/**
 * Copyright (c) 2026 Dominic Masters
 *
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#include "dusktest.h"
#include "savetestfixture.h"
#include "save/save.h"
#include "save/savedevicelinux.h"
#include "util/memory.h"
#include "util/string.h"
#include <stdio.h>
#include <stdlib.h>

// ============================================================
// Helpers
// ============================================================

static void noopAvailabilityCallback(savedevice_t *device, void *user) {}

// Skips saveFindAvailableDevice()'s bookkeeping (findingAvailableDevice
// etc.) and goes straight to "device 0 is current" - used by tests that
// only care about behavior once a device has been selected, not how it got
// selected. Still runs the real availability check underneath, since that
// is what actually creates the on-disk save directory via mkdirp - reads
// and writes fail without it.
static void makeDeviceAvailable(void) {
  saveDeviceCheckAvailability(&SAVE.devices[0], noopAvailabilityCallback, NULL);
  saveDeviceUpdate(&SAVE.devices[0]);
  assert_int_equal(SAVE.devices[0].state, SAVE_DEVICE_STATE_AVAILABLE);
  SAVE.deviceCurrent = 0;
}

static bool_t g_findCallbackFired;
static savedevice_t *g_findCallbackDevice;

static void findAvailableCallback(savedevice_t *device, void *user) {
  g_findCallbackFired = true;
  g_findCallbackDevice = device;
}

static void resetFindCallbackState(void) {
  g_findCallbackFired = false;
  g_findCallbackDevice = NULL;
}

// ============================================================
// saveInit
// ============================================================

static void test_saveInit_setsDefaults(void **state) {
  // saveTestFixtureSetup already called the real saveInit() - just assert
  // on the state it left behind.
  assert_int_equal(SAVE.deviceCurrent, 0xFF);
  assert_int_equal(SAVE.slotCurrent, 0xFF);
  assert_false(SAVE.findingAvailableDevice);
  assert_false(SAVE.noAvailableDeviceFound);
  assert_int_equal(SAVE.settings.someSetting, 0);
  assert_int_equal(SAVE.devices[0].state, SAVE_DEVICE_STATE_UNKNOWN);

  for(uint8_t i = 0; i < SAVE_SLOT_COUNT; i++) {
    assert_int_equal(SAVE.caches[i].name[0], '\0');
    assert_int_equal(SAVE.caches[i].playerLevel, 0);
  }
}

// ============================================================
// saveUpdate - no-op path
// ============================================================

static void test_saveUpdate_noopWhenNotFinding(void **state) {
  errorret_t ret = saveUpdate();
  assert_true(errorIsOk(ret));
  assert_int_equal(SAVE.deviceCurrent, 0xFF);
  assert_false(SAVE.findingAvailableDevice);
}

// ============================================================
// saveFindAvailableDevice / saveUpdate - discovery flow
// ============================================================

static void test_saveFindAvailableDevice_nullCallbackAsserts(void **state) {
  expect_assert_failure(saveFindAvailableDevice(NULL, NULL));
}

static void test_saveFindAvailableDevice_reentrantAsserts(void **state) {
  resetFindCallbackState();
  saveFindAvailableDevice(findAvailableCallback, NULL);
  expect_assert_failure(saveFindAvailableDevice(findAvailableCallback, NULL));
}

static void test_saveFindAvailableDevice_deviceAlreadyAvailable(void **state) {
  resetFindCallbackState();
  // Mark the device available ahead of time via a real check (this is also
  // what creates the on-disk save directory that the "found device" flow
  // below needs to write settings back out to).
  saveDeviceCheckAvailability(&SAVE.devices[0], noopAvailabilityCallback, NULL);
  saveDeviceUpdate(&SAVE.devices[0]);
  assert_int_equal(SAVE.devices[0].state, SAVE_DEVICE_STATE_AVAILABLE);

  saveFindAvailableDevice(findAvailableCallback, NULL);

  // Set synchronously inside the call itself - no need to wait for update.
  assert_int_equal(SAVE.deviceCurrent, 0);
  assert_false(g_findCallbackFired);

  errorret_t ret = saveUpdate();
  assert_true(errorIsOk(ret));
  assert_true(g_findCallbackFired);
  assert_ptr_equal(g_findCallbackDevice, &SAVE.devices[0]);
  assert_false(SAVE.findingAvailableDevice);
}

static void test_saveFindAvailableDevice_coldPath_oneUpdateResolves(
  void **state
) {
  resetFindCallbackState();

  saveFindAvailableDevice(findAvailableCallback, NULL);

