#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "linecut.h"

extern int errno;

unsigned long
count_lines (FILE *input)
{
    unsigned long lines = 0;

    while (!feof (input))
      if (fgetc (input) == '\n')
        lines++;

    return lines;
}

fpos_t *
build_offset_map (data_t *gl)
{
    unsigned long line = 0;
    fpos_t *map;

    map = xmalloc ((gl->lines_count + 1) * sizeof (fpos_t));

    seek_to_start (gl);

    fgetpos (gl->input, &map[line]);

    while (!feof (gl->input))
      if (fgetc (gl->input) == '\n')
        fgetpos (gl->input, &map[++line]);

    return map;
}

unsigned long
map_stdin_lines (data_t *gl)
{
    unsigned long i = 0, count = 1;
    char **lines;
    char buf[BUF_SIZE];

    lines = xmalloc (sizeof (char *));

    while (!feof (stdin))
      {
        char *p, *s;
        fgets (buf, BUF_SIZE, stdin);
        s = buf;
        while ((p = strchr (s, '\n')) && !feof (stdin))
          {
            char *str;
            unsigned int len;
            len = p - s;
            str = xmalloc (len + 1);
            strncpy (str, s, len);
            *(str + len) = '\0';
            lines[i++] = str;
            lines = xrealloc (lines, ++count * sizeof (char *));
            s = ++p;
          }
      }

    lines[i] = NULL;
    gl->stdin_lines = lines;

    return count - 1;
}

void
seek_to_start (data_t *gl)
{
    rewind (gl->input);
}

void
seek_to_offset (data_t *gl, fpos_t *offset_map, long line)
{
    short retval = fsetpos (gl->input, &offset_map[line]);

    if (retval != 0)
      {
        xfree (offset_map);
        error ("%s: could not seek to offset: %s", gl->file, strerror (errno));
      }
}

void
extract_range_file (data_t *gl, long range_start, long range_end)
{
    const long start_line = range_start - 1;
    const long end_line   = range_end   - 1;

    long line = start_line;

    while (line <= end_line)
      {
        if (gl->number_lines)
          print_line_number (gl, line + 1);
        while (!feof (gl->input))
          {
            char ch = fgetc (gl->input);
            if (is_char (ch))
              put (ch);
            else
              {
                if (line++ <= end_line)
                  put_newline ();
                break;
              }
          }
      }
}

void
extract_range_stdin (data_t *gl, long range_start, long range_end)
{
    const long start_line = range_start - 1;
    const long end_line   = range_end   - 1;

    long line;

    for (line = start_line; line <= end_line; line++)
      {
        if (gl->number_lines)
          print_line_number (gl, line + 1);

        fputs (gl->stdin_lines[line], stdout);
        put_newline ();
      }
}