#include <assert.h>
#include <ctype.h>
#include <getopt.h>
#include <limits.h>
#include <tgmath.h>
#include <pwd.h>
#include <stdbool.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_files.h"
#include "util/map.h"
#include "util/versie.h"

#include "io/read_file.h"

static int modeMap;

struct finfo {
  size_t values[3];
  char *fname;
};
static struct finfo *finfo = NULL;
static size_t finfolen = 0;
static size_t finfocap = 0;

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

    case M_WORDS: {
#define IN(i) (i < fb->sz)

      size_t words = 0;

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

      return words;

#undef IN
    }

    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 int mlog2(int val) {
#define C(n) case (1 << (n)): return (n);

  switch (val) {
    C(0) C(1) C(2)
  }
  assert(false);

#undef C
}

static void init_finfo(int argc) {
  assert(finfo == NULL);
  argc += 1; // one more for the total tally
  if (argc < 8) argc = 8;

  finfo = calloc(argc, sizeof(struct finfo));
  finfocap = argc;
}

static struct finfo *add_fname(char *fname) {
  assert(finfo != NULL);

  if (finfolen == finfocap) {
    finfocap *= 2;
    finfo = realloc(finfo, sizeof(struct finfo)*finfocap);
  }

  struct finfo *ptr = finfo + finfolen;
  ptr->values[0] = 0;
  ptr->values[1] = 0;
  ptr->values[2] = 0;
  ptr->fname = fname;

  finfolen++;
  return ptr;
}

static int process(struct filebuf *fb, char *fname, bool) {
  struct finfo *finfo = add_fname(fname);

  for (enum MODE mode = 1; mode <= M_BYTES; mode <<= 1) {
    if (mode & modeMap) {
      finfo->values[mlog2(mode)] = get_count(mode, fb);
    }
  }
  free_filebuf(fb);
  return 0;
}

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

int entry_toilet(int argc, char **argv) {
  init_finfo(argc);

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

  const int res = loop_files(args, process);

  // tally file totals
  {
    struct finfo *ptr = add_fname("total");

    for (size_t i = 0; i < 3; i++) {
      for (size_t j = 0; j < finfolen; j++) {
        ptr->values[i] += finfo[j].values[i];
      }
    }
  }

  // calculate required padding
  int pad[3] = {0};
  for (size_t i = 0; i < finfolen; i++) {
    for (size_t j = 0; j < 3; j++) {
      const int sz = ceill(log10l(finfo[i].values[j])) + 1;
      if (sz > pad[j]) pad[j] = sz;
    }
  }

  // print all results
  for (size_t i = 0; i < finfolen; i++) {
    struct finfo *ptr = finfo + i;
    for (size_t j = 0; j < 3; j++) {
      printf("% *li ", pad[j], ptr->values[j]);
    }
    printf("%s\n", ptr->fname);
  }


  return res;
}