#include "examples/fastcgi/fastcgi.h"
#include "muduo/base/Logging.h"
#include "muduo/net/Endian.h"

struct FastCgiCodec::RecordHeader
{
  uint8_t version;
  uint8_t type;
  uint16_t id;
  uint16_t length;
  uint8_t padding;
  uint8_t unused;
};

const unsigned FastCgiCodec::kRecordHeader = static_cast<unsigned>(sizeof(FastCgiCodec::RecordHeader));

enum FcgiType
{
  kFcgiInvalid = 0,
  kFcgiBeginRequest = 1,
  kFcgiAbortRequest = 2,
  kFcgiEndRequest = 3,
  kFcgiParams = 4,
  kFcgiStdin = 5,
  kFcgiStdout = 6,
  kFcgiStderr = 7,
  kFcgiData = 8,
  kFcgiGetValues = 9,
  kFcgiGetValuesResult = 10,
};

enum FcgiRole
{
  // kFcgiInvalid = 0,
  kFcgiResponder = 1,
  kFcgiAuthorizer = 2,
};

enum FcgiConstant
{
  kFcgiKeepConn = 1,
};

using namespace muduo::net;

bool FastCgiCodec::onParams(const char* content, uint16_t length)
{
  if (length > 0)
  {
    paramsStream_.append(content, length);
  }
  else if (!parseAllParams())
  {
    LOG_ERROR << "parseAllParams() failed";
    return false;
  }
  return true;
}

void FastCgiCodec::onStdin(const char* content, uint16_t length)
{
  if (length > 0)
  {
    stdin_.append(content, length);
  }
  else
  {
    gotRequest_ = true;
  }
}

bool FastCgiCodec::parseAllParams()
{
  while (paramsStream_.readableBytes() > 0)
  {
    uint32_t nameLen = readLen();
    if (nameLen == static_cast<uint32_t>(-1))
      return false;
    uint32_t valueLen = readLen();
    if (valueLen == static_cast<uint32_t>(-1))
      return false;
    if (paramsStream_.readableBytes() >= nameLen+valueLen)
    {
      std::string name = paramsStream_.retrieveAsString(nameLen);
      params_[name] = paramsStream_.retrieveAsString(valueLen);
    }
    else
    {
      return false;
    }
  }
  return true;
}

uint32_t FastCgiCodec::readLen()
{
  if (paramsStream_.readableBytes() >= 1)
  {
    uint8_t byte = paramsStream_.peekInt8();
    if (byte & 0x80)
    {
      if (paramsStream_.readableBytes() >= sizeof(uint32_t))
      {
        return paramsStream_.readInt32() & 0x7fffffff;
      }
      else
      {
        return -1;
      }
    }
    else
    {
      return paramsStream_.readInt8();
    }
  }
  else
  {
    return -1;
  }
}

using muduo::net::Buffer;

void FastCgiCodec::endStdout(Buffer* buf)
{
  RecordHeader header =
  {
    1,
    kFcgiStdout,
    sockets::hostToNetwork16(1),
    0,
    0,
    0,
  };
  buf->append(&header, kRecordHeader);
}

void FastCgiCodec::endRequest(Buffer* buf)
{
  RecordHeader header =
  {
    1,
    kFcgiEndRequest,
    sockets::hostToNetwork16(1),
    sockets::hostToNetwork16(kRecordHeader),
    0,
    0,
  };
  buf->append(&header, kRecordHeader);
  buf->appendInt32(0);
  buf->appendInt32(0);
}

void FastCgiCodec::respond(Buffer* response)
{
  if (response->readableBytes() < 65536
      && response->prependableBytes() >= kRecordHeader)
  {
    RecordHeader header =
    {
      1,
      kFcgiStdout,
      sockets::hostToNetwork16(1),
      sockets::hostToNetwork16(static_cast<uint16_t>(response->readableBytes())),
      static_cast<uint8_t>(-response->readableBytes() & 7),
      0,
    };
    response->prepend(&header, kRecordHeader);
    response->append("\0\0\0\0\0\0\0\0", header.padding);
  }
  else
  {
    // FIXME:
  }

  endStdout(response);
  endRequest(response);
}

bool FastCgiCodec::parseRequest(Buffer* buf)
{
  while (buf->readableBytes() >= kRecordHeader)
  {
    RecordHeader header;
    memcpy(&header, buf->peek(), kRecordHeader);
    header.id = sockets::networkToHost16(header.id);
    header.length = sockets::networkToHost16(header.length);
    size_t total = kRecordHeader + header.length + header.padding;
    if (buf->readableBytes() >= total)
    {
      switch (header.type)
      {
        case kFcgiBeginRequest:
          onBeginRequest(header, buf);
          // FIXME: check
          break;
        case kFcgiParams:
          onParams(buf->peek() + kRecordHeader, header.length);
          // FIXME: check
          break;
        case kFcgiStdin:
          onStdin(buf->peek() + kRecordHeader, header.length);
          break;
        case kFcgiData:
          // FIXME:
          break;
        case kFcgiGetValues:
          // FIXME:
          break;
        default:
          // FIXME:
          break;
      }
      buf->retrieve(total);
    }
    else
    {
      break;
    }
  }
  return true;
}

uint16_t readInt16(const void* p)
{
  uint16_t be16 = 0;
  ::memcpy(&be16, p, sizeof be16);
  return sockets::networkToHost16(be16);
}

bool FastCgiCodec::onBeginRequest(const RecordHeader& header, const Buffer* buf)
{
  assert(buf->readableBytes() >= header.length);
  assert(header.type == kFcgiBeginRequest);

  if (header.length >= kRecordHeader)
  {
    uint16_t role = readInt16(buf->peek()+kRecordHeader);
    uint8_t flags = buf->peek()[kRecordHeader + sizeof(int16_t)];
    if (role == kFcgiResponder)
    {
      keepConn_ = flags == kFcgiKeepConn;
      return true;
    }
  }
  return false;
}