#include <cstdlib>

#include <iostream>
#include <chrono>
#include <thread>
#include <sstream>
#include <algorithm>

#include "CodeDweller/child.hpp"

////////////////////////////////////////////////////////////////////////////////
// Configuration ///////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

/// Child program name.
const std::string childName("./childProgram");

////////////////////////////////////////////////////////////////////////////////
// End of configuration ////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

int nTotalTests = 0;
int nPass = 0;
int nFail = 0;

bool result;

#define NO_EXCEPTION_TERM(msg)			                  \
  std::cout                                                       \
  << msg << " failed to throw exception at line "		  \
  << __LINE__ << "." << std::endl

#define EXCEPTION_TERM(msg)			             	      \
  std::cout                                                  	      \
  << msg << " threw unexpected exception:  " << e.what() << std::endl

#define RETURN_FALSE(msg)					\
  std::cout							\
  << msg << " at line " << __LINE__ << std::endl;		\
  return false;

#define RUN_TEST(test)							\
  std::cout << "  " #test ":  ";					\
  std::cout.flush();							\
  result = test();							\
  std::cout << (result ? "ok" : "fail") << std::endl;			\
  nTotalTests++;							\
  if (result) nPass++; else nFail++;

#define SUMMARY \
  std::cout                                     \
  << "\nPass:  " << nPass                       \
  << ", Fail:  " << nFail                       \
  << ", Total:  " << nTotalTests << std::endl

////////////////////////////////////////////////////////////////////////////////
// Tests ///////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

bool
testIsDone() {

  try {

    CodeDweller::Child child(childName);

    // Test exception if called out-of-order.
    try {
      child.isDone();
      NO_EXCEPTION_TERM("isDone() called without run()");
      return false;
    } catch (std::exception &e) {
    }

    child.run();
    if (child.isDone()) {
      std::cout << "isDone() failure; returned true." << std::endl;
      return false;
    }

    // Command the child to exit.
    child.childStream << 'q';
    child.childStream.flush();

    // Sleep to let the child exit.
    std::this_thread::sleep_for(std::chrono::milliseconds(100));

    if (!child.isDone()) {
      std::cout << "isDone() failure; returned false." << std::endl;
      return false;
    }
  } catch (std::exception &e) {
    EXCEPTION_TERM("isDone()");
    return false;
  }

  return true;

}

bool
testResult() {

  try {
    std::vector<std::string> cmd;

    cmd.push_back(childName);
    cmd.push_back("quit");

    CodeDweller::Child child(cmd);

    // Test exception if called out-of-order.
    try {
      (void) child.result();
      NO_EXCEPTION_TERM("  result() called without run()");
      return false;
    } catch (std::exception &e) {
    }

    child.run();

    // Test exception if called while child is running.
    try {
      (void) child.result();
      NO_EXCEPTION_TERM("  result() called before child exited");
      return false;
    } catch (std::exception &e) {
    }

    // Wait for the child to exit.
    std::this_thread::sleep_for(std::chrono::milliseconds(100));

    int32_t result = child.result();
    if (25 != result) {
      std::cout << "result() failure; returned " << result
		<< " instead of 25." << std::endl;
      return false;
    }
  } catch (std::exception &e) {
    EXCEPTION_TERM("result()");
    return false;
  }
  return true;
}

bool
testTerminate() {

  // Test with no waiting.
  try {
      CodeDweller::Child child(childName);
      child.run();
      child.terminate();
  } catch (std::exception &e) {
    EXCEPTION_TERM("terminate() with no waiting");
    return false;
  }

  // Test with waiting.
  try {
      CodeDweller::Child child(childName);
      child.run();
      std::this_thread::sleep_for(std::chrono::milliseconds(100));
      child.terminate();
  } catch (std::exception &e) {
    EXCEPTION_TERM("terminate() with 100 ms waiting");
    return false;
  }

  // Test after the child exits.
  std::vector<std::string> cmd;

  cmd.push_back(childName);
  cmd.push_back("quit");

  try {
      CodeDweller::Child child(cmd);
      child.run();
      std::this_thread::sleep_for(std::chrono::milliseconds(100));
      child.terminate();
  } catch (std::exception &e) {
    EXCEPTION_TERM("terminate() after child exits");
    return false;
  }

