#include <common/fzl_builtins.h>
#include <common/fzl_extern.h>
#include <common/fzl_opcodes.h>
#include <common/fzl_types.h>
#include <compiler/fzl_parser.h>
#include <compiler/internals/gen.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

// Call definition
// NOTE: split by call type (builtin/declared/extern)
gen_res_t gen_call(fzl_gen_t *gen, fzl_node_t *node)
{
  if (!gen || !node)
    return gen_error;

  // `printline(x)` builtin function
  if (strcmp(node->token->value, "printline") == 0)
  {
    if (node->call.args_count > 0)
      for (size_t i = 0; i < node->call.args_count; i++)
        if (gen_common(gen, node->call.args[i]).error)
          return gen_error;

    gen_op(gen, FZL_OPCODE_CALL_BUILTIN);
    gen_word(gen, FZL_BUILTIN_PRINTLINE);
    if (node->call.args_count < 1)
      return gen_error;

    return gen_ok_null;
  }

  // `exit(x?)` builtin function
  if (strcmp(node->token->value, "exit") == 0)
  {
    if (node->call.args_count > 0)
    {
      for (size_t i = 0; i < node->call.args_count; i++)
        if (gen_common(gen, node->call.args[i]).error)
          return gen_error;

      gen_op(gen, FZL_OPCODE_CALL_BUILTIN);
      gen_word(gen, FZL_BUILTIN_EXIT);
      if (node->call.args_count < 1)
        return gen_error;
    }

    return gen_ok_null;
  }

  if (node->call.callee->type == FZL_NODETYPE_IDENTIFIER)
  {
    if (node->call.args_count > 0)
      for (size_t i = 0; i < node->call.args_count; i++)
        if (gen_common(gen, node->call.args[i]).error)
          return gen_error;

    char *name = (char *)node->token->value;
    fzl_sym_t sym;
    bool found = gen_resolve_name(gen, name, &sym);
    if (!found)
      return gen_error;

    if (sym.node->type == FZL_NODETYPE_EXTERN_FN)
    {
      size_t fn_n         = 0;
      fzl_extern_fn_t *fn = NULL;
      for (size_t i = 0; i < gen->extern_fns_count; i++)
      {
        if (strcmp(gen->extern_fns[i].used_name, name) == 0)
        {
          fn   = &gen->extern_fns[i];
          fn_n = i;
          break;
        }
      }

      if (!fn)
        return gen_error;

      fzl_type_t rettype;
      char *rettypecn = NULL;

      if (!fn->has_return)
      {
        rettype = FZL_TYPE_NULL;
      }
      else if (fn->ret_type.is_primitive)
      {
        rettype = fn->ret_type.primitive;
      }
      else
      {
        fzl_extern_type_t *type = &gen->extern_types[fn->ret_type.type_slot];
        switch (type->kind)
        {
          case FZL_EXTERN_KIND_REF:
            rettype   = FZL_TYPE_HANDLE;
            rettypecn = type->name;
            break;

          case FZL_EXTERN_KIND_STRUCT:
            rettype   = FZL_TYPE_STRUCT;
            rettypecn = type->name;
            break;

          case FZL_EXTERN_KIND_HANDLE:
            rettype   = FZL_TYPE_HANDLE;
            rettypecn = type->name;
            break;

          case FZL_EXTERN_KIND_ALIAS:
            if (type->alias_target.is_primitive)
            {
              rettype = type->alias_target.primitive;
            }
            else
            {
              fzl_extern_type_t *aliased =
                  &gen->extern_types[type->alias_target.type_slot];
              switch (aliased->kind)
              {
                case FZL_EXTERN_KIND_ALIAS:
                  return gen_error;

                case FZL_EXTERN_KIND_HANDLE:
                  rettype   = FZL_TYPE_HANDLE;
                  rettypecn = aliased->name;
                  break;

                case FZL_EXTERN_KIND_STRUCT:
                  rettype   = FZL_TYPE_STRUCT;
                  rettypecn = aliased->name;
                  break;

                case FZL_EXTERN_KIND_REF:
                  rettype   = FZL_TYPE_HANDLE;
                  rettypecn = aliased->name;
                  break;

                default:
                  return gen_error;
              }
            }
            break;

          default:
            return gen_error;
        }
      }

      gen_op(gen, FZL_OPCODE_CALL_EXTERN);
      gen_word(gen, fn_n);

      return (gen_res_t){
          .error = false, .type = rettype, .classname = rettypecn};
    }
    else
    {
      if (!sym.ip)
        return gen_error;

      gen_op(gen, FZL_OPCODE_CALL);
      gen_word(gen, sym.ip);

      return (gen_res_t){
          .error = false, .type = sym.type, .classname = sym.classname};
    }
  }

  if (node->call.callee->type == FZL_NODETYPE_FIELD)
  {
    fzl_node_t *parent_node = node->call.callee->memb.parent;
    fzl_node_t *method_node = node->call.callee->memb.field;

    gen_res_t parent_res = gen_common(gen, parent_node);
    if (parent_res.error)
      return gen_error;

    if (parent_res.type != FZL_TYPE_OBJECT || !parent_res.classname)
      return gen_error;

    char *classname   = parent_res.classname;
    bool class_exists = false;
    for (size_t i = 0; i < gen->classes_count; i++)
    {
      if (strcmp(classname, gen->classes[i]->name) == 0)
      {
        class_exists = true;
        break;
      }
    }

    if (!class_exists)
      return gen_error;

    size_t classlen  = strlen(classname);
    size_t fnlen     = strlen(method_node->token->value);
    char *methodname = malloc(classlen + fnlen + 2);
    strcpy(methodname, classname);
    strcpy((methodname + classlen + 1), method_node->token->value);
    methodname[classlen]             = '_';
    methodname[classlen + fnlen + 1] = 0;

    fzl_sym_t fn_sym;
    bool found_method = false;
    for (ssize_t i = gen->syms_top - 1; i >= 0; i--)
      if ((found_method = fzl_symt_get(gen->syms[i], methodname, &fn_sym)))
        break;

    free(methodname);
    if (!found_method)
      return gen_error;

    if (node->call.args_count > 0)
      for (size_t i = 0; i < node->call.args_count; i++)
        if (gen_common(gen, node->call.args[i]).error)
          return gen_error;

    gen_op(gen, FZL_OPCODE_CALL);
    gen_word(gen, fn_sym.ip);

    return (gen_res_t){
        .error = false, .type = fn_sym.type, .classname = fn_sym.classname};
  }

  return gen_error;
}