#include <cstdarg>
#include <cstdio>

#include "../config.h"

void cfg_seterr( CFG_PARSER* p, const char* fmt, ... ) {
  va_list args;
  va_start( args, fmt );
  vsnprintf( p->err, sizeof(p->err), fmt, args );
  p->iserr = 1;
  va_end( args );
}

inline U8 is_whitespace( char c ) {
  return c == ' ' || c == '\t' || c == '\n' || c == '\r';
}

inline void trim_whitespace( char* buf ) {
  if (!buf || !*buf) return;

  U32 start = 0;
  while( buf[start] && is_whitespace( buf[start] ) ) start++;

  U32 end = strlen( buf );
  while( end > start && is_whitespace( buf[end - 1] ) ) end--;

  U32 len = end - start;
  memmove( buf, buf + start, len );
  buf[len] = '\0';
}

inline void init_cfg_node( CFG_NODE* node, const char* name, CFG_NODE* parent, U8 type ) {
  node->name = name;
  node->parent = parent;
  if( parent )
    ( (CFG_SECTION*)parent )->children.push( node );
  node->type = type;
}

CFG_SECTION* cfg_section_new( const char* name, CFG_NODE* parent ) {
  CFG_SECTION* section = new CFG_SECTION;
  init_cfg_node( (CFG_NODE*)section, name, parent, CFGT_SECTION );
  return section;
}

CFG_BYTES* cfg_bytes( const char* name, CFG_NODE* parent, U8* bytes, U32 size ) {
  CFG_BYTES* cfg_bytes = new CFG_BYTES;
  init_cfg_node( (CFG_NODE*)cfg_bytes, name, parent, CFGT_BYTES );
  cfg_bytes->bytes = bytes;
  cfg_bytes->size = size;
  return cfg_bytes;
}

CFG_STR* cfg_str( const char* name, CFG_NODE* parent, const char* str, U32 len ) {
  CFG_STR* cfg_str = new CFG_STR;
  init_cfg_node( (CFG_NODE*)cfg_str, name, parent, CFGT_STR );
  cfg_str->str = (char*)malloc( len + 1 );
  strcpy( cfg_str->str, str );
  cfg_str->str[len] = '\0';
  cfg_str->len = len;
  return cfg_str;
}

CFG_INT* cfg_int( const char* name, CFG_NODE* parent, I32 value ) {
  CFG_INT* cfg_int = new CFG_INT;
  init_cfg_node( (CFG_NODE*)cfg_int, name, parent, CFGT_INT );
  cfg_int->value = value;
  return cfg_int;
}

CFG_FLOAT* cfg_float( const char* name, CFG_NODE* parent, F32 value) {
  CFG_FLOAT* cfg_float = new CFG_FLOAT;
  init_cfg_node( (CFG_NODE*)cfg_float, name, parent, CFGT_FLOAT );
  cfg_float->value = value;
  return cfg_float;
}

CFG_VEC2* cfg_vec2( const char* name, CFG_NODE* parent, VEC2 value ) {
  CFG_VEC2* cfg_vec2 = new CFG_VEC2;
  init_cfg_node( (CFG_NODE*)cfg_vec2, name, parent, CFGT_VEC2 );
  cfg_vec2->value = value;
  return cfg_vec2;
}

CFG_VEC3* cfg_vec3( const char* name, CFG_NODE* parent, VEC3 value ) {
  CFG_VEC3* cfg_vec3 = new CFG_VEC3;
  init_cfg_node( (CFG_NODE*)cfg_vec3, name, parent, CFGT_VEC3 );
  cfg_vec3->value = value;
  return cfg_vec3;
}

CFG_CLR* cfg_clr( const char* name, CFG_NODE* parent, CLR value ) {
  CFG_CLR* cfg_clr = new CFG_CLR;
  init_cfg_node( (CFG_NODE*)cfg_clr, name, parent, CFGT_CLR );
  cfg_clr->value = value;
  return cfg_clr;
}

CFG_SECTION* cfg_section( CFG_SECTION* parent, const char* name ) {
  for( I32 i = 0; i < parent->children.size; ++i ) {
    CFG_NODE* n = parent->children[i];
    if( n->type == CFGT_SECTION && strcmp( n->name, name ) == 0 )
      return (CFG_SECTION*)n;
  }

  return 0;
}

CFG_BYTES* cfg_bytes( CFG_SECTION* parent, const char* name ) {
  for( I32 i = 0; i < parent->children.size; ++i ) {
    CFG_NODE* n = parent->children[i];
    if( n->type == CFGT_BYTES && strcmp( n->name, name ) == 0 )
      return (CFG_BYTES*)n;
   }

  return 0;
}

CFG_STR* cfg_str( CFG_SECTION* parent, const char* name ) {
  for( I32 i = 0; i < parent->children.size; ++i ) {
    CFG_NODE* n = parent->children[i];
    if( n->type == CFGT_STR && strcmp( n->name, name ) == 0 )
      return (CFG_STR*)n;
   }

  return 0;
}

CFG_INT* cfg_int( CFG_SECTION* parent, const char* name ) {
  for( I32 i = 0; i < parent->children.size; ++i ) {
    CFG_NODE* n = parent->children[i];
    if( n->type == CFGT_INT && strcmp( n->name, name ) == 0 )
      return (CFG_INT*)n;
  }

  return 0;
}

CFG_FLOAT* cfg_float( CFG_SECTION* parent, const char* name ) {
   for( I32 i = 0; i < parent->children.size; ++i ) {
     CFG_NODE* n = parent->children[i];
     if( n->type == CFGT_FLOAT && strcmp( n->name, name ) == 0 )
       return (CFG_FLOAT*)n;
   }
   return 0;
}

