#include <iostream>
#include <fstream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <dirent.h>
#include <errno.h>
#include <time.h>

#define BLOG_TITLE "My blog"
#define STYLESHEET_REL_PATH "blogstyle.css"

//when compiling/linking, mention the object file: use "g++ blog.cpp markdown.o"
extern "C"
{
  extern char _binary_markdown_start;
  extern char _binary_markdown_end;
}

using namespace std;

enum Option
{
  NEW,
  EDIT,
  DELETE,
  HELP,
  UNKNOWN_ARG
};

int newPost();
int editPost();
int deletePost();
int help();

/* GLOBAL VARIABLES - START */

char g_path[80] = "\0"; //'g' for global variable

//Initialisation of all global variables
void initialiseGlobalVars()
{
  for(int i=0; i < 80; i++)
    g_path[i] = '\0';
}

/* GLOBAL VARIABLES - END */

void bugFound()
{
  cout << "\n\nYou have found a bug.\n"
       << "Please contact login@tilde.town with details on how to reproduce this bug.\n"
       << "Program will quit now.\n\n";

  exit(2);
}

int checkEDITORvar()
{
  char* editor_var = getenv("EDITOR");

  if(editor_var == NULL)
  {
    cout << "\n\nThe EDITOR environment variable is not set.\n"
         << "Please go to 'http://askubuntu.com/questions/432524/how-do-i-find-and-set-my-editor-environment-variable' to learn how to do so.";
    return 1;
  }

  return 0;
}


int checkBlogPath()
{
  char* home_var = getenv("HOME");
  char blog_rc_path[100] = "\0";
  for(int i=0; i<100; i++)
    blog_rc_path[i]='\0';

  strcpy(blog_rc_path, home_var);
  strcat(blog_rc_path, "/.blogrc");

  ifstream fin(blog_rc_path);

  if(!fin)
  {
    cout << "\n\nNo .blogrc file found in the user directory.\n"
         << "You must create a .blogrc file with only the path to the blog directory. This could be the public_html folder. Please include the trailing slash.";

    return 1;
  }

  fin.getline(g_path, 79); //79 so that we can add a slash


  //fix for trailing slash (if absent)
  int i;
  for(i=0; g_path[i]!='\0'; i++);

  --i;

  if(g_path[i] != '/')
  {
    ++i;
    g_path[i] = '/';
    ++i;
    g_path[i] = '\0';
  }

  DIR* dir = opendir(g_path);
  if(!dir)
  {
    if(ENOENT == errno)
    {
      cout << "\n\nThe user directory mentioned in .blogrc doesn't exist.\n"
           << "Please create \"" << g_path << "\".";

      return 1;
    }
    else
    {
      cout << "\n\nThe user directory mentioned in .blogrc could not be opened.\n"
           << "Please ensure you have read, write and execute permissions for \"" << g_path << "\".";

      return 1;
    }
  }

  cout << "\n\nThe directory of the index.html file is: \n"
       << g_path << " .";

  return 0;
}

void strtrim(char* str)
{
  int size=0;

  for(size=0; str[size]!='\0'; size++);

  int left_bound=0, right_bound=0;

  for(left_bound=0; str[left_bound]==' '; left_bound++);
  for(right_bound=size-1; str[right_bound]==' '; right_bound--);

  int j=0;
  for(int i=left_bound; i <= right_bound; i++, j++)
  {
    str[j] = str[i];
  }

  str[j] = '\0';

  //clean up
  for(int i=j; i < size; i++)
  {
    str[i] = '\0';
  }
}

void markdown(char* input_file, char* output_file)
{
  {
    char* markdown_ptr = &_binary_markdown_start;

    //create the markdown bashscript file
    ofstream fout_markdown("./blogmarkdown");

    while(markdown_ptr != &_binary_markdown_end)
      fout_markdown.put(*markdown_ptr++);

    fout_markdown.close();
  }

  system("chmod u+rx ./blogmarkdown");

  char command[100] = "\0";
  for(int i=0; i<100; i++)
    command[i]='\0';

  strcpy(command, "./blogmarkdown ");
  strcat(command, input_file);
  strcat(command, " -o ");
  strcat(command, output_file);

  system(command);

  remove("./blogmarkdown");
}

Option checkPassedArg(const int, char**);
/* MAIN FUNCTION */
int main(int argc, char *argv[])
{
  initialiseGlobalVars();

