#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <getopt.h>
#include <limits.h>
#include <pwd.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>

#include "util/debug.h"
#include "util/error.h"
#include "util/loop_args.h"
#include "util/map.h"
#include "util/versie.h"

#include "io/read_file.h"

static int modeMap;

#define BUF_SIZE 4096

static void usage(FILE *f) {
  fprintf(f,
      "Gebruik: toilet [-nchV] [BESTAND]...\n"
      "\n"
      "Toon de hoeveelheid regels, woorden en beten for elk BESTAND\n"
      "\n"
      "  -c          Geef het aantal beten weer\n"
      "  -w          Geef het aantal woorden weer\n"
      "  -l          Geef het aantal regels weer\n"
      "  -h          Toon deze hulptekst\n"
      "  -V          Toon versienummer\n");
}

enum MODE {
  M_LINES = 1 << 0,
  M_WORDS = 1 << 1,
  M_BYTES = 1 << 2,
};

// Returns pointer to argument array containing the file names
static char** parse_options(int argc, char **argv, int *modeMap) {
  int opt;
  while ((opt = getopt(argc, argv, "cwlhV")) != -1) {
    switch (opt) {
      case 'c':
        *modeMap |= M_BYTES;
        break;

      case 'w':
        *modeMap |= M_WORDS;
        break;

      case 'l':
        *modeMap |= M_LINES;
        break;

      case 'h':
        usage(stdout);
        exit(0);

      case 'V':
        drukkedoos_print_versie(stdout);
        exit(0);

      case '?':
        fprintf(stderr, "toilet: Ongeldige optie: -%c\n", optopt);
        usage(stderr);
        exit(1);
    }
  }

  return argv + optind;
}

static size_t count_lines(char *fname, FILE *f) {
  size_t nlines = 0;
  bool last_was_nl = false;

  while (!feof(f)) {
    static char buf[BUF_SIZE];
    const size_t n = fread(buf, 1, BUF_SIZE, f);

    for (size_t i = 0; i < n; i++) {
      last_was_nl = false;
      if (buf[i] == '\n') {
        nlines++;
        last_was_nl = true;
      }
    }
  }

  if (!last_was_nl) nlines++;

  if (errno != 0) {
    printf("toilet: fout bij lezen uit bestand '%s'\n", fname);
    exit(1);
  }

  rewind(f);
  return nlines;
}

static size_t count_words(FILE *f) {
  size_t nwords = 0;

  while (!feof(f)) {
    static char buf[BUF_SIZE];
    const size_t n = fread(buf, 1, BUF_SIZE, f);

    // (c) Tom Forging
    for (size_t i = 0; i<n;) {
      size_t previ = i;
      while (i<n && !isspace(buf[i])) i++;
      nwords += i != previ;
      while (i<n && isspace(buf[i])) i++;
    }
  }

  rewind(f);
  return nwords;
}

static size_t get_count(enum MODE mode, char *fname, FILE *f) {
  switch (mode) {
    case M_BYTES: {
      fseek(f, 0, SEEK_END);
      long offset = ftell(f);
      rewind(f);
      return offset;
    }

    case M_WORDS:
      return count_words(f);

    case M_LINES:
      return count_lines(fname, f);

    default:
      assert(false);
  }
}

static int process(char *fname, bool isstdin) {
  FILE *f = isstdin ? stdin : fopen(fname, "rb");

  for (enum MODE mode = 1; mode <= M_BYTES; mode <<= 1) {
    if (mode & modeMap) {
      const size_t count = get_count(mode, fname, f);
      printf("%li ", count);
    }
  }

  if (fname != NULL) printf("%s", fname);
  putchar('\n');

  if (!isstdin) fclose(f);
  return 0;
}

int entry_toilet(int argc, char **argv) {
  modeMap = 0;
  char **args = parse_options(argc, argv, &modeMap);
  if (modeMap == 0) {
    modeMap = INT_MAX;
  }

  return loop_args(args, process);
}