#include <common/fzl_extern.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <vm/fzl_vm_reader.h>
#include <vm/internals/reader.h>

char reader_err[512];

fzl_vm_reader_t *fzl_vm_mkreader(char *filepath)
{
  if (!filepath)
  {
    snprintf(reader_err, sizeof(reader_err),
             "init error - filepath is not defined");
    return NULL;
  }

  fzl_vm_reader_t *reader = malloc(sizeof(fzl_vm_reader_t));
  if (!reader)
  {
    snprintf(reader_err, sizeof(reader_err),
             "init error - couldn't allocate memory for reader");
    return NULL;
  }

  memset(reader, 0, sizeof(fzl_vm_reader_t));
  reader->filepath = filepath;

  return reader;
}

void wr_validation_err(char *section)
{
  if (internal_error[0])
    snprintf(reader_err, sizeof(reader_err), "init error - section '%s': %s",
             section, internal_error);
  else
    snprintf(reader_err, sizeof(reader_err),
             "init error - section '%s' is not valid", section);
}

bool fzl_vm_read(fzl_vm_reader_t *reader)
{
  if (!reader)
  {
    snprintf(reader_err, sizeof(reader_err),
             "init error - reader is not provided");
    return false;
  }

  FILE *fd = fopen(reader->filepath, "rb");
  if (!fd)
  {
    snprintf(reader_err, sizeof(reader_err),
             "init error - couldn't open file '%s'", reader->filepath);
    return false;
  }

  bool result = vm_rd_header(reader, fd);
  if (!result)
  {
    wr_validation_err("header");
    fclose(fd);
    return false;
  }

  result = vm_rd_sections_sz(reader, fd);
  if (!result)
  {
    wr_validation_err("sizes");
    fclose(fd);
    return false;
  }

  result = vm_rd_consts(reader, fd);
  if (!result)
  {
    wr_validation_err("constants table");
    fclose(fd);
    return false;
  }

  result = vm_rd_extern_libs(reader, fd);
  if (!result)
  {
    wr_validation_err("extern libs");
    fclose(fd);
    return false;
  }

  result = vm_rd_extern_types(reader, fd);
  if (!result)
  {
    wr_validation_err("extern types");
    fclose(fd);
    return false;
  }

  result = vm_rd_extern_fns(reader, fd);
  if (!result)
  {
    wr_validation_err("extern functions");
    fclose(fd);
    return false;
  }

  result = vm_rd_ops(reader, fd);
  if (!result)
  {
    wr_validation_err("opcodes");
    fclose(fd);
    return false;
  }

  fclose(fd);

  return true;
}

char *fzl_vm_getreadererror() { return reader_err; }

void fzl_vm_freereader(fzl_vm_reader_t *reader)
{
  if (!reader)
    return;

  if (reader->consts)
  {
    for (uint16_t i = 0; i < reader->consts_count; i++)
      if (reader->consts[i].as.s.value)
        free((void *)reader->consts[i].as.s.value);

    free(reader->consts);
  }

  if (reader->extern_libs)
  {
    for (uint16_t i = 0; i < reader->extern_libs_count; i++)
      free(reader->extern_libs[i]);

    free(reader->extern_libs);
  }

  if (reader->extern_types)
  {
    for (uint16_t i = 0; i < reader->extern_types_count; i++)
    {
      free(reader->extern_types[i].name);

      if (reader->extern_types[i].kind == FZL_EXTERN_KIND_STRUCT)
      {
        fzl_extern_struct_field_t *fields =
            reader->extern_types[i].structure.fields;
        for (uint16_t j = 0; j < reader->extern_types[i].structure.fields_count;
             j++)
        {
          if (fields[j].name)
            free(fields[j].name);
        }

        free(fields);
      }
    }

    free(reader->extern_types);
  }

  if (reader->extern_fns)
  {
    for (uint16_t i = 0; i < reader->extern_fns_count; i++)
    {
      fzl_extern_fn_t *fn = &reader->extern_fns[i];
      if (fn->used_name)
        free(fn->used_name);

      if (fn->symbol_name)
        free(fn->symbol_name);

      if (fn->args_count > 0)
        free(fn->args);
    }

    free(reader->extern_fns);
  }

  if (reader->ops)
    free(reader->ops);

  free(reader);
}