#ifndef IDENTITY_H
#define IDENTITY_H

#include "config.h"
#include <stdbool.h>
#include <stdint.h>
#include <sys/types.h>

/*
 * Identity mapping: --numeric-ids / --usermap / --groupmap / --chown.
 *
 * FastSync transmits uid/gid numerically (int32 on the wire) and, by design,
 * NEVER applies client-supplied ownership unless a user explicitly opts in with
 * an identity flag below.  This module is the controlled, opt-in,
 * privilege-gated path for applying ownership on the receiver: the wire config
 * is snapshotted once per connection via identity_set_active() and applied
 * through an fd-relative fchown() in the receiver's metadata-restore path.
 *
 * Because only numeric ids cross the wire, name-based values are resolved to
 * numbers at CLI parse time using the CLIENT (sender) machine's databases.  On
 * a shared-account source/destination this reproduces rsync's semantics; a
 * genuinely different destination database is a documented divergence (see
 * RSYNC_COMPAT.md).
 */

/* Parse one --usermap= / --groupmap= value (comma-separated FROM:TO rules,
 * first match wins) into config->usermap / config->groupmap.  is_group selects
 * the group tables and name databases.  Returns 0 on success, -1 on a
 * malformed spec or an unresolvable name (never a silent no-op). */
int identity_parse_map(Config* config, const char* value, bool is_group);

/* Parse --chown=USER:GROUP.  Supports USER:GROUP, USER (owner only), :GROUP
 * (group only), '*' (current/root as appropriate) and numeric ids.  Returns 0
 * on success, -1 on a malformed spec / unresolvable name. */
int identity_parse_chown(Config* config, const char* value);

/* Receiver-side snapshot of the negotiated identity config.  The server calls
 * identity_set_active() once per connection (before any file write) using the
 * config received over the wire; the snapshot is a deep copy so the caller may
 * free its Config immediately.  identity_clear_active() releases it. */
void identity_set_active(const Config* config);
void identity_clear_active(void);

/* True when any ownership-affecting identity option is present in the active
 * snapshot.  Ownership stays OFF ("do not apply") for every transfer that
 * requests none of them, preserving FastSync's existing behavior. */
bool identity_active_enabled(void);

/* Apply the negotiated ownership to an already-written file descriptor.
 * source_uid/source_gid are the transmitted numeric ids.  Resolution order:
 * a matching usermap/groupmap rule, then --chown, then --numeric-ids (raw),
 * then a best-effort name lookup on the receiver's own databases (skipped when
 * the transmitted id has no name on this system).  Only calls fchown() when the
 * result differs from the current value; EPERM/EACCES are logged and ignored,
 * never fatal (rsync parity: the transfer must not abort). */
void identity_apply_ownership(int fd, int32_t source_uid, int32_t source_gid);

/* Receiver-side wire validation of the resolved identity fields. */
bool identity_wire_valid(const Config* config);

#endif