#ifndef VERSEVDI_CORE_H
#define VERSEVDI_CORE_H

#include <stddef.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

#define VERSE_CORE_ABI_VERSION_1 UINT32_C(1)

typedef uint32_t verse_status_t;

#define VERSE_STATUS_OK UINT32_C(0)
#define VERSE_STATUS_INVALID_ARGUMENT UINT32_C(1)
#define VERSE_STATUS_INVALID_STATE UINT32_C(2)
#define VERSE_STATUS_UNSUPPORTED_ABI UINT32_C(3)
#define VERSE_STATUS_AUTHORITY_REJECTED UINT32_C(4)
#define VERSE_STATUS_TLS UINT32_C(5)
#define VERSE_STATUS_TRANSPORT UINT32_C(6)
#define VERSE_STATUS_PROTOCOL UINT32_C(7)
#define VERSE_STATUS_EXPIRED UINT32_C(8)
#define VERSE_STATUS_QUEUE_FULL UINT32_C(9)
#define VERSE_STATUS_CANCELLED UINT32_C(10)
#define VERSE_STATUS_REENTRANT UINT32_C(11)
#define VERSE_STATUS_BUSY UINT32_C(12)
#define VERSE_STATUS_INTERNAL UINT32_C(13)

#define VERSE_STATE_CONNECTING UINT32_C(1)
#define VERSE_STATE_CONNECTED UINT32_C(2)
#define VERSE_STATE_CANCELLED UINT32_C(3)

#define VERSE_INPUT_KEYBOARD UINT32_C(1)
#define VERSE_INPUT_MOUSE_BUTTON UINT32_C(2)
#define VERSE_INPUT_RELATIVE_MOUSE UINT32_C(3)
#define VERSE_INPUT_TEXT UINT32_C(4)
#define VERSE_INPUT_CONTROLLER UINT32_C(5)
#define VERSE_INPUT_ABSOLUTE_MOUSE UINT32_C(6)
#define VERSE_INPUT_SCROLL UINT32_C(7)

typedef struct verse_core verse_core_t;

/* data may be NULL only when length is zero. The view never transfers ownership. */
typedef struct verse_bytes_view {
    const uint8_t *data;
    size_t length;
} verse_bytes_view_t;

typedef struct verse_state_event_v1 {
    uint32_t struct_size;
    uint32_t abi_version;
    uint32_t state;
    uint32_t reason;
} verse_state_event_v1_t;

typedef struct verse_error_event_v1 {
    uint32_t struct_size;
    uint32_t abi_version;
    uint32_t code;
    uint32_t retryable;
    uint32_t phase;
    uint32_t reserved;
} verse_error_event_v1_t;

typedef struct verse_stats_event_v1 {
    uint32_t struct_size;
    uint32_t abi_version;
    uint64_t dropped_callbacks;
    uint64_t dropped_media_units;
    uint64_t dropped_input_events;
} verse_stats_event_v1_t;

typedef struct verse_media_event_v1 {
    uint32_t struct_size;
    uint32_t abi_version;
    uint32_t channel;
    uint32_t sequence;
    uint64_t timestamp_ms;
    verse_bytes_view_t encoded_unit;
} verse_media_event_v1_t;

typedef struct verse_control_event_v1 {
    uint32_t struct_size;
    uint32_t abi_version;
    uint32_t kind;
    uint32_t reserved;
    verse_bytes_view_t payload;
} verse_control_event_v1_t;

/*
 * Signers run synchronously. transcript/tls_message is borrowed only for the call;
 * signature_out is exactly 64 writable bytes. Admission may return OK,
 * AUTHORITY_REJECTED, CANCELLED, or INTERNAL. TLS may return OK, TLS, CANCELLED,
 * or INTERNAL. Any other value is normalized to INTERNAL.
 */
typedef verse_status_t (*verse_sign_admission_v1_fn)(
    void *signer_context,
    verse_bytes_view_t transcript,
    uint8_t signature_out[64]);
typedef verse_status_t (*verse_sign_tls_ed25519_v1_fn)(
    void *signer_context,
    verse_bytes_view_t tls_message,
    uint8_t signature_out[64]);
/*
 * Event callbacks are serialized with one another. Each event and nested byte view
 * is borrowed only for its callback and must not be retained.
 */
typedef void (*verse_state_event_v1_fn)(
    void *context,
    const verse_state_event_v1_t *event);
typedef void (*verse_error_event_v1_fn)(
    void *context,
    const verse_error_event_v1_t *event);
typedef void (*verse_stats_event_v1_fn)(
    void *context,
    const verse_stats_event_v1_t *event);
typedef void (*verse_media_event_v1_fn)(
    void *context,
    const verse_media_event_v1_t *event);
typedef void (*verse_control_event_v1_fn)(
    void *context,
    const verse_control_event_v1_t *event);

