/*

 * Path utility functions

 *

 * This file is part of mpv.

 *

 * mpv is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * mpv is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.

 */

#include <assert.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <stdbool.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <errno.h>

#include "config.h"

#include "mpv_talloc.h"

#include "common/common.h"

#include "osdep/io.h"

#include "misc/ctype.h"

#include "misc/path_utils.h"

#if HAVE_DOS_PATHS

#include <windows.h>

#include <pathcch.h>

#endif

char *mp_basename(const char *path)

{

    char *s;

#if HAVE_DOS_PATHS

    if (!mp_is_url(bstr0(path))) {

        s = strrchr(path, '\\');

        if (s)

            path = s + 1;

        s = strrchr(path, ':');

        if (s)

            path = s + 1;

    }

#endif

    s = strrchr(path, '/');

    return s ? s + 1 : (char *)path;

}

struct bstr mp_dirname(const char *path)

{

    struct bstr ret = {

        (uint8_t *)path, mp_basename(path) - path

    };

    if (ret.len == 0)

        return bstr0(".");

    return ret;

}

#if HAVE_DOS_PATHS

static const char mp_path_separators[] = "\\/";

#else

static const char mp_path_separators[] = "/";

#endif

// Mutates path and removes a trailing '/' (or '\' on Windows)

void mp_path_strip_trailing_separator(char *path)

{

    size_t len = strlen(path);

    if (len > 0 && strchr(mp_path_separators, path[len - 1]))

        path[len - 1] = '\0';

}

char *mp_splitext(const char *path, bstr *root)

{

    mp_assert(path);

    int skip = (*path == '.'); // skip leading dot for "hidden" unix files

    const char *split = strrchr(path + skip, '.');

    if (!split || !split[1] || strchr(split, '/'))

        return NULL;

    if (root)

        *root = (bstr){(char *)path, split - path};

    return (char *)split + 1;

}

bool mp_path_is_absolute(struct bstr path)

{

    if (path.len && strchr(mp_path_separators, path.start[0]))

        return true;

#if HAVE_DOS_PATHS

    // Note: "X:filename" is a path relative to the current working directory

    //       of drive X, and thus is not an absolute path. It needs to be

    //       followed by \ or /.

    if (path.len >= 3 && path.start[1] == ':' &&

        strchr(mp_path_separators, path.start[2]))

        return true;

#endif

    return false;

}

char *mp_path_join_bstr(void *talloc_ctx, struct bstr p1, struct bstr p2)

{

    if (p1.len == 0)

        return bstrdup0(talloc_ctx, p2);

    if (p2.len == 0)

        return bstrdup0(talloc_ctx, p1);

    if (mp_path_is_absolute(p2))

        return bstrdup0(talloc_ctx, p2);

    bool have_separator = strchr(mp_path_separators, p1.start[p1.len - 1]);

#if HAVE_DOS_PATHS

    // "X:" only => path relative to "X:" current working directory.

    if (p1.len == 2 && p1.start[1] == ':')

        have_separator = true;

#endif

    return talloc_asprintf(talloc_ctx, "%.*s%s%.*s", BSTR_P(p1),

                           have_separator ? "" : "/", BSTR_P(p2));

}

char *mp_path_join(void *talloc_ctx, const char *p1, const char *p2)

{

    return mp_path_join_bstr(talloc_ctx, bstr0(p1), bstr0(p2));

}

char *mp_getcwd(void *talloc_ctx)

{

    char *e_wd = getenv("PWD");

    if (e_wd)

        return talloc_strdup(talloc_ctx, e_wd);

    char *wd = talloc_array(talloc_ctx, char, 20);

    while (getcwd(wd, talloc_get_size(wd)) == NULL) {

        if (errno != ERANGE) {

            talloc_free(wd);

            return NULL;

        }

        wd = talloc_realloc(talloc_ctx, wd, char, talloc_get_size(wd) * 2);

    }

    return wd;

}

char *mp_normalize_path(void *talloc_ctx, const char *path)

{

    if (!path)

        return NULL;

    if (mp_is_url(bstr0(path)))

        return talloc_strdup(talloc_ctx, path);

    void *tmp = talloc_new(NULL);

    if (!mp_path_is_absolute(bstr0(path))) {

        char *cwd = mp_getcwd(tmp);

        if (!cwd) {

            talloc_free(tmp);

            return NULL;

