std::pair<std::string, const ImageInfo*>> results;

  FileSystem::FindResultsArray files;
  FileSystem::FindFiles(directory, "*",
                        FILESYSTEM_FIND_FILES | FILESYSTEM_FIND_HIDDEN_FILES | FILESYSTEM_FIND_RELATIVE_PATHS, &files);

  for (FILESYSTEM_FIND_DATA& fd : files)
  {
    if (fd.Size != BIOS_SIZE && fd.Size != BIOS_SIZE_PS2 && fd.Size != BIOS_SIZE_PS3)
      continue;

    std::string full_path(Path::Combine(directory, fd.FileName));
    std::optional<Image> found_image = LoadImageFromFile(full_path.c_str(), nullptr);
    if (!found_image)
      continue;

    results.emplace_back(std::move(fd.FileName), found_image->info);
  }

  return results;
}

bool BIOS::HasAnyBIOSImages()
{
  return FindBIOSImageInDirectory(ConsoleRegion::Auto, EmuFolders::Bios.c_str(), nullptr).has_value();
}
