#include <stdbool.h>
#include <stddef.h> // size_t
#include "sok.h"

#define UNUSED(a) ((void) (a))

#define IS_DIGIT(c) ((c) >= '0' && (c) <= '9')
#define CASE_DIGIT \
  case '0': \
  case '1': \
  case '2': \
  case '3': \
  case '4': \
  case '5': \
  case '6': \
  case '7': \
  case '8': \
  case '9':

void
sok_level_parser_init(
  sok_level_parser_t * const parser, 
  const sok_level_parser_cbs_t * const cbs,
  void * const user_data
) {
  parser->cbs = cbs;
  parser->user_data = user_data;
}

bool
sok_level_parser_parse(
  sok_level_parser_t * const parser,
  const char * const buf,
  const size_t buf_len
) {
  sok_pos_t size = { .x = 0, .y = 0 };

  for (size_t i = 0, ofs = 0, w = 0; i < buf_len; i++) {
    if (buf[i] == '|') {
      if (w > size.x) {
        size.x = w;
      }

      // reset column position, increment row count
      w = 0;
      size.y++;
    } else if (IS_DIGIT(buf[i])) {
      ofs = 10 * ofs + (buf[i] - '0');
    } else if (ofs > 0) {
      w += ofs;
      ofs = 0;
    } else {
      w++;
    }
  }

  // increment row count
  size.y++;

  // emit level size
  if (
    parser->cbs->on_size &&
    !parser->cbs->on_size(parser, size) 
  ) {
    // return failure
    return false;
  }

  sok_pos_t pos = { 0, 0 };
  for (size_t i = 0, ofs = 0; i < buf_len; i++) {
    switch (buf[i]) {
    case '|':
      // new line
      pos.x = 0;
      pos.y++;

      break;
    CASE_DIGIT
      ofs = 10 * ofs + (buf[i] - '0');
      break;
    case '-':
    case '_':
    case ' ':
      // advance
      pos.x += (ofs > 0) ? ofs : 1;
      ofs = 0;

      break;
    case '+':
      // emit goal
      if (parser->cbs->on_goal && !parser->cbs->on_goal(parser, pos)) {
        // return failure
        return false;
      }

      // emit home
      if (parser->cbs->on_home && !parser->cbs->on_home(parser, pos)) {
        // return failure
        return false;
      }

      // advance
      pos.x++;

      break;
    case '@':
      // emit home
      if (parser->cbs->on_home && !parser->cbs->on_home(parser, pos)) {
        // return failure
        return false;
      }

      // advance
      pos.x++;

      break;
    case '#':
      for (size_t j = (ofs > 0) ? ofs : 1; j; j--) {
        // emit wall
        if (parser->cbs->on_wall && !parser->cbs->on_wall(parser, pos)) {
          // return failure
          return false;
        }

        // advance
        pos.x++;
      }
      ofs = 0;

      break;
    case '*':
      for (size_t j = (ofs > 0) ? ofs : 1; j--;) {
        // emit goal
        if (parser->cbs->on_goal && !parser->cbs->on_goal(parser, pos)) {
          // return failure
          return false;
        }

        // emit box
        if (parser->cbs->on_box && !parser->cbs->on_box(parser, pos)) {
          // return failure
          return false;
        }

        // advance
        pos.x++;
      }
      ofs = 0;

      break;
    case '.':
      for (size_t j = (ofs > 0) ? ofs : 1; j--;) {
        // emit goal
        if (parser->cbs->on_goal && !parser->cbs->on_goal(parser, pos)) {
          // return failure
          return false;
        }

        // advance
        pos.x++;
      }
      ofs = 0;

      break;
    case '$':
      for (size_t j = (ofs > 0) ? ofs : 1; j--;) {
        // emit box
        if (parser->cbs->on_box && !parser->cbs->on_box(parser, pos)) {
          // return failure
          return false;
        }

        // advance
        pos.x++;
      }
      ofs = 0;

      break;
    default:
      // emit junk
      if (parser->cbs->on_junk && !parser->cbs->on_junk(parser, i, buf[i])) {
        // return failure
        return false;
      }

      // return failure
      return false;
    }
  }

  // return success
  return true;
}