/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=4 sts=4 sw=4 fenc=utf-8                               :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Python 3                                                                     │
│ https://docs.python.org/3/license.html                                       │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/struct/stat.h"
#include "libc/str/locale.h"
#include "third_party/python/Include/abstract.h"
#include "third_party/python/Include/boolobject.h"
#include "third_party/python/Include/codecs.h"
#include "third_party/python/Include/import.h"
#include "third_party/python/Include/object.h"
#include "third_party/python/Include/pydebug.h"
#include "third_party/python/Include/pyerrors.h"
#include "third_party/python/Include/pymem.h"
#include "third_party/python/Include/sysmodule.h"
#include "third_party/python/Include/yoink.h"

/* PYTHON_YOINK("io"); */
/* PYTHON_YOINK("encodings.aliases"); */
/* PYTHON_YOINK("encodings.latin_1"); */
/* PYTHON_YOINK("encodings.utf_8"); */

_Py_IDENTIFIER(name);
_Py_IDENTIFIER(stdin);
_Py_IDENTIFIER(stdout);
_Py_IDENTIFIER(stderr);

char *_Py_StandardStreamEncoding;
char *_Py_StandardStreamErrors;

/* Check if a file descriptor is valid or not.
   Return 0 if the file descriptor is invalid, return non-zero otherwise. */
static int
is_valid_fd(int fd)
{
    if (IsWindows()) {
        return __isfdopen(fd);
    }
    if (IsXnu()) {
        /* bpo-30225: On macOS Tiger, when stdout is redirected to a pipe
           and the other side of the pipe is closed, dup(1) succeed, whereas
           fstat(1, &st) fails with EBADF. Prefer fstat() over dup() to detect
           such error. */
        struct stat st;
        return fstat(fd, &st) == 0;
    }
    int fd2;
    if (fd < 0)
        return 0;
    _Py_BEGIN_SUPPRESS_IPH
    /* Prefer dup() over fstat(). fstat() can require input/output whereas
       dup() doesn't, there is a low risk of EMFILE/ENFILE at Python
       startup. */
    fd2 = dup(fd);
    if (fd2 >= 0)
        close(fd2);
    _Py_END_SUPPRESS_IPH
    return fd2 >= 0;
}

/* returns Py_None if the fd is not valid */
static PyObject*
create_stdio(PyObject* io,
    int fd, int write_mode, const char* name,
    const char* encoding, const char* errors)
{
    PyObject *buf = NULL, *stream = NULL, *text = NULL, *raw = NULL, *res;
    const char* mode;
    const char* newline;
    PyObject *line_buffering;
    int buffering, isatty;
    _Py_IDENTIFIER(open);
    _Py_IDENTIFIER(isatty);
    _Py_IDENTIFIER(TextIOWrapper);
    _Py_IDENTIFIER(mode);

    if (!is_valid_fd(fd))
        Py_RETURN_NONE;

    /* stdin is always opened in buffered mode, first because it shouldn't
       make a difference in common use cases, second because TextIOWrapper
       depends on the presence of a read1() method which only exists on
       buffered streams.
    */
    if (Py_UnbufferedStdioFlag && write_mode)
        buffering = 0;
    else
        buffering = -1;
    if (write_mode)
        mode = "wb";
    else
        mode = "rb";
    buf = _PyObject_CallMethodId(io, &PyId_open, "isiOOOi",
                                 fd, mode, buffering,
                                 Py_None, Py_None, /* encoding, errors */
                                 Py_None, 0); /* newline, closefd */
    if (buf == NULL)
        goto error;

    if (buffering) {
        _Py_IDENTIFIER(raw);
        raw = _PyObject_GetAttrId(buf, &PyId_raw);
        if (raw == NULL)
            goto error;
    }
    else {
        raw = buf;
        Py_INCREF(raw);
    }

#ifdef MS_WINDOWS
    /* Windows console IO is always UTF-8 encoded */
    if (PyWindowsConsoleIO_Check(raw))
        encoding = "utf-8";
#endif

    text = PyUnicode_FromString(name);
    if (text == NULL || _PyObject_SetAttrId(raw, &PyId_name, text) < 0)
        goto error;
    res = _PyObject_CallMethodId(raw, &PyId_isatty, NULL);
    if (res == NULL)
        goto error;
    isatty = PyObject_IsTrue(res);
    Py_DECREF(res);
    if (isatty == -1)
        goto error;
    if (isatty || Py_UnbufferedStdioFlag)
        line_buffering = Py_True;
    else
        line_buffering = Py_False;

    Py_CLEAR(raw);
    Py_CLEAR(text);

#ifdef MS_WINDOWS
    /* sys.stdin: enable universal newline mode, translate "\r\n" and "\r"
       newlines to "\n".
       sys.stdout and sys.stderr: translate "\n" to "\r\n". */
    newline = NULL;
#else
    /* sys.stdin: split lines at "\n".
       sys.stdout and sys.stderr: don't translate newlines (use "\n"). */
    newline = "\n";
#endif

    stream = _PyObject_CallMethodId(io, &PyId_TextIOWrapper, "OsssO",
                                    buf, encoding, errors,
                                    newline, line_buffering);
    Py_CLEAR(buf);
    if (stream == NULL)
        goto error;

    if (write_mode)
        mode = "w";
    else
        mode = "r";
    text = PyUnicode_FromString(mode);
    if (!text || _PyObject_SetAttrId(stream, &PyId_mode, text) < 0)
        goto error;
    Py_CLEAR(text);
    return stream;

error:
    Py_XDECREF(buf);
    Py_XDECREF(stream);
    Py_XDECREF(text);
    Py_XDECREF(raw);

    if (PyErr_ExceptionMatches(PyExc_OSError) && !is_valid_fd(fd)) {
        /* Issue #24891: the file descriptor was closed after the first
           is_valid_fd() check was called. Ignore the OSError and set the
           stream to None. */
        PyErr_Clear();
        Py_RETURN_NONE;
    }
    return NULL;
}