        }

        path = mp_path_join(tmp, cwd, path);

    }

#if HAVE_DOS_PATHS

    wchar_t *pathw = mp_from_utf8(tmp, path);

    wchar_t *read = pathw, *write = pathw;

    wchar_t prev = '\0';

    // preserve leading double backslashes

    if (read[0] == '\\' && read[1] == '\\') {

        prev = '\\';

        write += 2;

        read += 2;

    }

    wchar_t curr;

    while ((curr = *read)) {

        if (curr == '/')

            curr = '\\';

        if (curr != '\\' || prev != '\\')

            *write++ = curr;

        prev = curr;

        read++;

    }

    *write = '\0';

    size_t max_size = wcslen(pathw) + 1;

    wchar_t *pathc = talloc_array(tmp, wchar_t, max_size);

    HRESULT hr = PathCchCanonicalizeEx(pathc, max_size, pathw, PATHCCH_ALLOW_LONG_PATHS);

    char *ret = SUCCEEDED(hr) ? mp_to_utf8(talloc_ctx, pathc) : talloc_strdup(talloc_ctx, path);

    talloc_free(tmp);

    return ret;

#else

    char *result = talloc_strdup(tmp, "");

    const char *next;

    const char *end = path + strlen(path);

    for (const char *ptr = path; ptr < end; ptr = next + 1) {

        next = memchr(ptr, '/', end - ptr);

        if (next == NULL)

            next = end;

        switch (next - ptr) {

            case 0:

                continue;

            case 1:

                if (ptr[0] == '.')

                    continue;

                break;

            case 2:

                // Normalizing symlink/.. results in a wrong path: if the

                // current working directory is /tmp/foo, and it is a symlink to

                // /usr/bin, mpv ../file.mkv opens /usr/file.mkv, so we can't

                // normalize the path to /tmp/file.mkv. Resolve symlinks to fix

                // this. Otherwise we don't use realpath so users can use

                // symlinks e.g. to hide how media files are distributed over

                // real storage and move them while still resuming playback as

                // long as the symlinked path doesn't change.

                if (ptr[0] == '.' && ptr[1] == '.') {

                    char *tmp_result = realpath(path, NULL);

                    result = talloc_strdup(talloc_ctx, tmp_result);

                    free(tmp_result);

                    talloc_free(tmp);

                    return result;

                }

        }

        result = talloc_strdup_append_buffer(result, "/");

        result = talloc_strndup_append_buffer(result, ptr, next - ptr);

    }

    result = talloc_steal(talloc_ctx, result);

    talloc_free(tmp);

    return result;

#endif

}

bool mp_path_exists(const char *path)

{

    struct stat st;

    return path && stat(path, &st) == 0;

}

bool mp_path_isdir(const char *path)

{

    struct stat st;

    return stat(path, &st) == 0 && S_ISDIR(st.st_mode);

}

// Return false if it's considered a normal local filesystem path.

bool mp_is_url(bstr path)

{

    int proto = bstr_find0(path, "://");

    if (proto < 1)

        return false;

    // Per RFC3986, the first character of the protocol must be alphabetic.

    // The rest must be alphanumeric plus -, + and .

    for (int i = 0; i < proto; i++) {

        unsigned char c = path.start[i];

        if ((i == 0 && !mp_isalpha(c)) ||

            (!mp_isalnum(c) && c != '.' && c != '-' && c != '+'))

        {

            return false;

        }

    }

    return true;

}

// Return the protocol part of path, e.g. "http" if path is "http://...".

// On success, out_url (if not NULL) is set to the part after the "://".

bstr mp_split_proto(bstr path, bstr *out_url)

{

    if (!mp_is_url(path))

        return (bstr){0};

    bstr r;

    bstr_split_tok(path, "://", &r, out_url ? out_url : &(bstr){0});

    return r;

}

void mp_mkdirp(const char *dir)

{

    if (mp_path_exists(dir))

        return;

    char *path = talloc_strdup(NULL, dir);

    char *cdir = path + 1;

    while (cdir) {

        cdir = strchr(cdir, '/');

        if (cdir)

            *cdir = 0;

        mkdir(path, 0777);

        if (cdir)

            *cdir++ = '/';

    }

    talloc_free(path);

}