#include <vector>
#include <string>
#include <cstring>
#include <cstdio>

#include "csv.h"

using namespace std;

const char *csvProblem = NULL;

bool loadCsv(const char *fn, vector<vector<char*> > *content) {
  errno = 0;
  
  FILE *in = fopen(fn, "r");
  if (!in) {
     csvProblem = errno ? strerror(errno) : "Can't open file for reading.";
     return false;
  }
  
  content->clear();
  
  bool readAnotherLine = true;
  while (readAnotherLine) {
        vector<char*> row;
        bool readAnotherValue = true;
        bool foundSomething = false;
        bool atLeastALineBreak = true;
        
        while (readAnotherValue) {
              bool quoted = false;
              string valueBuilder;
              bool readAnotherChar = true;
              bool readUnquoteCandidate = false;
              
              int firstCharOfValue = getc(in);
              switch (firstCharOfValue) {
                     case EOF:
                          if (ferror(in)) {
                             csvProblem = errno ? strerror(errno) :
                               "Error in reading from file.";
                             fclose(in); // If that fails, what can I do?
                             destroyCsv(content);
                             return false;
                          } else {
                             readAnotherChar = false;
                             readAnotherValue = false;
                             readAnotherLine = false;
                             if (!foundSomething)
                                atLeastALineBreak = false;
                          }
                          break;
                     case '\0':
                          csvProblem = "Null character encountered.";
                          fclose(in); // If that fails, what can I do?
                          destroyCsv(content);
                          return false;
                     case ',':
                          foundSomething = true;
                          readAnotherChar = false;
                          break;
                     case '\"':
                          foundSomething = true;
                          quoted = true;
                          break;
                     case '\n':
                          readAnotherChar = false;
                          readAnotherValue = false;
                          break;
                     default:
                          foundSomething = true;
                          valueBuilder.push_back(firstCharOfValue);
              }
              
              while (readAnotherChar) {
                    int charRead = getc(in);
                    switch (charRead) {
                           case EOF:
                                if (ferror(in)) {
                                   csvProblem = errno ? strerror(errno) :
                                     "Error in reading from file.";
                                   fclose(in); // If that fails, what can I do?
                                   destroyCsv(content);
                                   return false;
                                } else {
                                   readAnotherChar = false;
                                   readAnotherValue = false;
                                   readAnotherLine = false;
                                }
                                readUnquoteCandidate = false;
                                break;
                           case '\0':
                                csvProblem = "Null character encountered.";
                                fclose(in); // If that fails, what can I do?
                                destroyCsv(content);
                                return false;
                           case ',':
                                if (quoted && !readUnquoteCandidate)
                                   valueBuilder.push_back(',');
                                else
                                   readAnotherChar = false;
                                readUnquoteCandidate = false;
                                break;
                           case '\"':
                                if (quoted && !readUnquoteCandidate)
                                   readUnquoteCandidate = true;
                                else {
                                   valueBuilder.push_back('\"');
                                   readUnquoteCandidate = false;
                                }
                                break;
                           case '\n':
                                readAnotherChar = false;
                                readAnotherValue = false;
                                readUnquoteCandidate = false;
                                break;
                           default:
                                if (readUnquoteCandidate)
                                   quoted = false;
                                valueBuilder.push_back(charRead);
                                readUnquoteCandidate = false;
                    }
              }
              
              if (foundSomething) {
                 const char *copyMe = valueBuilder.c_str();
                 char *valueRead = (char*)malloc((strlen(copyMe) + 1) *
                   sizeof(char));
                 if (!valueRead) {
                    csvProblem = "Not enough memory.";
                    fclose(in); // If that fails, what can I do?
                    destroyCsv(content);
                    return false;
                 }
                 strcpy(valueRead, copyMe);
                 row.push_back(valueRead);
              }
        }
        
        if (atLeastALineBreak)
           content->push_back(row);
  }
  
  if (fclose(in) == EOF) {
     csvProblem = errno ? strerror(errno) : "Error in closing file.";
     destroyCsv(content);
     return false;
  }
  
  csvProblem = NULL;
  return true;
}
bool saveCsv(const char *fn, vector<vector<char*> > *content) {
     errno = 0;
     
     FILE *out = fopen(fn, "w");
     if (!out) {
        csvProblem = errno ? strerror(errno) : "Can't open file for writing.";
        return false;
     }
     
     for (vector<vector<char*> >::iterator i = (*content).begin();
          i != (*content).end();
          i++) {
         vector<char*>::iterator j = (*i).begin();
         while (true) {
             if (strchr(*j, ',') || strchr(*j, '\"') || *j == '\0') {
                if (putc('\"', out) == EOF) {
                   csvProblem = strerror(errno);
                   fclose(out); // If that fails, what can I do?
                   return false;
                }
                for (const char *k = *j; *k != '\0'; k++)
                    if (*k == '\"') {
                       if (putc('\"', out) == EOF || putc('\"', out) == EOF) {
                          csvProblem = strerror(errno);
                          fclose(out); // If that fails, what can I do?
                          return false;
                       }
                    } else
                       if (putc(*k, out) == EOF) {
                          csvProblem = strerror(errno);
                          fclose(out); // If that fails, what can I do?
                          return false;
                       }
                if (putc('\"', out) == EOF) {
                   csvProblem = strerror(errno);
                   fclose(out); // If that fails, what can I do?
                   return false;
                }
             } else
                if (fputs(*j, out) == EOF) {
                   csvProblem = errno ? strerror(errno) :
                     "Error in writing to file.";
                   fclose(out); // If that fails, what can I do?
                   return false;
                }
             j++;
             if (j == (*i).end())
                break;
             if (putc(',', out) == EOF) {
                csvProblem = strerror(errno);
                fclose(out); // If that fails, what can I do?
                return false;
             }
         }
         if (putc('\n', out) == EOF) {
            csvProblem = strerror(errno);
            fclose(out); // If that fails, what can I do?
            return false;
         }
     }
     
     if (fclose(out) == EOF) {
        csvProblem = errno ? strerror(errno) : "Error in closing file.";
        return false;
     }
     
     csvProblem = NULL;
     return true;
}

void destroyCsv(vector<vector<char*> > *content) {
     for (vector<vector<char*> >::iterator i = (*content).begin();
          i != (*content).end();
          i++)
         for (vector<char*>::iterator j = (*i).begin();
              j != (*i).end();
              j++)
             free(*j);
     content->clear();
}