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#include "fileout.h"
#include "reporthandler.h"

#include <QFileInfo>
#include <QDir>

bool FileOut::dummy = false;
bool FileOut::diff = false;
bool FileOut::license = false;

#ifdef Q_OS_LINUX
const char* colorDelete = "\033[31m";
const char* colorAdd = "\033[32m";
const char* colorInfo = "\033[36m";
const char* colorReset = "\033[0m";
#else
const char* colorDelete = "";
const char* colorAdd = "";
const char* colorInfo = "";
const char* colorReset = "";
#endif

FileOut::FileOut(QString n)
  : name(n)
  , stream(&tmp)
  , isDone(false)
{
}

static int* lcsLength(QList<QByteArray> a, QList<QByteArray> b)
{
  const int height = a.size() + 1;
  const int width = b.size() + 1;

  int* res = new int[width * height];

  for (int row = 0; row < height; row++) {
    res[width * row] = 0;
  }
  for (int col = 0; col < width; col++) {
    res[col] = 0;
  }

  for (int row = 1; row < height; row++) {
    for (int col = 1; col < width; col++) {

      if (a[row - 1] == b[col - 1])
        res[width * row + col] = res[width * (row - 1) + col - 1] + 1;
      else
        res[width * row + col] = qMax(res[width * row + col - 1], res[width * (row - 1) + col]);
    }
  }
  return res;
}

enum Type { Add, Delete, Unchanged };

struct Unit {
  Unit(Type type, int pos)
    : type(type)
    , start(pos)
    , end(pos)
  {
  }

  Type type;
  int start;
  int end;

  void print(QList<QByteArray> a, QList<QByteArray> b)
  {
    {
      if (type == Unchanged) {
        if ((end - start) > 9) {
          for (int i = start; i <= start + 2; i++)
            printf("  %s\n", a[i].data());
          printf("%s=\n= %d more lines\n=%s\n", colorInfo, end - start - 6, colorReset);
          for (int i = end - 2; i <= end; i++)
            printf("  %s\n", a[i].data());
        } else
          for (int i = start; i <= end; i++)
            printf("  %s\n", a[i].data());
      } else if (type == Add) {
        printf("%s", colorAdd);
        for (int i = start; i <= end; i++) {
          printf("+ %s\n", b[i].data());
        }
        printf("%s", colorReset);
      } else if (type == Delete) {
        printf("%s", colorDelete);
        for (int i = start; i <= end; i++) {
          printf("- %s\n", a[i].data());
        }
        printf("%s", colorReset);
      }
    }
  }
};

static QList<Unit*>* unitAppend(QList<Unit*>* res, Type type, int pos)
{
  if (res == 0) {
    res = new QList<Unit*>;
    res->append(new Unit(type, pos));
    return res;
  }

  Unit* last = res->last();
  if (last->type == type) {
    last->end = pos;
  } else {
    res->append(new Unit(type, pos));
  }
  return res;
}

static QList<Unit*>* diffHelper(int* lcs, QList<QByteArray> a, QList<QByteArray> b, int row, int col)
{
  if (row > 0 && col > 0 && (a[row - 1] == b[col - 1])) {
    return unitAppend(diffHelper(lcs, a, b, row - 1, col - 1), Unchanged, row - 1);
  } else {
    int width = b.size() + 1;
    if ((col > 0) && ((row == 0) || lcs[width * row + col - 1] >= lcs[width * (row - 1) + col])) {
      return unitAppend(diffHelper(lcs, a, b, row, col - 1), Add, col - 1);
    } else if ((row > 0) && ((col == 0) || lcs[width * row + col - 1] < lcs[width * (row - 1) + col])) {
      return unitAppend(diffHelper(lcs, a, b, row - 1, col), Delete, row - 1);
      ;
    }
  }
  delete lcs;
  return 0;
}

static void diff(QList<QByteArray> a, QList<QByteArray> b)
{
  QList<Unit*>* res = diffHelper(lcsLength(a, b), a, b, a.size(), b.size());
  for (int i = 0; i < res->size(); i++) {
    Unit* unit = res->at(i);
    unit->print(a, b);
    delete (unit);
  }
  delete (res);
}

bool FileOut::done()
{
  Q_ASSERT(!isDone);
  isDone = true;
  bool fileEqual = false;
  QFile fileRead(name);
  QFileInfo info(fileRead);
  stream.flush();
  QByteArray original;
  if (info.exists() && (diff || (info.size() == tmp.size()))) {
    if (!fileRead.open(QIODevice::ReadOnly)) {
      ReportHandler::warning(QString("failed to open file '%1' for reading").arg(fileRead.fileName()));
      return false;
    }

    original = fileRead.readAll();
    fileRead.close();
    fileEqual = (original == tmp);
  }

  if (!fileEqual) {
    if (!FileOut::dummy) {
      QDir dir(info.absolutePath());
      if (!dir.mkpath(dir.absolutePath())) {
        ReportHandler::warning(QString("unable to create directory '%1'").arg(dir.absolutePath()));
        return false;
      }

      QFile fileWrite(name);
      if (!fileWrite.open(QIODevice::WriteOnly)) {
        ReportHandler::warning(QString("failed to open file '%1' for writing").arg(fileWrite.fileName()));
        return false;
      }
      stream.setDevice(&fileWrite);
      stream << tmp;
    }
    if (diff) {
      printf("%sFile: %s%s\n", colorInfo, qPrintable(name), colorReset);

      ::diff(original.split('\n'), tmp.split('\n'));

      printf("\n");
    }
    return true;
  }
  return false;
}
