#include <malloc.h>
#include <string.h>

#include "parser.h"

static void libretrodb_parser_match_any(pr_state_t* parser)
{
   switch (lx_next( &parser->lexer))
   {
      case LX_UNTERMINATED_STRING:
         longjmp( parser->env, PR_UNTERMINATED_STRING );
         break;
      case LX_INVALID_CHARACTER:
         longjmp( parser->env, PR_INVALID_CHARACTER );
         break;
   }
}

static void libretrodb_parser_match( pr_state_t* parser, int token )
{
   if (parser->lexer.token != token)
      longjmp( parser->env, PR_UNEXPECTED_TOKEN );

   libretrodb_parser_match_any( parser );
}

static void libretrodb_parser_match_tag( pr_state_t* parser, const char* tag )
{
  if ( parser->lexer.token != LX_TAG || strncmp( parser->lexer.lexeme.str, tag, strlen( tag ) ) )
    longjmp( parser->env, PR_UNEXPECTED_TOKEN );
  
  libretrodb_parser_match_any( parser );
}

static int libretrodb_parser_cmp_keys( const pr_key_t* key1, const pr_key_t* key2 )
{
   if ( !key1 && !key2 )
      return 1;

   if ( ( key1 && !key2 ) || ( !key1 && key2 ) )
      return 0;

   if ( key1->key.len != key2->key.len || strncmp( key1->key.str, key2->key.str, key1->key.len ) )
      return 0;

   return libretrodb_parser_cmp_keys( key1->prev, key2->prev );
}

static pr_pair_t* libretrodb_parser_find_key( pr_node_t* node, const pr_key_t* key )
{
  int i;
  
  for ( i = 0; i < node->count; i++ )
  {
    const pr_key_t* other = &node->pairs[ i ].key;
    
    if (libretrodb_parser_cmp_keys(key, other))
      return node->pairs + i;
  }
  
  return node->pairs + node->count++;
}

static void parse_value( pr_state_t* parser, const pr_key_t* key, pr_node_t* node )
{
  pr_pair_t* pair = libretrodb_parser_find_key( node, key );
  int token = parser->lexer.token;
  
  pair->key = *key;
  pair->value = parser->lexer.lexeme;
  
  if ( token == LX_STRING || token == LX_NUMBER || token == LX_VERSION || token == LX_TAG )
    libretrodb_parser_match_any( parser );
  else
    longjmp( parser->env, PR_UNEXPECTED_TOKEN );
}

static void libretrodb_parse_map( pr_state_t* parser, const pr_key_t* prev, int skip )
{
   pr_node_t  dummy;
   pr_node_t* node;
   pr_key_t   key;

   if ( skip )
   {
      dummy.count = 0;
      node = &dummy;
   }
   else
      node = parser->node;

   libretrodb_parser_match( parser, LX_LPAREN );

   while ( parser->lexer.token != LX_RPAREN )
   {
      key.key = parser->lexer.lexeme;
      key.prev = prev;
      libretrodb_parser_match( parser, LX_TAG );

      if ( parser->lexer.token == LX_LPAREN )
         libretrodb_parse_map( parser, &key, skip );
      else
         parse_value( parser, &key, node );
   }

   libretrodb_parser_match_any( parser );
}

static void libretrodb_parser_parse_clrmamepro( pr_state_t* parser )
{
  static const pr_key_t clrmamepro = { { "clrmamepro", 10 }, NULL };
  
  libretrodb_parser_match_tag( parser, clrmamepro.key.str );
  libretrodb_parse_map( parser, &clrmamepro, 1 );
}

static void libretrodb_parser_parse_game( pr_state_t* parser )
{
   static const pr_key_t game = { { "game", 4 }, NULL };

   libretrodb_parser_match_tag( parser, game.key.str );

   pr_node_t* node = (pr_node_t*)malloc( sizeof( pr_node_t ) );

   if ( node == NULL )
      longjmp( parser->env, PR_OUT_OF_MEMORY );

   node->count = 0;
   parser->node = node;
   *parser->prev = node;
   parser->prev = &node->next;
   libretrodb_parse_map( parser, NULL, 0 );
}

void pr_new( pr_state_t* parser, const char* source, unsigned srclen )
{
  lx_new( &parser->lexer, source, srclen );
  parser->prev = &parser->first;
}

int pr_parse( pr_state_t* parser )
{
   int res;

   if ( ( res = setjmp( parser->env ) ) == 0 )
   {
      libretrodb_parser_match_any( parser );
      libretrodb_parser_parse_clrmamepro( parser );

      while ( parser->lexer.token != LX_EOF )
         libretrodb_parser_parse_game( parser );
   }

   *parser->prev = NULL;
   return res;
}