/*
 * Copyright (c) 2026, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2026-03-06     user         first version
 * 2026-04-16     user         add power-loss protection, fix index wrap, reduce RAM
 */
#define DBG_TAG "ecode"
#define DBG_LVL DBG_INFO
#include <rtdbg.h>
#include <rthw.h>
#include <fal.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "ecode.h"

/* 分区名称 */
#define ECODE_PART_NAME "ecode"

/* NOR Flash 扇区大小 */
#define SECTOR_SIZE 4096

/* 每条记录固定为64字节 */
#define RECORD_SIZE sizeof(ecode_record_t)

/* 每扇区记录数 */
#define RECORDS_PER_SECTOR (SECTOR_SIZE / RECORD_SIZE)

_Static_assert(sizeof(ecode_record_t) == 64, "ecode_record_t size must be 64 bytes");

/* 头部结构 */
typedef struct
{
    uint32_t magic;
    uint32_t version;
    uint32_t write_seq;
} ecode_header_t;

/* 缓存扇区尾部信息（位于扇区末尾16字节） */
#define CACHE_MAGIC_VALID 0xA5A5A5A5
#define CACHE_TAIL_OFFSET (SECTOR_SIZE - 16)

typedef struct __attribute__((packed))
{
    uint32_t magic;
    uint32_t target_sector;
    uint32_t new_write_seq;
    uint32_t crc32;
} cache_tail_t;

static const struct fal_partition *ecode_part = RT_NULL;
static uint32_t max_sectors = 0; // 数据扇区总数（不含头部和缓存扇区）
static rt_mutex_t ecode_lock = RT_NULL;
static rt_bool_t initialized = RT_FALSE;
static rt_mutex_t init_mutex = RT_NULL;

/* 全局唯一缓冲区（受 ecode_lock 保护），用于所有 Flash 扇区操作 */
static uint8_t g_buf[SECTOR_SIZE];

extern struct rtc_time time_now;

/* 清理detail字符串，确保只包含可打印字符（保留中文UTF-8），遇垃圾数据或无效UTF-8序列截断 */
static void sanitize_detail(char *detail, size_t size)
{
    if (size == 0)
        return;
    detail[size - 1] = '\0'; /* 确保结尾有终止符 */

    for (size_t i = 0; i < size - 1; i++)
    {
        unsigned char c = detail[i];

        if (c == 0x00)
            break;     /* 正常结束 */
        if (c == 0xFF) /* Flash擦除状态，视为未写入数据 */
        {
            detail[i] = '\0';
            break;
        }
        /* 控制字符（除\t \n \r外）也截断 */
        if (c < 0x20 && c != '\t' && c != '\n' && c != '\r')
        {
            detail[i] = '\0';
            break;
        }

        /* UTF-8多字节序列验证 - 防止截断的UTF-8字符导致乱码 */
        if (c >= 0x80)
        {
            int bytes_needed = 0;

            /* 确定需要的字节数 */
            if ((c & 0xE0) == 0xC0)
                bytes_needed = 2; /* 2字节序列: 110xxxxx */
            else if ((c & 0xF0) == 0xE0)
                bytes_needed = 3; /* 3字节序列: 1110xxxx */
            else if ((c & 0xF8) == 0xF0)
                bytes_needed = 4; /* 4字节序列: 11110xxx */
            else                  /* 无效的UTF-8首字节 */
            {
                detail[i] = '\0';
                break;
            }

            /* 检查后续字节是否足够 */
            if (i + bytes_needed >= size)
            {
                detail[i] = '\0';
                break;
            }

            /* 验证后续字节是否符合UTF-8格式（必须是10xxxxxx） */
            int valid = 1;
            for (int j = 1; j < bytes_needed; j++)
            {
                if ((detail[i + j] & 0xC0) != 0x80) /* 必须以10开头 */
                {
                    valid = 0;
                    break;
                }
            }

            if (!valid)
            {
                detail[i] = '\0';
                break;
            }

