/* Mirror application printf calls to plain-text USB CDC without waiting
 * for the USB host in producers. UART still uses the SDK's original printf. */
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include "ql_rtos.h"
#include "ql_uart.h"
#include "field_log.h"
/* This module is also compiled with -Dprintf=field_log_printf. */
#undef printf
extern int printf(const char *format, ...);

#define LOG_RECORD_BYTES 512
#define LOG_QUEUE_DEPTH 16
struct log_record { unsigned int length; char text[LOG_RECORD_BYTES]; };
static ql_queue_t usb_queue;
static ql_task_t usb_task;
static volatile int ready;
static unsigned long dropped;

static void note_drop(void)
{
    ql_rtos_task_sched_lock();
    ++dropped;
    ql_rtos_task_sched_unlock();
}

int field_log_printf(const char *format, ...)
{
    struct log_record record;
    va_list args;
    int n, ret;
    va_start(args, format);
    n = vsnprintf(record.text, sizeof(record.text), format, args);
    va_end(args);
    if (n < 0) return n;
    if (n >= (int)sizeof(record.text)) {
        const char suffix[] = " [TRUNCATED]\r\n";
        size_t cut = sizeof(record.text) - sizeof(suffix);
        /* Keep the UTF-8 prefix valid if a multi-byte character crosses cut. */
        while (cut && ((unsigned char)record.text[cut] & 0xc0) == 0x80) --cut;
        memcpy(record.text + cut, suffix, sizeof(suffix));
    }
    record.length = (unsigned int)strlen(record.text);
    ret = printf("%s", record.text);
    if (ready && record.length &&
        ql_rtos_queue_release(usb_queue, sizeof(record), (u8 *)&record, QL_NO_WAIT) != 0)
        note_drop();
    return ret;
}

/* SDK variants return zero on success or a positive byte count. */
static int usb_write_all(const char *text, int length)
{
    int offset = 0;
    while (offset < length) {
        int n = ql_uart_write(QL_USB_CDC_PORT, (unsigned char *)text + offset, length - offset);
        if (n == 0) return 0;
        if (n < 0 || n > length - offset) return -1;
        offset += n;
    }
    return 0;
}

static void usb_worker(void *arg)
{
    struct log_record record;
    int opened = 0;
    unsigned long last_notice = 0, reported = 0;
    (void)arg;
    for (;;) {
        if (!opened) {
            int open_result = ql_uart_open(QL_USB_CDC_PORT, QL_UART_BAUD_115200, QL_FC_NONE);
            if (open_result == QL_UART_SUCCESS || open_result == QL_UART_ALREAD_OPEN) {
                const char banner[] = "\r\n[USB日志] 板板现场日志 CDC 已开启；UTF-8 / 115200 8N1；短按原报警键开始网络诊断\r\n";
                opened = usb_write_all(banner, sizeof(banner) - 1) == 0;
                if (!opened) ql_uart_close(QL_USB_CDC_PORT);
            }
            if (!opened) { ql_rtos_task_sleep_ms(1000); continue; }
        }
        if (ql_rtos_queue_wait(usb_queue, (u8 *)&record, sizeof(record), 1000) == 0) {
            if (usb_write_all(record.text, record.length) != 0) {
                note_drop();
                ql_uart_close(QL_USB_CDC_PORT);
                opened = 0;
                ql_rtos_task_sleep_ms(1000);
            }
        }
        /* Beacons identify the correct serial interface even when app is idle.
         * Drop totals are never reset: concurrent producers cannot lose them. */
        if (opened && (u32)(ql_rtos_get_systicks() - last_notice) >= 1000) {
            char status[160];
            unsigned long total;
            ql_rtos_task_sched_lock(); total = dropped; ql_rtos_task_sched_unlock();
            snprintf(status, sizeof(status), "\r\n[USB日志] 在线；累计丢弃=%lu 条%s\r\n", total,
                     total != reported ? "；USB拥塞或未连接，记录可能不完整" : "");
            if (usb_write_all(status, (int)strlen(status)) != 0) {
                ql_uart_close(QL_USB_CDC_PORT); opened = 0;
            } else reported = total;
            last_notice = ql_rtos_get_systicks();
        }
    }
}

int field_log_init(void)
{
    int ret;
    if (ready) return 0;
    ret = ql_rtos_queue_create(&usb_queue, sizeof(struct log_record), LOG_QUEUE_DEPTH);
    if (ret != 0) { printf("[USB日志] 队列创建失败=%d；仅保留UART日志\r\n", ret); return ret; }
    ret = ql_rtos_task_create(&usb_task, 4096, 130, "usb_log", usb_worker, NULL);
    if (ret != 0) {
        ql_rtos_queue_delete(usb_queue); usb_queue = NULL;
        printf("[USB日志] 转发任务创建失败=%d；仅保留UART日志\r\n", ret);
        return ret;
    }
    ready = 1;
    field_log_printf("[USB日志] 应用日志已同步到USB CDC；内核/基带日志不在此转发范围\r\n");
    return 0;
}