#include <assert.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>

#define LOG_LINE_SIZE 1024

enum LogLevel {
    LOG_INFO,
    LOG_WARN,
};

char g_log_buff[LOG_LINE_SIZE];

void log_msg_to_buff(char *out, int size, enum LogLevel level, bool colored, const char *format, va_list args) {
    assert(out);
    assert(size);
    assert(level == LOG_INFO || level == LOG_WARN);
    assert(format);

    struct timespec ts;
    clock_gettime(CLOCK_REALTIME, &ts);
    long msec = ts.tv_nsec / 1000000;
    struct tm tm = *localtime(&ts.tv_sec);
    pid_t pid = getpid();
    char *level_str = NULL;

    switch (level) {
    case LOG_INFO:
        level_str = "INFO";
        break;
    case LOG_WARN:
        level_str = "WARN";
        break;
    default:
        assert(false);
    }

    char *color_code = NULL;
    if (colored) {
        switch (level) {
        case LOG_INFO:
            color_code = "\033[1;32m";
            break;
        case LOG_WARN:
            color_code = "\033[1;33m";
            break;
        default:
            assert(false);
        }
    }

    // Imitate formatting style configured in 'salis.py'
    int col = snprintf(
        out,
        size,
        "%s%d-%02d-%02d %02d:%02d:%02d,%03ld %07d [%s]%s ",
        colored ? color_code : "",
        tm.tm_year + 1900,
        tm.tm_mon + 1,
        tm.tm_mday,
        tm.tm_hour,
        tm.tm_min,
        tm.tm_sec,
        msec,
        pid,
        level_str,
        colored ? "\033[0m" : ""
    );

    vsnprintf(out + col, size - col, format, args);
}

void log_msg(enum LogLevel level, bool colored, const char *format, va_list args) {
    assert(level == LOG_INFO || level == LOG_WARN);
    assert(format);

    log_msg_to_buff(g_log_buff, LOG_LINE_SIZE, level, colored, format, args);
    printf("\r%s\n", g_log_buff);
}

void log_info(const char *format, ...) {
    assert(format);

    va_list args;
    va_start(args, format);
    log_msg(LOG_INFO, true, format, args);
    va_end(args);
}

void log_warn(const char *format, ...) {
    assert(format);

    va_list args;
    va_start(args, format);
    log_msg(LOG_WARN, true, format, args);
    va_end(args);
}