            /* 跳过已验证的多字节字符 */
            i += bytes_needed - 1;
        }
    }
}

/* CRC32 计算 */
static uint32_t crc32_calc(const uint8_t *data, size_t len)
{
    uint32_t crc = 0xFFFFFFFF;
    for (size_t i = 0; i < len; i++)
    {
        crc ^= data[i];
        for (int j = 0; j < 8; j++)
        {
            if (crc & 1)
                crc = (crc >> 1) ^ 0xEDB88320;
            else
                crc >>= 1;
        }
    }
    return ~crc;
}

/* 获取有效记录数 */
static uint32_t get_valid_count(uint32_t write_seq)
{
    uint32_t max_records = max_sectors * RECORDS_PER_SECTOR;
    return (write_seq < max_records) ? write_seq : max_records;
}

/* 读取头部 */
static int read_header(ecode_header_t *hdr)
{
    if (fal_partition_read(ecode_part, 0, (uint8_t *)hdr, sizeof(ecode_header_t)) < 0)
    {
        LOG_E("read header failed");
        return -RT_ERROR;
    }
    return RT_EOK;
}

/* 写入头部 */
static int write_header(const ecode_header_t *hdr)
{
    int ret = RT_EOK;

    if (fal_partition_read(ecode_part, 0, g_buf, SECTOR_SIZE) < 0)
    {
        LOG_E("read header sector failed");
        return -RT_ERROR;
    }

    memcpy(g_buf, hdr, sizeof(ecode_header_t));

    if (fal_partition_erase(ecode_part, 0, SECTOR_SIZE) < 0)
    {
        LOG_E("erase header sector failed");
        return -RT_ERROR;
    }

    if (fal_partition_write(ecode_part, 0, g_buf, SECTOR_SIZE) != SECTOR_SIZE)
    {
        LOG_E("write header sector failed");
        ret = -RT_ERROR;
    }

    return ret;
}

/* 擦除整个分区 */
static int erase_whole_partition(void)
{
    if (fal_partition_erase(ecode_part, 0, ecode_part->len) < 0)
    {
        LOG_E("erase whole partition failed");
        return -RT_ERROR;
    }
    return RT_EOK;
}

/* 获取缓存扇区地址 */
static uint32_t get_cache_sector_addr(void)
{
    return ecode_part->len - SECTOR_SIZE;
}

/* 从缓存扇区恢复未完成写入 */
static void recover_from_cache(void)
{
    uint32_t cache_addr = get_cache_sector_addr();
    cache_tail_t tail;
    uint32_t calc_crc;

    if (fal_partition_read(ecode_part, cache_addr, g_buf, SECTOR_SIZE) < 0)
    {
        LOG_E("read cache sector failed");
        return;
    }

    /* 读取尾部信息 */
    memcpy(&tail, g_buf + CACHE_TAIL_OFFSET, sizeof(cache_tail_t));

    if (tail.magic != CACHE_MAGIC_VALID)
    {
        LOG_D("no valid cache found");
        return;
    }

    /* 计算数据部分 CRC */
    calc_crc = crc32_calc(g_buf, CACHE_TAIL_OFFSET);
    if (calc_crc != tail.crc32)
    {
        LOG_W("cache sector CRC mismatch, discard");
        fal_partition_erase(ecode_part, cache_addr, SECTOR_SIZE);
        return;
    }

    /* 校验目标扇区地址 */
    if (tail.target_sector < SECTOR_SIZE ||
        tail.target_sector >= cache_addr ||
        (tail.target_sector - SECTOR_SIZE) % SECTOR_SIZE != 0)
    {
        LOG_E("invalid target sector 0x%x in cache", tail.target_sector);
        fal_partition_erase(ecode_part, cache_addr, SECTOR_SIZE);
        return;
    }

    LOG_I("found incomplete write, recovering target sector 0x%x", tail.target_sector);

    /* 恢复目标扇区 */
    if (fal_partition_erase(ecode_part, tail.target_sector, SECTOR_SIZE) < 0)
    {
        LOG_E("erase target sector failed during recovery");
        return;
    }
    if (fal_partition_write(ecode_part, tail.target_sector, g_buf, SECTOR_SIZE) != SECTOR_SIZE)
    {
        LOG_E("write target sector failed during recovery");
        return;
    }

