/**
 ******************************************************************************
 * @file    offlog.c
 * @author  wfq
 * @version V1.0
 * @date    2026-08-04
 * @brief   DBN 脱机事件日志 — W25Q32 环形实现
 *
 *  依赖: storage.c (SPI_Flash_*), cmcng.h (mstick), net_srv.c (dev_time_now)
 *  所有写操作在主循环上下文调用 (不在中断), SPI 擦除 ~45ms 阻塞可接受。
 ******************************************************************************
 */

#include "offlog.h"
#include "storage.h"
#include "cmcng.h"
#include "net_srv.h"
#include <string.h>

/* 编译期断言: 记录必须是 32B (定长环形索引依赖, 踩过 36B padding 的坑) */
typedef char offlog_evt_size_must_be_32[(sizeof(OfflogEvt) == 32) ? 1 : -1];
typedef char offlog_head_size_must_be_32[(sizeof(OfflogHead) == 32) ? 1 : -1];

/*===========================================================================
 * 内部状态
 *===========================================================================*/
static uint32_t _wr_off;        /* 下一条记录写入的绝对地址              */
static uint16_t _wr_sector;     /* 当前写扇区号 (区内 1..63)             */
static uint32_t _wr_seq;        /* 下一条记录的全局 seq                  */
static uint16_t _boot_seq;      /* 当前 boot 序号                        */
static uint32_t _count;         /* 有效记录数 (0..max_records)           */
static uint8_t  _ready;         /* init 完成标志                         */

/*===========================================================================
 * 运行时分区表 (ROADMAP 2026-08-12: 上电读 JEDEC ID 决定事件区容量)
 *===========================================================================*/
OfflogPart g_offlog_part = {
    OFFLOG_CHIP_W25Q32,        /* 默认 */
    0x80000UL,                 /* 512KB */
    127,                       /* (512KB/4096) - 1 头扇区 */
    16256,                     /* 127 * 128 */
};

/* 读 JEDEC ID → 填分区表。未知芯片按 W25Q32 兜底 (与 storage_init 打印对照) */
static void offlog_part_detect(void)
{
    uint8_t  dev  = SPI_Flash_ReadJEDEC_ID();
    uint32_t size = 0x80000UL;
    uint8_t  chip = OFFLOG_CHIP_W25Q32;

    switch (dev) {
        case OFFLOG_CHIP_W25Q32:  size = 0x80000UL;  break;  /* 512KB  */
        case OFFLOG_CHIP_W25Q64:  size = 0x100000UL; break;  /* 1MB    */
        case OFFLOG_CHIP_W25Q128: size = 0x200000UL; break;  /* 2MB    */
        case OFFLOG_CHIP_W25Q256: size = 0x400000UL; break;  /* 4MB    */
        default:                  chip = OFFLOG_CHIP_W25Q32; break; /* 未知→默认 */
    }
    g_offlog_part.chip         = chip;
    g_offlog_part.area_size    = size;
    g_offlog_part.data_sectors = (size / 4096UL) - 1;
    g_offlog_part.max_records  = g_offlog_part.data_sectors * OFFLOG_EVT_PER_SECTOR;
}

/*===========================================================================
 * 基础读写
 *===========================================================================*/
static void offlog_head_write(const OfflogHead *h)
{
    uint8_t buf[32];
    memset(buf, 0xFF, sizeof(buf));
    memcpy(buf, h, sizeof(OfflogHead));
    SPI_Flash_Write(buf, OFFLOG_AREA_BASE, sizeof(buf));
}

static void offlog_head_read(OfflogHead *h)
{
    uint8_t buf[32];
    SPI_Flash_Read(buf, OFFLOG_AREA_BASE, sizeof(buf));
    memcpy(h, buf, sizeof(OfflogHead));
}

static int offlog_evt_read_at(uint32_t abs_off, OfflogEvt *out)
{
    SPI_Flash_Read((uint8_t *)out, abs_off, OFFLOG_EVT_SIZE);
    return (out->magic == OFFLOG_EVT_MAGIC) ? 0 : -1;
}

/*===========================================================================
 * 上电扫描恢复
 *  从头扇区记录的写位置向后扫, 校验 magic + seq 连续, 找真实写位置。
 *  正常情况 (无掉电) 第一条就无效, 立即恢复; 掉电则向前推进若干条。
 *===========================================================================*/
static void offlog_scan_recover(const OfflogHead *h)
{
    uint32_t pos = h->wr_off;
    uint32_t scanned = 0;
    uint32_t expect_seq = h->wr_seq;
    OfflogEvt e;