  // Nothing resolved synchronously yet - the Linux availability check is
  // synchronous, but the callback it queues is only drained by an explicit
  // saveDeviceUpdate() inside saveUpdate().
  assert_int_equal(SAVE.deviceCurrent, 0xFF);
  assert_false(g_findCallbackFired);

  errorret_t ret = saveUpdate();
  assert_true(errorIsOk(ret));
  assert_true(g_findCallbackFired);
  assert_ptr_equal(g_findCallbackDevice, &SAVE.devices[0]);
  assert_int_equal(SAVE.deviceCurrent, 0);
  assert_false(SAVE.findingAvailableDevice);
}

static void test_saveFindAvailableDevice_allUnavailable_firesNullCallback(
  void **state
) {
  unsetenv("HOME");
  resetFindCallbackState();

  saveFindAvailableDevice(findAvailableCallback, NULL);

  errorret_t ret = saveUpdate();
  assert_true(errorIsOk(ret));
  assert_true(g_findCallbackFired);
  assert_null(g_findCallbackDevice);
  assert_int_equal(SAVE.deviceCurrent, 0xFF);
  assert_false(SAVE.findingAvailableDevice);
}

// ============================================================
// saveOnDeviceAvailabilityChecked
// ============================================================

static void test_saveOnDeviceAvailabilityChecked_nullDeviceAsserts(
  void **state
) {
  SAVE.findingAvailableDevice = true;
  expect_assert_failure(saveOnDeviceAvailabilityChecked(NULL, NULL));
}

static void test_saveOnDeviceAvailabilityChecked_notFindingAsserts(
  void **state
) {
  SAVE.findingAvailableDevice = false;
  expect_assert_failure(
    saveOnDeviceAvailabilityChecked(&SAVE.devices[0], NULL)
  );
}

static void test_saveOnDeviceAvailabilityChecked_ignoresIfAlreadyResolved(
  void **state
) {
  SAVE.findingAvailableDevice = true;
  SAVE.deviceCurrent = 0;
  SAVE.devices[0].state = SAVE_DEVICE_STATE_UNAVAILABLE;

  saveOnDeviceAvailabilityChecked(&SAVE.devices[0], NULL);

  // Already resolved - unavailable status on a re-delivered callback must
  // not clobber the winning device or flip noAvailableDeviceFound.
  assert_int_equal(SAVE.deviceCurrent, 0);
  assert_false(SAVE.noAvailableDeviceFound);
}

static void test_saveOnDeviceAvailabilityChecked_singleDeviceUnavailable(
  void **state
) {
  SAVE.findingAvailableDevice = true;
  SAVE.deviceCurrent = 0xFF;
  SAVE.devices[0].state = SAVE_DEVICE_STATE_UNAVAILABLE;

  saveOnDeviceAvailabilityChecked(&SAVE.devices[0], NULL);

  // SAVE_DEVICE_COUNT is 1 on Linux, so an unavailable device 0 is always
  // "the last device" - there's no next device to chain to.
  assert_true(SAVE.noAvailableDeviceFound);
  assert_int_equal(SAVE.deviceCurrent, 0xFF);
}

static void test_saveOnDeviceAvailabilityChecked_deviceAvailable(
  void **state
) {
  SAVE.findingAvailableDevice = true;
  SAVE.deviceCurrent = 0xFF;
  SAVE.devices[0].state = SAVE_DEVICE_STATE_AVAILABLE;

  saveOnDeviceAvailabilityChecked(&SAVE.devices[0], NULL);

  assert_int_equal(SAVE.deviceCurrent, 0);
  assert_false(SAVE.noAvailableDeviceFound);
}