    /* 更新头部 */
    ecode_header_t hdr;
    if (read_header(&hdr) == RT_EOK)
    {
        if (tail.new_write_seq > hdr.write_seq)
        {
            hdr.write_seq = tail.new_write_seq;
            if (write_header(&hdr) != RT_EOK)
            {
                LOG_E("update header after recovery failed");
            }
        }
    }

    /* 清除缓存扇区 */
    fal_partition_erase(ecode_part, cache_addr, SECTOR_SIZE);
    LOG_I("recovery completed");
}

/* 核心初始化 */
static int ecode_init_core(void)
{
    ecode_header_t hdr;
    uint32_t part_size;

    ecode_part = fal_partition_find(ECODE_PART_NAME);
    if (ecode_part == RT_NULL)
    {
        LOG_E("partition '%s' not found", ECODE_PART_NAME);
        return -RT_ERROR;
    }

    part_size = ecode_part->len;
    LOG_D("partition size: %u bytes", part_size);

    if (part_size < SECTOR_SIZE * 3)
    {
        LOG_E("partition too small (need at least %d bytes)", SECTOR_SIZE * 3);
        return -RT_ERROR;
    }

    max_sectors = (part_size / SECTOR_SIZE) - 2; // 头部扇区 + 缓存扇区
    LOG_D("max_sectors=%u, records per sector=%u", max_sectors, RECORDS_PER_SECTOR);

    ecode_lock = rt_mutex_create("ecode", RT_IPC_FLAG_FIFO);
    if (ecode_lock == RT_NULL)
    {
        LOG_E("create mutex failed");
        return -RT_ERROR;
    }

    /* 尝试恢复未完成写入 */
    recover_from_cache();

    if (read_header(&hdr) == RT_EOK && hdr.magic == ECODE_MAGIC && hdr.version == ECODE_VERSION)
    {
        LOG_D("ecode already initialized, write_seq=%u", hdr.write_seq);
        return RT_EOK;
    }

    LOG_W("partition not initialized or invalid, erasing...");
    if (erase_whole_partition() != RT_EOK)
    {
        LOG_E("erase failed");
        return -RT_ERROR;
    }

    hdr.magic = ECODE_MAGIC;
    hdr.version = ECODE_VERSION;
    hdr.write_seq = 0;

    if (write_header(&hdr) != RT_EOK)
    {
        LOG_E("write header failed");
        return -RT_ERROR;
    }

    LOG_I("ecode initialized, max_sectors=%d", max_sectors);
    return RT_EOK;
}

static int ensure_initialized(void)
{
    if (initialized)
        return RT_EOK;

    if (init_mutex == RT_NULL)
    {
        init_mutex = rt_mutex_create("ecode_init", RT_IPC_FLAG_FIFO);
        if (init_mutex == RT_NULL)
        {
            LOG_E("create init mutex failed");
            return -RT_ERROR;
        }
    }

    rt_mutex_take(init_mutex, RT_WAITING_FOREVER);
    if (!initialized)
    {
        if (ecode_init_core() == RT_EOK)
            initialized = RT_TRUE;
        else
            LOG_E("ecode_init_core failed");
    }
    rt_mutex_release(init_mutex);

    return initialized ? RT_EOK : -RT_ERROR;
}

int ecode_init(void)
{
    return ensure_initialized();
}

/**
 * @brief 记录异常事件
 *
 * @param code 事件码
 * @param para 参数码
 * @param detail 描述
 */
void Recode_e_code(ecode_list code, uint16_t para, char *detail)
{
    ecode_header_t hdr;
    ecode_record_t rec;
    uint32_t seq, sector_index, record_offset_in_sector;
    uint32_t sector_start;
    uint32_t cache_addr;
    cache_tail_t tail;


    if (ensure_initialized() != RT_EOK)
    {
        LOG_E("ecode not initialized, abort write");
        return;
    }

    rt_mutex_take(ecode_lock, RT_WAITING_FOREVER);

    if (read_header(&hdr) != RT_EOK)
    {
        LOG_E("read header failed");
        rt_mutex_release(ecode_lock);
        return;
    }

    if (hdr.magic != ECODE_MAGIC || hdr.version != ECODE_VERSION)
    {
        LOG_E("header corrupted");
        rt_mutex_release(ecode_lock);
        return;
    }

    seq = hdr.write_seq;

