/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=8 et tw=80 : */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

// HttpLog.h should generally be included first
#include "HttpLog.h"
#include "Http3Session.h"
#include "Http3Stream.h"
#include "nsHttpRequestHead.h"
#include "nsHttpTransaction.h"
#include "nsIClassOfService.h"
#include "nsISocketTransport.h"
#include "nsSocketTransportService2.h"
#include "mozilla/StaticPrefs_network.h"
#include "mozilla/Telemetry.h"
#include "nsIOService.h"
#include "nsHttpHandler.h"

#include <stdio.h>

namespace mozilla {
namespace net {

Http3Stream::Http3Stream(nsAHttpTransaction* httpTransaction,
                         Http3Session* session, const ClassOfService& cos,
                         uint64_t bcId)
    : Http3StreamBase(httpTransaction, session),
      mCurrentTopBrowsingContextId(bcId) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG3(("Http3Stream::Http3Stream [this=%p]", this));

  nsHttpTransaction* trans = mTransaction->QueryHttpTransaction();
  if (trans) {
    mTransactionTabId = trans->TopBrowsingContextId();
  }

  SetPriority(cos.Flags());
  SetIncremental(cos.Incremental());
}

void Http3Stream::Close(nsresult aResult) {
  mRecvState = RECV_DONE;
  mTransaction->Close(aResult);
}

bool Http3Stream::GetHeadersString(const char* buf, uint32_t avail,
                                   uint32_t* countUsed) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG3(("Http3Stream::GetHeadersString %p avail=%u.", this, avail));

  mFlatHttpRequestHeaders.Append(buf, avail);
  // We can use the simple double crlf because firefox is the
  // only client we are parsing
  int32_t endHeader = mFlatHttpRequestHeaders.Find("\r\n\r\n");

  if (endHeader == kNotFound) {
    // We don't have all the headers yet
    LOG3(
        ("Http3Stream::GetHeadersString %p "
         "Need more header bytes. Len = %zu",
         this, mFlatHttpRequestHeaders.Length()));
    *countUsed = avail;
    return false;
  }

  uint32_t oldLen = mFlatHttpRequestHeaders.Length();
  mFlatHttpRequestHeaders.SetLength(endHeader + 2);
  *countUsed = avail - (oldLen - endHeader) + 4;

  return true;
}

void Http3Stream::SetPriority(uint32_t aCos) {
  if (aCos & nsIClassOfService::UrgentStart) {
    // coming from an user interaction => response should be the highest
    // priority
    mPriorityUrgency = 1;
  } else if (aCos & nsIClassOfService::Leader) {
    // main html document normal priority
    mPriorityUrgency = 2;
  } else if (aCos & nsIClassOfService::Unblocked) {
    mPriorityUrgency = 3;
  } else if (aCos & nsIClassOfService::Follower) {
    mPriorityUrgency = 4;
  } else if (aCos & nsIClassOfService::Speculative) {
    mPriorityUrgency = 6;
  } else if (aCos & nsIClassOfService::Background) {
    // background tasks can be deprioritzed to the lowest priority
    mPriorityUrgency = 6;
  } else if (aCos & nsIClassOfService::Tail) {
    mPriorityUrgency = 6;
  } else {
    // all others get a lower priority than the main html document
    mPriorityUrgency = 4;
  }
}

void Http3Stream::SetIncremental(bool incremental) {
  mPriorityIncremental = incremental;
}

nsresult Http3Stream::TryActivating() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG(("Http3Stream::TryActivating [this=%p]", this));
  nsHttpRequestHead* head = mTransaction->RequestHead();

  nsAutoCString authorityHeader;
  nsresult rv = head->GetHeader(nsHttp::Host, authorityHeader);
  if (NS_FAILED(rv)) {
    MOZ_ASSERT(false);
    return rv;
  }

  nsDependentCString scheme(head->IsHTTPS() ? "https" : "http");

  nsAutoCString method;
  nsAutoCString path;
  head->Method(method);
  head->Path(path);

