#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>

#define BUF_SIZE 256

typedef enum { Fileopen = 'o', Fileclose = 'c', Filesave = 's', Readtxt = 'r',
Writetxt = 'w', Overwrite = 'v', Copy = 'y',
Search = 'f', Erase = 'e', NoL = 'n', Cursor = 'u', Quit = 'q', Help = 'h'} Menu;
void filesave(FILE **fp, FILE **tp, char filename[], int *savecheck) {
  char fn[BUF_SIZE] = "";
  char a[BUF_SIZE];
  int i = 0;
  fgets(fn, BUF_SIZE, stdin);
  fn[strlen(fn) - 1] = '\0';

  rewind(*tp);

  if (fn[0] != ' ') {
    fclose(*fp);
    if ((*fp = fopen(fn, "r")) != NULL) {
      fclose(*fp);
      printf("%s is existed. Do you want to overwrite? [y/else] : ", fn);
      fgets(a, BUF_SIZE, stdin);
      fflush(stdin);
      if (a[0] == 'y')
        *fp = fopen(fn, "w");
    } else {
      *fp = fopen(fn, "w");
    }
  } else {
    *fp = fopen(filename, "w");
  }

  if(*fp != NULL) {
    while ((i = fgetc(*tp)) != EOF)
      fputc(i, *fp);
    rewind(*tp);
    fclose(*fp);
    *savecheck = 0;
  }
}


void fileclose(FILE **fp, FILE **tp, char fn[], int *savecheck) {
  char a[BUF_SIZE];
  if (*savecheck) {
    printf("current file was not saved, want to save?[y/c/n] : ");
    fflush(stdin);
    fgets(a, BUF_SIZE, stdin);
    if (a[0] == 'y')
      filesave(fp, tp, fn, savecheck);
  }
  if (*savecheck || a[0] == 'n')
    fclose(*tp);
}


void fileopen(FILE **fp, FILE **tp, char fn[], int *savecheck) {
  int i = 0;
  char x[BUF_SIZE];
  x[0] = '0';

  if (*fp != NULL) {
    fileclose(fp, tp, fn, savecheck);
  }
  
  fgets(fn, BUF_SIZE, stdin);
  fn[strlen(fn) - 1] = '\0';
  if (fn[0] != '\0') {
    if ((*fp = fopen(fn, "r+")) == NULL) {
      do {
        printf("No such file, create file?[y/n]");   fgets(x, BUF_SIZE, stdin);
        if (x[0] == 'y') {
          *fp = fopen(fn, "w+");
        }
      } while (x[0] != 'y' && x[0] != 'n');
    }
    if (*fp != NULL) {
      *tp = fopen("temp.dat", "w+");
    }
    if (x[0] != 'y' && x[0] != 'n') {
      while ((i = fgetc(*fp)) != EOF)
        fputc(i, *tp);
      rewind(*tp);
      fclose(*fp);
    }
  }
}


void readtxt(FILE **tp) {
  char buffer[BUF_SIZE];
  char re[BUF_SIZE];
  char *token_ptr;
  int i, j, k;

  rewind(*tp);
  fgets(re, BUF_SIZE, stdin);
  re[strlen(re) - 1] = '\0';
  
  token_ptr = strtok(re, "-");
  i = atoi(token_ptr);
  if (i != 0) {
    token_ptr = strtok(NULL, "-");
    j = atoi(token_ptr);
    if (j == 0 || j < i)
      j = i;
    
    fgets(buffer, BUF_SIZE, *tp);
    for (k = 1; k <= j; k++) {
      if (k >= i)
        printf("l%4d: %s", k, buffer);
      if (fgets(buffer, BUF_SIZE, *tp) == NULL)
        break;
    }
  }
  putchar('\n');
}


void writetxt(FILE **tp, int cur) {
  char buffer[BUF_SIZE];
  char wr[BUF_SIZE];
  char *temp;
  int i, l;
  int j = 0;
  int o = 0;
  fpos_t fpos, tpos;

  rewind(*tp);
  fgets(wr, BUF_SIZE, stdin);
  wr[strlen(wr) - 1] = '\0';

  l = atoi(wr);

  for (i = 1; i < l; i++)
    fgets(buffer, BUF_SIZE, *tp);