  Option choice = checkPassedArg(argc, argv);

  if(choice == UNKNOWN_ARG || argc > 2)
  {
    cout << "\n\nUnknown, no or too many arguments passed.\n"
         << "For help, pass '-h' or 'help' (without quotes) as argument.\n"
         << "Program will quit now.\n\n";

    return 1;
  }

  int return_value = 2;

  switch(choice)
  {
    case NEW: return_value = newPost();
              break;

    case EDIT: return_value = editPost();
               break;

    case DELETE: return_value = deletePost();
                 break;

    case HELP: return_value = help();
               break;

    default: bugFound();
             break;
  }

  if(return_value  == 0)
  {
    cout << "\n\nProgram executed successfully.\n"
         << "Program will quit now.\n\n";

    return 0;
  }
  else
  {
    if(return_value == 1)
      cout << "\n\nError";
    else
      cout << "\n\nUnknown error";

    cout << " encountered during execution of \""
         << argv[1] << "\".\n"
         << "Please contact login@tilde.town with details to reproduce this error.\n"
         << "Program will quit now.\n\n";

    return 2;
  }

  cout << "\n\nUnhandled error encountered.\n"
       << "Please contact login@tilde.town with details to reproduce this error."
       << "Program will quit now.\n\n";

  return 2;
}


Option checkPassedArg(const int argc_param, char** argv_param)
{
  char check_list[8][7] = {"new", "-n",
                           "edit", "-e",
                           "delete", "-d",
                           "help", "-h"};

  if(argc_param == 1)
    return UNKNOWN_ARG;
  else
  {
    for(int i=0; i < 8; i++)
     if(!strcasecmp(argv_param[1], check_list[i]))
     {
       return (Option)((int)(i/2));
     }
  }

  return UNKNOWN_ARG;
}


int newPost()
{
  if(checkEDITORvar() || checkBlogPath())
  {
    return 1;
  }
  else
  {
    cout << "\n\nEDITOR variable and .blogrc are okay.";
  }

  //post details (post number and post date)
  unsigned long int post_num = 0;
  char post_date[30] = "\0";
  for(int i=0; i<30; i++)
  {
    post_date[i] = '\0';
  }
  //post details - end

  char index_html_path[120] = "\0";
  for(int i=0; i < 120; i++)
    index_html_path[i] = '\0';

  strcpy(index_html_path, g_path);
  strcat(index_html_path, "index.html");

  char blogstyle_css_path[120] = "\0";
  for(int i=0; i < 120; i++)
    blogstyle_css_path[i] = '\0';

  strcat(blogstyle_css_path, g_path);
  strcat(blogstyle_css_path, STYLESHEET_REL_PATH);

  ifstream fin2(index_html_path);
  ifstream fin3(blogstyle_css_path);

  if(!fin3.is_open()) //blogstyle.css doesn't exist
  {
    //index.html doesn't exist, so let's create a template
    if(!fin2.is_open())
    {
      ofstream fout_index_html(index_html_path);
      fout_index_html << "<!doctype html>\n\n<html>\n  <head>\n    <title>" << BLOG_TITLE << "</title>\n    <link rel=\"stylesheet\" href=\"" << STYLESHEET_REL_PATH << "\" />\n  </head>\n\n";
      fout_index_html << "  <body>\n    <header><h1>" << BLOG_TITLE << "</h1></header>\n\n    <main>\n      <section id=\"blog\">\n";
      fout_index_html << "      <!-- { NEW_POST_HERE : 0 } -->\n      </section>\n    </main>\n\n    <footer>This is the footer.</footer>\n";
      fout_index_html << "  </body>\n</html>\n";
      fout_index_html.close();
    }

