global Intern_String keyword_s64;
global Intern_String keyword_u64;
global Intern_String keyword_void;
global Intern_String keyword_sizeu;
global Intern_String keyword_sizeof;

global Intern_String keyword_enum;
global Intern_String keyword_typedef;
global Intern_String keyword_struct;
global Intern_String keyword_union;
global Intern_String keyword_function;
global Intern_String keyword_global;

function void
parser_init(Parser *p){
  p->interns_count = 4096;
  p->interns = arena_push_array(&p->intern_table_arena, Intern_String, p->interns_count);
  memory_zero(p->interns, sizeof(Intern_String)*p->interns_count);
  
  p->symbols_count = 4096;
  p->symbols = arena_push_array(&p->intern_table_arena, Intern_String, p->symbols_count);
  memory_zero(p->symbols, sizeof(Intern_String)*p->symbols_count);
  
  keyword_s64 = intern_string(p, lit("S64"));
  keyword_u64 = intern_string(p, lit("U64"));
  keyword_void = intern_string(p, lit("void"));
  keyword_sizeu = intern_string(p, lit("SizeU"));
  keyword_sizeof = intern_string(p, lit("sizeof"));
  keyword_struct = intern_string(p, lit("struct"));
  keyword_enum = intern_string(p, lit("enum"));
  keyword_typedef = intern_string(p, lit("typedef"));
  keyword_union = intern_string(p, lit("union"));
  keyword_function = intern_string(p, lit("function"));
  keyword_global = intern_string(p, lit("global"));
  p->first_keyword = keyword_s64.s.str;
  p->last_keyword = keyword_global.s.str;
  
  type_insert(p, type_s64, keyword_s64);
  type_insert(p, type_u64, keyword_u64);
  type_insert(p, type_sizeu, keyword_sizeu);
  type_insert(p, type_void, keyword_void);
}

function B32
intern_is_keyword(Parser *p, Intern_String intern){
  if(intern.s.str >= p->first_keyword && intern.s.str <= p->last_keyword)
    return true;
  return false;
}

function void
parser_push_error(Parser *p, Token *token, char *str, ...){
  String string;
  {
    va_list args1, args2;
    va_start(args1, str);
    va_copy(args2, args1);
    string.len = vsnprintf(0, 0, str, args2);
    va_end(args2);
    
    string.str = arena_push_size(&p->main_arena, string.len + 1);
    vsnprintf((char*)string.str, string.len + 1, str, args1);
    va_end(args1);
  }
  
  Parser_Error *error = arena_push_struct(&p->main_arena, Parser_Error);
  error->message = string;
  error->next = 0;
  error->token = token;
  SLLQueuePush(p->first_error, p->last_error, error);
}

//-----------------------------------------------------------------------------
// 
//-----------------------------------------------------------------------------
typedef struct Table_Index{
  U64 hash;
  U64 index;
  U64 iter;
  U64 max_size;
}Table_Index;

function Table_Index
table_index_from_hash(U64 hash, U64 max_size){
  Table_Index result = {0};
  result.hash = hash;
  result.index = result.hash % max_size;
  result.iter = result.index;
  result.max_size = max_size;
  return result;
}

function Table_Index
table_index_from_string(String string, U64 max_size){
  U64 hash = hash_fnv(string);
  Table_Index result = table_index_from_hash(hash, max_size);
  return result;
}

function B32
table_index_advance(Table_Index *index){
  index->iter = wrap_around_pow2(index->iter + 1, index->max_size);
  B32 result = index->iter == index->index;
  return result;
}

function Intern_String
intern_string(Parser *p, String string){
  Intern_String result = {};
  Table_Index index = table_index_from_string(string, p->interns_count);
  for(;;){
    Intern_String *intern = p->interns + index.iter;
    if(intern->s.str == 0){
      result.s = arena_push_string_copy(&p->main_arena, string);
      *intern = result;
      break;
    }
    else if(string_compare(intern->s, string)){
      result = *intern;
      break;
    }
    
    if (table_index_advance(&index)) 
      break;
    
  }
  
  return result;
}

function void
intern_tokens(Parser *p){
  for(S64 i = 0; i < p->tokens.len; i++){
    Token *t = p->tokens.tokens + i;
    if(t->kind == TK_Identifier){
      t->intern_val = intern_string(p, t->string);
      if(intern_is_keyword(p, t->intern_val)){
        t->kind = TK_Keyword;
      }
    }
  }
}

function void
symbol_insert(Parser *p, Symbol symbol){
  String string = symbol.string.s;
  Table_Index index = table_index_from_string(string, p->symbols_count);
  
  for(;;){
    Symbol *slot = p->symbols + index.iter;
    if(slot->string.s.str == 0){
      *slot = symbol;
      break;
    }
    else if(slot->string.s.str == string.str){
      invalid_codepath;
      break;
    }
    
    if (table_index_advance(&index)) 
      break;
    
  }
}

function Symbol *
symbol_get(Parser *p, Intern_String string){
  Table_Index index = table_index_from_string(string.s, p->symbols_count);
  for(;;){
    Symbol *slot = p->symbols + index.iter;
    if(slot->string.s.str == string.s.str){
      return slot;
    }
    
    if (table_index_advance(&index))
      break;
    
  }
  return 0;
}

function void
type_insert(Parser *p, Type *type, Intern_String string){
  Symbol symbol = {.kind=SK_Type, .string=string, .type=type};
  symbol_insert(p, symbol);
}

function Type *
type_get(Parser *p, Token *token){
  Type *result = 0;
  if(token->kind == TK_Identifier || token->kind == TK_Keyword){
    Symbol *symbol = symbol_get(p, token->intern_val);
    if(symbol){
      if(symbol->kind == SK_Type){
        result = symbol->type;
      }
      else {
        parser_push_error(p, token, "Symbol is not a type");
      }
    }
    else{
      parser_push_error(p, token, "Undefined type");
    }
  }
  else {
    parser_push_error(p, token, "Trying to lookup a type with token of wrong kind");
  }
  
  if(!result){
    result = type_undefined;
  }
  
  return result;
}