#include "oslib.h"
#include <dirent.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/times.h>
#include <time.h>
#include <utime.h>
#include <fcntl.h>
#include <unistd.h>

enum {
    OSErrNeg2 = -2
};

static char *lastdlerr;
static char intbuf[256];
enum { MAX_PATH = 256 };

#define CONVERT_SPEC(spec, pathbuf) \
do {                                \
int _plen = strlen((spec)->path.s);  \
int _nlen = strlen((spec)->name.s);  \
if (_plen + _nlen >= sizeof(pathbuf)) return 63; \
memcpy((pathbuf), (spec)->path.s, _plen); \
memcpy((pathbuf) + _plen, (spec)->name.s, _nlen + 1); \
} while (0)

#define CONVERT_PATHSPEC(spec, pathbuf) \
do {                                    \
int _plen = strlen((spec)->s);          \
if (_plen >= sizeof(pathbuf)) return 63;\
memcpy((pathbuf), (spec)->s, _plen + 1);\
if (_plen > 1) {                        \
if ((pathbuf)[_plen - 1] == '/')        \
(pathbuf)[_plen - 1] = 0;               \
}                                       \
} while (0)

const char *OS_GetErrText(int err) {
    if (err == -2) {
        return !lastdlerr ? "Shared library function failed" : lastdlerr;
    } else {
        return strerror(err);
    }
}

int OS_InitProgram(int *pArgc, const char ***pArgv) {
    return 0;
}

int OS_TermProgram() {
    return 0;
}

uOSTypePair OS_TEXTTYPE = {0666};

int OS_Create(const OSSpec *spec, const uOSTypePair *type) {
    int h;
    int err;
    CONVERT_SPEC(spec, intbuf);
    h = open(intbuf, O_CREAT | O_TRUNC, type->perm);
    if (h < 0)
        return errno;
    close(h);

    err = OS_SetFileType(spec, type);
    return (err < 1) ? EPERM : 0;
}

int OS_Status(const OSSpec *spec) {
    struct stat st;
    CONVERT_SPEC(spec, intbuf);
    if (stat(intbuf, &st))
        return errno;
    else
        return 0;
}

int OS_GetFileType(const OSSpec *spec, uOSTypePair *type) {
    struct stat st;
    CONVERT_SPEC(spec, intbuf);
    if (stat(intbuf, &st) < 0)
        return errno;
    type->perm = st.st_mode;
    return 0;
}

int OS_SetFileType(const OSSpec *spec, const uOSTypePair *type) {
    int err, oldmask;

    CONVERT_SPEC(spec, intbuf);
    oldmask = umask(0) & UF_SETTABLE;
    err = chmod(intbuf, type->perm & ~oldmask);
    umask(oldmask);

    if (err < 0)
        return errno;
    return 0;
}

int OS_GetFileTime(const OSSpec *spec, time_t *crtm, time_t *chtm) {
    struct stat st;
    CONVERT_SPEC(spec, intbuf);
    if (stat(intbuf, &st) < 0)
        return errno;
    if (crtm)
        *crtm = st.st_ctimespec.tv_sec;
    if (chtm)
        *chtm = st.st_mtimespec.tv_sec;
    return 0;
}

int OS_SetFileTime(const OSSpec *spec, const time_t *crtm, const time_t *chtm) {
    struct utimbuf buf;
    struct stat st;
    CONVERT_SPEC(spec, intbuf);
    if (stat(intbuf, &st) < 0)
        return errno;
    buf.actime = chtm ? *chtm : st.st_atimespec.tv_sec;
    buf.modtime = crtm ? *crtm : st.st_mtimespec.tv_sec;
    if (utime(intbuf, &buf) < 0)
        return errno;
    return 0;
}

int OS_Open(const OSSpec *spec, OSOpenMode mode, int *ref) {
    static int modetrans[4] = {
            O_RDONLY,
            O_WRONLY,
            O_RDWR,
            O_RDONLY | O_APPEND
    };
    CONVERT_SPEC(spec, intbuf);
    *ref = open(intbuf, modetrans[mode]);
    if (*ref < 0) {
        *ref = -1;
        return errno;
    }
    return 0;
}

int OS_Write(int ref, const void *buffer, UInt32 *length) {
    struct stat st;
    UInt32 pos;

    if (fstat(ref, &st) < 0)
        return errno;

    pos = lseek(ref, 0, SEEK_CUR);
    if (pos > st.st_size && !*length) {
        lseek(ref, -1, SEEK_CUR);
        if (write(ref, "", 1) != 1) {
            *length = 0;
            return errno;
        }
    }