  // Test exception thrown for out-of-order calling.
  try {
      CodeDweller::Child child(cmd);
      child.terminate();
      NO_EXCEPTION_TERM("terminate() called without run()");
      return false;
  } catch (std::exception &e) {
  }

  return true;
}

bool
testReaderWriter() {

  try {
    size_t bufSize = 15;
    CodeDweller::Child child(childName, bufSize);
    std::ostringstream childOutput;
    std::vector<std::string> expectedChildOutput;
    char readChar;

    // Generate input.
    char randomLetter[] = "abcdefghijklmnop#rstuvwxyz";
    int nChar = bufSize - 1;
    int nLines = 2;
    for (int iLine = 0; iLine < nLines; iLine++) {
      std::string line;
      line.erase();
      for (int iChar = 0; iChar < nChar; iChar++) {
	line.push_back(randomLetter[std::rand() % 26]);
      }
      expectedChildOutput.push_back(line);
    }

    // Test exception.
    try {
      child.childStream.exceptions(std::ostream::failbit | std::ostream::badbit);
      child.childStream << bufSize;
      child.childStream.flush();
      NO_EXCEPTION_TERM("  writer called without run()");
      return false;
    } catch (std::exception &e) {
    }

    // Clear the writer stream.
    try {
      child.childStream.clear();
    } catch (std::exception &e) {
    }

    child.run();

    // Write, read, put back, and reread each character.
    for (std::string line : expectedChildOutput) {

      // Write one line.
      const char *ptr;

      ptr = line.data();
      for (std::string::size_type i = 0; i < line.length(); i++) {
	child.childStream << ptr[i];
	if (!child.childStream) {
	  RETURN_FALSE("  Failure in testReaderWriter:  writer stream is bad");
	}
      }
      child.childStream.flush();
      if (!child.childStream) {
	RETURN_FALSE("  Failure in testReaderWriter:  writer stream is bad");
      }

      // Read one line.
      std::string readLine;

      readLine.erase();
      for (std::string::size_type i = 0; i < line.length(); i++) {
	child.childStream >> readChar;
	if (!child.childStream) {
	  RETURN_FALSE("  Failure in testReaderWriter:  reader stream is bad");
	}
	readLine.push_back(readChar);
      }

      // Convert to upper case.
      std::string expectedLine;

      expectedLine = line;
      for (auto &c : expectedLine) {

	c = toupper(c);

      }

      // Compare.
      if (expectedLine != readLine) {
	std::cout << "  Failure in testReaderWriter." << std::endl;
	std::cout << "    Expected:  '" << expectedLine
		  << "'\n    Received:  '" << readLine << "'" << std::endl;
	return false;

      }

    }

    // Send exit message.
    child.childStream << 'q';
    child.childStream.flush();
    if (!child.childStream) {
      RETURN_FALSE("  Failure in testReaderWriter:  writer stream is bad");
    }

    // Verify exit.
    std::this_thread::sleep_for(std::chrono::milliseconds(100));

    if (!child.isDone()) {
      std::cout << "  Failure in testReaderWriter:  "
		<< "Child program did not exit."  << std::endl;
      return false;
    }

  } catch (std::exception &e) {
    EXCEPTION_TERM("reader()/writer()");
    return false;
  }

  return true;

}

bool
testReader() {

  try {
    std::vector<std::string> cmd;

    cmd.push_back(childName);
    cmd.push_back("write");

    size_t bufSize = 32;
    CodeDweller::Child child(cmd, bufSize);

    // Test exception.
    try {
      int temp;
      child.childStream.exceptions(std::istream::failbit | std::istream::badbit);
      child.childStream >>  temp;
      NO_EXCEPTION_TERM("  reader called without run()");
      return false;
    } catch (std::exception &e) {
    }

    child.childStream.clear();
    child.childStream.clear();
    std::ostringstream childOutput;
    std::string expectedChildOutput("This is a test");
    char readChar;

    child.run();
    child.childStream.exceptions(std::istream::badbit);
    child.childStream >> std::noskipws;
    if (!child.childStream) {
      RETURN_FALSE("  Failure in testReader:  reader stream is bad");
    }

    while (child.childStream >> readChar) {

      if (!child.childStream) {
	RETURN_FALSE("  Failure in testReader:  reader stream is bad");
      }
      child.childStream.putback(readChar);
      if (!child.childStream) {
	RETURN_FALSE("  Failure in testReader:  reader stream is bad");
      }
      child.childStream >> readChar;
      if (!child.childStream) {
	RETURN_FALSE("  Failure in testReader:  reader stream is bad");
      }
      childOutput << readChar;