    /* 构建记录 */
    rec.time_stamp.tm_year = time_now.year - 2000;
    rec.time_stamp.tm_mon = time_now.month;
    rec.time_stamp.tm_mday = time_now.date;
    rec.time_stamp.tm_hour = time_now.hour;
    rec.time_stamp.tm_min = time_now.minute;
    rec.time_stamp.tm_sec = time_now.second;
    rec.code = (uint16_t)code;
    rec.para = para;
    rec.num = seq;
    rt_strncpy(rec.detail, detail, sizeof(rec.detail) - 1);
    rec.detail[sizeof(rec.detail) - 1] = '\0';

    /* 计算物理位置（修正循环逻辑） */
    sector_index = (seq / RECORDS_PER_SECTOR) % max_sectors;
    sector_start = SECTOR_SIZE + sector_index * SECTOR_SIZE;
    record_offset_in_sector = (seq % RECORDS_PER_SECTOR) * RECORD_SIZE;

    LOG_D("write: seq=%u sector_index=%u sector_start=0x%x offset=%u",
          seq, sector_index, sector_start, record_offset_in_sector);

    /* 读取目标扇区到 g_buf */
    if (fal_partition_read(ecode_part, sector_start, g_buf, SECTOR_SIZE) < 0)
    {
        LOG_E("read target sector failed");
        rt_mutex_release(ecode_lock);
        return;
    }

    /* 修改对应记录 */
    memcpy(g_buf + record_offset_in_sector, &rec, RECORD_SIZE);

    /* 准备缓存扇区尾部信息 */
    cache_addr = get_cache_sector_addr();
    tail.magic = CACHE_MAGIC_VALID;
    tail.target_sector = sector_start;
    tail.new_write_seq = seq + 1;
    tail.crc32 = crc32_calc(g_buf, CACHE_TAIL_OFFSET);

    /* 将尾部信息填入 g_buf 末尾 */
    memcpy(g_buf + CACHE_TAIL_OFFSET, &tail, sizeof(cache_tail_t));

    /* 步骤1：写入缓存扇区 */
    if (fal_partition_erase(ecode_part, cache_addr, SECTOR_SIZE) < 0)
    {
        LOG_E("erase cache sector failed");
        rt_mutex_release(ecode_lock);
        return;
    }
    if (fal_partition_write(ecode_part, cache_addr, g_buf, SECTOR_SIZE) != SECTOR_SIZE)
    {
        LOG_E("write cache sector failed");
        rt_mutex_release(ecode_lock);
        return;
    }

    /* 步骤2：擦除目标扇区 */
    if (fal_partition_erase(ecode_part, sector_start, SECTOR_SIZE) < 0)
    {
        LOG_E("erase target sector failed");
        /* 尝试清除缓存扇区 */
        fal_partition_erase(ecode_part, cache_addr, SECTOR_SIZE);
        rt_mutex_release(ecode_lock);
        return;
    }

    /* 步骤3：写回目标扇区（注意此时 g_buf 末尾仍带有缓存信息，但不影响数据部分） */
    if (fal_partition_write(ecode_part, sector_start, g_buf, SECTOR_SIZE) != SECTOR_SIZE)
    {
        LOG_E("write target sector failed, data may be lost!");
        /* 缓存扇区仍有效，下次上电可恢复 */
        rt_mutex_release(ecode_lock);
        return;
    }

    /* 步骤4：更新头部 */
    hdr.write_seq = seq + 1;
    if (write_header(&hdr) != RT_EOK)
    {
        LOG_E("write header failed, but data written");
    }

    /* 步骤5：清除缓存扇区 */
    if (fal_partition_erase(ecode_part, cache_addr, SECTOR_SIZE) < 0)
    {
        LOG_W("clear cache sector failed");
    }