    ofstream fout_blogstyle_css(blogstyle_css_path);
    fout_blogstyle_css << "header\n{\n  border-bottom: 2px solid #CCC;\n  position: fixed;\n  top: 0;\n  left: 0;\n  width: 100%;\n  background-color: #FFF;\n  opacity: 0.9;\n}\n\n";
    fout_blogstyle_css << "header h1\n{\n  text-align: center;\n  font-family: monospace;\n  font-weight: normal;\n}\n\n";
    fout_blogstyle_css << "header a\n{\n  color: inherit;\n  text-decoration: none;\n}\n\n";
    fout_blogstyle_css << "footer\n{\n  border-top: 1px solid #CCC;\n  padding: 10px 0;\n  text-align: center;\n}\n\n";
    fout_blogstyle_css << "main\n{\n  padding: 100px;\n}\n\n";
    fout_blogstyle_css << "article time\n{\n  font-style: italic;\n  display: list-item;\n  list-style: circle outside;\n}\n\n";
    fout_blogstyle_css << "article\n{\n  border: 8px solid #CCC;\n  border-width: 8px 0;\n  padding: 15px 0 21px;\n}\n\n";
    fout_blogstyle_css << "article h2\n{\n  list-style: disc outside;\n  display: list-item;\n}\n\n";
    fout_blogstyle_css << ".placeholder\n{\n  display: block;\n margin-top: -100px;\n  height: 100px;\n  visibility: hidden;\n  pointer-events: none;\n  z-index: -100;\n}\n\n";
    fout_blogstyle_css << "article li\n{\n  margin: 1em 0;\n}\n\n";
    fout_blogstyle_css << "article:first-child\n{\n  border-top: 0;\n}\n\n";
    fout_blogstyle_css << "article:last-child\n{\n  border-bottom: 0;\n}\n\n";
    fout_blogstyle_css.close();
  }
  fin2.close();
  fin3.close();

  ifstream fin(index_html_path);

  //finding out post number
  {
    char line[100] = "\0";
    for(int i=0; i<100; i++)
      line[i]='\0';

    char line_trunc[24] = "\0";
    for(int i=0; i<24; i++)
      line_trunc[i]='\0';

    while(fin.getline(line, 100))
    {
      int i=0;

      strtrim(line);

      for(i=0; i<23; i++)
      {
        line_trunc[i] = line[i];
      }

      line_trunc[i] = '\0';

      if(!strcmp(line_trunc, "<!-- { NEW_POST_HERE : "))
      {
        //obtaining next post number from index.html
        char post_num_char[11] = "\0";
        for(int i=0; i<11; i++)
          post_num_char[i] = '\0';

        int j=0;
        for(int i=23; line[i]>='0' && line[i]<='9'; i++, j++)
        {
          post_num_char[j] = line[i];
        }
        post_num_char[j] = '\0';

        //converting characters to number
        post_num = 0;
        for(int i=0; post_num_char[i]!='\0'; i++)
        {
          //48 is the ascii number for zero (0)
          post_num *= 10; //making room for one right-hand-side digit
          post_num += (unsigned long int)(post_num_char[i] - 48);
        }

        break;
      }//end of if statement
    }//end of while loop to go through the file index.html
  }//end of "getting post number from file"

  //closing the file index.html
  fin.close();

  //create a file with the required layout
  char draft_full_path[120] = "\0";
  for(int i=0; i < 120; i++)
    draft_full_path[i] = '\0';

  strcpy(draft_full_path, g_path);
  strcat(draft_full_path, ".draft_txt");

  {
    ifstream fin(draft_full_path);
    if(fin) //file exists, don't overwrite previous draft file
    {
      fin.close();
    }
    else
    {
      fin.close();

      ofstream fout(draft_full_path);

      fout << "Title: \nDate: ";

      //automatic local date insertion, in dd-mm-yyyy format
      {
        time_t t = time(NULL);
        tm mytm = *localtime(&t);
        if(mytm.tm_mday < 10)
          fout << '0';
        fout << mytm.tm_mday << '-';
        if(mytm.tm_mon < 9)
          fout << '0';
        fout << mytm.tm_mon+1 << '-' << mytm.tm_year+1900;
      }

      fout << "\n\n";

      fout.close();
    }
  }

  //give EDITOR a chance to edit the (presently blank) draft file
  char* editor_full_path = getenv("EDITOR");
  if(editor_full_path == NULL)
  {
    cout << "\n\nError: EDITOR variable not set.\n"
         << "First check for EDITOR variable failed to detect this earlier.";

    //graceful clean up
    remove(draft_full_path);

    bugFound();
  }
  //no 'else' statement because bugFound() exits program.

