#include "dtl.h"
#include <time.h>
#include <string.h>

static enum LOG_LEVEL low_show_level                = LOG_INFO;
static uint32_t log_number                          = 1;
static FILE *log_out_fp                             = NULL;
static char log_head_format[LOG_HEAD_MAX_FORMAT]    = "[%y-%m-%d-%n]";
static char log_head[LOG_HEAD_MAX_FORMAT << 3];


/*
 * 解析日志头 
 *
 * Description:
 *      解析log_head_format中的特殊符号
 *      ret 0   -> success
 *      ret !0  -> Unrecognized symbol
 */
static void
get_loghead(void);

static void
int_to_str(char *restrict dst, uint32_t num, size_t n);


/*-----------------------------------------------------------*/
/*-----------------------------------------------------------*/


void
log_setoutfile(const char *restrict filename)
{
        if((log_out_fp = fopen(filename, "w")) == NULL)
                perror("log-dtl.c:log_setoutfile: Failed to open file !\n");
}


void
log_setlevel(enum LOG_LEVEL level) {
        if(level < LOG_INFO || level > LOG_FATAL)
                low_show_level = LOG_INFO;
        else
                low_show_level = level;
}


void
log_sethead(const char *restrict head) {
        if(strlen(head) >= LOG_HEAD_MAX_FORMAT)
                return;
        strncpy(log_head_format, head, LOG_HEAD_MAX_FORMAT);
}


void
log_print(enum LOG_LEVEL level, const char *restrict message) {
        if(log_out_fp == NULL)             
                log_out_fp = stdout;
        if(level < low_show_level) 
                return;

        get_loghead();
        fputs(log_head, log_out_fp);

        switch(level) {    // 打印错误等级
                case LOG_INFO: 
                        fputs("INFO:", log_out_fp);break;
                case LOG_WARNING: 
                        fputs("WARNING:", log_out_fp);break;
                case LOG_ERROR: 
                        fputs("ERROR:", log_out_fp);break;
                case LOG_FATAL: 
                        fputs("FATAL:", log_out_fp);break;
        }
        
        fputs(message, log_out_fp);
        fputc('\n', log_out_fp);
        log_number++;                   // 日志计数++
}    


void
get_loghead(void) {
        char buf[32];
        time_t now_time     = time(NULL);
        clock_t core_time   = clock() / CLOCKS_PER_SEC;
        struct tm *tm_time  = localtime(&now_time);

        memset(log_head, '\0', sizeof(log_head));

        for(int i = 0; i < strlen(log_head_format); i++) {
                if(log_head_format[i] != '%') { 
                        log_head[strlen(log_head)] = log_head_format[i];
                        continue;
                }
                i++;
                switch(log_head_format[i]) {        // 特殊字符转换
                case 'Y':
                        strftime(buf, 32, "%Y", tm_time);break;
                case 'M':
                        strftime(buf, 32, "%m", tm_time);break;
                case 'd':
                        strftime(buf, 32, "%d", tm_time);break;
                case 'h':
                        strftime(buf, 32, "%H", tm_time);break;
                case 'm':
                        strftime(buf, 32, "%M", tm_time);break;
                case 's':
                        strftime(buf, 32, "%S", tm_time);break;
                case 'n':
                        int_to_str(buf, log_number, 32);break;
                case 'c':
                        int_to_str(buf, core_time, 32);break;
                default: 
                        strcpy(buf, "!!");
                }
                strcat(log_head, buf);
    }
}

void
int_to_str(char *restrict dst, uint32_t num, size_t n) {
    // 逐位提取数字（反向存储）
    int start = 0;
    do {
        dst[start++] = num % 10 + '0';
        num /= 10;
    } while (num > 0);
    dst[start] = '\0';

    // 反转数字部分
    char buf[16];
    strncpy(buf, dst, 15);
    for(int i = 0; i < strlen(buf); i++)
        dst[--start] = buf[i];
}