// Copyright 2026 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#pragma once

#include <functional>
#include <string>

#include <fmt/format.h>

#include "Common/CommonTypes.h"

// What StarletBootstrapProbe requires of a finished StarOS panic path (StarOS ADR-0014 R6). The
// path sets __panic_state first, then __panic_code, then publishes the SBR1 boot record when
// there is one, so the first nonzero guard can show it half done: the probe keeps running until
// every condition holds. Words come through a callback, so the check is tested without a CPU.
namespace StarletBootstrapProbe
{
// StarOS's SBR1 boot record in MEM1 (StarOS crates/boot-contract, report.rs).
enum class SBR1Mode
{
  None,
  // --sbr1-record: the probe creates the record as the loader does.
  Record,
  // --sbr1-absent: no record; its area must stay zero.
  Absent,
};
constexpr u32 SBR1_BASE = 0x00200000;
constexpr u32 SBR1_SIZE = 0x1000;
constexpr u32 SBR1_MAGIC = 0x53425231;
constexpr u32 SBR1_VERSION = 1;
// Word offsets.
constexpr u32 SBR1_EXI_OWNER = 0x0c;
constexpr u32 SBR1_RELAY_STATUS = 0x10;
constexpr u32 SBR1_STARLET_STATE = 0x18;
constexpr u32 SBR1_FATAL_REASON = 0x1c;
constexpr u32 SBR1_FAULT_CODE = 0x20;
constexpr u32 SBR1_RING_LENGTH = 0x2c;
constexpr u32 SBR1_RING_DROPPED = 0x30;
// Values.
constexpr u32 SBR1_EXI_PPC = 1;
constexpr u32 SBR1_EXI_STARLET = 2;
constexpr u32 SBR1_RELAY_JUMPING = 4;
constexpr u32 SBR1_STATE_PANIC = 5;
// __panic_state once the path is entered; __panic_code of a Rust panic.
constexpr u32 PANIC_ENTERED = 1;
constexpr u32 PANIC_CODE_RUST = 1;

// The first condition of a finished panic path that does not hold, or an empty string:
// - __panic_state 1 and __panic_code 1;
// - with --sbr1-record: STARLET_STATE 5 (Panic), FATAL_REASON 0 and EXI_OWNER 1 (PPC);
// - with --sbr1-absent: every word of the record area still zero.
// read_mem1 returns the big-endian MEM1 word at an address.
inline std::string UnmetPanicCondition(u32 panic_state, u32 panic_code, SBR1Mode sbr1,
                                       const std::function<u32(u32)>& read_mem1)
{
  if (panic_state != PANIC_ENTERED)
    return fmt::format("__panic_state is {}, not {}", panic_state, PANIC_ENTERED);
  if (panic_code != PANIC_CODE_RUST)
    return fmt::format("__panic_code is {}, not {}", panic_code, PANIC_CODE_RUST);
  if (sbr1 == SBR1Mode::Record)
  {
    const struct
    {
      const char* name;
      u32 offset;
      u32 expected;
    } fields[] = {{"STARLET_STATE", SBR1_STARLET_STATE, SBR1_STATE_PANIC},
                  {"FATAL_REASON", SBR1_FATAL_REASON, 0},
                  {"EXI_OWNER", SBR1_EXI_OWNER, SBR1_EXI_PPC}};
    for (const auto& field : fields)
    {
      const u32 value = read_mem1(SBR1_BASE + field.offset);
      if (value != field.expected)
        return fmt::format("SBR1 {} is {}, not {}", field.name, value, field.expected);
    }
  }
  if (sbr1 == SBR1Mode::Absent)
  {
    for (u32 offset = 0; offset < SBR1_SIZE; offset += 4)
    {
      const u32 value = read_mem1(SBR1_BASE + offset);
      if (value != 0)
        return fmt::format("SBR1 area word +{:#x} is {:#x} without a record", offset, value);
    }
  }
  return {};
}
}  // namespace StarletBootstrapProbe