    *length = write(ref, buffer, *length);
    if (((SInt32) *length) < 0)
        return errno;
    return 0;
}

int OS_Read(int ref, void *buffer, UInt32 *length) {
    *length = read(ref, buffer, *length);
    if (((SInt32) *length) < 0)
        return errno;
    return 0;
}

int OS_Seek(int ref, OSSeekMode how, SInt32 offset) {
    static int howtrans[3] = {
            SEEK_CUR,
            SEEK_SET,
            SEEK_END
    };

    return (lseek(ref, offset, howtrans[how]) < 0) ? errno : 0;
}

int OS_Tell(int ref, SInt32 *offset) {
    *offset = lseek(ref, 0, SEEK_CUR);
    if (*offset < 0)
        return errno;
    else
        return 0;
}

int OS_Close(int ref) {
    if (ref == -1)
        return EBADF;

    if (close(ref))
        return errno;
    else
        return 0;
}

int OS_GetSize(int ref, UInt32 *length) {
    struct stat st;
    if (fstat(ref, &st) < 0) {
        return errno;
    } else {
        *length = st.st_size;
        return 0;
    }
}

int OS_SetSize(int ref, UInt32 size) {
    if (ftruncate(ref, size))
        return errno;
    else
        return 0;
}

int OS_Delete(const OSSpec *spec) {
    CONVERT_SPEC(spec, intbuf);
    if (unlink(intbuf))
        return errno;
    else
        return 0;
}

int OS_Rename(const OSSpec *oldspec, const OSSpec *newspec) {
    char newbuf[256];
    CONVERT_SPEC(newspec, newbuf);
    CONVERT_SPEC(oldspec, intbuf);
    return rename(intbuf, newbuf) ? errno : 0;
}

int OS_Mkdir(const OSSpec *spec) {
    CONVERT_SPEC(spec, intbuf);
    if (mkdir(intbuf, 0777))
        return errno;
    else
        return 0;
}

int OS_Rmdir(const OSPathSpec *spec) {
    CONVERT_PATHSPEC(spec, intbuf);
    if (rmdir(intbuf))
        return errno;
    else
        return 0;
}

int OS_Chdir(const OSPathSpec *spec) {
    CONVERT_PATHSPEC(spec, intbuf);
    if (chdir(intbuf))
        return errno;
    else
        return 0;
}

int OS_GetCWD(OSPathSpec *spec) {
    char *ptr;
    if (!getcwd(spec->s, sizeof(spec->s)))
        return errno;

    ptr = &spec->s[strlen(spec->s)];
    if (ptr[-1] != '/')
        strcpy(ptr, "/");
    return 0;
}

extern char **environ;
int OS_Execute(OSSpec *spec, char **argv, char **envp, const char *stdoutfile, const char *stderrfile, int *exitcode) {
    int svstdout;
    int svstderr;
    pid_t kidpid;
    int status;
    int err; // not in stabs but i think this exists...?

    if (stdoutfile) {
        svstdout = dup(1);
        close(1);
        if (open(stdoutfile, O_CREAT|O_TRUNC|O_WRONLY, 0666) < 0) {
            status = errno;
            dup2(svstdout, 1);
            close(svstdout);
            return status;
        }
    }

    if (stderrfile) {
        svstderr = dup(2);
        close(2);
        if (open(stderrfile, O_CREAT|O_TRUNC|O_WRONLY, 0666) < 0) {
            status = errno;
            dup2(svstderr, 2);
            close(svstderr);
            return status;
        }
    }

    kidpid = fork();
    if (!kidpid) {
        if (execve(argv[0], argv, (envp && envp[0]) ? envp : environ) < 0)
            exit(-1);
        return EINVAL;
    } else {
        if (stdoutfile) {
            dup2(svstdout, 1);
            close(svstdout);
        }
        if (stderrfile) {
            dup2(svstderr, 2);
            close(svstderr);
        }
        *exitcode = 0;

        err = (waitpid(kidpid, &status, 0) <= 0) ? errno : 0;

        if (!(status & 0x7F))
            *exitcode = status >> 8;

        if ((status & 0x7F) != 0x7F && (status & 0x7F) != 0)
            *exitcode = -(status & 0x7F);

        return err;
    }
}

int OS_IsLegalPath(const char *path) {
    const char *scan = path;
    int pthlen;
    int fnlen;

    pthlen = 0;
    fnlen = 0;