// ============================================================
// saveSaveSettings / saveLoadSettings
// ============================================================

static void test_saveSaveSettings_noCurrentDeviceAsserts(void **state) {
  expect_assert_failure(saveSaveSettings());
}

static void test_saveSaveSettings_notDirty_isNoop(void **state) {
  // Documents a real, currently-shipping bug: nothing anywhere in the
  // codebase ever sets SAVE.settingsDirty = true, so saveSaveSettings() is
  // permanently a no-op in practice. This test locks in that (surprising)
  // behavior rather than the presumably-intended one, so it fails loudly
  // if someone changes the no-op condition without meaning to.
  makeDeviceAvailable();
  assert_false(SAVE.settingsDirty);
  SAVE.settings.someSetting = 123;

  errorret_t ret = saveSaveSettings();
  assert_true(errorIsOk(ret));

  savesettings_t onDisk;
  saveSettingsInit(&onDisk);
  errorret_t readRet = saveDeviceSettingsRead(&SAVE.devices[0], &onDisk);
  assert_true(errorIsOk(readRet));
  assert_int_equal(onDisk.someSetting, 0);// never actually written
}

static void test_saveSaveSettings_dirtyForced_writesAndClearsFlag(
  void **state
) {
  makeDeviceAvailable();
  SAVE.settingsDirty = true;// nothing in real code sets this - forced here
  SAVE.settings.someSetting = 55;

  errorret_t ret = saveSaveSettings();
  assert_true(errorIsOk(ret));
  assert_false(SAVE.settingsDirty);

  savesettings_t onDisk;
  saveSettingsInit(&onDisk);
  errorret_t readRet = saveDeviceSettingsRead(&SAVE.devices[0], &onDisk);
  assert_true(errorIsOk(readRet));
  assert_int_equal(onDisk.someSetting, 55);
}

static void test_saveLoadSettings_noCurrentDeviceAsserts(void **state) {
  expect_assert_failure(saveLoadSettings());
}

static void test_saveLoadSettings_readsAndClearsDirtyFlag(void **state) {
  makeDeviceAvailable();

  savesettings_t onDisk;
  saveSettingsInit(&onDisk);
  onDisk.someSetting = 99;
  errorret_t writeRet = saveDeviceSettingsWrite(&SAVE.devices[0], &onDisk);
  assert_true(errorIsOk(writeRet));

  SAVE.settingsDirty = true;
  SAVE.settings.someSetting = 0;

  errorret_t ret = saveLoadSettings();
  assert_true(errorIsOk(ret));
  assert_int_equal(SAVE.settings.someSetting, 99);
  assert_false(SAVE.settingsDirty);
}

// ============================================================
// saveSaveSlot / saveLoadSlot
// ============================================================

static void test_saveSaveSlot_noCurrentDeviceAsserts(void **state) {
  expect_assert_failure(saveSaveSlot());
}

static void test_saveSaveSlot_invalidSlotIndexAsserts(void **state) {
  makeDeviceAvailable();
  // slotCurrent is still 0xFF (unset) from saveInit().
  expect_assert_failure(saveSaveSlot());
}

static void test_saveSaveSlot_success(void **state) {
  makeDeviceAvailable();
  SAVE.slotCurrent = 1;
  saveSlotInit(&SAVE.slot);
  stringCopy(SAVE.slot.cachedData.name, "Hero", sizeof(SAVE.slot.cachedData.name));
  SAVE.slot.cachedData.playerLevel = 12;
  SAVE.slotDirty = true;

  errorret_t ret = saveSaveSlot();
  assert_true(errorIsOk(ret));
  assert_false(SAVE.slotDirty);
  assert_true(stringEquals(SAVE.caches[1].name, "Hero"));
  assert_int_equal(SAVE.caches[1].playerLevel, 12);

  saveslot_t onDisk;
  saveSlotInit(&onDisk);
  errorret_t readRet = saveDeviceSlotRead(&SAVE.devices[0], &onDisk, 1);
  assert_true(errorIsOk(readRet));
  assert_true(stringEquals(onDisk.cachedData.name, "Hero"));
  assert_int_equal(onDisk.cachedData.playerLevel, 12);
}

static void test_saveLoadSlot_noCurrentDeviceAsserts(void **state) {
  expect_assert_failure(saveLoadSlot());
}

static void test_saveLoadSlot_invalidSlotIndexAsserts(void **state) {
  makeDeviceAvailable();
  expect_assert_failure(saveLoadSlot());
}

static void test_saveLoadSlot_success(void **state) {
  makeDeviceAvailable();

  saveslot_t onDisk;
  saveSlotInit(&onDisk);
  stringCopy(onDisk.cachedData.name, "Zelda", sizeof(onDisk.cachedData.name));
  onDisk.cachedData.playerLevel = 30;
  errorret_t writeRet = saveDeviceSlotWrite(&SAVE.devices[0], &onDisk, 2);
  assert_true(errorIsOk(writeRet));

