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

#include "dusktest.h"
#include "asset/asset.h"
#include "asset/loader/assetloader.h"
#include "asset/loader/assetentry.h"
#include "asset/loader/dmf/assetmodelloader.h"
#include "asset/loader/dmf/assetmeshloader.h"
#include "display/mesh/meshvertex.h"
#include "display/color.h"
#include "util/memory.h"
#include <zip.h>
#include <string.h>

// ============================================================
// This drives the REAL asset system end-to-end (real background loading
// thread, real JSON/MESH/MODEL loaders) rather than hand-stepping a single
// loader. assetModelLoaderSync blocks on assetRequireLoaded for its JSON
// and mesh sub-entries, which only resolves if something is actually
// servicing ASSET_ENTRY_STATE_PENDING_ASYNC on a separate thread -- exactly
// like production. Every mesh fixture uses vertCount == 0 so the mesh's
// own sync phase never touches the GPU.
// ============================================================

typedef struct {
  uint8_t magic[3];
  uint8_t pad;
  uint32_t version;
  uint32_t vertCount;
} dmfheader_t;

static size_t buildEmptyMeshFixture(uint8_t *out) {
  dmfheader_t header = {
    .magic = { 'D', 'M', 'F' }, .pad = 0,
    .version = ASSET_MESH_FILE_VERSION, .vertCount = 0,
  };
  memcpy(out, &header, sizeof(header));
  return sizeof(header);
}

static const char_t *JSON_VALID = "{\"mesh\":\"shared.mesh\"}";
static const char_t *JSON_WITH_COLOR =
  "{\"mesh\":\"shared.mesh\",\"color\":[10,20,30,40]}";
static const char_t *JSON_MISSING_MESH_FIELD = "{\"notmesh\":\"x\"}";
static const char_t *JSON_MESH_NOT_FOUND = "{\"mesh\":\"nonexistent.mesh\"}";

static zip_t *g_zip = NULL;

static int model_zip_add(
  zip_t *za, const char_t *name, const void *data, size_t len
) {
  zip_source_t *s = zip_source_buffer(za, data, len, 0);
  return (int)zip_file_add(za, name, s, ZIP_FL_OVERWRITE);
}

static int model_setup(void **state) {
  zip_error_t err;
  zip_error_init(&err);

  zip_source_t *write_src = zip_source_buffer_create(NULL, 0, 1, &err);
  if(!write_src) return -1;

  zip_t *za = zip_open_from_source(write_src, ZIP_TRUNCATE, &err);
  if(!za) { zip_source_free(write_src); return -1; }

  static uint8_t meshBuf[64];
  size_t meshLen = buildEmptyMeshFixture(meshBuf);

  if(
    model_zip_add(za, "shared.mesh", meshBuf, meshLen) < 0 ||
    model_zip_add(za, "valid.model", JSON_VALID, strlen(JSON_VALID)) < 0 ||
    model_zip_add(za, "color.model", JSON_WITH_COLOR, strlen(JSON_WITH_COLOR)) < 0 ||
    model_zip_add(za, "nomeshfield.model", JSON_MISSING_MESH_FIELD, strlen(JSON_MISSING_MESH_FIELD)) < 0 ||
    model_zip_add(za, "meshnotfound.model", JSON_MESH_NOT_FOUND, strlen(JSON_MESH_NOT_FOUND)) < 0 ||
    model_zip_add(za, "modelA.model", JSON_VALID, strlen(JSON_VALID)) < 0 ||
    model_zip_add(za, "modelB.model", JSON_VALID, strlen(JSON_VALID)) < 0
  ) {
    zip_close(za); return -1;
  }

  zip_source_keep(write_src);
  if(zip_close(za) != 0) { zip_source_free(write_src); return -1; }

  zip_stat_t zs;
  memset(&zs, 0, sizeof(zs));
  if(zip_source_stat(write_src, &zs) != 0 || !(zs.valid & ZIP_STAT_SIZE)) {
    zip_source_free(write_src); return -1;
  }

