#include <unistd.h>

#include "alloc.h"
#include "buffer.h"
#include "exit.h"
#include "logmsg.h"
#include "readclose.h"
#include "stralloc.h"

#define WHO "columnt"

#define BSIZE 4096

char outbuf[BSIZE];
buffer bo = BUFFER_INIT(write, 1, outbuf, sizeof(outbuf));

static void nomem()
{
  logmsg(WHO, 111, FATAL, "out of memory");
}

static void die_read()
{
  logmsg(WHO, 110, ERROR, "unable to read input: ");
}

static void die_write()
{
  logmsg(WHO, 110, ERROR, "unable to write output: ");
}

stralloc file = {0};
int *width;
int maxfield = 0;

static void nothing() {}

static void printline()
{
  if (buffer_put(&bo, "\n", 1) == -1) die_write();
}

static void maxfield_check(int fieldnum, char *buf, int len)
{
  if (fieldnum > maxfield) maxfield = fieldnum;
}

static void width_check(int fieldnum, char *buf, int len)
{
  if (len > width[fieldnum]) width[fieldnum] = len;
}

static void width_init()
{
  int i;

  width = (int *)alloc((maxfield + 1) * sizeof(int));
  if (!width) nomem();
  for (i = 0; i <= maxfield; ++i) width[i] = 0;
}

static void printfield(int fieldnum, char *buf, int len)
{
  int i;

  if (fieldnum < maxfield)
    for (i = len; i < width[fieldnum]; ++i)
      if (buffer_put(&bo, " ", 1) == -1) die_write();

  if (buffer_put(&bo, buf, len) == -1) die_write();

  if (fieldnum < maxfield)
    if (buffer_put(&bo, "  ", 2) == -1) die_write();
}

static void split(void (*dofield)(int, char *, int), void (*doline)(void))
{
  int i;
  int j;
  int fieldpos;
  int fieldnum;

  for (j = i = 0; j < file.len; ++j)
    if (file.s[j] == '\n') {
      fieldnum = 0;
      for (;;) {
        while ((file.s[i] == ' ') || (file.s[i] == '\t')) ++i;
        if (i == j) break;
        fieldpos = i;
        while ((file.s[i] != ' ') && (file.s[i] != '\t') && (file.s[i] != '\n')) ++i;
        dofield(fieldnum++, file.s + fieldpos, i - fieldpos);
      }
      doline();
      i = j + 1;
    }
}

int main()
{
  if (readclose_append(0, &file, BSIZE) == -1) die_read();
  if (!file.len) _exit(0);
  if (file.s[file.len - 1] != '\n')
    if (!stralloc_append(&file, "\n")) nomem();

  split(maxfield_check, nothing);
  width_init();
  split(width_check, nothing);
  split(printfield, printline);

  if (buffer_flush(&bo) == -1) die_write();
  _exit(0);
}