/**
 * Copyright (c) 2021 Dominic Masters
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#include "assetmanager.h"

assetmanagerloaderdefinition_t ASSET_MANAGER_LOADERS[] = {
  {
    &_assetManagerLoaderTextureAsync,
    &_assetManagerLoaderTextureSync,
    &_assetManagerLoaderTextureDispose
  },
  {
    &_assetManagerLoaderFontAsync,
    &_assetManagerLoaderFontSync,
    &_assetManagerLoaderFontDispose
  },
  {
    &_assetManagerLoaderShaderAsync,
    &_assetManagerLoaderShaderSync,
    &_assetManagerLoaderShaderDispose
  },
  {
    &_assetManagerLoaderScaledTextureAsync,
    NULL,
    NULL
  },
  {
    &_assetManagerLoaderTextureScaleAsync,
    &_assetManagerLoaderTextureScaleSync,
    &_assetManagerLoaderTextureScaleDispose
  }
};


void assetManagerInit(assetmanager_t *manager) {
  threadInit(&manager->thread, &_assetManagerThread);
  manager->thread.user = manager;
  manager->itemCount = 0;
  manager->finished = false;
  manager->holderCount = 0;
}

float assetManagerProgressGet(assetmanager_t *manager) {
  float done;
  uint8_t i;

  done = 0.0f;

  for(i = 0; i < manager->itemCount; i++) {
    if(!assetManagerItemIsFinished(manager->items + i)) continue;
    done++;
  }

  return done / ((float) manager->itemCount);
}

assetmanagerowner_t assetManagerHolderCreate(assetmanager_t *man) {
  uint8_t i;

  // Find first available number.
  for(i = 0; i < 0xFF; i++) {
    if(arrayFind(
      sizeof(assetmanagerowner_t), man->holders, man->holderCount, &i
    ) == -1) break;
  }

  man->holders[man->holderCount++] = i;
  return i;// No slots left.
}

void assetManagerHolderRelease(assetmanager_t *man, assetmanagerowner_t hold) {
  int32_t i;
  uint8_t j;
  assetmanageritem_t *item;
  size_t s;

  s = sizeof(assetmanagerowner_t);
  i = arrayFind(s, man->holders,man->holderCount,&hold);
  if(i == -1) return;

  arraySplice(sizeof(uint8_t), man->holders, i, 1, man->holderCount);
  man->holderCount--;

  for(j = 0; j < man->itemCount; j++) {
    item = man->items + j;
    i = arrayFind(s, item->holders, item->holderCount, &hold);
    if(i == -1) continue;
    arraySplice(s, item->holders, i, 1, item->holderCount);
    item->holderCount--;
  }
}

void assetManagerDisposeReleased(assetmanager_t *man) {
  uint8_t i;
  assetmanagerloader_t *disp;
  assetmanageritem_t *item;

  for(i = 0; i < man->itemCount; i++) {
    item = man->items + i;
    disp = ASSET_MANAGER_LOADERS[item->type].dispose;
    if(item->holderCount > 0) continue;
    if(disp != NULL) disp(item);
    arraySplice(sizeof(assetmanageritem_t), man->items, i, 1, man->itemCount);
    man->itemCount--;
  }
}

// Thread Management
void assetManagerStart(assetmanager_t *manager) {
  threadStart(&manager->thread);
}

int32_t _assetManagerThread(thread_t *thread) {
  // TODO: Can I allow multiple threads to run?
  uint8_t i;
  assetmanager_t *manager;
  assetmanageritem_t *item;
  assetmanagerloaderdefinition_t *definition;
  bool result;
  manager = thread->user;

  for(i = 0; i < manager->itemCount; i++) {
    item = manager->items + i;
    definition = ASSET_MANAGER_LOADERS + item->type;

    // Only bother with ASYNC items
    if(definition->loadAsync == NULL) continue;

    // Are we already loading or already tried to load?
    if(item->state != ASSET_MANAGER_STATE_PENDING) continue;

    // Begin loading
    item->state = ASSET_MANAGER_STATE_ASYNC_LOADING;
    result = definition->loadAsync(item);

