#include <ulibc/stdio.h>
#include <usr/errno.h>
#include <usr/fcntl.h>
#include <usr/sys/lunaix.h>
#include <usr/unistd.h>

void
_iotest_main()
{
    char test_sequence[] = "Once upon a time, in a magical land of Equestria. "
                           "There were two regal sisters who ruled together "
                           "and created harmony for all the land.";
    char read_out[256];

    // 切换工作目录至 /dev
    int status = chdir("/dev");
    if (status) {
        write(stdout, "fail to chdir", 15);
        return;
    }

    if (getcwd(read_out, sizeof(read_out))) {
        printf("current working dir: %s\n", read_out);
    }

    // sda 设备 - 硬盘
    //  sda设备属于容积设备（Volumetric Device），
    //  Lunaix会尽可能缓存任何对此设备的上层读写，并使用延迟写入策略。（FO_DIRECT可用于屏蔽该功能）
    int fd = open("./sda", 0);

    if (fd < 0) {
        printf("fail to open (%d)\n", errno);
        return;
    }

    // 移动指针至512字节，在大多数情况下，这是第二个逻辑扇区的起始处
    lseek(fd, 512, FSEEK_SET);

    // 总共写入 64 * 136 字节，会产生3个页作为缓存
    for (size_t i = 0; i < 64; i++) {
        write(fd, test_sequence, sizeof(test_sequence));
    }

    // 随机读写测试
    lseek(fd, 4 * 4096, FSEEK_SET);
    write(fd, test_sequence, sizeof(test_sequence));

    printf("input: ");
    int size = read(stdin, read_out, 256);

    printf("your said: %s\n", read_out);

    write(fd, read_out, size);

    // 读出我们写的内容
    lseek(fd, 512, FSEEK_SET);
    read(fd, read_out, sizeof(read_out));

    // 将读出的内容直接写入tty设备
    write(stdout, read_out, sizeof(read_out));
    write(stdout, "\n", 1);

    // 关闭文件，这同时会将页缓存中的数据下发到底层驱动
    close(fd);
}