#ifdef DEBUG
  nsAutoCString contentLength;
  if (NS_SUCCEEDED(head->GetHeader(nsHttp::Content_Length, contentLength))) {
    int64_t len;
    if (nsHttp::ParseInt64(contentLength.get(), nullptr, &len)) {
      mRequestBodyLenExpected = len;
    }
  }
#endif

  return mSession->TryActivating(method, scheme, authorityHeader, path,
                                 mFlatHttpRequestHeaders, &mStreamId, this);
}

void Http3Stream::TopBrowsingContextIdChanged(uint64_t id) {
  MOZ_ASSERT(gHttpHandler->ActiveTabPriority());

  bool previouslyFocused = (mCurrentTopBrowsingContextId == mTransactionTabId);
  mCurrentTopBrowsingContextId = id;
  bool nowFocused = (mCurrentTopBrowsingContextId == mTransactionTabId);

  if (!StaticPrefs::
          network_http_http3_send_background_tabs_deprioritization() ||
      previouslyFocused == nowFocused) {
    return;
  }

  mSession->SendPriorityUpdateFrame(mStreamId, PriorityUrgency(),
                                    PriorityIncremental());
}

nsresult Http3Stream::OnReadSegment(const char* buf, uint32_t count,
                                    uint32_t* countRead) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  LOG(("Http3Stream::OnReadSegment count=%u state=%d [this=%p]", count,
       mSendState, this));

  nsresult rv = NS_OK;

  switch (mSendState) {
    case PREPARING_HEADERS: {
      bool done = GetHeadersString(buf, count, countRead);

      if (*countRead) {
        mTotalSent += *countRead;
      }

      if (!done) {
        break;
      }
      mSendState = WAITING_TO_ACTIVATE;
    }
      [[fallthrough]];
    case WAITING_TO_ACTIVATE:
      rv = TryActivating();
      if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
        LOG3(("Http3Stream::OnReadSegment %p cannot activate now. queued.\n",
              this));
        rv = *countRead ? NS_OK : NS_BASE_STREAM_WOULD_BLOCK;
        break;
      }
      if (NS_FAILED(rv)) {
        LOG3(("Http3Stream::OnReadSegment %p cannot activate error=0x%" PRIx32
              ".",
              this, static_cast<uint32_t>(rv)));
        break;
      }

      // Successfully activated.
      mTransaction->OnTransportStatus(nullptr, NS_NET_STATUS_SENDING_TO,
                                      mTotalSent);

      mSendState = SENDING_BODY;
      break;
    case SENDING_BODY: {
      rv = mSession->SendRequestBody(mStreamId, buf, count, countRead);
      if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
        mSendingBlockedByFlowControlCount++;
      }

      if (NS_FAILED(rv)) {
        LOG3(
            ("Http3Stream::OnReadSegment %p sending body returns "
             "error=0x%" PRIx32 ".",
             this, static_cast<uint32_t>(rv)));
        break;
      }

#ifdef DEBUG
      mRequestBodyLenSent += *countRead;
#endif
      mTotalSent += *countRead;
      mTransaction->OnTransportStatus(nullptr, NS_NET_STATUS_SENDING_TO,
                                      mTotalSent);
    } break;
    case EARLY_RESPONSE:
      // We do not need to send the rest of the request, so just ignore it.
      *countRead = count;
#ifdef DEBUG
      mRequestBodyLenSent += count;
#endif
      break;
    default:
      MOZ_ASSERT(false, "We are done sending this request!");
      rv = NS_ERROR_UNEXPECTED;
      break;
  }

  mSocketOutCondition = rv;

  return mSocketOutCondition;
}

void Http3Stream::SetResponseHeaders(nsTArray<uint8_t>& aResponseHeaders,
                                     bool aFin, bool interim) {
  MOZ_ASSERT(mRecvState == BEFORE_HEADERS ||
             mRecvState == READING_INTERIM_HEADERS);
  mFlatResponseHeaders.AppendElements(aResponseHeaders);
  mRecvState = (interim) ? READING_INTERIM_HEADERS : READING_HEADERS;
  mDataReceived = true;
  mFin = aFin;
}

void Http3Stream::StopSending() {
  MOZ_ASSERT((mSendState == SENDING_BODY) || (mSendState == SEND_DONE));
  if (mSendState == SENDING_BODY) {
    mSendState = EARLY_RESPONSE;
  }
}

nsresult Http3Stream::OnWriteSegment(char* buf, uint32_t count,
                                     uint32_t* countWritten) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  LOG(("Http3Stream::OnWriteSegment [this=%p, state=%d", this, mRecvState));
  nsresult rv = NS_OK;
  switch (mRecvState) {
    case BEFORE_HEADERS: {
      *countWritten = 0;
      rv = NS_BASE_STREAM_WOULD_BLOCK;
    } break;
    case READING_HEADERS:
    case READING_INTERIM_HEADERS: {
      // SetResponseHeaders should have been previously called.
      MOZ_ASSERT(!mFlatResponseHeaders.IsEmpty(), "Headers empty!");
      *countWritten = (mFlatResponseHeaders.Length() > count)
                          ? count
                          : mFlatResponseHeaders.Length();
      memcpy(buf, mFlatResponseHeaders.Elements(), *countWritten);

