#include "eval.h"
#include <stdlib.h>
#include <string.h>
#include "pattern.h"
#include "pairmap.h"

#define EVAL_FOREACH_MALLOC 1

static liblex_result foreach_errors[2] = {
  LIBLEX_SUCCESS,
  LIBLEX_MALLOC
};

void eval_config_init(eval_config* config){
  ll_init(&config->states);
}
liblex_result eval_config_add(eval_config* config, const char* ptrn, int pattern_id){
  liblex_result result;
  pattern* new_pattern;
  eval_state* new_state;
  new_pattern = malloc(sizeof(*new_pattern));
  new_state = malloc(sizeof(*new_pattern));
  if(new_pattern && new_state){
    result = pattern_compile(new_pattern, ptrn, pattern_id);
    if(result == LIBLEX_SUCCESS){
      new_state->source = ptrn;
      new_state->pattern = new_pattern;
      result = (ll_append(&config->states, new_state) == LIBDS_SUCCESS) ?
        LIBLEX_SUCCESS : LIBLEX_MALLOC;
    }
    if(result != LIBLEX_SUCCESS){
      pattern_free(new_pattern);
    }
  } else {
    result = LIBLEX_MALLOC;
  }
  if(result != LIBLEX_SUCCESS) {
    free(new_pattern);
    free(new_state);
  }
  return result;
}

liblex_result _eval_config_free_state(eval_state* state) {
  liblex_result result = pattern_free(state->pattern);
  free(state->pattern);
  free(state);
  return result;
}

liblex_result eval_config_remove(eval_config* config, const char* pattern, int pattern_id) {
  liblex_result result = LIBLEX_SUCCESS;
  ll_node* head = config->states.head;
  while(head && result == LIBLEX_SUCCESS) {
    eval_state* current_state = head->data;
    if(strcmp(current_state->source, pattern) == 0 && current_state->pattern->head->pattern_id == pattern_id) {
      ll_node* to_delete = head;
      head = head->next;
      *(to_delete->prev ? &to_delete->prev->next : &(config->states.head)) = to_delete->next;
      *(to_delete->next ? &to_delete->next->prev : &(config->states.tail)) = to_delete->prev;
      free(to_delete);
      result = _eval_config_free_state(current_state);
    } else {
      head = head->next;
    }
  }
  return result;
}

int _eval_config_foreach_free(void* data, va_list args){
  return _eval_config_free_state(data) == LIBLEX_SUCCESS ? 0 : EVAL_FOREACH_MALLOC;
}

liblex_result eval_config_free(eval_config* config){
  liblex_result result = foreach_errors[ll_foreach(&config->states, NULL, compare_always, _eval_config_foreach_free)];
  ll_free(&config->states);
  return result;
}

pattern_node* _eval_pattern_node_get_next(pattern_node *node){
  pattern_node* to_return = NULL;
  if(node->type == PNODE_VALUE){
    to_return = node->data_u.value_s.next;
  } else if(node->type == PNODE_ANY){
    to_return = node->data_u.any_s.next;
  } else if(node->type == PNODE_RANGE){
    to_return = node->data_u.range_s.next;
  } else if(node->type == PNODE_CONNECT){
    to_return = node->data_u.connect_s.next;
  }
  return to_return;
}

liblex_result _eval_pairmap_add_node(ht *table, pattern_node *node){
  liblex_result result = LIBLEX_SUCCESS;

  if(node->type == PNODE_ANY || node->type == PNODE_VALUE || node->type == PNODE_RANGE ||
      node->type == PNODE_END){
    pairmap_key tmp_key;
    result = PAIRMAP_PUT(table, &tmp_key, node->pattern_id, node->id, node) == LIBDS_SUCCESS ? LIBLEX_SUCCESS : LIBLEX_MALLOC;
  } else if(node->type == PNODE_CONNECT){
    result = _eval_pairmap_add_node(table, _eval_pattern_node_get_next(node));
  } else if(node->type == PNODE_FORK){
    result = _eval_pairmap_add_node(table, node->data_u.fork_s.left);
    if(result == LIBLEX_SUCCESS){
      result = _eval_pairmap_add_node(table, node->data_u.fork_s.right);
    }
  }
  return result;
}

int _eval_foreach_add_node(void *data, va_list args){
  eval_state* state = data;
  ht* pairmap = va_arg(args, ht*);
  pattern_node* pattern_head = state->pattern->head;
  return _eval_pairmap_add_node(pairmap, pattern_head) == LIBLEX_SUCCESS? 0 : EVAL_FOREACH_MALLOC;
}

int _eval_node_matches(pattern_node *node, eval *eval){
  int matches = 0;
  char value = eval->string[eval->index];
  if(node->type == PNODE_ANY){
    matches = value != '\0';
  } else if(node->type == PNODE_VALUE){
    matches = value == node->data_u.value_s.value;
  } else if(node->type == PNODE_RANGE) {
    matches = value >= node->data_u.range_s.from && value <= node->data_u.range_s.to;
  }
  return matches;
}