    while (*scan) {
        if (*scan == '/')
            fnlen = 0;
        else
            fnlen++;
        ++pthlen;
        if (fnlen > 63 || pthlen > 255)
            return ENAMETOOLONG;
        //if ((fnlen = (*scan == '/') ? 0 : (fnlen + 1)) > 63 || ++pthlen > 255)
        //    return ENAMETOOLONG;
        ++scan;
    }

    return 0;
}

int OS_IsFullPath(const char *path) {
    return path[0] == '/';
}

char *OS_GetDirPtr(char *path) {
    return path;
}

static int OS_CompactPath(const char *src, char *dst) {
    char buf[256];
    char *bptr;
    char *to;
    char *from;
    char *start;
    char *brk;
}

int OS_EqualPath(const char *a, const char *b) {
    return !strcmp(a, b);
}

int OS_CanonPath(char *src, char *dst) {
    int idx;

    if (strlen(src) > 255)
        return ENAMETOOLONG;

    if (!dst)
        dst = src;

    for (idx = 0; src[idx]; idx++) {
        if (src[idx] == '\\')
            dst[idx] = '/';
        else
            dst[idx] = src[idx];
    }

    dst[idx] = 0;
    return 0;
}

int OS_MakeSpec(const char *path, OSSpec *spec, Boolean *isfile) {
    char tmp[256];
    struct stat st;
    char *ptr;
    int len;
    int err;
    char *end;
    char orig[256];

    spec->name.s[0] = 0;
    spec->path.s[0] = 0;
    err = OS_CanonPath((char *) path, tmp);
    if (err)
        return err;

    if (!OS_IsFullPath(tmp)) {
        strcpy(orig, tmp);
        if (!getcwd(tmp, sizeof(tmp)))
            return errno;

        ptr = tmp + strlen(tmp) - 1;
        if (ptr[0] != '/') {
            ptr[1] = '/';
            ptr[2] = 0;
            ptr += 2;
        }

        if (((ptr - tmp) + strlen(orig)) >= 256)
            return ENAMETOOLONG;

        strcpy(ptr, orig);
    } else {
        if (strlen(tmp) >= 256)
            return ENAMETOOLONG;
    }

    err = OS_CompactPath(tmp, 0);
    if (err)
        return err;
    err = OS_IsLegalPath(tmp);
    if (err)
        return err;

    if (!stat(tmp, &st)) {
        ptr = tmp + strlen(tmp);
        if (ptr[-1] == '/')
            ptr--;
        if ((st.st_mode & S_IFMT) == S_IFDIR) {
            if (isfile)
                *isfile = 0;
            ptr[0] = '/';
            ptr++;
        } else {
            if (isfile)
                *isfile = 1;
        }
        *ptr = 0;
    } else {
        if (errno != ENOENT)
            return errno;
        if (isfile)
            *isfile = 1;
    }

    ptr = strrchr(tmp, '/') + 1;
    len = ptr - tmp;
    if (len >= 256) {
        spec->path.s[0] = 0;
        return ENAMETOOLONG;
    }

    memcpy(spec->path.s, tmp, len);
    spec->path.s[len] = 0;

    len = strlen(ptr);
    if (len >= 64) {
        spec->name.s[0] = 0;
        return ENAMETOOLONG;
    }

    memcpy(spec->name.s, ptr, len);
    spec->name.s[len] = 0;

    return 0;
}

int OS_MakeFileSpec(const char *path, OSSpec *spec) {
    Boolean isfile;
    int err;

    err = OS_MakeSpec(path, spec, &isfile);
    if (err)
        return err;
    else
        return (isfile != 0) ? 0 : EISDIR;
}

int OS_MakePathSpec(const char *vol, const char *dir, OSPathSpec *spec) {
    Boolean isfile;
    OSSpec tmp;
    int err;
    char path[256];

    if (((vol ? strlen(vol) : 0) + (dir ? strlen(dir) : 0) + 2) > 256)
        return ENAMETOOLONG;

    sprintf(path,
            "%s%s%s",
            vol ? (strchr("/\\:", vol[0]) ? "" : "/") : "",
            vol ? vol : "",
            dir ? dir : ""
            );

    err = OS_MakeSpec(path, &tmp, &isfile);
    strcpy(spec->s, tmp.path.s);
    if (err)
        return err;

    if (isfile)
        return !OS_Status(&tmp) ? ENOTDIR : ENOENT;

    return 0;
}

int OS_MakeNameSpec(const char *name, OSNameSpec *spec) {
    int len;

    len = strlen(name);
    spec->s[0] = 0;
    if (len > 63)
        return ENAMETOOLONG;
    if (strchr(name, '/'))
        return EISDIR;
    if (strlen(name) > 63)
        return ENAMETOOLONG;
    memcpy(spec->s, name, len + 1);
    return 0;
}

