// posix_dir.c - chdir, getcwd, opendir, readdir, closedir
#include <string.h>
#include <syscall.h>
#include "posix.h"
#include "posix_path.h"

// KDIR_ENTRY layout mirrors io_file.h - duplicated here to avoid
// pulling kernel headers into posix.dll
#define KDIR_NAME_MAX 260
typedef struct {
    char    Name[KDIR_NAME_MAX];
    uint8_t Attr;
    uint32_t FileSize;
} KDIR_ENTRY;

#define KATTR_DIR  0x10

__declspec(dllexport) int chdir(const char* path) {
    char native[512];
    PosixTranslatePath(path, native, sizeof(native));
    uint32_t s = SysSetCwd(native);
    if (s != 0) { errno = ENOENT; return -1; }
    return 0;
}

__declspec(dllexport) char* getcwd(char* buf, size_t size) {
    if (!buf || size == 0) { errno = EINVAL; return (char*)0; }
    char native[512];
    uint32_t s = SysGetCwd(native, sizeof(native));
    if (s != 0) { errno = ERANGE; return (char*)0; }
    NativeToPosix(native, buf, size);
    return buf;
}

__declspec(dllexport) DIR* opendir(const char* path) {
    char native[512];
    PosixTranslatePath(path, native, sizeof(native));
    uint32_t kh;
    uint32_t s = SysOpenDir(native, &kh);
    if (s != 0) { errno = ENOENT; return (DIR*)0; }

    // Allocate DIR on the kernel heap (SysAlloc) so it outlives the stack.
    DIR* d = (DIR*)SysAlloc(sizeof(DIR));
    if (!d) { SysCloseHandle(kh); errno = ENOMEM; return (DIR*)0; }
    d->KHandle = kh;
    d->Valid   = false;
    return d;
}

__declspec(dllexport) struct dirent* readdir(DIR* d) {
    if (!d) { errno = EBADF; return (struct dirent*)0; }
    KDIR_ENTRY ke;
    uint32_t s = SysReadDir(d->KHandle, &ke);
    if (s != 0) return (struct dirent*)0;   // end of directory or error

    size_t len = strlen(ke.Name);
    if (len > NAME_MAX) len = NAME_MAX;
    memcpy(d->Current.d_name, ke.Name, len);
    d->Current.d_name[len] = '\0';
    d->Current.d_type = (ke.Attr & KATTR_DIR) ? DT_DIR : DT_REG;
    d->Valid = true;
    return &d->Current;
}

__declspec(dllexport) int closedir(DIR* d) {
    if (!d) { errno = EBADF; return -1; }
    SysCloseHandle(d->KHandle);
    SysFree(d);
    return 0;
}