    // Finish Loading
    if(!result) {
      item->state = ASSET_MANAGER_STATE_ASYNC_ERROR;
    } else {
      item->state = ASSET_MANAGER_STATE_ASYNC_DONE;
    }
  }

  manager->finished = assetManagerProgressGet(manager) >= 1.0f;

  return 0;
}

void assetManagerUpdate(assetmanager_t *manager) {
  uint8_t i;
  assetmanageritem_t *item;
  assetmanagerloaderdefinition_t *definition;
  bool result;

  for(i = 0; i < manager->itemCount; i++) {
    item = manager->items + i;
    definition = ASSET_MANAGER_LOADERS + item->type;

    // If requires ASYNC loading, then confirm it has finished loading.
    if(definition->loadAsync != NULL) {
      if(item->state != ASSET_MANAGER_STATE_ASYNC_DONE) continue;
    } else if(item->state != ASSET_MANAGER_STATE_PENDING) {
      continue;
    }
    
    if(definition->loadSync == NULL) {
      continue;
    }
    
    // Begin sync loading
    item->state = ASSET_MANAGER_STATE_SYNC_LOADING;
    result = definition->loadSync(item);

    // Finish loading
    if(!result) {
      item->state = ASSET_MANAGER_STATE_SYNC_ERROR;
    } else {
      item->state = ASSET_MANAGER_STATE_SYNC_DONE;
    }
  }

  manager->finished = assetManagerProgressGet(manager) >= 1.0f;
}

assetmanageritem_t * assetManagerItemGet(assetmanager_t *man, char *key) {
  uint8_t i;
  assetmanageritem_t *item;

  for(i = 0; i < man->itemCount; i++) {
    item = man->items + i;
    if(strcmp(item->key, key) == 0) return item;
  }

  return NULL;
}

assetmanageritem_t * assetManagerItemAdd(assetmanager_t *manager, char *key) {
  // Check if key already exists.
  assetmanageritem_t *item = manager->items + manager->itemCount++;
  item->state = ASSET_MANAGER_STATE_PENDING;
  memcpy(item->key, key, strlen(key) + 1);
  item->holderCount = 0x00;
  return item;
}

uint8_t assetManagerItemGetOrAddHolder(
  assetmanageritem_t *item, assetmanagerowner_t owner
) {
  uint8_t i, firstEmpty;
  firstEmpty = 0xFF;

  for(i = 0; i < item->holderCount; i++) {
    if(item->holders[i] == owner) return i;
    if(firstEmpty == 0xFF && item->holders[i] == 0xFF) {
      firstEmpty = i;
    }
  }

  if(firstEmpty == 0xFF) firstEmpty = item->holderCount++;
  item->holders[firstEmpty] = owner;
  return firstEmpty;
}

bool assetManagerItemIsFinished(assetmanageritem_t *item) {
  // Sync done is always done
  if(item->state == ASSET_MANAGER_STATE_SYNC_DONE) return true;
  // Only check if ASYNC is done.
  if(item->state != ASSET_MANAGER_STATE_ASYNC_DONE) return false;
  // Does it need to still sync load?
  if(ASSET_MANAGER_LOADERS[item->type].loadSync == NULL) return true;
  return false;
}

// Font
assetmanageritem_t * assetManagerLoadFont(
  assetmanager_t *manager, assetmanagerowner_t owner,
  font_t *font, char *fileName
) {
  assetmanageritem_t *item; 
  item = assetManagerItemGet(manager, fileName);
  if(item == NULL) {
    item = assetManagerItemAdd(manager, fileName);
    item->type = ASSET_MANAGER_TYPE_FONT;
    item->data.font.fileName = fileName;
    item->data.font.font = font;
  }
  assetManagerItemGetOrAddHolder(item, owner);

  return item;
}

bool _assetManagerLoaderFontAsync(assetmanageritem_t *item) {
  item->data.font.data = assetStringLoad(item->data.font.fileName);
  return item->data.font.data != NULL;
}

bool _assetManagerLoaderFontSync(assetmanageritem_t *item) {
  fontInit(item->data.font.font, item->data.font.data);
  free(item->data.font.data);
  return true;
}

bool _assetManagerLoaderFontDispose(assetmanageritem_t *item) {
  fontDispose(item->data.font.font);
  return true;
}

