/*!
 * @file kdgo.cpp
 * Loading DGO Files.  Also has some general SIF RPC stuff used for RPCs other than DGO loading.
 * DONE!
 */

#include <cstring>
#include "kdgo.h"
#include "kprint.h"
#include "kmalloc.h"
#include "fileio.h"
#include "klink.h"
#include "game/sce/sif_ee.h"
#include "game/common/dgo_rpc_types.h"
#include "game/common/player_rpc_types.h"
#include "game/common/ramdisk_rpc_types.h"
#include "game/common/loader_rpc_types.h"
#include "game/common/play_rpc_types.h"

using namespace ee;

sceSifClientData cd[6];  //! client data for each IOP Remove Procedure Call.
u16 x[8];                //! stupid temporary for storing a message
u32 sShowStallMsg;       //! setting to show a "stalled on iop" message
u32 sMsgNum;             //! Toggle for double buffered message sending.
RPC_Dgo_Cmd* sLastMsg;   //! Last DGO command sent to IOP
RPC_Dgo_Cmd sMsg[2];     //! DGO message buffers

void kdgo_init_globals() {
  memset(cd, 0, sizeof(cd));
  memset(x, 0, sizeof(x));
  sShowStallMsg = 1;
  sLastMsg = nullptr;
  memset(sMsg, 0, sizeof(sMsg));
}

/*!
 * Call the given RPC with the given function number and buffers.
 */
s32 RpcCall(s32 rpcChannel,
            u32 fno,
            bool async,
            void* sendBuff,
            s32 sendSize,
            void* recvBuff,
            s32 recvSize) {
  return sceSifCallRpc(&cd[rpcChannel], fno, async, sendBuff, sendSize, recvBuff, recvSize, nullptr,
                       nullptr);
}

/*!
 * GOAL Wrapper for RpcCall.
 */
u64 RpcCall_wrapper(s32 rpcChannel,
                    u32 fno,
                    u32 async,
                    u64 send_buff,
                    s32 send_size,
                    u64 recv_buff,
                    s32 recv_size) {
  return sceSifCallRpc(&cd[rpcChannel], fno, async, Ptr<u8>(send_buff).c(), send_size,
                       Ptr<u8>(recv_buff).c(), recv_size, nullptr, nullptr);
}

/*!
 * Check if the given RPC is busy, by channel.
 */
u32 RpcBusy(s32 channel) {
  return sceSifCheckStatRpc(&cd[channel].rpcd);
}

/*!
 * Wait for an RPC to not be busy. Prints a stall message if sShowStallMsg is true and we have
 * to wait on the IOP.  Stalling here is bad because it means the rest of the game can't run.
 */
void RpcSync(s32 channel) {
  if (RpcBusy(channel)) {
    if (sShowStallMsg) {
      Msg(6, "STALL: [kernel] waiting for IOP on RPC port #%d\n", channel);
    }
    while (RpcBusy(channel)) {
      // an attempt to avoid spamming SIF?
      u32 i = 0;
      while (i < 1000) {
        i++;
      }
    }
  }
}

/*!
 * Setup an RPC.
 */
u32 RpcBind(s32 channel, s32 id) {
  while (true) {
    if (sceSifBindRpc(&cd[channel], id, 1) < 0) {
      MsgErr("Error: RpcBind failed on port #%d [%4.4X]\n", channel, id);
      return 1;
    }
    Msg(6, "kernel: RPC port #%d started [%4.4X]\n", channel, id);
    //    FlushCache(0);

    // this was not optimized out in Jak 1, but is _almost_ optimized out in Jak 2 and later.
    u32 i = 0;
    while (i < 10000) {
      i++;
    }

    if (cd[channel].serve) {
      break;
    }
    Msg(6, "kernel: RPC port #%d not responding.\n", channel);
    // it might seem like looping here is a bad idea (unclear if sceSifBindRpc can be called
    // multiple times!) but this actually happens sometimes, at least on development hardware!
    // (also, it's not clear that the "serve" field having data in it really means anything - maybe
    // the sceSifBindRpc doesn't wait for the connection to be fully set up?  This seems likely
    // because they had to put that little delay in there before checking.)
  }
  return 0;
}

/*!
 * Setup all RPCs
 */
u32 InitRPC() {
  if (!RpcBind(PLAYER_RPC_CHANNEL, PLAYER_RPC_ID) && !RpcBind(LOADER_RPC_CHANNEL, LOADER_RPC_ID) &&
      !RpcBind(RAMDISK_RPC_CHANNEL, RAMDISK_RPC_ID) && !RpcBind(DGO_RPC_CHANNEL, DGO_RPC_ID) &&
      !RpcBind(4, 0xdeb5) && !RpcBind(PLAY_RPC_CHANNEL, PLAY_RPC_ID)) {
    return 0;
  }
  printf("Entering endless loop ... please wait\n");
  for (;;) {
  }
}