/* Initialize sys.stdin, stdout, stderr and builtins.open */
int
_Py_InitStdio(void)
{
    PyObject *iomod = NULL, *wrapper;
    PyObject *bimod = NULL;
    PyObject *m;
    PyObject *std = NULL;
    int status = 0, fd;
    PyObject * encoding_attr;
    char *pythonioencoding = NULL, *encoding, *errors;

    /* Hack to avoid a nasty recursion issue when Python is invoked
       in verbose mode: pre-import the Latin-1 and UTF-8 codecs */
    if ((m = PyImport_ImportModule("encodings.utf_8")) == NULL) {
        goto error;
    }
    Py_DECREF(m);

    if (!(m = PyImport_ImportModule("encodings.latin_1"))) {
        goto error;
    }
    Py_DECREF(m);

    if (!(bimod = PyImport_ImportModule("builtins"))) {
        goto error;
    }

    if (!(iomod = PyImport_ImportModule("io"))) {
        goto error;
    }
    if (!(wrapper = PyObject_GetAttrString(iomod, "OpenWrapper"))) {
        goto error;
    }

    /* Set builtins.open */
    if (PyObject_SetAttrString(bimod, "open", wrapper) == -1) {
        Py_DECREF(wrapper);
        goto error;
    }
    Py_DECREF(wrapper);

    encoding = _Py_StandardStreamEncoding;
    errors = _Py_StandardStreamErrors;
    if (!encoding || !errors) {
        pythonioencoding = Py_GETENV("PYTHONIOENCODING");
        if (pythonioencoding) {
            char *err;
            pythonioencoding = _PyMem_Strdup(pythonioencoding);
            if (pythonioencoding == NULL) {
                PyErr_NoMemory();
                goto error;
            }
            err = strchr(pythonioencoding, ':');
            if (err) {
                *err = '\0';
                err++;
                if (*err && !errors) {
                    errors = err;
                }
            }
            if (*pythonioencoding && !encoding) {
                encoding = pythonioencoding;
            }
        }
        if (!errors && !(pythonioencoding && *pythonioencoding)) {
            /* When the LC_CTYPE locale is the POSIX locale ("C locale"),
               stdin and stdout use the surrogateescape error handler by
               default, instead of the strict error handler. */
            char *loc = setlocale(LC_CTYPE, NULL);
            if (loc != NULL && strcmp(loc, "C") == 0)
                errors = "surrogateescape";
        }
    }

    /* Set sys.stdin */
    fd = fileno(stdin);
    /* Under some conditions stdin, stdout and stderr may not be connected
     * and fileno() may point to an invalid file descriptor. For example
     * GUI apps don't have valid standard streams by default.
     */
    std = create_stdio(iomod, fd, 0, "<stdin>", encoding, errors);
    if (std == NULL)
        goto error;
    PySys_SetObject("__stdin__", std);
    _PySys_SetObjectId(&PyId_stdin, std);
    Py_DECREF(std);

    /* Set sys.stdout */
    fd = fileno(stdout);
    std = create_stdio(iomod, fd, 1, "<stdout>", encoding, errors);
    if (std == NULL)
        goto error;
    PySys_SetObject("__stdout__", std);
    _PySys_SetObjectId(&PyId_stdout, std);
    Py_DECREF(std);

#if 1 /* Disable this if you have trouble debugging bootstrap stuff */
    /* Set sys.stderr, replaces the preliminary stderr */
    fd = fileno(stderr);
    std = create_stdio(iomod, fd, 1, "<stderr>", encoding, "backslashreplace");
    if (std == NULL)
        goto error;

    /* Same as hack above, pre-import stderr's codec to avoid recursion
       when import.c tries to write to stderr in verbose mode. */
    encoding_attr = PyObject_GetAttrString(std, "encoding");
    if (encoding_attr != NULL) {
        const char * std_encoding;
        std_encoding = PyUnicode_AsUTF8(encoding_attr);
        if (std_encoding != NULL) {
            PyObject *codec_info = _PyCodec_Lookup(std_encoding);
            Py_XDECREF(codec_info);
        }
        Py_DECREF(encoding_attr);
    }
    PyErr_Clear();  /* Not a fatal error if codec isn't available */

    if (PySys_SetObject("__stderr__", std) < 0) {
        Py_DECREF(std);
        goto error;
    }
    if (_PySys_SetObjectId(&PyId_stderr, std) < 0) {
        Py_DECREF(std);
        goto error;
    }
    Py_DECREF(std);
#endif

    if (0) {
  error:
        status = -1;
    }

    /* We won't need them anymore. */
    if (_Py_StandardStreamEncoding) {
        PyMem_RawFree(_Py_StandardStreamEncoding);
        _Py_StandardStreamEncoding = NULL;
    }
    if (_Py_StandardStreamErrors) {
        PyMem_RawFree(_Py_StandardStreamErrors);
        _Py_StandardStreamErrors = NULL;
    }
    PyMem_Free(pythonioencoding);
    Py_XDECREF(bimod);
    Py_XDECREF(iomod);
    return status;
}