CFG_VEC2* cfg_vec2( CFG_SECTION* parent, const char* name ) {
   for( I32 i = 0; i < parent->children.size; ++i ) {
      CFG_NODE* n = parent->children[i];
      if( n->type == CFGT_VEC2 && strcmp( n->name, name ) == 0 )
        return (CFG_VEC2*)n;
   }
   return 0;
}

CFG_VEC3* cfg_vec3( CFG_SECTION* parent, const char* name ) {
   for( I32 i = 0; i < parent->children.size; ++i ) {
     CFG_NODE* n = parent->children[i];
     if( n->type == CFGT_VEC3 && strcmp( n->name, name ) == 0 )
       return (CFG_VEC3*)n;
   }
   return 0;
}

CFG_CLR* cfg_clr( CFG_SECTION* parent, const char* name ) {
   for( I32 i = 0; i < parent->children.size; ++i ) {
      CFG_NODE* n = parent->children[i];
      if( n->type == CFGT_CLR && strcmp( n->name, name ) == 0 )
         return (CFG_CLR*)n;
   }
   return 0;
}

void parse_section( CFG_PARSER* parser, CFG_SECTION* current_section ) {
  char line[8192];
  char* token;
  char* next_token;

  while( fgets( line, sizeof(line), parser->file ) ) {
    parser->linen++;

    trim_whitespace( line );
    if( strlen( line ) == 0 )
      continue;

    char line_copy[8192];
    strcpy( line_copy, line );

    token = strtok( line_copy, " \t\r\n" );
    if( !token ) continue;

    if( strcmp( token, "{" ) == 0 ) {
      continue;
    } else if( strcmp( token, "}" ) == 0 ) {
      return;
    } else if( strcmp( token, cfg_types[CFGT_SECTION].def ) == 0 ) {
      next_token = strtok( NULL, " \t\r\n" );
      if( !next_token ) {
        cfg_seterr( parser, "missing section name at line %d", parser->linen );
        return;
      }

      char sectname[64];
      strncpy( sectname, next_token, sizeof(sectname) - 1 );
      sectname[sizeof(sectname) - 1] = '\0';
      trim_whitespace( sectname );

      CFG_SECTION* new_section = cfg_section_new( sectname, (CFG_NODE*)current_section );

      char* brace = strtok( NULL, " \t\r\n" );
      if( !brace || strcmp( brace, "{" ) != 0 ) {
        cfg_seterr( parser, "expected '{' after section name at line %d", parser->linen );
        return;
      }

      parse_section( parser, new_section );
    } else {
      char name[64];
      strncpy( name, token, sizeof(name) - 1 );
      name[sizeof(name) - 1] = '\0';
      trim_whitespace( name );

      token = strtok( NULL, "=[" );
      if( !token ) {
        cfg_seterr( parser, "invalid variable declaration at line %d", parser->linen );
        continue;
      }

      char varname[64];
      strncpy( varname, token, sizeof(varname) - 1 );
      varname[sizeof(varname) - 1] = '\0';
      trim_whitespace( varname );

      U8 found = 0;
      for( I32 i = 0; i < sizeof(cfg_types) / sizeof(CFG_TYPE); ++i ) {
        const CFG_TYPE* fn = &cfg_types[i];
        if( strcmp( name, fn->def ) == 0 ) {
          strcpy( line_copy, line );
          strtok( line_copy, " \t\r\n" );
          strtok( NULL, "=[" );

          fn->parser( parser, current_section, varname );
          found = true;
          break;
        }
      }

      if( !found ) {
        cfg_seterr( parser, "unknown type '%s' at line %d", name, parser->linen );
        return;
      }

      if( parser->iserr ) {
        dlog( "parse_section() : %s parse error:\n  - %s\n", name, parser->err );
        return;
      }
    }
  }
}

CFG_SECTION* cfg_load( const char* path ) {
  FILE* f = fopen( path, "r" );
  if( !f )
    return 0;

  CFG_PARSER p;
  memset( &p, 0, sizeof(p) );
  p.iserr = 0;
  p.file = f;
  p.linen = 0;
  p.root = cfg_section_new( "root", 0 );

  parse_section( &p, p.root );

  fclose( f );

  if( p.iserr ) {
    cfg_free( (CFG_NODE*)p.root );
    return 0;
  }

  return p.root;
}

STAT cfg_save( CFG_SECTION* root, const char* path ) {
  FILE* f = fopen( path, "w" );
  if( !f )
    return STAT_ERR;

  CFG_SERIALIZER s;
  s.tabc = 0;
  s.f = f;

  STR buf = cfg_serialize_section( &s, (CFG_NODE*)root );
  fwrite( buf, 1, buf.size, f );

  fclose( f );
  return STAT_OK;
}