/*
 * create copies this table. context and every non-NULL callback must remain valid
 * until destroy succeeds; BUSY does not end that lifetime.
 */
typedef struct verse_core_config_v1 {
    uint32_t struct_size;
    uint32_t abi_version;
    void *context;
    verse_sign_admission_v1_fn sign_admission;
    verse_sign_tls_ed25519_v1_fn sign_tls_ed25519;
    verse_state_event_v1_fn on_state;
    verse_error_event_v1_fn on_error;
    verse_stats_event_v1_fn on_stats;
    verse_media_event_v1_fn on_media;
    verse_control_event_v1_fn on_control;
} verse_core_config_v1_t;

typedef struct verse_connect_request_v1 {
    uint32_t struct_size;
    uint32_t abi_version;
    verse_bytes_view_t manifest_json;
    verse_bytes_view_t tunnel_credential_json;
} verse_connect_request_v1_t;

/* values are kind-specific signed fields; every unused field and flags must be zero. */
typedef struct verse_input_event_v1 {
    uint32_t struct_size;
    uint32_t abi_version;
    uint32_t kind;
    uint32_t flags;
    int32_t values[12];
} verse_input_event_v1_t;

uint32_t verse_core_abi_version(void);
/*
 * During a signer callback, every API below except verse_core_abi_version returns
 * REENTRANT for every handle. During an event callback, only cancel on that event's
 * originating handle is allowed; all other calls and cross-handle cancel return
 * REENTRANT. Connect copies both byte inputs before returning, so callers may
 * mutate or release their buffers afterward.
 */
verse_status_t verse_core_create_v1(
    const verse_core_config_v1_t *config,
    verse_core_t **out_core);
verse_status_t verse_core_connect_v1(
    verse_core_t *core,
    const verse_connect_request_v1_t *request);
verse_status_t verse_core_send_input_v1(
    verse_core_t *core,
    const verse_input_event_v1_t *event);
verse_status_t verse_core_request_idr_v1(verse_core_t *core);
/* Idempotent and nonblocking; it does not wait for an internal state lock. */
verse_status_t verse_core_cancel_v1(verse_core_t *core);
/*
 * OK suppresses all later callbacks, releases session resources, and invalidates
 * core. Calls admitted before destruction are accounted safely, but no API call
 * may begin after OK. BUSY retains core, context, and callback ownership and
 * requires a later retry.
 */
verse_status_t verse_core_destroy_v1(verse_core_t *core, uint32_t timeout_ms);

#if defined(__APPLE__) && defined(__aarch64__)
_Static_assert(sizeof(verse_bytes_view_t) == 16, "verse_bytes_view_t arm64 layout");
_Static_assert(sizeof(verse_core_config_v1_t) == 72, "verse_core_config_v1_t arm64 layout");
_Static_assert(offsetof(verse_core_config_v1_t, sign_admission) == 16, "config callback offset");
_Static_assert(sizeof(verse_connect_request_v1_t) == 40, "verse_connect_request_v1_t arm64 layout");
_Static_assert(offsetof(verse_connect_request_v1_t, manifest_json) == 8, "request view offset");
_Static_assert(sizeof(verse_input_event_v1_t) == 64, "verse_input_event_v1_t arm64 layout");
_Static_assert(sizeof(verse_state_event_v1_t) == 16, "verse_state_event_v1_t arm64 layout");
_Static_assert(sizeof(verse_error_event_v1_t) == 24, "verse_error_event_v1_t arm64 layout");
_Static_assert(sizeof(verse_stats_event_v1_t) == 32, "verse_stats_event_v1_t arm64 layout");
_Static_assert(sizeof(verse_media_event_v1_t) == 40, "verse_media_event_v1_t arm64 layout");
_Static_assert(sizeof(verse_control_event_v1_t) == 32, "verse_control_event_v1_t arm64 layout");
#endif

#ifdef __cplusplus
}
#endif

#endif