  SAVE.slotCurrent = 2;
  saveSlotInit(&SAVE.slot);
  SAVE.slotDirty = true;

  errorret_t ret = saveLoadSlot();
  assert_true(errorIsOk(ret));
  assert_false(SAVE.slotDirty);
  assert_true(stringEquals(SAVE.slot.cachedData.name, "Zelda"));
  assert_int_equal(SAVE.slot.cachedData.playerLevel, 30);
  assert_true(stringEquals(SAVE.caches[2].name, "Zelda"));
  assert_int_equal(SAVE.caches[2].playerLevel, 30);
}

static void test_saveLoadSlot_deviceReadFails_cacheStaysStale(void **state) {
  makeDeviceAvailable();

  char_t slotPath[512];
  errorret_t pathRet = saveDeviceLinuxGetSlotPath(slotPath, sizeof(slotPath), 0);
  assert_true(errorIsOk(pathRet));
  FILE *file = fopen(slotPath, "w");
  assert_non_null(file);
  fprintf(file, "not valid json {{{");
  fclose(file);

  SAVE.slotCurrent = 0;
  saveSlotInit(&SAVE.slot);
  SAVE.caches[0].playerLevel = 77;// sentinel

  errorret_t ret = saveLoadSlot();
  assert_true(errorIsNotOk(ret));
  errorCatch(ret);

  // The device read failed before the cache-sync line ever ran.
  assert_int_equal(SAVE.caches[0].playerLevel, 77);
}

// ============================================================
// saveLoadAllSlots
// ============================================================

static void test_saveLoadAllSlots_loadsAllAndEndsAtLastIndex(void **state) {
  makeDeviceAvailable();

  for(uint8_t i = 0; i < SAVE_SLOT_COUNT; i++) {
    SAVE.slotCurrent = i;
    saveSlotInit(&SAVE.slot);
    SAVE.slot.cachedData.playerLevel = (int32_t)(i + 1);
    errorret_t saveRet = saveSaveSlot();
    assert_true(errorIsOk(saveRet));
  }

  errorret_t ret = saveLoadAllSlots();
  assert_true(errorIsOk(ret));
  assert_int_equal(SAVE.slotCurrent, SAVE_SLOT_COUNT - 1);

  for(uint8_t i = 0; i < SAVE_SLOT_COUNT; i++) {
    assert_int_equal(SAVE.caches[i].playerLevel, (int32_t)(i + 1));
  }
}

static void test_saveLoadAllSlots_missingFileLeavesInitDefaults(void **state) {
  makeDeviceAvailable();

  SAVE.slotCurrent = 0;
  saveSlotInit(&SAVE.slot);
  SAVE.slot.cachedData.playerLevel = 5;
  errorret_t saveRet = saveSaveSlot();
  assert_true(errorIsOk(saveRet));
  // Slots 1 and 2 are never written - no file exists for them.

  errorret_t ret = saveLoadAllSlots();
  assert_true(errorIsOk(ret));

  assert_int_equal(SAVE.caches[0].playerLevel, 5);
  // Missing-file slots fall back to saveSlotInit()'s default (0), not the
  // JSON-missing-field default of 1 that a corrupt-but-present file with no
  // playerLevel key would produce - these are two different defaults.
  assert_int_equal(SAVE.caches[1].playerLevel, 0);
  assert_int_equal(SAVE.caches[2].playerLevel, 0);
}

static void test_saveLoadAllSlots_middleSlotCorrupt_stopsAtFailingIndex(
  void **state
) {
  makeDeviceAvailable();

  SAVE.slotCurrent = 0;
  saveSlotInit(&SAVE.slot);
  errorret_t saveRet = saveSaveSlot();
  assert_true(errorIsOk(saveRet));

  char_t slotPath[512];
  errorret_t pathRet = saveDeviceLinuxGetSlotPath(slotPath, sizeof(slotPath), 1);
  assert_true(errorIsOk(pathRet));
  FILE *file = fopen(slotPath, "w");
  assert_non_null(file);
  fprintf(file, "not valid json {{{");
  fclose(file);

  errorret_t ret = saveLoadAllSlots();
  assert_true(errorIsNotOk(ret));
  errorCatch(ret);

