// Host-side test harness for the FAT12 emulator.
//
// Builds a 64 KB disk image by walking LBAs 0..127 through MscDisk::read_lba,
// then verifies it with mtools. We mimic the two virtual files the production
// component installs in install_virtual_files_().
//
// Build with: make -C test

#include "msc_disk.h"

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <string>

using esphome::grub_boot_switch::MscDisk;

int main(int argc, char **argv) {
  const char *out_path = (argc > 1) ? argv[1] : "disk.img";
  const uint8_t target = (argc > 2) ? static_cast<uint8_t>(atoi(argv[2])) : 0;

  MscDisk disk;
  disk.set_volume_serial(0x55AA6922);
  disk.set_volume_label("SWITCH");
  disk.set_file_date(2026, 5, 4);

  static const char kPrefix[] = "set os_hw_switch=";
  static const size_t kPrefixLen = sizeof(kPrefix) - 1;
  static const size_t kFileLen = kPrefixLen + 2;

  disk.add_file("switch_position", "SWITCH~1", "   ", 1,
                [target](uint8_t *out) { out[0] = '0' + (target % 10); });

  disk.add_file("switch_position_grub.cfg", "SWITCH~1", "CFG", kFileLen,
                [target](uint8_t *out) {
                  memcpy(out, kPrefix, kPrefixLen);
                  out[kPrefixLen] = '0' + (target % 10);
                  out[kPrefixLen + 1] = '\n';
                });

  std::ofstream f(out_path, std::ios::binary);
  if (!f) {
    fprintf(stderr, "could not open %s\n", out_path);
    return 1;
  }

  uint8_t sector[512];
  for (uint32_t lba = 0; lba < disk.sector_count(); ++lba) {
    disk.read_lba(lba, sector);
    f.write(reinterpret_cast<const char *>(sector), sizeof(sector));
  }
  f.close();

  fprintf(stderr, "wrote %u sectors (%u bytes) to %s with target=%u\n",
          disk.sector_count(), disk.sector_count() * disk.sector_size(),
          out_path, target);
  return 0;
}