#include "../include/syscalls.h"

#define STDIN    0
#define STDOUT  1

unsigned strlen(const char* str)
{
    unsigned len = 0;
    while (*str)
    {
        ++len;
        ++str;
    }
    return len;
}

static int strcmp(const char* a, const char* b)
{
    while (*a && (*a == *b)) {
        a++;
        b++;
    }
    return *(unsigned char*)a - *(unsigned char*)b;
}

static void print(const char* s)
{
    syscall(SYS_WRITE, STDOUT, (unsigned long)s, strlen(s), 0, 0, 0);
}

static void readline(char* buf, unsigned long max)
{
    unsigned long i = 0;

    while (i < max - 1)
    {
        char c;
        long n = syscall(SYS_READ, STDIN, (unsigned long)&c, 1, 0, 0, 0);

        if (n <= 0)
            continue;

        if (c == '\n')
            break;

        if (c == '\b') {
            if (i > 0) i--;
            continue;
        }

        buf[i++] = c;
    }

    buf[i] = '\0';
}

static void cat(const char* path)
{
    unsigned char buf[256];

    long fd = syscall(SYS_OPEN, (unsigned long)path, 0, 0, 0, 0, 0);
    if (fd < 0) {
        print("cat: cannot open file\n");
        return;
    }

    long n = syscall(SYS_READ, fd, (unsigned long)buf, sizeof(buf), 0, 0, 0);
    syscall(SYS_CLOSE, fd, 0, 0, 0, 0, 0);

    if (n > 0)
        syscall(SYS_WRITE, STDOUT, (unsigned long)buf, n, 0, 0, 0);
}


void main()
{
    const unsigned char* path = "/qwerty.txt";
    const unsigned char* msg  = "Suki Suki Daisuki Kekkon Shiyo, my honey!";

    unsigned char buf[128];

    // ── open file ─────────────────────────────
    unsigned long fd = syscall(SYS_OPEN, (long)path, 0, 0, 0, 0, 0);

    // ── write message ─────────────────────────
    syscall(SYS_WRITE, fd, (long)msg, strlen(msg), 0, 0, 0);

    // ── close ────────────────────────────────
    syscall(SYS_CLOSE, fd, 0, 0, 0, 0, 0);

    // ── reopen ───────────────────────────────
    fd = syscall(SYS_OPEN, (long)path, 0, 0, 0, 0, 0);

    // ── read into buffer ─────────────────────
    unsigned long n = syscall(SYS_READ, fd, (unsigned long)buf, sizeof(buf), 0, 0, 0);

    // ── close ────────────────────────────────
    syscall(SYS_CLOSE, fd, 0, 0, 0, 0, 0);

    // ── print buffer to stdout ───────────────
    syscall(SYS_WRITE, STDOUT, (unsigned long)buf, n, 0, 0, 0);

    char line[128];

    while (1)
    {
        print("> ");

        readline(line, sizeof(line));

        if (strcmp(line, "exit") == 0)
            break;

        // simple "cat <path>"
        if (line[0] == 'c' && line[1] == 'a' && line[2] == 't' && line[3] == ' ')
        {
            cat(&line[4]);
            continue;
        }

        if (line[0] != '\0')
            print("Unknown command\n");
    }

    while (1);

    // ── done ────────────────────────────────
    while (1);
}