// Texture
assetmanageritem_t * assetManagerLoadTexture(
  assetmanager_t *manager, assetmanagerowner_t owner,
  texture_t *texture, char *fileName
) {
  assetmanageritem_t *item;
  item = assetManagerItemGet(manager, fileName);
  if(item == NULL) {
    item = assetManagerItemAdd(manager, fileName);
    item->type = ASSET_MANAGER_TYPE_TEXTURE;
    item->data.texture.fileName = fileName;
    item->data.texture.texture = texture;
  }
  assetManagerItemGetOrAddHolder(item, owner);
  
  return item;
}

bool _assetManagerLoaderTextureAsync(assetmanageritem_t *item) {
  assetbuffer_t *buffer;
  int channels;
  stbi_io_callbacks OPENGL_STBI_CALLBACKS;

  buffer = assetBufferOpen(item->data.texture.fileName);
  if(buffer == NULL) return false;

  // Setup the interface for STBI
  OPENGL_STBI_CALLBACKS.read = &assetBufferRead;
  OPENGL_STBI_CALLBACKS.skip = &assetBufferSkip;
  OPENGL_STBI_CALLBACKS.eof = &assetBufferEnd; 

  // Buffer the image
  channels = 0;
  item->data.texture.data = (pixel_t *)stbi_load_from_callbacks(
    &OPENGL_STBI_CALLBACKS, buffer,
    &item->data.texture.width, &item->data.texture.height,
    &channels, STBI_rgb_alpha
  );

  // Close the buffer
  assetBufferClose(buffer);
  if(item->data.texture.data == NULL) return false;
  return true;
}

bool _assetManagerLoaderTextureSync(assetmanageritem_t *item) {
  // Turn into a texture.
  textureInit(
    item->data.texture.texture,
    item->data.texture.width,
    item->data.texture.height,
    item->data.texture.data
  );

  // Cleanup
  stbi_image_free(item->data.texture.data);
  return true;
}

bool _assetManagerLoaderTextureDispose(assetmanageritem_t *item) {
  textureDispose(item->data.texture.texture);
  return true;
}

// Scaled Texture
assetmanageritem_t * assetManagerLoadScaledTexture(
  assetmanager_t *manager, assetmanagerowner_t owner, 
  scaledtexture_t *st, char *path, char *file
) {
  assetmanageritem_t *item;
  char buffer[ASSET_MANAGER_ITEM_NAME_MAX];
  sprintf(buffer, "%s/%s", path, file);
  item = assetManagerItemGet(manager, buffer);
  if(item == NULL) {
    item = assetManagerItemAdd(manager, buffer);

    item->type = ASSET_MANAGER_TYPE_SCALED_TEXTURE;
    item->data.scaledTexture.scaledTexture = st;

    st->scaleCount = 0;
    st->baseWidth = 0;
    st->baseHeight = 0;
    st->path = path;
    st->file = file;
  }
  assetManagerItemGetOrAddHolder(item, owner);

  return item;
}

bool _assetManagerLoaderScaledTextureAsync(assetmanageritem_t *item) {
  char buffer[128];
  char *xmlData;
  xml_t xml;
  xml_t *child;
  int16_t i, j;
  scaledtexture_t *st;
  st = item->data.scaledTexture.scaledTexture;

  // Begin loading texture XML
  sprintf(buffer, "%s/%s.xml", st->path, st->file);

  xmlData = assetStringLoad(buffer);
  if(xmlData == NULL) return false;
  xmlLoad(&xml, xmlData);
  free(xmlData);

  // Parse root texture info
  i = xmlGetAttributeByName(&xml, "channels");
  st->channels = (uint8_t)atoi(xml.attributeDatas[i]);
  i = xmlGetAttributeByName(&xml, "width");
  st->baseWidth = (int16_t)atoi(xml.attributeDatas[i]);
  i = xmlGetAttributeByName(&xml, "height");
  st->baseHeight = (int16_t)atoi(xml.attributeDatas[i]);

  for(j = 0; j < xml.childrenCount; j++) {
    child = xml.children + j;
    i = xmlGetAttributeByName(child, "scale");
    st->scales[st->scaleCount].scale = (uint8_t)atoi(child->attributeDatas[i]);
    i = xmlGetAttributeByName(child, "width");
    st->scales[st->scaleCount].width = (int16_t)atoi(child->attributeDatas[i]);
    i = xmlGetAttributeByName(child, "height");
    st->scales[st->scaleCount].height = (int16_t)atoi(child->attributeDatas[i]);
    st->scaleCount++;
  }