/*!
 * Send a message to the IOP to stop it.
 */
void StopIOP() {
  x[2] = 0x14;  // todo - this type and message
  RpcSync(PLAYER_RPC_CHANNEL);
  RpcCall(PLAYER_RPC_CHANNEL, 0, false, x, 0x50, nullptr, 0);
  printf("IOP shut down\n");
  //  sceDmaSync(0x10009000, 0, 0);
  printf("DMA shut down\n");
}

/*!
 * Send message to IOP to start loading a new DGO file
 * Uses a double-buffered message buffer
 * @param name: the name of the DGO file
 * @param buffer1 : one of the two file loading buffers
 * @param buffer2 : the other of the two file loading buffers
 * @param currentHeap : the current heap (for loading directly into the heap).
 *
 * DONE,
 * MODIFIED : Added print statement to indicate when DGO load starts.
 */
void BeginLoadingDGO(const char* name, Ptr<u8> buffer1, Ptr<u8> buffer2, Ptr<u8> currentHeap) {
  u8 msgID = sMsgNum;
  RPC_Dgo_Cmd* mess = sMsg + sMsgNum;
  sMsgNum = sMsgNum ^ 1;     // toggle message buffer.
  RpcSync(DGO_RPC_CHANNEL);  // make sure old RPC is finished

  // put a dummy value here just to make sure the IOP overwrites it.
  sMsg[msgID].result = DGO_RPC_RESULT_INIT;  // !! this is 666

  // inform IOP of buffers
  sMsg[msgID].buffer1 = buffer1.offset;
  sMsg[msgID].buffer2 = buffer2.offset;

  // also give a heap pointer so it can load the last object file directly into the heap to save the
  // precious time.
  sMsg[msgID].buffer_heap_top = currentHeap.offset;

  // file name
  strcpy(sMsg[msgID].name, name);
  printf("[Begin Loading DGO RPC] %s, 0x%x, 0x%x, 0x%x\n", name, buffer1.offset, buffer2.offset,
         currentHeap.offset);

  // this RPC will return once we have loaded the first object file.
  // but we call async, so we don't block here.
  RpcCall(DGO_RPC_CHANNEL, DGO_RPC_LOAD_FNO, true, mess, sizeof(RPC_Dgo_Cmd), mess,
          sizeof(RPC_Dgo_Cmd));
  sLastMsg = mess;
}

/*!
 * Get the next object in the DGO.  Will block until something is loaded.
 * @param lastObjectFlag: will get set to 1 if this is the last object.
 *
 * DONE,
 * MODIFIED : added exception if the sLastMessage isn't set (game just returns null as buffer)
 */
Ptr<u8> GetNextDGO(u32* lastObjectFlag) {
  *lastObjectFlag = 1;
  // Wait for RPC function to respond. This will happen once the first object file is loaded.
  RpcSync(DGO_RPC_CHANNEL);
  Ptr<u8> buffer(0);
  if (sLastMsg) {
    // if we got a good result, get pointer to object
    if ((sLastMsg->result == DGO_RPC_RESULT_MORE) || (sLastMsg->result == DGO_RPC_RESULT_DONE)) {
      buffer.offset =
          sLastMsg->buffer1;  // buffer 1 always contains location of most recently loaded object.
    }

    // not the last one, so don't set the flag.
    if (sLastMsg->result == DGO_RPC_RESULT_MORE) {
      *lastObjectFlag = 0;
    }

    // no pending message.
    sLastMsg = nullptr;
  } else {
    // I don't see how this case can happen unless there's a bug. The game does check for this and
    // nothing in this case. (maybe from GOAL this can happen?)
    printf("last message not set!\n");
  }
  return buffer;
}

/*!
 * Instruct the IOP to continue loading the next object.
 * Only should be called once it is safe to overwrite the previous.
 * @param heapPtr : pointer to heap so the IOP could try to load directly into a heap if it wants.
 * This should be updated after each object file load to make sure the IOP knows the exact location
 * of the end of the GOAL heap data.
 * DONE,
 * EXACT
 */
void ContinueLoadingDGO(Ptr<u8> heapPtr) {
  u32 msgID = sMsgNum;
  RPC_Dgo_Cmd* sendBuff = sMsg + sMsgNum;
  sMsgNum = sMsgNum ^ 1;
  sendBuff->result = DGO_RPC_RESULT_INIT;
  sMsg[msgID].buffer1 = 0;
  sMsg[msgID].buffer2 = 0;
  sMsg[msgID].buffer_heap_top = heapPtr.offset;
  // the IOP will wait for this RpcCall to continue the DGO state machine.
  RpcCall(DGO_RPC_CHANNEL, DGO_RPC_LOAD_NEXT_FNO, true, sendBuff, sizeof(RPC_Dgo_Cmd), sendBuff,
          sizeof(RPC_Dgo_Cmd));
  // this async RPC call will complete when the next object is fully loaded.
  sLastMsg = sendBuff;
}