  // The loop bails out as soon as slot 1 fails - it never reaches slot 2.
  assert_int_equal(SAVE.slotCurrent, 1);
}

// ============================================================
// saveDispose
// ============================================================

static void test_saveDispose_succeeds(void **state) {
  errorret_t ret = saveDispose();
  assert_true(errorIsOk(ret));
}

// ============================================================
// saveUpdate - the unconditional settings write-back on device found
// ============================================================

static void test_saveUpdate_foundDevice_rewritesSettingsUnconditionally(
  void **state
) {
  // Documents another surprising bit of current behavior: as soon as a
  // device is found, saveUpdate() writes SAVE.settings straight back out to
  // it, regardless of settingsDirty - independent of (and unguarded by) the
  // same dirty-flag check saveSaveSettings() itself honors.
  resetFindCallbackState();
  SAVE.settings.someSetting = 321;
  assert_false(SAVE.settingsDirty);

  saveFindAvailableDevice(findAvailableCallback, NULL);
  errorret_t ret = saveUpdate();
  assert_true(errorIsOk(ret));
  assert_true(g_findCallbackFired);

  savesettings_t onDisk;
  saveSettingsInit(&onDisk);
  errorret_t readRet = saveDeviceSettingsRead(&SAVE.devices[0], &onDisk);
  assert_true(errorIsOk(readRet));
  assert_int_equal(onDisk.someSetting, 321);
}

int main(void) {
  assertInit();
  const struct CMUnitTest tests[] = {
    cmocka_unit_test_setup_teardown(
      test_saveInit_setsDefaults, saveTestFixtureSetup, saveTestFixtureTeardown
    ),

    cmocka_unit_test_setup_teardown(
      test_saveUpdate_noopWhenNotFinding, saveTestFixtureSetup, saveTestFixtureTeardown
    ),

    cmocka_unit_test_setup_teardown(
      test_saveFindAvailableDevice_nullCallbackAsserts,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveFindAvailableDevice_reentrantAsserts,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveFindAvailableDevice_deviceAlreadyAvailable,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveFindAvailableDevice_coldPath_oneUpdateResolves,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveFindAvailableDevice_allUnavailable_firesNullCallback,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),

    cmocka_unit_test_setup_teardown(
      test_saveOnDeviceAvailabilityChecked_nullDeviceAsserts,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveOnDeviceAvailabilityChecked_notFindingAsserts,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveOnDeviceAvailabilityChecked_ignoresIfAlreadyResolved,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveOnDeviceAvailabilityChecked_singleDeviceUnavailable,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveOnDeviceAvailabilityChecked_deviceAvailable,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),

    cmocka_unit_test_setup_teardown(
      test_saveSaveSettings_noCurrentDeviceAsserts,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveSaveSettings_notDirty_isNoop, saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveSaveSettings_dirtyForced_writesAndClearsFlag,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveLoadSettings_noCurrentDeviceAsserts,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveLoadSettings_readsAndClearsDirtyFlag,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),

    cmocka_unit_test_setup_teardown(
      test_saveSaveSlot_noCurrentDeviceAsserts, saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveSaveSlot_invalidSlotIndexAsserts, saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveSaveSlot_success, saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveLoadSlot_noCurrentDeviceAsserts, saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveLoadSlot_invalidSlotIndexAsserts, saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveLoadSlot_success, saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveLoadSlot_deviceReadFails_cacheStaysStale,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),

    cmocka_unit_test_setup_teardown(
      test_saveLoadAllSlots_loadsAllAndEndsAtLastIndex,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveLoadAllSlots_missingFileLeavesInitDefaults,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
    cmocka_unit_test_setup_teardown(
      test_saveLoadAllSlots_middleSlotCorrupt_stopsAtFailingIndex,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),

    cmocka_unit_test_setup_teardown(
      test_saveDispose_succeeds, saveTestFixtureSetup, saveTestFixtureTeardown
    ),

    cmocka_unit_test_setup_teardown(
      test_saveUpdate_foundDevice_rewritesSettingsUnconditionally,
      saveTestFixtureSetup, saveTestFixtureTeardown
    ),
  };

  return cmocka_run_group_tests(tests, NULL, NULL);
}