/// \copyright SPDX-License-Identifier: Apache-2.0
/// \author Леонид Юрьев aka Leonid Yuriev <leo@yuriev.ru> \date 2015-2024

#include "internals.h"

struct audit_ctx {
  size_t used;
  uint8_t *const done_bitmap;
};

static int audit_dbi(void *ctx, const MDBX_txn *txn, const MDBX_val *name,
                     MDBX_db_flags_t flags, const struct MDBX_stat *stat,
                     MDBX_dbi dbi) {
  struct audit_ctx *audit_ctx = ctx;
  (void)name;
  (void)txn;
  (void)flags;
  audit_ctx->used += (size_t)stat->ms_branch_pages +
                     (size_t)stat->ms_leaf_pages +
                     (size_t)stat->ms_overflow_pages;
  if (dbi)
    audit_ctx->done_bitmap[dbi / CHAR_BIT] |= 1 << dbi % CHAR_BIT;
  return MDBX_SUCCESS;
}

static size_t audit_db_used(const tree_t *db) {
  return db ? (size_t)db->branch_pages + (size_t)db->leaf_pages +
                  (size_t)db->large_pages
            : 0;
}

__cold static int audit_ex_locked(MDBX_txn *txn, size_t retired_stored,
                                  bool dont_filter_gc) {
  const MDBX_env *const env = txn->env;
  size_t pending = 0;
  if ((txn->flags & MDBX_TXN_RDONLY) == 0)
    pending = txn->tw.loose_count + MDBX_PNL_GETSIZE(txn->tw.relist) +
              (MDBX_PNL_GETSIZE(txn->tw.retired_pages) - retired_stored);

  cursor_couple_t cx;
  int rc = cursor_init(&cx.outer, txn, FREE_DBI);
  if (unlikely(rc != MDBX_SUCCESS))
    return rc;

  size_t gc = 0;
  MDBX_val key, data;
  rc = outer_first(&cx.outer, &key, &data);
  while (rc == MDBX_SUCCESS) {
    if (!dont_filter_gc) {
      if (unlikely(key.iov_len != sizeof(txnid_t))) {
        ERROR("%s/%d: %s %u", "MDBX_CORRUPTED", MDBX_CORRUPTED,
              "invalid GC-key size", (unsigned)key.iov_len);
        return MDBX_CORRUPTED;
      }
      txnid_t id = unaligned_peek_u64(4, key.iov_base);
      if (txn->tw.gc.reclaimed) {
        for (size_t i = 1; i <= MDBX_PNL_GETSIZE(txn->tw.gc.reclaimed); ++i)
          if (id == txn->tw.gc.reclaimed[i])
            goto skip;
      } else if (id <= txn->tw.gc.last_reclaimed)
        goto skip;
    }
    gc += *(pgno_t *)data.iov_base;
  skip:
    rc = outer_next(&cx.outer, &key, &data, MDBX_NEXT);
  }
  tASSERT(txn, rc == MDBX_NOTFOUND);

  const size_t done_bitmap_size = (txn->n_dbi + CHAR_BIT - 1) / CHAR_BIT;
  if (txn->parent) {
    tASSERT(txn, txn->n_dbi == txn->parent->n_dbi &&
                     txn->n_dbi == txn->env->txn->n_dbi);
#if MDBX_ENABLE_DBI_SPARSE
    tASSERT(txn, txn->dbi_sparse == txn->parent->dbi_sparse &&
                     txn->dbi_sparse == txn->env->txn->dbi_sparse);
#endif /* MDBX_ENABLE_DBI_SPARSE */
  }

  struct audit_ctx ctx = {0, alloca(done_bitmap_size)};
  memset(ctx.done_bitmap, 0, done_bitmap_size);
  ctx.used = NUM_METAS + audit_db_used(dbi_dig(txn, FREE_DBI, nullptr)) +
             audit_db_used(dbi_dig(txn, MAIN_DBI, nullptr));

  rc = mdbx_enumerate_tables(txn, audit_dbi, &ctx);
  tASSERT(txn, rc == MDBX_SUCCESS);

  for (size_t dbi = CORE_DBS; dbi < txn->n_dbi; ++dbi) {
    if (ctx.done_bitmap[dbi / CHAR_BIT] & (1 << dbi % CHAR_BIT))
      continue;
    const tree_t *db = dbi_dig(txn, dbi, nullptr);
    if (db)
      ctx.used += audit_db_used(db);
    else if (dbi_state(txn, dbi))
      WARNING("audit %s@%" PRIaTXN
              ": unable account dbi %zd / \"%*s\", state 0x%02x",
              txn->parent ? "nested-" : "", txn->txnid, dbi,
              (int)env->kvs[dbi].name.iov_len,
              (const char *)env->kvs[dbi].name.iov_base, dbi_state(txn, dbi));
  }

  if (pending + gc + ctx.used == txn->geo.first_unallocated)
    return MDBX_SUCCESS;

  if ((txn->flags & MDBX_TXN_RDONLY) == 0)
    ERROR("audit @%" PRIaTXN ": %zu(pending) = %zu(loose) + "
          "%zu(reclaimed) + %zu(retired-pending) - %zu(retired-stored)",
          txn->txnid, pending, txn->tw.loose_count,
          MDBX_PNL_GETSIZE(txn->tw.relist),
          txn->tw.retired_pages ? MDBX_PNL_GETSIZE(txn->tw.retired_pages) : 0,
          retired_stored);
  ERROR("audit @%" PRIaTXN ": %zu(pending) + %zu"
        "(gc) + %zu(count) = %zu(total) <> %zu"
        "(allocated)",
        txn->txnid, pending, gc, ctx.used, pending + gc + ctx.used,
        (size_t)txn->geo.first_unallocated);
  return MDBX_PROBLEM;
}

__cold int audit_ex(MDBX_txn *txn, size_t retired_stored, bool dont_filter_gc) {
  MDBX_env *const env = txn->env;
  int rc = osal_fastmutex_acquire(&env->dbi_lock);
  if (likely(rc == MDBX_SUCCESS)) {
    rc = audit_ex_locked(txn, retired_stored, dont_filter_gc);
    ENSURE(txn->env, osal_fastmutex_release(&env->dbi_lock) == MDBX_SUCCESS);
  }
  return rc;
}