  // Cleanup XML
  xmlDispose(&xml);
  return true;
}

// Texture Scale
assetmanageritem_t * assetManagerLoadTextureScale(
  assetmanager_t *manager, assetmanagerowner_t owner, 
  scaledtexture_t *st, texture_t *text, uint8_t scale
) {
  assetmanageritem_t *item;
  char buffer[ASSET_MANAGER_ITEM_NAME_MAX];
  sprintf(buffer, "%s/%s_%u", st->path, st->file, scale);
  item = assetManagerItemGet(manager, buffer);
  if(item == NULL) {
    item = assetManagerItemAdd(manager, buffer);
    item->type = ASSET_MANAGER_TYPE_SCALE_TEXTURE;
    item->data.scaleTexture.scale = scale;
    item->data.scaleTexture.texture = text;
    item->data.scaleTexture.scaledTexture = st;
  }
  assetManagerItemGetOrAddHolder(item, owner);
  return item;
}

bool _assetManagerLoaderTextureScaleAsync(assetmanageritem_t *item) {
  char buffer[128];
  scaledtexture_t *st;
  scaledtexturescale_t *sts;
  size_t length;

  st = item->data.scaleTexture.scaledTexture;
  sts = st->scales + item->data.scaleTexture.scale;

  // Get filename
  sprintf(buffer, "%s/%s_%i.texture", st->path, st->file, sts->scale);

  // Create some space
  length = assetRawLoad(buffer, NULL);
  if(length == 0) return false;
  item->data.scaleTexture.data = malloc(sizeof(pixel_t) * length);

  // Load
  length = assetRawLoad(buffer, (uint8_t *)item->data.scaleTexture.data);
  if(length == 0) {
    free(item->data.scaleTexture.data);
    return false;
  }
  
  return true;
}

bool _assetManagerLoaderTextureScaleSync(assetmanageritem_t *item) {
  scaledtexture_t *st;
  scaledtexturescale_t *sts;
  st = item->data.scaleTexture.scaledTexture;
  sts = st->scales + item->data.scaleTexture.scale;

  textureInit(
    item->data.scaleTexture.texture,
    sts->width, sts->height,
    item->data.scaleTexture.data
  );

  free(item->data.scaleTexture.data);
  return true;
}

bool _assetManagerLoaderTextureScaleDispose(assetmanageritem_t *item) {
  textureDispose(item->data.scaleTexture.texture);
  return true;
}

// Shader
assetmanageritem_t * assetManagerLoadShader(
  assetmanager_t *manager, assetmanagerowner_t owner,
  shader_t *shader, char *fileVert, char *fileFrag
) {
  assetmanageritem_t *item;
  char buffer[ASSET_MANAGER_ITEM_NAME_MAX];
  sprintf(buffer, "%s/%s", fileVert, fileFrag);
  item = assetManagerItemGet(manager, buffer);
  if(item == NULL) {
    item = assetManagerItemAdd(manager, buffer);
    item->type = ASSET_MANAGER_TYPE_SHADER;
    item->data.shader.shader = shader;
    item->data.shader.fileVert = fileVert;
    item->data.shader.fileFrag = fileFrag;
  }
  assetManagerItemGetOrAddHolder(item, owner);
  return item;
}

bool _assetManagerLoaderShaderAsync(assetmanageritem_t *item) {
  item->data.shader.dataVert = assetStringLoad(item->data.shader.fileVert);
  if(item->data.shader.dataVert == NULL) return false;

  item->data.shader.dataFrag = assetStringLoad(item->data.shader.fileFrag);
  if(item->data.shader.dataFrag == NULL) {
    free(item->data.shader.fileVert);
    return false;
  }
  
  return true;
}

bool _assetManagerLoaderShaderSync(assetmanageritem_t *item) {
  shaderInit(
    item->data.shader.shader,
    item->data.shader.dataVert,
    item->data.shader.dataFrag
  );
  free(item->data.shader.dataFrag);
  free(item->data.shader.dataVert);
  return true;
}

bool _assetManagerLoaderShaderDispose(assetmanageritem_t *item) {
  shaderDispose(item->data.shader.shader);
  return true;
}