  void *zipbuf = malloc((size_t)zs.size);
  if(!zipbuf) { zip_source_free(write_src); return -1; }

  if(zip_source_open(write_src) != 0) {
    free(zipbuf); zip_source_free(write_src); return -1;
  }
  zip_source_read(write_src, zipbuf, (zip_uint64_t)zs.size);
  zip_source_close(write_src);
  zip_source_free(write_src);

  zip_error_init(&err);
  zip_source_t *read_src = zip_source_buffer_create(
    zipbuf, (zip_uint64_t)zs.size, 1, &err
  );
  if(!read_src) { free(zipbuf); return -1; }

  g_zip = zip_open_from_source(read_src, 0, &err);
  if(!g_zip) { zip_source_free(read_src); return -1; }

  memoryZero(&ASSET, sizeof(ASSET));
  ASSET.zip = g_zip;
  for(size_t i = 0; i < ASSET_LOADING_COUNT_MAX; i++) {
    threadMutexInit(&ASSET.loading[i].mutex);
  }
  threadInit(&ASSET.loadThread, assetUpdateAsync);
  threadStart(&ASSET.loadThread);

  return 0;
}

static int model_teardown(void **state) {
  threadStop(&ASSET.loadThread);

  for(int i = 0; i < ASSET_ENTRY_COUNT_MAX; i++) {
    if(ASSET.entries[i].type != ASSET_LOADER_TYPE_NULL) {
      errorret_t ret = assetEntryDispose(&ASSET.entries[i]);
      if(errorIsNotOk(ret)) errorCatch(ret);
    }
  }

  for(size_t i = 0; i < ASSET_LOADING_COUNT_MAX; i++) {
    threadMutexDispose(&ASSET.loading[i].mutex);
  }

  if(g_zip) { zip_close(g_zip); g_zip = NULL; }
  ASSET.zip = NULL;
  memoryZero(&ASSET, sizeof(ASSET));
  return 0;
}

// ============================================================
// Tests
// ============================================================

static void test_model_valid_loads_mesh_with_default_color(void **state) {
  assetentry_t *model = assetLock(
    "valid.model", ASSET_LOADER_TYPE_MODEL, NULL
  );

  errorret_t ret = assetRequireLoaded(model);
  assert_true(errorIsOk(ret));
  assert_int_equal(model->state, ASSET_ENTRY_STATE_LOADED);

  assetmodeloutput_t *out = &model->data.model;
  assert_non_null(out->meshEntry);
  assert_int_equal(out->meshEntry->state, ASSET_ENTRY_STATE_LOADED);
  assert_null(out->texEntry);
  assert_int_equal((int)out->color.r, (int)COLOR_WHITE.r);
  assert_int_equal((int)out->color.g, (int)COLOR_WHITE.g);
  assert_int_equal((int)out->color.b, (int)COLOR_WHITE.b);
  assert_int_equal((int)out->color.a, (int)COLOR_WHITE.a);

  assetUnlockEntry(model);
  errorret_t reapRet = assetReapUnused();
  assert_true(errorIsOk(reapRet));
  assert_int_equal(memoryGetAllocatedCount(), 0);
}

static void test_model_parses_optional_color(void **state) {
  assetentry_t *model = assetLock(
    "color.model", ASSET_LOADER_TYPE_MODEL, NULL
  );

  errorret_t ret = assetRequireLoaded(model);
  assert_true(errorIsOk(ret));

  assetmodeloutput_t *out = &model->data.model;
  assert_int_equal((int)out->color.r, 10);
  assert_int_equal((int)out->color.g, 20);
  assert_int_equal((int)out->color.b, 30);
  assert_int_equal((int)out->color.a, 40);

  assetUnlockEntry(model);
  errorret_t reapRet = assetReapUnused();
  assert_true(errorIsOk(reapRet));
  assert_int_equal(memoryGetAllocatedCount(), 0);
}

