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

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

#include "io/read_file.h"

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;
}

size_t get_count(enum MODE mode, struct filebuf *fb) {
  switch (mode) {
    case M_BYTES:
      return fb->sz;

    case M_WORDS: {
      size_t words = 0;

      assert(fb->sz >= 0);
      // (c) Tom Forging
      for (size_t i = 0; i < (size_t)fb->sz;) {
        size_t previ = i;
        while (!isspace(fb->buf[i])) i++;
        words += i != previ;
        while (isspace(fb->buf[i])) i++;
      }

      return words;
    }

    case M_LINES: {
      size_t lines = 0;
      size_t i = 0;

      while (i != fb->sz) {
        if (fb->buf[i] == '\n') lines++;
        i++;
      }

      // handle case if file does not have trailing newline
      if (fb->buf[i - 1] != '\n') {
        lines++;
      }

      return lines;
    }

    default:
      assert(false);
  }
}

static void process(char *fname, struct filebuf *fb, int modeMap) {
  for (enum MODE mode = 1; mode <= M_BYTES; mode <<= 1) {
    if (mode & modeMap) {
      const size_t count = get_count(mode, fb);
      printf("%li ", count);
    }
  }
  printf("%s\n", fname);
  free_filebuf(fb);
}

// TODO: be smarter, toilet doesn't have to read the whole file in memory (for
// unmappable files)

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

  if (*args == NULL) {
    struct filebuf *fb = stream_to_filebuf(stdin, 0);
    if (fb == NULL) goto err_stdin;

    process("", fb, modeMap);
    return 0;
  }

  while (*args != NULL) {
    struct filebuf *fb = NULL;

    if (!strcmp(*args, "-")) {
      fb = stream_to_filebuf(stdin, 0);
      if (fb == NULL) goto err_stdin;
      *args = ""; // no filename when stdin
    } else {
      bool isdir = false;
      fb = file_to_filebuf(*args, 0, &isdir);
      if (isdir) goto err_isdir;
      else if (fb == NULL) goto err_file;
    }

    process(*args, fb, modeMap);

    args++;
  }

  return 0;

err_stdin:
  fprintf(stderr, "toilet: fout bij lezen van standaard invoer\n");
  return 1;

err_file:
  fprintf(stderr, "toilet: fout bij lezen van bestand\n");
  return 1;

err_isdir:
  fprintf(stderr, "toilet: bestand '%s' is een mapje\n", *args);
  return 1;
}