int _eval_foreach_check_node(void *data, va_list args){
  int inverted_matches = 1;
  int return_code = 0;
  pattern_node* node = data;
  eval* evl = va_arg(args, eval*);
  while(node && node->invert && inverted_matches) {
    inverted_matches &= !_eval_node_matches(node, evl);
    node = _eval_pattern_node_get_next(node);
  }
  if(inverted_matches && _eval_node_matches(node, evl)){
    return_code = _eval_pairmap_add_node(evl->set_next, _eval_pattern_node_get_next(node)) == LIBLEX_SUCCESS ? 0 : EVAL_FOREACH_MALLOC;
    if(return_code == 0){
      evl->matched++;
    }
  } else if(node->type == PNODE_END){
    match* new_match = malloc(sizeof(*new_match));
    if(new_match){
      new_match->from = evl->begin;
      new_match->to = evl->index;
      new_match->pattern = node->pattern_id;

      return_code = ll_append(&evl->matches, new_match) == LIBDS_SUCCESS ? 0 : EVAL_FOREACH_MALLOC;
      if(return_code){
        free(new_match);
      }
    } else {
      return_code = EVAL_FOREACH_MALLOC;
    }
  }
  return return_code;
}

liblex_result _eval_step(eval *eval){
  ht* tmp;
  liblex_result result;
  eval->matched = 0;
  result = foreach_errors[ht_foreach(eval->set_current, NULL, compare_always, _eval_foreach_check_node,
                                                   eval)];

  tmp = eval->set_current;
  eval->set_current = eval->set_next;
  eval->set_next = tmp;
  if(eval->matched){
    eval->index++;
  }

  ht_free(eval->set_next);
  pairmap_init_ht(eval->set_next);
  return result;
}

int _eval_foreach_find_match(void *data, va_list args){
  match* current_match = data;
  int* max_match_id = va_arg(args, int*);
  match* fill_match = va_arg(args, match*);
  if(*max_match_id < current_match->pattern || current_match->to > fill_match->to){
    *max_match_id = current_match->pattern;
    memcpy(fill_match, current_match, sizeof(*current_match));
  }
  return 0;
}

liblex_result eval_word(const char* string, size_t index, eval_config* config, match* mtch){
  liblex_result result = LIBLEX_SUCCESS;
  eval evl;
  evl.index = evl.begin = index;
  evl.string = string;
  evl.matched = 0;
  pairmap_init_ht(&evl.set_a);
  pairmap_init_ht(&evl.set_b);
  ll_init(&evl.matches);
  evl.set_current = &evl.set_a;
  evl.set_next = &evl.set_b;

  result = foreach_errors[ll_foreach(&config->states, NULL, compare_always, _eval_foreach_add_node, evl.set_current)];
  if(result == LIBLEX_SUCCESS){
    do {
      result = _eval_step(&evl);
    } while(result == LIBLEX_SUCCESS && evl.matched && *(evl.string));
  }

  if(result == LIBLEX_SUCCESS && evl.matches.tail){
    int largest_id = -1;
    ll_foreach(&evl.matches, NULL, compare_always, _eval_foreach_find_match, &largest_id, mtch);
  } else {
    mtch->from = 0;
    mtch->to = 0;
    mtch->pattern = -1;
  }

  ll_foreach(&evl.matches, NULL, compare_always, eval_foreach_match_free);
  ll_free(&evl.matches);
  ht_free(&evl.set_a);
  ht_free(&evl.set_b);

  return result;
}
liblex_result eval_all(const char* string, size_t index, eval_config* config, ll* matches){
  liblex_result result = LIBLEX_SUCCESS;
  match* new_match = NULL;
  int done = 0;

  do {
    new_match = malloc(sizeof(*new_match));
    if(new_match){
      result = eval_word(string, index, config, new_match);
      if(result == LIBLEX_SUCCESS){
        if(new_match->pattern < 0 || new_match->from - new_match->to == 0){
          done = 1;
          free(new_match);
          if(string[index]){
            result = LIBLEX_UNRECOGNIZED;
          }
        } else {
          result = ll_append(matches, new_match) == LIBDS_SUCCESS ? LIBLEX_SUCCESS : LIBLEX_MALLOC;
        }
      }
      if(result == LIBLEX_SUCCESS && string[index] != '\0'){
        index += new_match->to - new_match->from;
      }
    } else {
      result = LIBLEX_MALLOC;
    }
  } while (result == LIBLEX_SUCCESS && done == 0);

  if(result != LIBLEX_SUCCESS){
    ll_foreach(matches, NULL, compare_always, eval_foreach_match_free);
    ll_clear(matches);
  }

  return result;
}
int eval_foreach_match_free(void *data, va_list args){
  free(data);
  return 0;
}