  {
    char editor_command[200]="\0";
    for(int i=0; i<200; i++)
      editor_command[i] = '\0';

    strcpy(editor_command, editor_full_path);
    strcat(editor_command, " ");
    strcat(editor_command, draft_full_path);

    //calls editor to edit the file
    system(editor_command);
  }

  //GOAL: create a new file and copy index.html till NEW_POST_HERE comment

  //open file index.html
  ifstream fin_index_html(index_html_path);

  char index2_html_path[120] = "\0";
  for(int i=0; i<120; i++)
    index2_html_path[i] = '\0';

  strcpy(index2_html_path, g_path);
  strcat(index2_html_path, ".index2_html");

  //create file .index2_html
  ofstream fout_index2_html(index2_html_path);
  //not-needed: long int offset_to_start_of_line = 0;

  //copy index.html to .index2_html till (non-inclusive) <!-- NEW_POST_HERE..."
  //and do some other stuff, then copy the rest too
  {
    //create variable to read line of file into
    char line[100] = "\0";
    for(int i=0; i<100; i++)
    {
      line[i] = '\0';
    }
    //becomes 1 after first instance of NEW_POST_HERE found
    int flag_for_first_instance_of_new_post_here = 0;

    //copy index.html to .index2_html till "<!-- NEW_POST_HERE : <num> -->
    //"|| !fin_index_html.eof()" is there so that when there are
    //less than 100 characters left to read, it'll go to the body of
    //the while loop one last time
    while(fin_index_html.getline(line, 100) || !fin_index_html.eof())
    {
      char line_trimmed[100] = "\0";
      for(int i=0; i<100; i++)
      {
        line_trimmed[100] = '\0';
      }

      strcpy(line_trimmed, line);
      strtrim(line_trimmed);

      if(strstr(line_trimmed, "<!-- { NEW_POST_HERE : ")!=NULL &&
         (!flag_for_first_instance_of_new_post_here)
        )
      {
        ifstream fin_draft(draft_full_path);

        fin_draft.seekg(7, ios::beg);//skips "Title: "

        fout_index2_html << "      <!-- { NEW_POST_HERE : " << post_num+1 << " } -->\n\n";
        fout_index2_html << "        <article data-postnum=\"" << post_num << "\">\n";
        fout_index2_html << "          <span class=\"placeholder\" id=\"post-" << post_num << "\"></span>\n";
        fout_index2_html << "          <h2>";

        {
          bool first_character = true;
          char ch = '\0';
          //writing the title out
          while(fin_draft.get(ch))
          {
            if(ch == '\n')
            {
              if(first_character) //i.e., Title is empty
              {
                cout << "\n\nError. The title of the post was empty. Post was not published, but is still saved as a dotfile in the blog's directory for manual recovery. If you want to get a new draft, you should delete '" << g_path << ".draft_txt" << "'.";

                //cleanup
                fin_draft.close();
                fin_index_html.close();
                fout_index2_html.close();
                remove(index2_html_path);
                //I'm leaving the draft file intact so that it can be recovered (manually)

                bugFound();
              }
              break;
            }
            else
              fout_index2_html << ch;
            first_character = false;
          }
        }

        fout_index2_html << "</h2>\n";

        fin_draft.seekg(6, ios::cur);//skips "Date: "
        fin_draft.getline(post_date, 30); //getting date
        fin_draft.seekg(1, ios::cur); //skips the extra "\n";
        char datetime[11] = "\0";
        for(int i=0; i<11; i++)
          datetime[i] = '\0';