  if (wr[strlen(wr) -1] == '/') {
    for ( ; i < l + 1; i++)
      fgets(buffer, BUF_SIZE, *tp);
    if(buffer[strlen(buffer) - 1] != '\n') {
      fputc('\n', *tp);
      fgetpos(*tp, &tpos);
      fflush(*tp);
      fsetpos(*tp, &tpos);
    }
    o = 1;
  }
  else if (wr[strlen(wr) -1] == '*') {
    for (j = 0; j < cur; j++) {
      fgetc(*tp);
      fgetpos(*tp, &tpos);
      fflush(*tp);
      fsetpos(*tp, &tpos);
    }
  }

  fgets(wr, BUF_SIZE, stdin);
  wr[strlen(wr) - 1] = '\0';
  if (o == 1)
    wr[strlen(wr)] = '\n';


  l = 0;

  temp = calloc(strlen(wr), sizeof(char));

  while(1) {
    fflush(*tp);
    fsetpos(*tp, &fpos);
    for(i = 0; i < strlen(wr); i++) {
      if((temp[i] = fgetc(*tp)) == EOF)
        break;
      fgetpos(*tp, &tpos);
      fflush(*tp);
      fsetpos(*tp, &tpos);
      putchar('*');
    }
    fsetpos(*tp, &fpos);
    if(temp[i] == EOF)
      break;
    temp[i] = '\0';
    fputs(wr, *tp);
    strcpy(wr, temp);
    
    l++;
  }
  temp[i] = '\0';
  fgetpos(*tp, &tpos);
  fflush(*tp);
  fsetpos(*tp, &tpos);
  fputs(wr, *tp);
  fgetpos(*tp, &tpos);
  fflush(*tp);
  fsetpos(*tp, &tpos);
  fputs(temp, *tp);
  free(temp);
  
}


void search(FILE **tp) {
  char buffer[BUF_SIZE];
  char se[BUF_SIZE];
  int i, j;
  int l = 1;
  int len;

  rewind(*tp);
  fgets(se, BUF_SIZE, stdin);
  se[strlen(se) - 1] = '\0';
  len = strlen(se);
  while ( (fgets(buffer, BUF_SIZE, *tp)) != NULL ) {
    for (i = 0; buffer[i] != '\n'; i++) {
      if (strncmp(se, buffer + i, len) == 0) {
        printf("l%4d :%s", l, buffer);
        if(buffer[strlen(buffer) - 1] != '\n')
          putchar('\n');
        printf("%3d    ", i + 1);
        for (j = 0; j <= i; j++)
          putchar('*');
        putchar('\n');
      }
    }
    l++;
  }
}


void erase(FILE **tp, int cur) {
  char buffer[BUF_SIZE];
  char er[BUF_SIZE];
  char *token_ptr;
  int i, j, k;
  int a = 1;
  struct stat  st;
  fpos_t fpos, tmppos;
  off_t x = 0;
  int fd;

  rewind(*tp);
  fgets(er, BUF_SIZE, stdin);
  er[strlen(er) - 1] = '\0';

  for(i = 0; er[i] != '-' && er[i] != '*' && er[i] != '\0'; i++)
    ;
  if(er[i] == '-' || er[i] == '\0') {
    token_ptr = strtok(er, "-");
    i = atoi(token_ptr);
    if (i != 0) {                                    //行消去
      token_ptr = strtok(NULL, "-");
      j = atoi(token_ptr);
      if (j == 0 || j < i)
        j = i;
      fgetpos(*tp, &fpos);
      fgets(buffer, BUF_SIZE, *tp);
      for (k = 1; k < j; k++) {
        if (k == i - 1) {
          fgetpos(*tp, &fpos);
        }
        else if (k <= i) {
          x += strlen(buffer) + 1;
        }
        if (fgets(buffer, BUF_SIZE, *tp) == NULL)
          break;
      }
      x += strlen(buffer) + 1;
    }
  }
  else {                                            //文字消去
    token_ptr = strtok(er, "*");
    i = atoi(token_ptr);
    token_ptr = strtok(NULL, "*");
    j = atoi(token_ptr);
    for (k = 1; k < i; k++)
      fgets(buffer, BUF_SIZE, *tp);
    fgetpos(*tp, &fpos);
    fgets(buffer, BUF_SIZE, *tp);
    if (strlen(buffer) - 1 < cur)
      a = 0;
    else {
      fsetpos(*tp, &fpos);
      fseek(*tp, (long)(cur - 1), SEEK_CUR);
      fgetpos(*tp, &fpos);
      x = j;
    }
  }