    /* 防御: wr_off 必须在数据区范围内且 32B 对齐 */
    if (pos < OFFLOG_DATA_BASE || pos >= OFFLOG_AREA_BASE + OFFLOG_AREA_SIZE) {
        pos = OFFLOG_DATA_BASE;
    }
    if ((pos - OFFLOG_DATA_BASE) % OFFLOG_EVT_SIZE != 0) {
        pos = OFFLOG_DATA_BASE;    /* 未对齐 → 从头开始 */
    }

    while (scanned < OFFLOG_MAX_RECORDS) {
        if (offlog_evt_read_at(pos, &e) != 0) {
            break;                  /* 找到真实写位置 */
        }
        if (expect_seq != 0 && e.seq != expect_seq) {
            break;                  /* seq 不连续 (损坏/残留) → 视为写位置 */
        }
        pos += OFFLOG_EVT_SIZE;
        if (pos >= OFFLOG_DATA_BASE + OFFLOG_DATA_SIZE) {
            pos = OFFLOG_DATA_BASE; /* 回绕数据区 */
        }
        scanned++;
        expect_seq++;
    }

    _wr_off    = pos;
    _wr_sector = (uint16_t)((pos - OFFLOG_DATA_BASE) / 4096) + 1;  /* 区内 1..63 */
    _wr_seq    = expect_seq;        /* 下一条 = 最后有效 seq + 1 */
    _count     = h->count + scanned;
    if (_count > OFFLOG_MAX_RECORDS) _count = OFFLOG_MAX_RECORDS;
    _boot_seq  = (uint16_t)(h->boot_seq + 1);
    if (_boot_seq == 0) _boot_seq = 1;
}

/*===========================================================================
 * 初始化
 *===========================================================================*/
void offlog_init(void)
{
    OfflogHead h;

    offlog_part_detect();       /* JEDEC ID → 事件区容量 (W25Q32/Q64/Q128/Q256) */
    memset(&h, 0xFF, sizeof(h));
    offlog_head_read(&h);

    if (!(h.magic[0] == OFFLOG_HEAD_MAGIC0 && h.magic[1] == OFFLOG_HEAD_MAGIC1 &&
          h.magic[2] == OFFLOG_HEAD_MAGIC2 && h.magic[3] == OFFLOG_HEAD_MAGIC3)) {
        /* 全新区: 擦全部数据扇区, 写头 */
        uint32_t i;
        for (i = 0; i < OFFLOG_DATA_SECTOR_CNT; i++) {
            SPI_Flash_Erase_Sector(OFFLOG_DATA_BASE / 4096 + i);
        }
        memset(&h, 0xFF, sizeof(h));
        h.magic[0] = OFFLOG_HEAD_MAGIC0;
        h.magic[1] = OFFLOG_HEAD_MAGIC1;
        h.magic[2] = OFFLOG_HEAD_MAGIC2;
        h.magic[3] = OFFLOG_HEAD_MAGIC3;
        h.boot_seq  = 0;
        h.wr_sector = 1;
        h.wr_off    = OFFLOG_DATA_BASE;
        h.wr_seq    = 0;
        h.count     = 0;
        offlog_head_write(&h);

        _wr_off    = OFFLOG_DATA_BASE;
        _wr_sector = 1;
        _wr_seq    = 1;
        _count     = 0;
        _boot_seq  = 1;
    } else {
        offlog_scan_recover(&h);
    }

    /* 回写头: boot_seq 递增 */
    h.magic[0] = OFFLOG_HEAD_MAGIC0;
    h.magic[1] = OFFLOG_HEAD_MAGIC1;
    h.magic[2] = OFFLOG_HEAD_MAGIC2;
    h.magic[3] = OFFLOG_HEAD_MAGIC3;
    h.boot_seq  = _boot_seq;
    h.wr_sector = _wr_sector;
    h.wr_off    = _wr_off;
    h.wr_seq    = _wr_seq;
    h.count     = _count;
    offlog_head_write(&h);