    LOG_W("e_code SET 0 c %d p %d d %s", code, para, detail);

    uint32_t total_records = max_sectors * RECORDS_PER_SECTOR;
    uint32_t used_records = hdr.write_seq;
    if (used_records > total_records)
        used_records = total_records;
    uint32_t used_bytes = used_records * RECORD_SIZE;
    LOG_I("e_code used %d cnt %d/%d", used_bytes, used_records, total_records);

    rt_mutex_release(ecode_lock);
}

/* 读取记录 */
int ecode_read(uint32_t index, ecode_record_t *rec)
{
    ecode_header_t hdr;
    uint32_t valid_count;
    uint32_t logical_seq, sector_index, record_offset_in_sector;
    uint32_t sector_start;

    if (ensure_initialized() != RT_EOK)
        return -RT_ERROR;

    rt_mutex_take(ecode_lock, RT_WAITING_FOREVER);

    if (read_header(&hdr) != RT_EOK)
    {
        rt_mutex_release(ecode_lock);
        return -RT_ERROR;
    }

    if (hdr.magic != ECODE_MAGIC || hdr.version != ECODE_VERSION)
    {
        LOG_E("header corrupted");
        rt_mutex_release(ecode_lock);
        return -RT_ERROR;
    }

    valid_count = get_valid_count(hdr.write_seq);
    if (index >= valid_count)
    {
        rt_mutex_release(ecode_lock);
        return -RT_ERROR;
    }

    logical_seq = hdr.write_seq - 1 - index;
    sector_index = (logical_seq / RECORDS_PER_SECTOR) % max_sectors;
    sector_start = SECTOR_SIZE + sector_index * SECTOR_SIZE;
    record_offset_in_sector = (logical_seq % RECORDS_PER_SECTOR) * RECORD_SIZE;

    LOG_D("read: index=%u logical_seq=%u sector_start=0x%x offset=%u",
          index, logical_seq, sector_start, record_offset_in_sector);

    if (fal_partition_read(ecode_part, sector_start, g_buf, SECTOR_SIZE) < 0)
    {
        LOG_E("read sector failed");
        rt_mutex_release(ecode_lock);
        return -RT_ERROR;
    }

    memcpy(rec, g_buf + record_offset_in_sector, RECORD_SIZE);
    sanitize_detail(rec->detail, sizeof(rec->detail)); // 新增这一行

    /* 检查是否为全0xFF */
    uint8_t *p = (uint8_t *)rec;
    int all_ff = 1;
    for (uint32_t i = 0; i < RECORD_SIZE; i++)
    {
        if (p[i] != 0xFF)
        {
            all_ff = 0;
            break;
        }
    }
    if (all_ff)
    {
        LOG_W("record at index %d is all 0xFF (empty)", index);
        rt_mutex_release(ecode_lock);
        return -RT_ERROR;
    }

    if (rec->num > hdr.write_seq)
    {
        LOG_W("record at index %d has invalid num %u", index, rec->num);
        rt_mutex_release(ecode_lock);
        return -RT_ERROR;
    }

    rt_mutex_release(ecode_lock);
    return RT_EOK;
}

uint32_t ecode_get_count(void)
{
    ecode_header_t hdr;
    uint32_t count;

    if (ensure_initialized() != RT_EOK)
        return 0;

    rt_mutex_take(ecode_lock, RT_WAITING_FOREVER);
    if (read_header(&hdr) != RT_EOK)
    {
        rt_mutex_release(ecode_lock);
        return 0;
    }
    if (hdr.magic != ECODE_MAGIC || hdr.version != ECODE_VERSION)
    {
        rt_mutex_release(ecode_lock);
        return 0;
    }
    count = get_valid_count(hdr.write_seq);
    rt_mutex_release(ecode_lock);
    return count;
}

void ecode_clear(void)
{
    ecode_header_t hdr;

    if (ensure_initialized() != RT_EOK)
    {
        LOG_E("ecode not initialized");
        return;
    }

    rt_mutex_take(ecode_lock, RT_WAITING_FOREVER);

