#include <dirent.h>
#include <errno.h>
#include <md4c.h>
#include <md4c-html.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MD4C_USE_UTF8

char* combine_strs(char* str1, char* str2) {
  int str1_len = strlen(str1);
  int str2_len = strlen(str2);
  char* output_buffer = malloc((str1_len + str2_len + 1) * sizeof(char));
  if (output_buffer == NULL) {
    printf("Error: Allocation Error\n");
    return NULL;
  }
  memset(output_buffer, '\0', str1_len + str2_len + 1);
  strncat(output_buffer, str1, str1_len);
  strncat(output_buffer, str2, str2_len);
  return output_buffer;
}

void* process(const MD_CHAR* text, MD_SIZE text_size, void* output) {
  char* output_filename = combine_strs("output/", output);
  if (output_filename == NULL) {
    printf("Error: Unable to create filename buffer... Exiting\n");
    exit(3);
  }
  FILE* output_file = fopen(output_filename, "");
  if (output_file == NULL) {
    printf("Error: Cannot open output file %s... Exiting\n", output_filename);
    free(output_filename);
    exit(4);
  }
  free(output_filename);
  int bytes = fwrite(text, sizeof(char), text_size, output_file);
  if (bytes != text_size) {
    printf("Warning: %d bytes written when %d bytes were expected\n", bytes, text_size);
  }
  fclose(output_file);
  return NULL;
}

void render_html(char* markdown_dir) {
  int pf = MD_FLAG_COLLAPSEWHITESPACE | MD_FLAG_TABLES | MD_FLAG_TASKLISTS | MD_FLAG_STRIKETHROUGH | MD_FLAG_UNDERLINE;
  int rf = 0;

  struct dirent* de;
  DIR* dr = opendir(markdown_dir);
  errno = 0;
  if (dr == NULL) {
    printf("Error: Couldn't open directory %s\n", markdown_dir);
    exit(2);
  }
  while ((de = readdir(dr)) != NULL) {
    switch (de->d_type) {
      case DT_DIR:
        render_html(de->d_name);
        break;
      case DT_REG:
        md_html(input, strlen(input), process, NULL, pf, rf);
        break;
    }
  }
  if (errno != 0) {
    printf("Warning: Error occured while scanning directory %s\n", markdown_dir);
  }
}

int main(int argv, char** argc) {
  if (argv != 2) {
    printf("Usage: ssg MARKDOWN_DIR\n");
    exit(1);
  }  
}