    }

    if (!child.childStream.eof()) {
      RETURN_FALSE("  Failure in testReader:  Error occured before "
		   "EOF was reached while reading");
    }

    // Check.
    if (childOutput.str() != expectedChildOutput) {
      std::cout << "  reader() failure in testReader." << std::endl;
      std::cout << "    Expected:  '" << expectedChildOutput
		<< "'\n    Received:  '" << childOutput.str() << "'"
		<< std::endl;
      return false;
    }

    // Sleep to let the child exit.
    std::this_thread::sleep_for(std::chrono::milliseconds(100));

    if (!child.isDone()) {
      std::cout << "first isDone() failure in testReader." << std::endl;
      return false;
    }

    if (!child.isDone()) {
      std::cout << "second isDone() failure in testReader." << std::endl;
      return false;
    }

  } catch (std::exception &e) {
    EXCEPTION_TERM("reader()");
    return false;
  }

  return true;

}

bool
testBinaryRead() {

  try {
    std::vector<std::string> cmd;

    cmd.push_back(childName);

    size_t bufSize = 164;
    CodeDweller::Child child(cmd, bufSize);

    child.run();

    // Write.
    std::string childInput("abc");

    child.childStream << childInput;
    child.childStream.flush();
    std::this_thread::sleep_for(std::chrono::milliseconds(100));
    
    // Read one character.
    char ch;

    child.childStream.read(&ch, 1);

    if (ch != 'A') {
      RETURN_FALSE("  reader.read() returned incorrect value");
    }

    // Read.
    char buf[bufSize * 2];

    child.childStream.read(buf, 2);
    buf[2] = '\0';

    std::string input(buf);

    if (input != "BC") {
      RETURN_FALSE("  reader.read() returned incorrect value");
    }

    // Fill input buffer.
    std::string output("abcdefghijklmnopprstuvwxyz");
    std::string expectedInput(output);

    for (int i = 0; i < output.size(); i++) {
      expectedInput[i] = std::toupper(output[i]);
    }

    child.childStream << output;
    child.childStream.flush();
    std::this_thread::sleep_for(std::chrono::milliseconds(100));

    child.childStream.read(&ch, 1);

    int index = 0;

    if (ch != expectedInput[index++]) {
      RETURN_FALSE("  reader.read() returned incorrect value");
    }

    size_t nBytesRead = expectedInput.size() - 1;

    child.childStream.read(buf, nBytesRead);
    buf[nBytesRead] = '\0';

    if (expectedInput.substr(index, nBytesRead) != std::string(buf)) {
      RETURN_FALSE("  reader.read() failure");
    }

    // Send exit message.
    child.childStream << 'q';
    child.childStream.flush();
    if (!child.childStream) {
      RETURN_FALSE("  Failure in testNonblockingReader:  writer stream is bad");
    }

    // Verify exit.
    std::this_thread::sleep_for(std::chrono::milliseconds(100));

    if (!child.isDone()) {
      std::cout << "  Failure in testNonblockingReader:  "
		<< "Child program did not exit."  << std::endl;
      return false;
    }

  } catch (std::exception &e) {
    EXCEPTION_TERM("Binary read test");
    return false;
  }

  return true;

}

bool
testNonBlockingRead() {

  try {
    std::vector<std::string> cmd;

    cmd.push_back(childName);

    size_t bufSize = 16;
    CodeDweller::Child child(cmd, bufSize);

    child.run();

    // Check for available input with no input.
    if (child.numBytesAvailable() != 0) {
      RETURN_FALSE("  numBytesAvailable() did not return expected 0");
    }