      mFlatResponseHeaders.RemoveElementsAt(0, *countWritten);
      if (mFlatResponseHeaders.Length() == 0) {
        if (mRecvState == READING_INTERIM_HEADERS) {
          // neqo makes sure that fin cannot be received before the final
          // headers are received.
          MOZ_ASSERT(!mFin);
          mRecvState = BEFORE_HEADERS;
        } else {
          mRecvState = mFin ? RECEIVED_FIN : READING_DATA;
        }
      }

      if (*countWritten == 0) {
        rv = NS_BASE_STREAM_WOULD_BLOCK;
      } else {
        mTotalRead += *countWritten;
        mTransaction->OnTransportStatus(nullptr, NS_NET_STATUS_RECEIVING_FROM,
                                        mTotalRead);
      }
    } break;
    case READING_DATA: {
      rv = mSession->ReadResponseData(mStreamId, buf, count, countWritten,
                                      &mFin);
      if (NS_FAILED(rv)) {
        break;
      }
      if (*countWritten == 0) {
        if (mFin) {
          mRecvState = RECV_DONE;
          rv = NS_BASE_STREAM_CLOSED;
        } else {
          rv = NS_BASE_STREAM_WOULD_BLOCK;
        }
      } else {
        mTotalRead += *countWritten;
        mTransaction->OnTransportStatus(nullptr, NS_NET_STATUS_RECEIVING_FROM,
                                        mTotalRead);

        if (mFin) {
          mRecvState = RECEIVED_FIN;
        }
      }
    } break;
    case RECEIVED_FIN:
      rv = NS_BASE_STREAM_CLOSED;
      mRecvState = RECV_DONE;
      break;
    case RECV_DONE:
      rv = NS_ERROR_UNEXPECTED;
  }

  // Remember the error received from lower layers. A stream pipe may overwrite
  // it.
  // If rv == NS_OK this will reset mSocketInCondition.
  mSocketInCondition = rv;

  return rv;
}

nsresult Http3Stream::ReadSegments() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  if (mRecvState == RECV_DONE) {
    // Don't transmit any request frames if the peer cannot respond or respone
    // is already done.
    LOG3(
        ("Http3Stream %p ReadSegments request stream aborted due to"
         " response side closure\n",
         this));
    return NS_ERROR_ABORT;
  }

  nsresult rv = NS_OK;
  uint32_t transactionBytes;
  bool again = true;
  do {
    transactionBytes = 0;
    rv = mSocketOutCondition = NS_OK;
    LOG(("Http3Stream::ReadSegments state=%d [this=%p]", mSendState, this));
    switch (mSendState) {
      case WAITING_TO_ACTIVATE: {
        // A transaction that had already generated its headers before it was
        // queued at the session level (due to concurrency concerns) may not
        // call onReadSegment off the ReadSegments() stack above.
        LOG3(
            ("Http3Stream %p ReadSegments forcing OnReadSegment call\n", this));
        uint32_t wasted = 0;
        nsresult rv2 = OnReadSegment("", 0, &wasted);
        LOG3(("  OnReadSegment returned 0x%08" PRIx32,
              static_cast<uint32_t>(rv2)));
        if (mSendState != SENDING_BODY) {
          break;
        }
      }
        // If we are in state SENDING_BODY we can continue sending data.
        [[fallthrough]];
      case PREPARING_HEADERS:
      case SENDING_BODY: {
        rv = mTransaction->ReadSegmentsAgain(
            this, nsIOService::gDefaultSegmentSize, &transactionBytes, &again);
      } break;
      default:
        transactionBytes = 0;
        rv = NS_OK;
        break;
    }

    LOG(("Http3Stream::ReadSegments rv=0x%" PRIx32 " read=%u sock-cond=%" PRIx32
         " again=%d [this=%p]",
         static_cast<uint32_t>(rv), transactionBytes,
         static_cast<uint32_t>(mSocketOutCondition), again, this));