int OS_GetRootSpec(OSPathSpec *spec) {
    strcpy(spec->s, "/");
    return 0;
}

char *OS_SpecToString(const OSSpec *spec, char *path, int size) {
    int plen;
    int nlen;

    if (!size)
        size = 256;

    if (!path) {
        path = malloc(size);
        if (!path)
            return 0;
    }

    plen = strlen(spec->path.s);
    nlen = strlen(spec->name.s);
    if ((plen + nlen) >= size) {
        if (plen >= size) {
            nlen = 0;
            plen = size - 1;
        } else {
            nlen = (size - plen) - 1;
        }
    }

    memcpy(path, spec->path.s, plen);
    memcpy(&path[plen], spec->name.s, nlen);
    path[plen + nlen] = 0;
    return path;
}

char *OS_PathSpecToString(const OSPathSpec *pspec, char *path, int size) {
    int plen;

    if (!size)
        size = 256;

    if (!path) {
        path = malloc(size);
        if (!path)
            return 0;
    }

    plen = strlen(pspec->s);
    if (plen >= size)
        plen = size - 1;

    memcpy(path, pspec->s, plen);
    path[plen] = 0;
    return path;
}

char *OS_NameSpecToString(const OSNameSpec *nspec, char *name, int size) {
    int nlen;

    if (!size)
        size = 64;

    if (!name) {
        name = malloc(size);
        if (!name)
            return 0;
    }

    nlen = strlen(nspec->s);
    if (nlen >= size)
        nlen = size - 1;

    memcpy(name, nspec->s, nlen);
    name[nlen] = 0;
    return name;
}

int OS_SizeOfPathSpec(const OSPathSpec *spec) {
    return strlen(spec->s) + 1;
}

int OS_SizeOfNameSpec(const OSNameSpec *spec) {
    return strlen(spec->s) + 1;
}

int OS_EqualSpec(const OSSpec *a, const OSSpec *b) {
    return OS_EqualPathSpec(&a->path, &b->path) && OS_EqualNameSpec(&a->name, &b->name);
}

int OS_EqualPathSpec(const OSPathSpec *a, const OSPathSpec *b) {
    return !strcmp(a->s, b->s);
}

int OS_EqualNameSpec(const OSNameSpec *a, const OSNameSpec *b) {
    return !strcmp(a->s, b->s);
}

int OS_IsDir(const OSSpec *spec) {
    struct stat st;

    if (!OS_SpecToString(spec, intbuf, sizeof(intbuf)))
        return 0;
    if (stat(intbuf, &st) < 0)
        return 0;
    return ((st.st_mode & S_IFMT) == S_IFDIR);
}

int OS_IsFile(const OSSpec *spec) {
    struct stat st;

    if (!OS_SpecToString(spec, intbuf, sizeof(intbuf)))
        return 0;
    if (stat(intbuf, &st) < 0)
        return 0;
    return ((st.st_mode & S_IFMT) != S_IFDIR);
}

int OS_IsLink(const OSSpec *spec) {
    struct stat st;
    char *ptr;

    if (!OS_SpecToString(spec, intbuf, sizeof(intbuf)))
        return 0;

    ptr = intbuf + strlen(intbuf) - 1;
    if (*ptr == '/')
        *ptr = 0;

    if (lstat(intbuf, &st) < 0)
        return 0;

    return ((st.st_mode & S_IFMT) == S_IFLNK);
}

int OS_ResolveLink(const OSSpec *link, OSSpec *target) {
    char fn[64];
    char path[256];
    int len;

    if (!OS_SpecToString(link, intbuf, sizeof(intbuf)))
        return ENAMETOOLONG;

    len = readlink(intbuf, fn, sizeof(fn));
    if (len < 0)
        return errno;
    fn[len] = 0;

    sprintf(path, "%s%s", (fn[0] != '/') ? link->path.s : "", fn);
    return OS_MakeSpec(path, target, 0);
}

int OS_OpenDir(const OSPathSpec *spec, OSOpenedDir *ref) {
    DIR *dptr;