    // Check for available input with input.
    std::string childInput("abc");
    
    child.childStream << childInput;
    child.childStream.flush();
    std::this_thread::sleep_for(std::chrono::milliseconds(100));
    
    // Check that input is available.
    if (child.numBytesAvailable() != 1) {
      RETURN_FALSE("  numBytesAvailable() did not return expected 1");
    }

    // Read one character.
    char ch;

    child.childStream.read(&ch, 1);

    if (ch != 'A') {
      RETURN_FALSE("  reader.read() returned incorrect value");
    }

    // Check that input is available.
    if (child.numBytesAvailable() != 2) {
      RETURN_FALSE("  numBytesAvailable() did not return expected 2");
    }

    // Read.
    char buf[bufSize * 2];

    child.childStream.read(buf, 2);
    buf[2] = '\0';

    std::string input(buf);

    if (input != "BC") {
      RETURN_FALSE("  reader.read() returned incorrect value");
    }

    // Check that no input is available.
    if (child.numBytesAvailable() != 0) {
      RETURN_FALSE("  numBytesAvailable() did not return expected 0 "
		   "after reading");
    }

    // Fill input buffer.
    std::string output("abcdefghijklmnopprstuvwxyz");
    std::string expectedInput(output);

    for (int i = 0; i < output.size(); i++) {
      expectedInput[i] = std::toupper(output[i]);
    }

    child.childStream << output;
    child.childStream.flush();
    std::this_thread::sleep_for(std::chrono::milliseconds(100));

    if (child.numBytesAvailable() != 1) {
      RETURN_FALSE("  numBytesAvailable() did not return expected 1");
    }

    child.childStream.read(&ch, 1);

    int index = 0;

    if (ch != expectedInput[index++]) {
      RETURN_FALSE("  reader.read() returned incorrect value");
    }

    size_t nBytesAvailable;

    nBytesAvailable = child.numBytesAvailable();
    if (nBytesAvailable != bufSize) {
      RETURN_FALSE("  numBytesAvailable() did not return expected value");
    }
    std::fill_n(buf, sizeof(buf), 0);

    child.childStream.read(buf, nBytesAvailable);

    if (expectedInput.substr(index, nBytesAvailable) != std::string(buf)) {
      RETURN_FALSE("  reader.read() failure");
    }
    index += nBytesAvailable;

    nBytesAvailable = child.numBytesAvailable();
    if (nBytesAvailable != expectedInput.size() - 1 - bufSize) {
      RETURN_FALSE("  numBytesAvailable() did not return expected value");
    }
    std::fill_n(buf, sizeof(buf), 0);

    child.childStream.read(buf, nBytesAvailable);

    if (expectedInput.substr(index, nBytesAvailable) != std::string(buf)) {
      RETURN_FALSE("  reader.read() failure");
    }
    index += nBytesAvailable;

    if (expectedInput.size() != index) {
      RETURN_FALSE("  not all data was read by reader.read()");
    }
      
    if (child.numBytesAvailable() != 0) {
      RETURN_FALSE("  numBytesAvailable() did not return expected 0");
    }

    // Send exit message.
    child.childStream << 'q';
    child.childStream.flush();
    if (!child.childStream) {
      RETURN_FALSE("  Failure in testNonblockingReader:  writer stream is bad");
    }

    // Verify exit.
    std::this_thread::sleep_for(std::chrono::milliseconds(100));

    if (!child.isDone()) {
      std::cout << "  Failure in testNonblockingReader:  "
		<< "Child program did not exit."  << std::endl;
      return false;
    }

  } catch (std::exception &e) {
    EXCEPTION_TERM("Non-blocking reader test");
    return false;
  }

  return true;

}

////////////////////////////////////////////////////////////////////////////////
// End of tests ////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

int main()
{
  std::cout << "CodeDweller::Child unit tests" << std::endl << std::endl;

  CodeDweller::Child child(childName);

  RUN_TEST(testIsDone);
  RUN_TEST(testResult);
  RUN_TEST(testTerminate);
  RUN_TEST(testReader);
  RUN_TEST(testReaderWriter);
  RUN_TEST(testBinaryRead);
  RUN_TEST(testNonBlockingRead);

  SUMMARY;

  return 0;
}