static void test_model_missing_mesh_field_errors(void **state) {
  assetentry_t *model = assetLock(
    "nomeshfield.model", ASSET_LOADER_TYPE_MODEL, NULL
  );

  errorret_t ret = assetRequireLoaded(model);
  assert_true(errorIsNotOk(ret));
  errorCatch(ret);
  assert_int_equal(model->state, ASSET_ENTRY_STATE_ERROR);

  assetUnlockEntry(model);
  errorret_t reapRet = assetReapUnused();
  assert_true(errorIsOk(reapRet));
  assert_int_equal(memoryGetAllocatedCount(), 0);
}

static void test_model_mesh_not_found_errors(void **state) {
  assetentry_t *model = assetLock(
    "meshnotfound.model", ASSET_LOADER_TYPE_MODEL, NULL
  );

  errorret_t ret = assetRequireLoaded(model);
  assert_true(errorIsNotOk(ret));
  errorCatch(ret);
  assert_int_equal(model->state, ASSET_ENTRY_STATE_ERROR);

  assetUnlockEntry(model);
  errorret_t reapRet = assetReapUnused();
  assert_true(errorIsOk(reapRet));
  assert_int_equal(memoryGetAllocatedCount(), 0);
}

// ------------------------------------------------------------
// Caching: two models sharing one mesh sub-asset
// ------------------------------------------------------------

static void test_two_models_share_one_cached_mesh(void **state) {
  assetentry_t *modelA = assetLock(
    "modelA.model", ASSET_LOADER_TYPE_MODEL, NULL
  );
  assetentry_t *modelB = assetLock(
    "modelB.model", ASSET_LOADER_TYPE_MODEL, NULL
  );

  errorret_t retA = assetRequireLoaded(modelA);
  assert_true(errorIsOk(retA));
  errorret_t retB = assetRequireLoaded(modelB);
  assert_true(errorIsOk(retB));

  assetentry_t *meshA = modelA->data.model.meshEntry;
  assetentry_t *meshB = modelB->data.model.meshEntry;

  // Both models reference "shared.mesh" -- the asset cache must have
  // dedupe'd this to a single loaded entry, not two independent loads.
  assert_ptr_equal(meshA, meshB);
  assert_int_equal((int)meshA->refs.count, 2);

  // Disposing modelA must release its lock on the shared mesh but leave the
  // mesh itself intact, since modelB still holds a reference to it.
  assetUnlockEntry(modelA);
  errorret_t reapRet = assetReapUnused();
  assert_true(errorIsOk(reapRet));
  assert_int_equal((int)meshB->type, (int)ASSET_LOADER_TYPE_MESH);
  assert_int_equal((int)meshB->refs.count, 1);
  assert_int_equal(meshB->state, ASSET_ENTRY_STATE_LOADED);

  // Now release the second model too -- the mesh becomes reapable.
  assetUnlockEntry(modelB);
  reapRet = assetReapUnused();
  assert_true(errorIsOk(reapRet));

  assert_int_equal(memoryGetAllocatedCount(), 0);
}

// ============================================================
// main
// ============================================================

int main(void) {
  assertInit();
  const struct CMUnitTest tests[] = {
    cmocka_unit_test_setup_teardown(test_model_valid_loads_mesh_with_default_color, model_setup, model_teardown),
    cmocka_unit_test_setup_teardown(test_model_parses_optional_color, model_setup, model_teardown),
    cmocka_unit_test_setup_teardown(test_model_missing_mesh_field_errors, model_setup, model_teardown),
    cmocka_unit_test_setup_teardown(test_model_mesh_not_found_errors, model_setup, model_teardown),
    cmocka_unit_test_setup_teardown(test_two_models_share_one_cached_mesh, model_setup, model_teardown),
  };
  return cmocka_run_group_tests(tests, NULL, NULL);
}