/*
 * chat_core_priv.h — внутренний заголовок для под-модулей chat_core
 *
 * Предоставляет доступ к глобальному состоянию g_cc и общим хелперам.
 * Не включать извне chat/ — только для chat_core*.c.
 */

#ifndef CHAT_CORE_PRIV_H
#define CHAT_CORE_PRIV_H

#include "chat_core.h"

#include "db_sync.h"
#include "../../lib/debug_config.h"

#include <sqlite3.h>
#include <string.h>
#include <stdio.h>
#include <stdint.h>

#define CC_ID "chat_core"

/* ── Base64 encode/decode (URL-safe, used for msg "d" field prefix) ── */

static const char B64_ALPHABET[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";

static inline int b64_decode_char(char c) {
    if (c >= 'A' && c <= 'Z') return c - 'A';
    if (c >= 'a' && c <= 'z') return c - 'a' + 26;
    if (c >= '0' && c <= '9') return c - '0' + 52;
    if (c == '-') return 62;
    if (c == '_') return 63;
    return -1;
}

static inline size_t b64_encode(const uint8_t* src, size_t src_len, char* dst, size_t dst_cap) {
    size_t out = 0;
    for (size_t i = 0; i < src_len; i += 3) {
        if (out + 4 > dst_cap) break;
        uint32_t v = (uint32_t)src[i] << 16;
        if (i + 1 < src_len) v |= (uint32_t)src[i + 1] << 8;
        if (i + 2 < src_len) v |= (uint32_t)src[i + 2];
        dst[out++] = B64_ALPHABET[(v >> 18) & 0x3F];
        dst[out++] = B64_ALPHABET[(v >> 12) & 0x3F];
        dst[out++] = (i + 1 < src_len) ? B64_ALPHABET[(v >> 6) & 0x3F] : '=';
        dst[out++] = (i + 2 < src_len) ? B64_ALPHABET[v & 0x3F] : '=';
    }
    return out;
}

static inline size_t b64_decode(const char* src, size_t src_len, uint8_t* dst, size_t dst_cap) {
    size_t out = 0;
    int vals[4]; size_t vi = 0;
    for (size_t i = 0; i < src_len && out < dst_cap; i++) {
        if (src[i] == '=') break;
        int v = b64_decode_char(src[i]);
        if (v < 0) continue;
        vals[vi++] = v;
        if (vi == 4) {
            dst[out++] = (uint8_t)((vals[0] << 2) | (vals[1] >> 4));
            if (out < dst_cap) dst[out++] = (uint8_t)((vals[1] << 4) | (vals[2] >> 2));
            if (out < dst_cap)
                dst[out++] = (uint8_t)((vals[2] << 6) | vals[3]);
            vi = 0;
        }
    }
    if (vi == 3 && out < dst_cap) {
        dst[out++] = (uint8_t)((vals[0] << 2) | (vals[1] >> 4));
        if (out < dst_cap) dst[out++] = (uint8_t)((vals[1] << 4) | (vals[2] >> 2));
    } else if (vi == 2 && out < dst_cap) {
        dst[out++] = (uint8_t)((vals[0] << 2) | (vals[1] >> 4));
    }
    return out;
}

/* ── Глобальное состояние (определено в chat_core.c) ── */

struct ms_props_cbk;    /* member_sync.c */
struct ms_apply_cbk;    /* member_sync.c */

struct chat_core_ctx {
    struct UTUN_INSTANCE* inst;
    sqlite3*              db;
    char                  db_path[512];
    uint8_t               shared_db;
    uint64_t              my_node_id;
    uint8_t       initialized;
    /* per-instance sub-module state (was file-scope statics) */
    struct ms_props_cbk* props_cbks;   /* was member_sync.c g_props_cbks */
    struct ms_apply_cbk* apply_cbks;   /* was member_sync.c g_apply_cbks */
    uint64_t              media_cache_bytes;   /* was chat_msg.c g_media_cache_bytes */
    void*                 media_backfill_timer;/* was chat_msg.c g_media_startup_backfill_timer */
    int                   media_backfill_ran;  /* was chat_msg.c g_media_startup_backfill_ran */
    struct UTUN_INSTANCE* media_backfill_inst; /* was chat_msg.c g_media_startup_backfill_inst */
    void*                 media_channel_backfill_timer; /* debounce per-channel докачки */
    char                  media_channel_backfill[16][64]; /* pending ch_id */
    int                   media_channel_backfill_pending;
};

/* Per-instance chat context. inst->chat_core обязателен после chat_core_init. */
#define CC(inst) ((inst)->chat_core)

/* ── Хелперы ── */

void sanitize_ch_id(const char* ch_id, char* out, size_t out_sz);
void msg_table_name(const char* ch_id, char* buf, size_t sz);
void peers_table_name(const char* ch_id, char* buf, size_t sz);

/* ── db_sync registry (chat_core.c) ── */

struct DB_SYNC_INSTANCE* si_find(struct UTUN_INSTANCE* inst, const char* ch_id);
void si_register(struct UTUN_INSTANCE* inst, struct DB_SYNC_INSTANCE* si, const char* ch_id);

/* ── db_sync callback (chat_msg.c) ── */

struct msg_insert_arg { struct UTUN_INSTANCE* inst; char ch_id[64]; };
void on_msg_inserted(struct DB_SYNC_INSTANCE* si, uint64_t record_ts, const char* data, size_t len, uint64_t author, int initial_sync, void* arg);

/* ── применить настройку group_autoconnect ко всем CHAT-группам (chat_channel.c) ── */

void chat_core_apply_group_autoconnect(struct UTUN_INSTANCE* inst);

#endif /* CHAT_CORE_PRIV_H */