#ifndef _AIO_H
#define _AIO_H 1

#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <io.h>
#include <errno.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Control operations for aio_cancel() */
#define AIO_CANCELED     0
#define AIO_NOTCANCELED  1
#define AIO_ALLDONE      2

/* Notification types */
#define AIO_LIO_NOP      0
#define AIO_LIO_READ     1
#define AIO_LIO_WRITE    2

/* Error values for aio_error() */
#define AIO_INPROGRESS   -1
#define AIO_SUCCESS       0

/* Structure for asynchronous I/O operations */
struct aiocb {
    int             aio_fildes;     /* File descriptor */
    volatile void  *aio_buf;        /* Buffer location */
    size_t          aio_nbytes;     /* Length of transfer */
    off_t           aio_offset;     /* File offset */
    int             aio_reqprio;    /* Request priority offset */
    struct sigevent aio_sigevent;   /* Signal number and value */
    int             aio_lio_opcode; /* Operation to be performed */
    int             aio_result;     /* Result of operation */
    int             aio_state;      /* State of operation */
    int             aio_errno;      /* Error code */
};

/* Simplified sigevent structure (minimal implementation) */
struct sigevent {
    int sigev_notify;               /* Notification type */
    int sigev_signo;                /* Signal number */
    union sigval sigev_value;       /* Signal value */
};

/* Union for signal values */
union sigval {
    int sival_int;                  /* Integer value */
    void *sival_ptr;                /* Pointer value */
};

/* Asynchronous I/O control block list for lio_listio */
struct aiocb_list {
    struct aiocb *cb;
    struct aiocb_list *next;
};

/* Function prototypes */
int aio_cancel(int fildes, struct aiocb *aiocbp);
int aio_error(const struct aiocb *aiocbp);
int aio_fsync(int op, struct aiocb *aiocbp);
int aio_read(struct aiocb *aiocbp);
ssize_t aio_return(struct aiocb *aiocbp);
int aio_suspend(const struct aiocb *const list[], int nent, const struct timespec *timeout);
int aio_write(struct aiocb *aiocbp);
int lio_listio(int mode, struct aiocb *const list[], int nent, struct sigevent *sig);

/* Minimal implementation of required functions */

int aio_error(const struct aiocb *aiocbp) {
    if (aiocbp == NULL) {
        return -1;  /* Invalid argument */
    }
    return aiocbp->aio_errno;
}

ssize_t aio_return(struct aiocb *aiocbp) {
    if (aiocbp == NULL) {
        return -1;  /* Invalid argument */
    }
    return aiocbp->aio_result;
}

int aio_read(struct aiocb *aiocbp) {
    if (aiocbp == NULL) {
        return -1;
    }
    
    /* For a minimal implementation, we'll just do synchronous I/O */
    lseek(aiocbp->aio_fildes, aiocbp->aio_offset, SEEK_SET);
    aiocbp->aio_result = read(aiocbp->aio_fildes, aiocbp->aio_buf, aiocbp->aio_nbytes);
    aiocbp->aio_errno = (aiocbp->aio_result >= 0) ? AIO_SUCCESS : errno;
    aiocbp->aio_state = AIO_SUCCESS;
    
    return 0;
}

int aio_write(struct aiocb *aiocbp) {
    if (aiocbp == NULL) {
        return -1;
    }
    
    /* For a minimal implementation, we'll just do synchronous I/O */
    lseek(aiocbp->aio_fildes, aiocbp->aio_offset, SEEK_SET);
    aiocbp->aio_result = write(aiocbp->aio_fildes, aiocbp->aio_buf, aiocbp->aio_nbytes);
    aiocbp->aio_errno = (aiocbp->aio_result >= 0) ? AIO_SUCCESS : errno;
    aiocbp->aio_state = AIO_SUCCESS;
    
    return 0;
}

int aio_cancel(int fildes, struct aiocb *aiocbp) {
    /* In this minimal implementation, we can't actually cancel I/O */
    (void)fildes;
    (void)aiocbp;
    return AIO_ALLDONE;
}

int aio_suspend(const struct aiocb *const list[], int nent, const struct timespec *timeout) {
    /* In this minimal implementation where all I/O is synchronous,
       we can just return immediately */
    (void)list;
    (void)nent;
    (void)timeout;
    return 0;
}

int lio_listio(int mode, struct aiocb *const list[], int nent, struct sigevent *sig) {
    /* Minimal synchronous implementation */
    int i;
    int result = 0;
    
    for (i = 0; i < nent; i++) {
        if (list[i] == NULL) continue;
        
        switch (list[i]->aio_lio_opcode) {
            case AIO_LIO_READ:
                if (aio_read(list[i]) != 0) {
                    result = -1;
                }
                break;
            case AIO_LIO_WRITE:
                if (aio_write(list[i]) != 0) {
                    result = -1;
                }
                break;
            case AIO_LIO_NOP:
                break;
            default:
                result = -1;
                break;
        }
    }
    
    /* In a real implementation, we would handle the signal notification here */
    (void)sig;
    (void)mode;
    
    return result;
}

#ifdef __cplusplus
}
#endif

#endif /* _AIO_H */
