#ifndef PURE_STORE_H
#define PURE_STORE_H
#include "flow.h"
#include "result.h"
#include <stdint.h>

#define PURE_OBJECT_LIMIT ((2u * 6u + 32u) * 32768u + 8192u)
/* A document (what a host carries whole, as an HTTP body) is at most
 * PURE_OBJECT_LIMIT bytes. A value the runtime owns (an app's list or text
 * state: a key starting with '.', or a draft without a key) may grow to
 * PURE_STATE_LIMIT: a table of a million rows is one such value. */
#define PURE_STATE_LIMIT (UINT64_C(1) << 30)
typedef struct {
    void *mapping;
    size_t mapped_size, object_size;
    PureSpan body;
    int64_t revision;
} PureStoredView;

PureResult pure_store_init(const char *path);
PureResult pure_store_get(const char *path, const char *key, size_t available,
                          PureStoredView *out);
PureResult pure_store_get_range(const char *path, const char *key, size_t offset,
                                size_t length, size_t available, PureStoredView *out);
/* Inspect once: guards and mapping refer to the same immutable file version.
 * minimum preserves bounds checks from eliminated intermediate views.
 * whole selects the suffix starting at offset; otherwise length is exact. */
PureResult pure_store_select(const char *path, const char *key, size_t offset,
                            size_t length, bool whole, size_t minimum,
                            size_t available, PureStoredView *out);
void pure_store_release(PureStoredView *);
PureResult pure_store_put(const char *path, const char *key, int64_t expected,
                          PureSpan body, int64_t *revision);
/* Atomic byte replacement: retain [0,offset), insert bytes, retain suffix after
 * remove bytes. Check the expected revision and bounds under the same writer
 * lock. expected=0 permits creating an empty base (offset=remove=0).
 * Retained bytes use bounded scratch space or a selected platform file copy;
 * never assembles a whole new object in application memory. The immutable
 * file is still rewritten. max_size is the final-body policy from the
 * prepared app and is checked with the current size under the writer lock. */
PureResult pure_store_splice(const char *path, const char *key, int64_t expected,
                             size_t offset, size_t remove, PureSpan insert,
                             size_t max_size, int64_t *revision);

/* Visit each stored key once; the order is store-defined. Returning false
 * from visit stops early. key is valid only during the call. Hosts that
 * browse documents use this instead of reading a store's file layout. */
PureResult pure_store_keys(const char *path, bool (*visit)(void *, const char *key),
                           void *context);

/* Fault hooks exist only in the separately built unit-test binary. */
typedef enum {
    PURE_AFTER_HEADER, PURE_BEFORE_FILE_SYNC, PURE_BEFORE_RENAME, PURE_BEFORE_DIR_SYNC,
    PURE_COPY_RANGE_UNSUPPORTED_AFTER_PARTIAL
} PureStoreStage;
#ifdef PURE_STORE_TEST
int pure_store_test_fault(PureStoreStage stage);
#endif
#endif