  if (a != 0) {
    while (fgets(buffer, BUF_SIZE, *tp) != NULL) {
      fgetpos(*tp, &tmppos);
      fsetpos(*tp, &fpos);
      fputs(buffer, *tp);
      fgetpos(*tp, &fpos);
      fsetpos(*tp, &tmppos);
    }

    fclose(*tp);
    stat("temp.dat", &st);
    fd = open( "temp.dat", O_RDWR);
    ftruncate(fd, st.st_size - x);
    close(fd);
    *tp = fopen("temp.dat", "r+");
  }
}


void copy(FILE **tp, int cur, char clipboard[]) {
  char co[BUF_SIZE];
  char buffer[BUF_SIZE];
  char *token_ptr;
  int i, j, k;
  fpos_t fpos;

  fgets(co, BUF_SIZE, stdin);
  co[strlen(co) - 1] = '\0';
  rewind(*tp);
  for(i = 0; co[i] != '-' && co[i] != '*' && co[i] != '\0'; i++)
    ;
  if(co[i] == '-' || co[i] == '\0') {
    token_ptr = strtok(co, "-");
    i = atoi(token_ptr);
    if (i != 0) {
      token_ptr = strtok(NULL, "-");
      j = atoi(token_ptr);
      if (j == 0 || j < i)
        j = i;
      fgets(buffer, BUF_SIZE, *tp);
      for (k = 1; k <= j; k++) {
        if (k >= i) {
          strncat(clipboard, buffer, 254 - strlen(buffer) - strlen(clipboard));
        }
        if (fgets(buffer, BUF_SIZE, *tp) == NULL)
          break;
      }
    }
  }
  else {
    token_ptr = strtok(co, "*");
    i = atoi(token_ptr);
    token_ptr = strtok(NULL, "*");
    j = atoi(token_ptr);
    for (k = 1; k < i; k++)
      fgets(buffer, BUF_SIZE, *tp);
    for (k = 1; k < cur; k++)
      fgetc(*tp);
    fgetpos(*tp, &fpos);
    fflush(*tp);
    fsetpos(*tp, &fpos);
    for (k = 0; k < j; k++) {
      *(clipboard + k) = fgetc(*tp);
      fgetpos(*tp, &fpos);
      fflush(*tp);
      fsetpos(*tp, &fpos);
    }
    *(clipboard + k) = fgetc(*tp);
  }
}


void quit(FILE **fp, FILE **tp, char fn[], int *savecheck) {
  fileclose(fp, tp, fn, savecheck);
  fclose(*tp);
  if (remove("temp.dat") != 0)
    puts("cannot delete temp.dat");
}


void cursor(int *cur) {
  int i;
  char cu[BUF_SIZE];

  printf("      ");
  for (i = 0; i < *cur; i++)
    putchar(' ');
  printf("*\n");

  fgets(cu, BUF_SIZE, stdin);
  cu[strlen(cu) - 1] = '\0';

  if(cu[0] == '+')
    *cur += atoi(cu + 1);
  else if(cu[0] == '-')
    *cur -= atoi(cu + 1);
  else if(atoi(cu) != 0)
    *cur = atoi(cu);
}


Menu selectmenu(void) {
  char ch[BUF_SIZE];

  fgets(ch, BUF_SIZE, stdin);
  return (Menu)ch[0];
}

int main(void)
{
  Menu menu;
  FILE *fp = NULL;
  FILE *tp = NULL;
  char filename[BUF_SIZE];
  char clipboard[BUF_SIZE] = "";
  int  cur = 1;
  int  savecheck = 1;

  do {
    putchar('*');
    menu = selectmenu();
    switch (menu) {
      case Fileopen  : fileopen(&fp, &tp, filename, &savecheck);    break;
      case Fileclose : fileclose(&fp, &tp, filename, &savecheck);   break;
      case Filesave  : filesave(&fp, &tp, filename, &savecheck);   break;
      case Readtxt   : readtxt(&tp);   break;
      case Writetxt  : writetxt(&tp, cur);   break;
      case Copy      : copy(&tp, cur, clipboard);  printf("%s\n", clipboard); break;
      case Search    : search(&tp);   break;
      case Erase     : erase(&tp, cur);   break;
      case NoL       :    break;
      case Cursor    : cursor(&cur);   break;
      case Quit      : quit(&fp, &tp, filename, &savecheck);   break;
      case Help      :    break;

      default        : printf("no such command\n");   break;
    }
  } while (menu != Quit);

  return 0;
}