#include <compiler/fzl_parser.h>
#include <compiler/internals/parser.h>
#include <stdio.h>
#include <stdlib.h>

// Functions parsing
fzl_node_t *pa_function(fzl_parser_t *parser)
{
  if (!parser)
    return NULL;

  fzl_token_t *fn = consume(parser);
  if (!fn || fn->type != FZL_TOKTYPE_FUNCTION)
  {
    snprintf(plast_err, sizeof(plast_err),
             "'%s': expected keyword 'fn' at %ld:%ld", last_known_tok->filename,
             last_known_tok->ln, last_known_tok->cn);
    return NULL;
  }

  fzl_token_t *name = consume(parser);
  if (!name || name->type != FZL_TOKTYPE_NAME)
  {
    snprintf(plast_err, sizeof(plast_err),
             "'%s': expected function name at %ld:%ld",
             last_known_tok->filename, last_known_tok->ln, last_known_tok->cn);
    return NULL;
  }

  fzl_token_t *lpar = consume(parser);
  if (!lpar || lpar->type != FZL_TOKTYPE_LPAREN)
  {
    snprintf(plast_err, sizeof(plast_err), "'%s': expected '(' at %ld:%ld",
             last_known_tok->filename, last_known_tok->ln, last_known_tok->cn);
    return NULL;
  }

  size_t remainder  = 1;
  size_t count      = 0;
  fzl_node_t **args = malloc(remainder * sizeof(fzl_node_t *));

  while (peek(parser) && !is(parser, FZL_TOKTYPE_RPAREN))
  {
    fzl_node_t *arg = pa_expression(parser);
    if (!arg)
      return NULL;

    if (remainder <= count)
    {
      remainder *= 2;
      args = realloc(args, remainder * sizeof(fzl_node_t *));
    }

    args[count++] = arg;

    if (is(parser, FZL_TOKTYPE_COMMA))
      consume(parser);
  }

  fzl_token_t *rpar = consume(parser);
  if (!rpar || rpar->type != FZL_TOKTYPE_RPAREN)
  {
    free(args);
    snprintf(plast_err, sizeof(plast_err),
             "'%s': expected ')' after argument list at %ld:%ld",
             last_known_tok->filename, last_known_tok->ln, last_known_tok->cn);
    return NULL;
  }

  fzl_token_t *type = NULL;
  if (is(parser, FZL_TOKTYPE_TYPE) || is(parser, FZL_TOKTYPE_NAME))
    type = consume(parser);

  if (!type)
    type = &null_tok;

  if (!is(parser, FZL_TOKTYPE_LBRACE))
  {
    free(args);
    snprintf(plast_err, sizeof(plast_err),
             "'%s': expected '{' after function declaration at %ld:%ld",
             last_known_tok->filename, last_known_tok->ln, last_known_tok->cn);
    return NULL;
  }

  fzl_node_t *body = pa_statement(parser);
  if (!body)
  {
    free(args);
    return NULL;
  }

  fzl_node_t *node    = fzl_mknode(FZL_NODETYPE_FUNCTION, name);
  node->fn.args       = args;
  node->fn.args_count = count;
  node->fn.body       = body;
  node->fn.name       = name;
  node->fn.type       = type;

  return node;
}