    _ready = 1;
}

/*===========================================================================
 * 写一条记录 (主循环上下文)
 *===========================================================================*/
static void offlog_flush_head(void)
{
    OfflogHead h;
    h.magic[0] = OFFLOG_HEAD_MAGIC0;
    h.magic[1] = OFFLOG_HEAD_MAGIC1;
    h.magic[2] = OFFLOG_HEAD_MAGIC2;
    h.magic[3] = OFFLOG_HEAD_MAGIC3;
    h.boot_seq  = _boot_seq;
    h.wr_sector = _wr_sector;
    h.wr_off    = _wr_off;
    h.wr_seq    = _wr_seq;
    h.count     = _count;
    offlog_head_write(&h);
}

/* 目标扇区是否已有数据 (环形覆盖判定): 读首条记录 magic。
   扇区整擦后顺序写, 首条必先写, 故首条 0xA5 即可判定有数据 */
static int offlog_sector_has_data(uint32_t abs_sec_off)
{
    OfflogEvt e;
    SPI_Flash_Read((uint8_t *)&e, abs_sec_off, OFFLOG_EVT_SIZE);
    return (e.magic == OFFLOG_EVT_MAGIC) ? 1 : 0;
}

static void offlog_write_raw(const OfflogEvt *e)
{
    /* 环形回绕: 写指针越过数据区末尾 → 回到区首 */
    if (_wr_off >= OFFLOG_DATA_BASE + OFFLOG_DATA_SIZE) {
        _wr_off = OFFLOG_DATA_BASE;
    }

    /* 切扇区判定: 写指针所在扇区与 _wr_sector 不一致 → 擦除目标扇区。
       覆盖两种情形: ① 正好落在扇区边界 (sec_pos==0, 上一轮写满)
       ② 当前扇区放不下下一条 (sec_pos + 32 > 4096) */
    {
        uint32_t sec_index = (_wr_off - OFFLOG_DATA_BASE) / 4096;   /* 0..62 */
        if ((uint32_t)(_wr_sector - 1) != sec_index) {
            uint32_t target_abs = (OFFLOG_DATA_BASE / 4096 + sec_index) * 4096;
            /* 仅环形覆盖 (目标扇区有旧数据) 才扣减 count;
               顺序推进到空扇区擦除无记录损失 */
            if (offlog_sector_has_data(target_abs)) {
                uint32_t erased = (_count > OFFLOG_EVT_PER_SECTOR)
                                ? OFFLOG_EVT_PER_SECTOR : _count;
                _count -= erased;
            }
            SPI_Flash_Erase_Sector(target_abs / 4096);
            _wr_sector = (uint16_t)(sec_index + 1);                 /* 区内 1..63 */
            offlog_flush_head();        /* 扇区切换 → 更新头 (掉电恢复锚点) */
        }
    }

    SPI_Flash_Write_NoCheck((uint8_t *)e, _wr_off, OFFLOG_EVT_SIZE);
    _wr_off += OFFLOG_EVT_SIZE;
    _wr_seq++;
    if (_count < OFFLOG_MAX_RECORDS) _count++;
}

/* 内部: 支持外部指定 unix_ts (TIME_ANCHOR 用平台下发值, 严格一致) */
static void offlog_evt_ts(uint8_t type, const uint8_t *payload, uint8_t len, uint32_t unix_ts)
{
    OfflogEvt e;
    uint32_t now = mstick();

    if (!_ready) return;

    memset(&e, 0, sizeof(e));
    e.magic   = OFFLOG_EVT_MAGIC;
    e.type    = type;
    e.len     = (len > 12) ? 12 : len;
    e.seq     = _wr_seq;
    e.boot_seq= _boot_seq;
    e.ts_ms   = now;
    e.unix_ts = unix_ts;
    if (unix_ts >= 1600000000UL) {   /* 与 dev_time_sync 合法性门槛一致 */
        e.flags |= OFFLOG_UNIX_VALID_FLAG;
    }
    if (payload != NULL && e.len > 0) {
        memcpy(e.payload, payload, e.len);
    }
    offlog_write_raw(&e);
}

void offlog_evt(uint8_t type, const uint8_t *payload, uint8_t len)
{
    offlog_evt_ts(type, payload, len, dev_time_now());
}