    // XXX some streams return NS_BASE_STREAM_CLOSED to indicate EOF.
    if (rv == NS_BASE_STREAM_CLOSED && !mTransaction->IsDone()) {
      rv = NS_OK;
      transactionBytes = 0;
    }

    if (NS_FAILED(rv)) {
      // if the transaction didn't want to write any more data, then
      // wait for the transaction to call ResumeSend.
      if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
        rv = NS_OK;
      }
      again = false;
    } else if (NS_FAILED(mSocketOutCondition)) {
      if (mSocketOutCondition != NS_BASE_STREAM_WOULD_BLOCK) {
        rv = mSocketOutCondition;
      }
      again = false;
    } else if (!transactionBytes) {
      mTransaction->OnTransportStatus(nullptr, NS_NET_STATUS_WAITING_FOR, 0);
      mSession->CloseSendingSide(mStreamId);
      mSendState = SEND_DONE;
      Telemetry::Accumulate(
          Telemetry::HTTP3_SENDING_BLOCKED_BY_FLOW_CONTROL_PER_TRANS,
          mSendingBlockedByFlowControlCount);

#ifdef DEBUG
      MOZ_ASSERT(mRequestBodyLenSent == mRequestBodyLenExpected);
#endif
      rv = NS_OK;
      again = false;
    }
    // write more to the socket until error or end-of-request...
  } while (again && gHttpHandler->Active());
  return rv;
}

nsresult Http3Stream::WriteSegments() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG(("Http3Stream::WriteSegments [this=%p]", this));
  nsresult rv = NS_OK;
  uint32_t countWrittenSingle = 0;
  bool again = true;

  do {
    mSocketInCondition = NS_OK;
    countWrittenSingle = 0;
    rv = mTransaction->WriteSegmentsAgain(
        this, nsIOService::gDefaultSegmentSize, &countWrittenSingle, &again);
    LOG(("Http3Stream::WriteSegments rv=0x%" PRIx32
         " countWrittenSingle=%" PRIu32 " socketin=%" PRIx32 " [this=%p]",
         static_cast<uint32_t>(rv), countWrittenSingle,
         static_cast<uint32_t>(mSocketInCondition), this));
    if (mTransaction->IsDone()) {
      // If a transaction has read the amount of data specified in
      // Content-Length it is marked as done.The Http3Stream should be
      // marked as done as well to start the process of cleanup and
      // closure.
      mRecvState = RECV_DONE;
    }

    if (NS_FAILED(rv)) {
      // if the transaction didn't want to take any more data, then
      // wait for the transaction to call ResumeRecv.
      if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
        rv = NS_OK;
      }
      again = false;
    } else if (NS_FAILED(mSocketInCondition)) {
      if (mSocketInCondition != NS_BASE_STREAM_WOULD_BLOCK) {
        rv = mSocketInCondition;
      }
      again = false;
    }
    // read more from the socket until error...
  } while (again && gHttpHandler->Active());

  return rv;
}

bool Http3Stream::Do0RTT() {
  MOZ_ASSERT(mTransaction);
  mAttempting0RTT = mTransaction->Do0RTT();
  return mAttempting0RTT;
}

nsresult Http3Stream::Finish0RTT(bool aRestart) {
  MOZ_ASSERT(mTransaction);
  mAttempting0RTT = false;
  nsresult rv = mTransaction->Finish0RTT(aRestart, false);
  if (aRestart) {
    nsHttpTransaction* trans = mTransaction->QueryHttpTransaction();
    if (trans) {
      trans->Refused0RTT();
    }

    // Reset Http3Sream states as well.
    mSendState = PREPARING_HEADERS;
    mRecvState = BEFORE_HEADERS;
    mStreamId = UINT64_MAX;
    mFlatHttpRequestHeaders = "";
    mQueued = false;
    mDataReceived = false;
    mResetRecv = false;
    mFlatResponseHeaders.TruncateLength(0);
    mTotalSent = 0;
    mTotalRead = 0;
    mFin = false;
    mSendingBlockedByFlowControlCount = 0;
    mSocketInCondition = NS_ERROR_NOT_INITIALIZED;
    mSocketOutCondition = NS_ERROR_NOT_INITIALIZED;
  }

  return rv;
}

uint8_t Http3Stream::PriorityUrgency() {
  if (!StaticPrefs::network_http_http3_priority()) {
    // send default priority which is equivalent to sending no priority
    return 3;
  }

  if (StaticPrefs::network_http_http3_send_background_tabs_deprioritization() &&
      mCurrentTopBrowsingContextId != mTransactionTabId) {
    // Low priority
    return 6;
  }
  return mPriorityUrgency;
}

bool Http3Stream::PriorityIncremental() {
  if (!StaticPrefs::network_http_http3_priority()) {
    // send default priority which is equivalent to sending no priority
    return false;
  }
  return mPriorityIncremental;
}

}  // namespace net
}  // namespace mozilla