#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <limits.h>
#include <string.h>
#include <emacs-module.h>

#include "big_endian.h"
#include "helper.h"

int
main(int argc, char **argv)
{
  unsigned char error_vec_len[8] = { 0 };
  unsigned char error_vec_cap[8] = { 0 };

  struct SignedVec error_vec = { 0 };

  error_vec.len = error_vec_len;
  error_vec.capacity = error_vec_cap;

  char *grammar_string = "document     =  1*( item )\n"
"\n"
"item         =  header [ price ] *1( note )\n"
"\n"
"item         =/ header [ note ] *1( price )\n"
"\n"
"header       =  *1star \"SP\" title %xA *( \"SP\" / %xA )\n"
"\n"
"title        =  1*\"TEXT\"\n"
"\n"
"star         =  %x2A\n"
"\n"
"note         =  \"note:\" \"SP\" note-content %xA *( \"SP\" / %xA )\n"
"\n"
"note-content =  1*\"TEXT\"\n"
"\n"
"price        =  \"price:\" \"SP\" 1*\"DIGIT\" %xA *( \"SP\" / %xA )\n";

  struct parser *parser = new_parser(grammar_string, &error_vec);
  /* struct parser *parser = new_parser("start  = \"a\"\"b\"\n", &error_vec); */

  uint64_t error_length = from_big_endian(error_vec.len);

  if (error_length) {
    printf("error: ");

    char *error_str = error_vec.data;

    for (int i = 0; i < error_length; i++) {
      printf("%c", *(error_str+i));
    }

    printf("\n");

    clean_signed(&error_vec, 4);

    return 1;
  }

  /* int input_unenc[] = { 3, 0, 2, 1, 5, 0, 6, 1 }; */
  
  /* int input_unenc[] = { 3, 0, 2, 2, 2, 2, 1, 5, 0,
   *                       6, 6, 6, 1, 3, 0, 2, 2, 2,
   *                       2, 1, 5, 0, 6, 6, 6, 1, 3,
   *                       0, 2, 2, 2, 2, 1, 5, 0, 6,
   *                       6, 6, 1, 4, 2, 2, 2, 2, 2,
   *                       2, 2, 2, 2, 2, 2, 2, 2, 2,
   *                       2, 2, 1 }; */
  
  int input_unenc[] = { 3, 0, 2, 1,
                        5, 0, 6, 1,
                        3, 0, 2, 1,
                        5, 0, 6, 1,
                        3, 0, 2, 1,
                        5, 0, 6, 1,
                        4, 0, 2, 1 };
  
  int input_unenc_len = (int) (sizeof (input_unenc) /
                               sizeof(input_unenc[0]));

  printf("input length = %d\n", input_unenc_len);

  unsigned char *input = malloc (sizeof(unsigned char) *
                                 input_unenc_len * 8);

  if (input == NULL) {
    clean_parser(parser);
    clean_signed(&error_vec, 4);
    printf("malloc fails at %s:%d\n", __FILE__, __LINE__);

    return EXIT_FAILURE;
  }
  
  for (int i = 0; i < input_unenc_len; i++)
    to_big_endian(input_unenc[i], input + (8 * i));

  unsigned char input_len[8] = { 0 };
  /* input_len[7] = 8*10; */

  to_big_endian((uint64_t) (8 * input_unenc_len), input_len);

  struct UnsignedVec input_vec =
    (struct UnsignedVec) { input_len, NULL, input };

  int result = parser_recognize
    (parser,
     &input_vec,
     &error_vec,
     (unsigned char) 0);

  error_length = from_big_endian(error_vec.len);

  if (error_length) {
    clean_parser((void *) parser);
    free(input);

    printf("error: ");

    char *error_str = error_vec.data;

    for (uint64_t i = 0; i < error_length; i++) {
      printf("%c", *(error_str + (unsigned long) i));
    }

    printf("\n");

    clean_signed(&error_vec, 4);

    return 1;
  }

  if (result)
    printf("result = true\n");
  else
    printf("result = false\n");

  for (int i = 0; i < 8; i++) {
    error_vec.len[i] = 0;
    error_vec.capacity[i] = 0;
  }

  struct UnsignedVec *forest_ptr = parser_parse
    (parser,
     &input_vec,
     &error_vec,
     (unsigned char) 1);

  error_length = from_big_endian(error_vec.len);

  if (error_length) {
    clean_parser((void *) parser);
    free(input);

    printf("error: ");

    char *error_str = error_vec.data;

    for (uint64_t i = 0; i < error_length; i++) {
      printf("%c", *(error_str + (unsigned long) i));
    }

    printf("\n");

    clean_signed(&error_vec, 4);

    return 1;
  }

  free(input);
  clean_parser((void *) parser);

  if (forest_ptr) {
    uint64_t forest_len = from_big_endian(forest_ptr->len);