/*===========================================================================
 * 便捷事件包装
 *===========================================================================*/
void offlog_boot(uint32_t reset_reason)
{
    uint8_t p[4];
    p[0] = (uint8_t)(reset_reason >> 24);
    p[1] = (uint8_t)(reset_reason >> 16);
    p[2] = (uint8_t)(reset_reason >> 8);
    p[3] = (uint8_t)reset_reason;
    offlog_evt(OFFLOG_EVT_BOOT, p, 4);
}

void offlog_iot_connect(void)
{
    offlog_evt(OFFLOG_EVT_IOT_CONNECT, NULL, 0);
}

void offlog_iot_ready(void)
{
    offlog_evt(OFFLOG_EVT_IOT_READY, NULL, 0);
}

void offlog_iot_disconnect(uint8_t reason)
{
    offlog_evt(OFFLOG_EVT_IOT_DISCONN, &reason, 1);
}

void offlog_iot_reconn(uint32_t backoff_ms)
{
    uint8_t p[4];
    p[0] = (uint8_t)(backoff_ms >> 24);
    p[1] = (uint8_t)(backoff_ms >> 16);
    p[2] = (uint8_t)(backoff_ms >> 8);
    p[3] = (uint8_t)backoff_ms;
    offlog_evt(OFFLOG_EVT_IOT_RECONN, p, 4);
}

void offlog_evt_retry(uint32_t msg_id, uint8_t retry)
{
    uint8_t p[5];
    p[0] = (uint8_t)(msg_id >> 24);
    p[1] = (uint8_t)(msg_id >> 16);
    p[2] = (uint8_t)(msg_id >> 8);
    p[3] = (uint8_t)msg_id;
    p[4] = retry;
    offlog_evt(OFFLOG_EVT_EVT_RETRY, p, 5);
}

void offlog_evt_giveup(uint32_t msg_id)
{
    uint8_t p[4];
    p[0] = (uint8_t)(msg_id >> 24);
    p[1] = (uint8_t)(msg_id >> 16);
    p[2] = (uint8_t)(msg_id >> 8);
    p[3] = (uint8_t)msg_id;
    offlog_evt(OFFLOG_EVT_EVT_GIVEUP, p, 4);
}

void offlog_coil(uint8_t sub, uint8_t ch, uint32_t value)
{
    uint8_t p[6];
    p[0] = sub;
    p[1] = ch;
    p[2] = (uint8_t)(value >> 24);
    p[3] = (uint8_t)(value >> 16);
    p[4] = (uint8_t)(value >> 8);
    p[5] = (uint8_t)value;
    offlog_evt(OFFLOG_EVT_COIL, p, 6);
}

void offlog_time_anchor(uint32_t unix_ts)
{
    offlog_evt_ts(OFFLOG_EVT_TIME_ANCHOR, NULL, 0, unix_ts);  /* 严格用平台下发值 */
}

/*===========================================================================
 * 查询
 *===========================================================================*/
uint32_t offlog_boot_seq(void)
{
    return _boot_seq;
}

uint16_t offlog_count(void)
{
    return (uint16_t)_count;
}

int offlog_read_idx(uint16_t idx, OfflogEvt *out)
{
    uint32_t cnt = _count;
    if (!_ready || idx >= cnt) return -1;

    /* 逻辑首 = 写位置向前 cnt 条 (环形) */
    uint32_t phys = (_wr_off - OFFLOG_DATA_BASE);           /* 0..DATA_SIZE */
    uint32_t start = (phys + OFFLOG_DATA_SIZE - (uint32_t)cnt * OFFLOG_EVT_SIZE) % OFFLOG_DATA_SIZE;
    uint32_t read_off = OFFLOG_DATA_BASE + (start + (uint32_t)idx * OFFLOG_EVT_SIZE) % OFFLOG_DATA_SIZE;

    return offlog_evt_read_at(read_off, out);
}

/*===========================================================================
 * 协议导出 (MQTT V1.06 / TCP JSON V1.02 共用)
 *===========================================================================*/
uint8_t offlog_enabled(void)
{
    return _ready;
}

uint32_t offlog_seq_last(void)
{
    return (_wr_seq > 0) ? (_wr_seq - 1) : 0;
}

const char *offlog_type_str(uint8_t type)
{
    switch (type) {
        case OFFLOG_EVT_BOOT:        return "boot";
        case OFFLOG_EVT_IOT_CONNECT: return "iot_connect";
        case OFFLOG_EVT_IOT_READY:   return "iot_ready";
        case OFFLOG_EVT_IOT_DISCONN: return "iot_disconnect";
        case OFFLOG_EVT_IOT_RECONN:  return "iot_reconn";
        case OFFLOG_EVT_EVT_RETRY:   return "evt_retry";
        case OFFLOG_EVT_EVT_GIVEUP:  return "evt_giveup";
        case OFFLOG_EVT_COIL:        return "coil";
        case OFFLOG_EVT_TIME_ANCHOR: return "time_anchor";
        case OFFLOG_EVT_LOG_CLEAR:   return "log_clear";
        default:                     return "unknown";
    }
}

