/*

 * Copyright (C) the libgit2 contributors. All rights reserved.

 *

 * This file is part of libgit2, distributed under the GNU GPL v2 with

 * a Linking Exception. For full terms see the included COPYING file.

 */

#include "path_w32.h"

#include "utf-conv.h"

#include "path.h"

#include "findfile.h"

#define REG_MSYSGIT_INSTALL_LOCAL L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\Git_is1"

#ifndef _WIN64

#define REG_MSYSGIT_INSTALL REG_MSYSGIT_INSTALL_LOCAL

#else

#define REG_MSYSGIT_INSTALL L"SOFTWARE\\Wow6432Node\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\Git_is1"

#endif

typedef struct {

	git_win32_path path;

	DWORD len;

} _findfile_path;

static int git_win32__expand_path(_findfile_path *dest, const wchar_t *src)

{

	dest->len = ExpandEnvironmentStringsW(src, dest->path, ARRAY_SIZE(dest->path));

	if (!dest->len || dest->len > ARRAY_SIZE(dest->path))

		return -1;

	return 0;

}

static int win32_path_to_8(git_buf *dest, const wchar_t *src)

{

	git_win32_utf8_path utf8_path;

	if (git_win32_path_to_utf8(utf8_path, src) < 0) {

		giterr_set(GITERR_OS, "unable to convert path to UTF-8");

		return -1;

	}

	/* Convert backslashes to forward slashes */

	git_path_mkposix(utf8_path);

	return git_buf_sets(dest, utf8_path);

}

static wchar_t* win32_walkpath(wchar_t *path, wchar_t *buf, size_t buflen)

{

	wchar_t term, *base = path;

	assert(path && buf && buflen);

	term = (*path == L'"') ? *path++ : L';';

	for (buflen--; *path && *path != term && buflen; buflen--)

		*buf++ = *path++;

	*buf = L'\0'; /* reserved a byte via initial subtract */

	while (*path == term || *path == L';')

		path++;

	return (path != base) ? path : NULL;

}

static int win32_find_git_in_path(git_buf *buf, const wchar_t *gitexe, const wchar_t *subdir)

{

	wchar_t *env = _wgetenv(L"PATH"), lastch;

	_findfile_path root;

	size_t gitexe_len = wcslen(gitexe);

	if (!env)

		return -1;

	while ((env = win32_walkpath(env, root.path, MAX_PATH-1)) && *root.path) {

		root.len = (DWORD)wcslen(root.path);

		lastch = root.path[root.len - 1];

		/* ensure trailing slash (MAX_PATH-1 to walkpath guarantees space) */

		if (lastch != L'/' && lastch != L'\\') {

			root.path[root.len++] = L'\\';

			root.path[root.len]   = L'\0';

		}

		if (root.len + gitexe_len >= MAX_PATH)

			continue;

		wcscpy(&root.path[root.len], gitexe);

		if (_waccess(root.path, F_OK) == 0 && root.len > 5) {

			/* replace "bin\\" or "cmd\\" with subdir */

			wcscpy(&root.path[root.len - 4], subdir);

			win32_path_to_8(buf, root.path);

			return 0;

		}

	}

	return GIT_ENOTFOUND;

}

static int win32_find_git_in_registry(

	git_buf *buf, const HKEY hive, const wchar_t *key, const wchar_t *subdir)

{

	HKEY hKey;

	int error = GIT_ENOTFOUND;

	assert(buf);

	if (!RegOpenKeyExW(hive, key, 0, KEY_READ, &hKey)) {

		DWORD dwType, cbData;

		git_win32_path path;

		/* Ensure that the buffer is big enough to have the suffix attached

		 * after we receive the result. */

		cbData = (DWORD)(sizeof(path) - wcslen(subdir) * sizeof(wchar_t));

		/* InstallLocation points to the root of the git directory */

		if (!RegQueryValueExW(hKey, L"InstallLocation", NULL, &dwType, (LPBYTE)path, &cbData) &&

			dwType == REG_SZ) {

			/* Append the suffix */

			wcscat(path, subdir);

			/* Convert to UTF-8, with forward slashes, and output the path

			 * to the provided buffer */

			if (!win32_path_to_8(buf, path))

				error = 0;

		}

		RegCloseKey(hKey);

	}

	return error;

}

static int win32_find_existing_dirs(

	git_buf *out, const wchar_t *tmpl[])

{

	_findfile_path path16;

	git_buf buf = GIT_BUF_INIT;

	git_buf_clear(out);

	for (; *tmpl != NULL; tmpl++) {

		if (!git_win32__expand_path(&path16, *tmpl) &&

			path16.path[0] != L'%' &&

			!_waccess(path16.path, F_OK))

		{

			win32_path_to_8(&buf, path16.path);

			if (buf.size)

				git_buf_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, buf.ptr);

		}

	}

	git_buf_free(&buf;;

	return (git_buf_oom(out) ? -1 : 0);

}

int git_win32__find_system_dirs(git_buf *out, const wchar_t *subdir)

{

	git_buf buf = GIT_BUF_INIT;

	/* directories where git.exe & git.cmd are found */

	if (!win32_find_git_in_path(&buf, L"git.exe", subdir) && buf.size)

		git_buf_set(out, buf.ptr, buf.size);

	else

		git_buf_clear(out);

	if (!win32_find_git_in_path(&buf, L"git.cmd", subdir) && buf.size)

		git_buf_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, buf.ptr);

	/* directories where git is installed according to registry */

	if (!win32_find_git_in_registry(

			&buf, HKEY_CURRENT_USER, REG_MSYSGIT_INSTALL_LOCAL, subdir) && buf.size)

		git_buf_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, buf.ptr);

	if (!win32_find_git_in_registry(

			&buf, HKEY_LOCAL_MACHINE, REG_MSYSGIT_INSTALL, subdir) && buf.size)

		git_buf_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, buf.ptr);

	git_buf_free(&buf;;

	return (git_buf_oom(out) ? -1 : 0);

}

int git_win32__find_global_dirs(git_buf *out)

{

	static const wchar_t *global_tmpls[4] = {

		L"%HOME%\\",

		L"%HOMEDRIVE%%HOMEPATH%\\",

		L"%USERPROFILE%\\",

		NULL,

	};

	return win32_find_existing_dirs(out, global_tmpls);

}

int git_win32__find_xdg_dirs(git_buf *out)

{

	static const wchar_t *global_tmpls[7] = {

		L"%XDG_CONFIG_HOME%\\git",

		L"%APPDATA%\\git",

		L"%LOCALAPPDATA%\\git",

		L"%HOME%\\.config\\git",

		L"%HOMEDRIVE%%HOMEPATH%\\.config\\git",

		L"%USERPROFILE%\\.config\\git",

		NULL,

	};

	return win32_find_existing_dirs(out, global_tmpls);

}

int git_win32__find_programdata_dirs(git_buf *out)

{

	static const wchar_t *programdata_tmpls[2] = {

		L"%PROGRAMDATA%\\Git",

		NULL,

	};

	return win32_find_existing_dirs(out, programdata_tmpls);

}