A crappy editor

forge.c

#include <ncurses.h>
#include <stdlib.h>
#include <string.h>

enum mode {
  NORMAL,
  INSERT,
  COMMAND
};

typedef struct line {
  int length;
  int max_length;
  char *string;
} line_t;

typedef struct document {
  char* filename;
  line_t** buffer;
  int lines_allocated;
} document_t;

void render_buffer(document_t* document, WINDOW *window) {
  int i;
  int width;
  int height;
  getmaxyx(window, height, width);
  for(i = 0; i < document->lines_allocated && i < height; i++) {
    wmove(window, i, 0);
    wprintw(window, document->buffer[i]->string);
  }
  wmove(window, 0, 0);
}

line_t* new_line_of_length(int length) {
  line_t* line = (line_t *)malloc(sizeof(line_t));
  line->string = (char *)malloc(sizeof(char) * length);
  line->length = 0;
  line->max_length = length;
  return line;
}

line_t* new_line() {
  return new_line_of_length(100);
}

document_t* new_document() {
  document_t* document = (document_t *)malloc(sizeof(document_t));
  document->buffer = (line_t **)calloc(100, sizeof(line_t *));
  document->buffer[0] = new_line();
  document->lines_allocated = 1;
  return document;
}

void free_document(document_t* document) {
  if(document->filename != NULL) {
    free(document->filename);
  }
  free(document->buffer);
  free(document);
}

char* insert_char(char* string, int pos, char c) {
  char *new = (char *)malloc(sizeof(char) * strlen(string) + 2);
  strncpy(new, string, pos);
  new[pos] = c;
  new[pos+1] = '\0';
  strcat(new, string+pos);
  return new;
}

void load_file(document_t* document, char* filename) {
  int current_line = 0;
  char *line = NULL;
  size_t linecap = 0;
  ssize_t linelen;
  FILE* file;

  file = fopen(filename, "r");
  document->filename = strdup(filename);

  if(file != NULL) {
    while((linelen = getline(&line, &linecap, file)) > 0) {
      if(current_line >= document->lines_allocated) {
        document->buffer[current_line] = new_line_of_length(100 + linelen);
        document->lines_allocated++;
      } else if(linelen > document->buffer[current_line]->max_length) {
        realloc(document->buffer[current_line]->string, sizeof(char) * (100 + linelen));
        document->buffer[current_line]->max_length = 100 + linelen;
      }
      strcpy(document->buffer[current_line++]->string, line);
    }
    fclose(file);
  }
}

void write_file(document_t* document) {
  FILE* file;
  file = fopen(document->filename, "w");
  for(int i = 0; i < document->lines_allocated; i++) {
    fprintf(file, "%s", document->buffer[i]->string);
  }
  fclose(file);
}

int main(int argc, char **argv) {
  int mode = NORMAL;
  int x = 0;
  int y = 0;
  int width;
  int height;
  int line_length;
  char cmd[2048];
  int cmdpos = 0;

  document_t* document = new_document();
  if(argc > 1) {
    load_file(document, argv[1]);
  }

  initscr();
  refresh();
  noecho();
  raw();

  getmaxyx(stdscr, height, width);
  WINDOW* details = newwin(1, width, height - 1, 0);
  WINDOW* mainwin = newwin(height - 1, width, 0, 0);
  wmove(mainwin, 0, 0);

  if(argc > 1) {
    render_buffer(document, mainwin);
    wrefresh(mainwin);
  }

  while(1) {

    char c = wgetch(mainwin);

    if(mode == NORMAL) {
      if(c == ':') {
        wprintw(details, ":");
        wrefresh(details);
        cmdpos = 0;
        mode = COMMAND;
      } else if(c == 'i') {
        mode = INSERT;
      } else if(c == 'j') {
        wmove(mainwin, ++y, x);
      } else if(c == 'k') {
        wmove(mainwin, --y, x);
      } else if(c == 'l') {
        wmove(mainwin, y, ++x);
      } else if(c == 'h') {
        wmove(mainwin, y, --x);
      }

    } else if(mode == INSERT) {
      if(c == 27) {
        mode = NORMAL;
      } else if(c == 127) {
        line_length = document->buffer[y]->length;
        memmove(&document->buffer[y]->string[x-1], &document->buffer[y]->string[x], strlen(document->buffer[y]->string) - x);
        if(x == 0) {
          y -= 1;
          x = strlen(document->buffer[y]->string);
        } else {
          x -= 1;
        }
        wmove(mainwin, y, x);
        wdelch(mainwin);
      } else if(c == 10) {
        y += 1;
        x = 0;
        if(document->buffer[y] == NULL) {
          document->buffer[y] = new_line();
          document->lines_allocated++;
        }
        wmove(mainwin, y, x);
      } else {
        document->buffer[y]->string = insert_char(document->buffer[y]->string, x, c);
        winsch(mainwin, c);
        wmove(mainwin, y, ++x);
      }
      wrefresh(mainwin);

    } else if(mode == COMMAND) {
      if(c == 10) {
        if(strcmp(cmd, "q") == 0) {
          break;
        } else if (strcmp(cmd, "wq") == 0) {
          write_file(document);
          break;
        }
        mode = NORMAL;
        wclear(details);
        cmdpos = 0;
        cmd[cmdpos] = '\0';
      } else if(c == 127) {
        wmove(details, 0, cmdpos--);
        wdelch(details);
        cmd[cmdpos] = '\0';
      } else if(c == 27) {
        mode = NORMAL;
        wclear(details);
        cmdpos = 0;
        cmd[cmdpos] = '\0';
      } else {
        wprintw(details, "%c", c);
        cmd[cmdpos++] = c;
        cmd[cmdpos] = '\0';
      }
      wrefresh(details);
    }
  }

  endwin();
  free_document(document);
  return EXIT_SUCCESS;
}