/* 线圈事件子类型: 1=进 2=出 3=断开 4=恢复
   (与 iot_mqtt_srv.c offlog_coil 调用一致) */
static const char *offlog_coil_sub_str(uint8_t sub)
{
    switch (sub) {
        case 1:  return "car_enter";
        case 2:  return "car_leave";
        case 3:  return "loop_cut";
        case 4:  return "loop_restore";
        default: return "unknown";
    }
}

/* payload 大端 uint32 (与 offlog_boot/offlog_coil 写入一致) */
static uint32_t offlog_payload_u32(const uint8_t *p)
{
    return ((uint32_t)p[0] << 24) | ((uint32_t)p[1] << 16) | ((uint32_t)p[2] << 8) | p[3];
}

/* 记录 → JSON 对象 (data 按事件类型组装; 无参数事件 data=null)
   回返 snprintf 写入长度; 调用方须保证 buf_len 充足 (一条最大约130B) */
int offlog_evt_to_json(const OfflogEvt *e, char *buf, int buf_len)
{
    const char *type = offlog_type_str(e->type);
    char data[96];

    switch (e->type) {
        case OFFLOG_EVT_BOOT:
            snprintf(data, sizeof(data), "{\"rst\":%lu}",
                     (unsigned long)offlog_payload_u32(e->payload));
            break;
        case OFFLOG_EVT_IOT_DISCONN:
            snprintf(data, sizeof(data), "{\"reason\":%u}", e->payload[0]);
            break;
        case OFFLOG_EVT_IOT_RECONN:
            snprintf(data, sizeof(data), "{\"backoff_ms\":%lu}",
                     (unsigned long)offlog_payload_u32(e->payload));
            break;
        case OFFLOG_EVT_EVT_RETRY:
            snprintf(data, sizeof(data), "{\"msg_id\":%lu,\"retry\":%u}",
                     (unsigned long)offlog_payload_u32(e->payload), e->payload[4]);
            break;
        case OFFLOG_EVT_EVT_GIVEUP:
            snprintf(data, sizeof(data), "{\"msg_id\":%lu}",
                     (unsigned long)offlog_payload_u32(e->payload));
            break;
        case OFFLOG_EVT_COIL:
            snprintf(data, sizeof(data), "{\"sub\":\"%s\",\"ch\":%u,\"value\":%lu}",
                     offlog_coil_sub_str(e->payload[0]), e->payload[1],
                     (unsigned long)offlog_payload_u32(e->payload + 2));
            break;
        default:
            data[0] = '\0';    /* iot_connect/iot_ready/time_anchor/log_clear → null */
            break;
    }

    if (data[0] == '\0') {
        return snprintf(buf, buf_len,
            "{\"seq\":%lu,\"boot_seq\":%u,\"ts_ms\":%lu,\"unix_ts\":%lu,\"type\":\"%s\",\"data\":null}",
            (unsigned long)e->seq, (unsigned)e->boot_seq,
            (unsigned long)e->ts_ms, (unsigned long)e->unix_ts, type);
    }
    return snprintf(buf, buf_len,
        "{\"seq\":%lu,\"boot_seq\":%u,\"ts_ms\":%lu,\"unix_ts\":%lu,\"type\":\"%s\",\"data\":%s}",
        (unsigned long)e->seq, (unsigned)e->boot_seq,
        (unsigned long)e->ts_ms, (unsigned long)e->unix_ts, type, data);
}

/*===========================================================================
 * 清空 (审计: 清空后写一条 LOG_CLEAR)
 *===========================================================================*/
void offlog_clear(void)
{
    uint32_t i;
    if (!_ready) return;

    for (i = 0; i < OFFLOG_DATA_SECTOR_CNT; i++) {
        SPI_Flash_Erase_Sector(OFFLOG_DATA_BASE / 4096 + i);
    }
    _wr_off    = OFFLOG_DATA_BASE;
    _wr_sector = 1;
    _count     = 0;
    /* _wr_seq / _boot_seq 不重置: 序号单调递增, 保证日志全局唯一 */

    offlog_evt(OFFLOG_EVT_LOG_CLEAR, NULL, 0);
    offlog_flush_head();
}