        int datepos_i=0;
        if(post_date[datepos_i] >= '0' && post_date[datepos_i] <= '9')
          datepos_i=0;
        else
        {  //day of week is mentioned in date
          for(datepos_i=0; post_date[datepos_i]!=' '; datepos_i++); //skips "Day-Of-Week,"
          datepos_i++; //skips the space after the comma and lands on date of month
        }

        if((post_date[datepos_i+2]=='-' && (post_date[datepos_i+5=='-'] || post_date[datepos_i+4]=='-'))
           || (post_date[datepos_i+1]=='-' && (post_date[datepos_i+4]=='-' || post_date[datepos_i+3]=='-'))) //date in (d)d-(m)m-yyyy or (d)d-(m)m-yy format
        {
          if(post_date[datepos_i+1]=='-') //single digit date of month
          {
            datetime[8]='0';
            datetime[9]=post_date[datepos_i];
          }
          else
          {
            datetime[8]=post_date[datepos_i];
            datepos_i++; //second digit of "date of month"
            datetime[9]=post_date[datepos_i];
          }

          datetime[7]='-'; datetime[4]='-';

          datepos_i+=2; //skips - and lands on month of year (expressed as a number between (0)1 and 12)

          if(post_date[datepos_i+1]=='-') //single digit month of year
          {
            datetime[5]='0';
            datetime[6]=post_date[datepos_i];
          }
          else
          {
            datetime[5]=post_date[datepos_i];
            datepos_i++; //moving to second digit of month of year
            datetime[6]=post_date[datepos_i];
          }
          datepos_i+=2; //skips - and lands on year (either expressed as a two-digit or four-digit number)

          if(post_date[datepos_i+2]>='0' && post_date[datepos_i+2]<='9') //year is four digits
          {
            datetime[0] = post_date[datepos_i++];
            datetime[1] = post_date[datepos_i++];
            datetime[2] = post_date[datepos_i++];
            datetime[3] = post_date[datepos_i++];
          }
          else
          {
            datetime[0] = '2'; //good for approximately 1000 years
            datetime[1] = '0'; //good for approximately 100 years
            datetime[2] = post_date[datepos_i++];
            datetime[3] = post_date[datepos_i++];
          }
          datetime[10] = '\0';
        }
        else
        {
          if(post_date[datepos_i+1]==' ') //i.e., "date of month" is a single digit
          {
            datetime[8]='0';
            datetime[9]=post_date[datepos_i];
          }
          else
          {
            datetime[8]=post_date[datepos_i];
            datepos_i++; //second digit of "date of month"
            datetime[9]=post_date[datepos_i];
          }

          datetime[7]='-'; datetime[4]='-';

          datepos_i+=2; //skips space after first/second digit and lands on "Month of Year"

          //for the month
          {
            char months_of_year[13][10] = { "\0", "January", "February", "March", "April", "May",
                                            "June", "July", "August", "September", "October",
                                            "November", "December" };
            char month[10] = "\0";

            for(int i1=0; i1<10; i1++)
              month[i1] = '\0';

            {
              int j=0;
              for(j=0; post_date[datepos_i]!=' '; datepos_i++, j++)
              {
                month[j] = post_date[datepos_i];
              }
              month[j]='\0';
            }

            datepos_i++; //skip space and land on year

            for(int j=1; j<=12; j++)
            {
              if(!strncasecmp(months_of_year[j], month, 3))
              {
                if(j<10)
                {
                  datetime[5]='0';
                  datetime[6]=(char)(48+j); //48 is ascii for '0'
                }
                else
                {
                  datetime[5]=(char)( 48 + (j - j%10)/10 );//tens place
                  datetime[6]=(char)( 48 + j%10 );//ones place
                }
                break;
              }
            }

            //for the year
            datetime[0] = post_date[datepos_i++];
            datetime[1] = post_date[datepos_i++];
            datetime[2] = post_date[datepos_i++];
            datetime[3] = post_date[datepos_i++];

            datetime[10] = '\0';
          }
        }

        if(post_date[datepos_i] != '\0')
        {
          cout << "\n\nError. Converting post date to datetime format failed. post_date was '" << post_date << "', datetime was '" << datetime << "' and datepos_i was '" << datepos_i << "'";