    /* forest_len++; */

    printf("a non-empty forest of length %llu\n", forest_len);

    unsigned char *forest = forest_ptr->data;

    uint64_t forest_real_len = from_big_endian(forest);

    if (forest_real_len != forest_len) {
      fprintf(stderr, "wrong length: %llu\n", forest_real_len);

      clean_unsigned(forest_ptr, 15);

      return 1;
    }

    if (forest_len < 27) {
      fprintf(stderr, "length too small: %llu\n", forest_len);

      clean_unsigned(forest_ptr, 15);

      return 1;
    }

    printf("the lengths match\n");

    if (*(forest+8) != 114 || *(forest+9) != 101 || *(forest+10) != 112) {
      fprintf(stderr, "the forest does not begin with the special mark\n");

      fprintf(stderr, "the first bytes are: ");
      fprintf(stderr, "%c", *(forest+8));
      fprintf(stderr, "%c", *(forest+9));
      fprintf(stderr, "%c\n", *(forest+10));

      clean_unsigned(forest_ptr, 15);

      return 1;
    }

    printf("the special mark is correct.\n");

    uint64_t nodes_len = from_big_endian(forest+11);

    printf("forest has %llu nodes\n", nodes_len);

    uint64_t labels_offset = from_big_endian(forest+19);

    printf("the offset of labels is %llu\n", labels_offset);

    if (forest_len < labels_offset ||
        forest_len < (27 + 16 * nodes_len)) {
      fprintf(stderr, "length too small: %llu\n", forest_len);

      clean_unsigned(forest_ptr, 15);

      return 1;
    }

    uint64_t total_degree = 0;

    for (uint64_t i = 0; i < nodes_len; i++) {
      uint64_t offset = 27 + 16 * i;

      uint64_t degree = from_big_endian(forest+offset);
      uint64_t node_offset = from_big_endian(forest+offset+8);

      total_degree += degree;

      printf("the %llu-th node has degree %llu and offset %llu\n",
             i, degree, node_offset);

      printf("label: ");
      print_label(read_label(forest + labels_offset + 34 * i));

      for (uint64_t j = 0; j < degree; j++) {
        uint64_t child = from_big_endian(forest+node_offset+8*j);

        printf("the %llu-th child is %llu\n", j, child);
      }

      printf("\n");
    }

    uint64_t correct = 27 + 50 * nodes_len + 8 * total_degree;

    if (forest_len != correct) {
      fprintf(stderr, "length does not conform to the format: %llu\n", correct);

      clean_unsigned(forest_ptr, 15);

      return 1;
    }

    printf("the forest has the correct length according to the format\n");

    printf("saving to the file \"forest.rep\"\n");

    char *open_mode = "a";

    if (fopen("forest.rep", "r") != NULL) {
      printf("The file \"forest.rep\" already exists.\n"
             "Do you want to overwrite it? [y/n] ");

      fflush(stdout);

      #define UNANSWERED 0
      #define YES 1
      #define NO 2

      int yes = UNANSWERED;

      while (yes == UNANSWERED) {
        char input = getchar();

        switch (input) {
        case 'y':
          yes = YES;
          break;
        case 'n':
          yes = NO;
          break;
        default:
          printf("Please answer 'y' or 'n'.\n");
          yes = UNANSWERED;
          break;
        }
      }

      if (yes == NO) {
        printf("Exiting without saving...\n");

        clean_unsigned(forest_ptr, 15);

        return 0;
      }

      open_mode = "w";

      #undef UNANSWERED
      #undef YES
      #undef NO
    }

    FILE *forest_file = fopen("forest.rep", open_mode);

    if (forest_file == NULL) {
      fprintf(stderr, "Cannot open file \"forest.rep\" to write\n");

      clean_unsigned(forest_ptr, 15);

      return 1;
    }

    fwrite(forest, 1, forest_len, forest_file);

    fclose(forest_file);

    printf("Successfully saved the forest to the file \"forest.rep\"\n");

    clean_unsigned(forest_ptr, 15);
  } else {
    printf("no forest\n");
  }

  return 0;
}