    CONVERT_PATHSPEC(spec, intbuf);
    dptr = opendir(intbuf);
    if (!dptr) {
        ref->dir = 0;
        return errno;
    }

    ref->spec = *spec;
    ref->dir = dptr;
    return 0;
}

int OS_ReadDir(OSOpenedDir *ref, OSSpec *spec, char *filename, Boolean *isfile) {
    struct dirent *de;
    char fn[256];
    int err;
    int len;

    do {
        de = readdir(ref->dir);
        if (!de)
            return ENOENT;
    } while (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..") || (strlen(ref->spec.s) + strlen(de->d_name) >= 256));

    len = strlen(ref->spec.s);
    strncpy(fn, ref->spec.s, 255);
    if (len < 256) {
        strncpy(&fn[len], de->d_name, 255 - len);
        fn[255] = 0;
    } else {
        return ENAMETOOLONG;
    }

    strncpy(filename, de->d_name, 63);
    filename[63] = 0;

    return OS_MakeSpec(fn, spec, isfile);
}

int OS_CloseDir(OSOpenedDir *ref) {
    if (ref->dir)
        return closedir(ref->dir);
    else
        return 0;
}

UInt32 OS_GetMilliseconds() {
    struct tms tms;
    return times(&tms) * 1000 / CLOCKS_PER_SEC;
}

void OS_GetTime(time_t *p) {
    time(p);
}

int OS_NewHandle(UInt32 size, OSHandle *hand) {
    hand->addr = 0;
    hand->used = size;
    hand->size = (size + 256) & ~255;
    hand->addr = malloc(hand->size);
    return !hand->addr ? ENOMEM : 0;
}

int OS_ResizeHandle(OSHandle *hand, UInt32 size) {
    UInt32 nsize;
    void *naddr;

    nsize = (size + 256) & ~255;
    naddr = realloc(hand->addr, nsize);
    if (!naddr)
        return ENOMEM;

    hand->addr = naddr;
    hand->size = nsize;
    hand->used = size;
    return 0;
}

void *OS_LockHandle(OSHandle *hand) {
    return hand->addr;
}

void OS_UnlockHandle(OSHandle *hand) {
}

int OS_FreeHandle(OSHandle *hand) {
    if (!hand->addr)
        return ENOMEM;

    free(hand->addr);
    hand->size = 0;
    hand->used = 0;
    hand->addr = 0;
    return 0;
}

int OS_GetHandleSize(OSHandle *hand, UInt32 *size) {
    if (hand->addr) {
        *size = hand->used;
        return 0;
    } else {
        *size = 0;
        return ENOMEM;
    }
}

void OS_InvalidateHandle(OSHandle *hand) {
    hand->addr = 0;
    hand->used = 0;
}

Boolean OS_ValidHandle(OSHandle *hand) {
    return (hand && hand->addr);
}

OSErr OS_MacError(int err) {
    switch (err) {
        case 0: return noErr;
        case ENOENT /*2*/: return fnfErr;
        case EFAULT /*14*/:
        case EINVAL /*22*/: return paramErr;
        case ENOTDIR /*20*/: return dirNFErr;
        case EISDIR /*21*/: return notAFileErr;
        case ENAMETOOLONG /*63*/: return bdNamErr;
        case EBUSY /*16*/: return memLockedErr;
        case E2BIG /*7*/:
        case ENOMEM /*12*/: return memFullErr;
        case EACCES /*13*/: return permErr;
        case EIO /*5*/: return ioErr;
        case EEXIST /*17*/: return dupFNErr;
        case EMFILE /*24*/: return tmfoErr;
        case EFBIG /*27*/: return fsDataTooBigErr;
        case EBADF /*9*/: return rfNumErr;
        case EINTR /*4*/: return abortErr;
        default: return (OSErr) (0xFFFF8000 | err);
    }
}

void OS_TimeToMac(time_t sectm, UInt32 *secs) {
    struct tm *tmrec;
    int years;
    int ydays;

    tmrec = localtime(&sectm);
    // this is horrendous lol
}

void OS_MacToTime(UInt32 secs, time_t *sectm) {
    struct tm tmrec;
    int month;
}

SInt16 OS_RefToMac(int ref) {
    //return (ref >= -1) ? (ref + 1) : ref;
    // wtf is going on here augh
}

int OS_MacToRef(SInt16 refnum) {
    return (refnum >= 0) ? (refnum - 1) : -1;
}

int OS_OpenLibrary(const char *a, void **lib) {
    *lib = 0;
    lastdlerr = "No support for shared libraries";
    return OSErrNeg2;
}

int OS_GetLibrarySymbol(void *a, void *b, void **sym) {
    *sym = 0;
    lastdlerr = "No support for shared libraries";
    return OSErrNeg2;
}

int OS_CloseLibrary(void *a) {
    lastdlerr = "No support for shared libraries";
    return OSErrNeg2;
}

int OS_LoadMacResourceFork(const OSSpec *spec, void **file_data, SInt32 *file_len) {
    return ENOENT;
}

int OS_IsMultiByte(const char *str, int offset) {
    return 0;
}