/*!
 * Load the TEST.DGO file.
 * Presumably used for debugging DGO loads.
 * We don't have the TEST.DGO file, so this isn't very useful.
 *
 * DONE,
 * EXACT,
 * UNUSED
 */
void LoadDGOTest() {
  u32 lastObject = 0;

  // backup show stall message and set it to false
  // EE will be loading DGO in a loop, so it will always be stalling
  // no need to print it.
  u32 lastShowStall = sShowStallMsg;
  sShowStallMsg = 0;

  // pick somewhat arbitrary memory to load the DGO into
  BeginLoadingDGO("TEST.DGO", Ptr<u8>(0x4800000), Ptr<u8>(0x4c00000), Ptr<u8>(0x4000000));
  while (true) {
    // keep trying to load.
    Ptr<u8> dest_buffer(0);
    do {
      dest_buffer = GetNextDGO(&lastObject);
    } while (!dest_buffer.offset);

    // print the name of the object we loaded, its destination, and its size.
    Msg(6, "Loaded %s at %8.8X length %d\n", (dest_buffer + 4).cast<char>().c(), dest_buffer.offset,
        *(dest_buffer.cast<u32>()));
    if (lastObject) {
      break;
    }

    // okay to load the next one
    ContinueLoadingDGO(Ptr<u8>(0x4000000));
  }

  sShowStallMsg = lastShowStall;
}

/*!
 * Load and link a DGO file.
 * This does not use the mutli-threaded linker and will block until the entire file is done.
 */
void load_and_link_dgo(u64 name_gstr, u64 heap_info, u64 flag, u64 buffer_size) {
  auto name = Ptr<char>(name_gstr + 4).c();
  auto heap = Ptr<kheapinfo>(heap_info);
  load_and_link_dgo_from_c(name, heap, flag, buffer_size);
}

/*!
 * Load and link a DGO file.
 * This does not use the mutli-threaded linker and will block until the entire file is done.e
 */
void load_and_link_dgo_from_c(const char* name, Ptr<kheapinfo> heap, u32 linkFlag, s32 bufferSize) {
  printf("[Load and Link DGO From C] %s\n", name);
  u32 oldShowStall = sShowStallMsg;

  // remember where the heap top point is so we can clear temporary allocations
  auto oldHeapTop = heap->top;

  // allocate temporary buffers from top of the given heap
  // align 64 for IOP DMA
  // note: both buffers named dgo-buffer-2
  auto buffer2 = kmalloc(heap, bufferSize, KMALLOC_TOP | KMALLOC_ALIGN_64, "dgo-buffer-2");
  auto buffer1 = kmalloc(heap, bufferSize, KMALLOC_TOP | KMALLOC_ALIGN_64, "dgo-buffer-2");

  // build filename.  If no extension is given, default to CGO.
  char fileName[16];
  kstrcpyup(fileName, name);
  if (fileName[strlen(fileName) - 4] != '.') {
    strcat(fileName, ".CGO");
  }

  // no stall messages, as this is a blocking load and when spending 100% CPU time on linking,
  // the linker can beat the DVD drive.
  sShowStallMsg = 0;

  // start load on IOP.
  BeginLoadingDGO(
      fileName, buffer1, buffer2,
      Ptr<u8>((heap->current + 0x3f).offset & 0xffffffc0));  // 64-byte aligned for IOP DMA

  u32 lastObjectLoaded = 0;
  while (!lastObjectLoaded) {
    // check to see if next object is loaded (I believe it always is?)
    auto dgoObj = GetNextDGO(&lastObjectLoaded);
    if (!dgoObj.offset) {
      continue;
    }

    // if we're on the last object, it is loaded at cheap->current.  So we can safely reset the two
    // dgo-buffer allocations. We do this _before_ we link! This way, the last file loaded has more
    // heap available, which is important when we need to use the entire memory.
    if (lastObjectLoaded) {
      heap->top = oldHeapTop;
    }

    // determine the size and name of the object we got
    auto obj = dgoObj + 0x40;             // seek past dgo object header
    u32 objSize = *(dgoObj.cast<u32>());  // size from object's link block

    char objName[64];
    strcpy(objName, (dgoObj + 4).cast<char>().c());  // name from dgo object header
    printf("[link and exec] %s %d\n", objName, lastObjectLoaded);
    link_and_exec(obj, objName, objSize, heap, linkFlag);  // link now!

    // inform IOP we are done
    if (!lastObjectLoaded) {
      ContinueLoadingDGO(Ptr<u8>((heap->current + 0x3f).offset & 0xffffffc0));
    }
  }
  sShowStallMsg = oldShowStall;
}