          //cleanup
          fin_draft.close();
          fin_index_html.close();
          fout_index2_html.close();
          remove(index2_html_path);
          //I'm leaving the draft file intact so that it can be recovered (manually)

          bugFound();
        }
        //no 'else' because bugFound() exits the program

        fout_index2_html << "          <a href=\"#post-" << post_num << "\"><time datetime=\"" << datetime << "\">" << post_date << "</time></a>\n\n";

        //converting the rest of the draft file to a draft2 file (which has only html post content)
        //then, I will convert it to html using the markdown(<input file>, <output file>) function
        //then, I will copy the draft2_html file as it is to index2_html
        {
          char draft2_full_path[120] = "\0";
          for(int i=0; i < 120; i++)
            draft2_full_path[i] = '\0';

          strcpy(draft2_full_path, g_path);
          strcat(draft2_full_path, ".draft2_txt");

          ofstream fout_draft2(draft2_full_path);
          char ch = '\0';

          //copies the rest of the draft file to the draft2 file.
          while(fin_draft.get(ch))
          {
            fout_draft2.put(ch);
          }

          //close draft file and delete draft file
          fin_draft.close();
          remove(draft_full_path);

          //close draft2 file
          fout_draft2.close();

          //converts draft2 file into draft2_html file
          char draft2_html_path[120] = "\0";
          for(int i=0; i < 120; i++)
            draft2_html_path[i] = '\0';

          strcpy(draft2_html_path, g_path);
          strcat(draft2_html_path, ".draft2_html");

          markdown(draft2_full_path, draft2_html_path);

          ifstream fin_draft2_html(draft2_html_path);
          ch = '\0';

          //copies the draft2_html file to index2_html
          while(fin_draft2_html.get(ch))
          {
            fout_index2_html.put(ch);
          }

          //close draft2_html and draft2 files
          fin_draft2_html.close();

          //delete draft2_html and draft2 files
          remove(draft2_html_path);
          remove(draft2_full_path);
        }


        fout_index2_html << "\n</article>\n";

        flag_for_first_instance_of_new_post_here = 1;
        continue;
      }
      else
      {
        fout_index2_html << line; //copy rest of index.html to index2.html

        int i=0;
        for(i=0; line[i]!='\0'; i++);

        //if failbit is set, then no '\n' is required
        if(i<99 && !fin_index_html.fail())
        {
          fout_index2_html << '\n';
        }

        //this clears the failbit every time, so that istream::getline()
        //can continue to read in chunks of 100 chars even if the
        //delimiting character is not found just after those 100 chars
        fin_index_html.clear(fin_index_html.rdstate() & ~ios::failbit);

      }//end of 'else' statement
    }//end of while loop

  //remove original index file and replace it with index2_html
  remove(index_html_path);
  rename(index2_html_path, index_html_path);

  }//end of block


/*
  //use xmllint to reformat the index.html file
  {
    char command[100] = "\0";
    for(int i=0; i < 100; i++)
      command[i] = '\0';

    strcat(command, "xmllint --format ");
    strcat(command, index_html_path);
    strcat(command, " --output ");
    strcat(command, index_html_path);

    system(command);
  }
*/

  cout << "\n\nNew post successfully added to index.html file.";
  return 0;
}


int editPost()
{
  if(checkEDITORvar() || checkBlogPath())
  {
    return 1;
  }
  else
  {
    cout << "\n\nEDITOR variable and .blogrc are okay.";
  }

  cout << "\n\nSorry. Editing posts is not implemented yet. You'll have to do it manually.";
  return 0;
}

int deletePost()
{
  cout << "\n\nSorry. Deleting is not implemented yet. You'll have to do it manually.";
  return 0;
}

int help()
{
  cout << "\n\nSorry. Help information not written yet.\n"
       << "You'll have you see the source code at http://tilde.town/~login/blog.cpp.txt .";
  return 0;
}