    if (erase_whole_partition() != RT_EOK)
    {
        LOG_E("erase whole partition failed");
        rt_mutex_release(ecode_lock);
        return;
    }

    hdr.magic = ECODE_MAGIC;
    hdr.version = ECODE_VERSION;
    hdr.write_seq = 0;
    if (write_header(&hdr) != RT_EOK)
    {
        LOG_E("write header failed after clear");
    }
    else
    {
        LOG_I("ecode cleared");
    }

    rt_mutex_release(ecode_lock);
}

/*====================== MSH 命令（保持不变）======================*/
#include <finsh.h>

static void recode_test(void)
{
    Recode_e_code(e_test_fun, 6, "3-6 is a test record 123456789");
}
MSH_CMD_EXPORT(recode_test, write a test ecode);

static void pre(void)
{
    ecode_record_t rec;
    uint32_t cnt = ecode_get_count();
    LOG_I("ecode count: %u", cnt);
    for (uint32_t i = 0; i < cnt; i++)
    {
        if (ecode_read(i, &rec) == 0)
        {
            LOG_I("%u - %02u/%02u/%02u %02u:%02u:%02u: (%5u-%-5u) %s",
                  rec.num,
                  rec.time_stamp.tm_year, rec.time_stamp.tm_mon, rec.time_stamp.tm_mday,
                  rec.time_stamp.tm_hour, rec.time_stamp.tm_min, rec.time_stamp.tm_sec,
                  rec.code, rec.para, rec.detail);
        }
        else
        {
            LOG_I("read error at index %u", i);
        }
    }
}
MSH_CMD_EXPORT(pre, print all ecode records from newest to oldest);

static void delecode(void)
{
    ecode_clear();
}
MSH_CMD_EXPORT(delecode, clear all ecode records);

static void ecode_test(int argc, char **argv)
{
    ecode_record_t rec;
    uint32_t cnt_before, cnt_after;
    int i, ret;

    LOG_I("===== ecode module test start =====");

    ecode_clear();
    cnt_before = ecode_get_count();
    LOG_I("after clear, count=%u", cnt_before);
    if (cnt_before != 0)
    {
        LOG_E("clear failed");
        return;
    }

    for (i = 0; i < 10; i++)
    {
        char detail[64];
        rt_snprintf(detail, sizeof(detail), "test data %d", i);
        Recode_e_code(e_test_fun, i, detail);
    }

    cnt_after = ecode_get_count();
    LOG_I("after write 10, count=%u", cnt_after);
    if (cnt_after != 10)
    {
        LOG_E("write count mismatch");
        return;
    }

    for (i = 0; i < 10; i++)
    {
        ret = ecode_read(i, &rec);
        if (ret != 0)
        {
            LOG_E("read index %d failed", i);
            return;
        }
        LOG_I("read[%d]: num=%u time=%02u/%02u/%02u %02u:%02u:%02u code=%u para=%u detail=%s",
              i, rec.num,
              rec.time_stamp.tm_year, rec.time_stamp.tm_mon, rec.time_stamp.tm_mday,
              rec.time_stamp.tm_hour, rec.time_stamp.tm_min, rec.time_stamp.tm_sec,
              rec.code, rec.para, rec.detail);
        if (rec.num != (uint32_t)(9 - i))
        {
            LOG_E("num mismatch: expected %d, got %u", 9 - i, rec.num);
        }
        if (rec.code != e_test_fun || rec.para != (uint16_t)(9 - i))
        {
            LOG_E("code/para mismatch");
        }
    }

    ret = ecode_read(10, &rec);
    if (ret == 0)
    {
        LOG_E("read beyond count should fail");
    }
    else
    {
        LOG_I("read beyond count failed as expected");
    }

    ecode_clear();
    cnt_after = ecode_get_count();
    if (cnt_after != 0)
    {
        LOG_E("clear after test failed");
    }
    else
    {
        LOG_I("clear ok");
    }

    LOG_I("===== ecode module test passed =====");
}
MSH_CMD_EXPORT(ecode_test, run ecode module self - test);