#include <dolphin/card.h>
#include <dolphin/dsp.h>
#include <dolphin/dvd.h>
#include <dolphin/os.h>

#include <dolphin/CARDPriv.h>

s32 __CARDSeek(CARDFileInfo* fileInfo, s32 length, s32 offset, CARDControl** pcard) {
  CARDControl* card;
  CARDDir* dir;
  CARDDir* ent;
  s32 result;
  u16* fat;

  result = __CARDGetControlBlock(fileInfo->chan, &card);
  if (result < 0) {
    return result;
  }

  if (!CARDIsValidBlockNo(card, fileInfo->iBlock) ||
      card->cBlock * card->sectorSize <= fileInfo->offset) {
    return __CARDPutControlBlock(card, CARD_RESULT_FATAL_ERROR);
  }

  dir = __CARDGetDirBlock(card);
  ent = &dir[fileInfo->fileNo];
  if (ent->length * card->sectorSize <= offset ||
      ent->length * card->sectorSize < offset + length) {
    return __CARDPutControlBlock(card, CARD_RESULT_LIMIT);
  }

  card->fileInfo = fileInfo;
  fileInfo->length = length;
  if (offset < fileInfo->offset) {
    fileInfo->offset = 0;
    fileInfo->iBlock = ent->startBlock;
    if (!CARDIsValidBlockNo(card, fileInfo->iBlock)) {
      return __CARDPutControlBlock(card, CARD_RESULT_BROKEN);
    }
  }
  fat = __CARDGetFatBlock(card);
  while (fileInfo->offset < TRUNC(offset, card->sectorSize)) {
    fileInfo->offset += card->sectorSize;
    fileInfo->iBlock = fat[fileInfo->iBlock];
    if (!CARDIsValidBlockNo(card, fileInfo->iBlock)) {
      return __CARDPutControlBlock(card, CARD_RESULT_BROKEN);
    }
  }

  fileInfo->offset = offset;

  *pcard = card;
  return CARD_RESULT_READY;
}

static void ReadCallback(s32 chan, s32 result) {
  CARDControl* card;
  CARDCallback callback;
  u16* fat;
  CARDFileInfo* fileInfo;
  s32 length;

  card = &__CARDBlock[chan];
  if (result < 0) {
    goto error;
  }

  fileInfo = card->fileInfo;
  if (fileInfo->length < 0) {
    result = CARD_RESULT_CANCELED;
    goto error;
  }

  length = (s32)TRUNC(fileInfo->offset + card->sectorSize, card->sectorSize) - fileInfo->offset;
  fileInfo->length -= length;
  if (fileInfo->length <= 0) {
    goto error;
  }

  fat = __CARDGetFatBlock(card);
  fileInfo->offset += length;
  fileInfo->iBlock = fat[fileInfo->iBlock];
  if (!CARDIsValidBlockNo(card, fileInfo->iBlock)) {
    result = CARD_RESULT_BROKEN;
    goto error;
  }

  result = __CARDRead(chan, card->sectorSize * (u32)fileInfo->iBlock,
                      (fileInfo->length < card->sectorSize) ? fileInfo->length : card->sectorSize,
                      card->buffer, ReadCallback);
  if (result < 0) {
    goto error;
  }

  return;

error:
  callback = card->apiCallback;
  card->apiCallback = 0;
  __CARDPutControlBlock(card, result);
  callback(chan, result);
}

s32 CARDReadAsync(CARDFileInfo* fileInfo, void* buf, s32 length, s32 offset,
                  CARDCallback callback) {
  CARDControl* card;
  s32 result;
  CARDDir* dir;
  CARDDir* ent;

  if (OFFSET(offset, CARD_SEG_SIZE) != 0 || OFFSET(length, CARD_SEG_SIZE) != 0) {
    return CARD_RESULT_FATAL_ERROR;
  }
  result = __CARDSeek(fileInfo, length, offset, &card);
  if (result < 0) {
    return result;
  }

  dir = __CARDGetDirBlock(card);
  ent = &dir[fileInfo->fileNo];
  result = __CARDAccess(card, ent);
  if (result == CARD_RESULT_NOPERM) {
    result = __CARDIsWritable(ent);
  }

  if (result < 0) {
    return __CARDPutControlBlock(card, result);
  }

  DCInvalidateRange(buf, (u32)length);
  card->apiCallback = callback ? callback : __CARDDefaultApiCallback;

  offset = (s32)OFFSET(fileInfo->offset, card->sectorSize);
  length = (length < card->sectorSize - offset) ? length : card->sectorSize - offset;
  result = __CARDRead(fileInfo->chan, card->sectorSize * (u32)fileInfo->iBlock + offset, length,
                      buf, ReadCallback);
  if (result < 0) {
    __CARDPutControlBlock(card, result);
  }
  return result;
}