// Copyright 2017-2021 The Mumble Developers. All rights reserved.
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file at the root of the
// Mumble source tree or at <https://www.mumble.info/LICENSE>.

#include "ancestor.h"
#include "lib.h"
#include "olsettings.h"
#include "util.h"

#include <algorithm>
#include <string>
#include <vector>

static bool bExcludeCheckInitialized = false;

static OverlayExclusionMode oemExcludeMode = LauncherFilterExclusionMode;
static std::vector< std::string > vLaunchers;
static std::vector< std::string > vWhitelist;
static std::vector< std::string > vPaths;
static std::vector< std::string > vBlacklist;

/// Ensure the ExcludeCheck module is initialized.
static void ExcludeCheckEnsureInitialized() {
	if (bExcludeCheckInitialized) {
		return;
	}

	oemExcludeMode = SettingsGetExclusionMode();
	vLaunchers     = SettingsGetLaunchers();
	vWhitelist     = SettingsGetWhitelist();
	vPaths         = SettingsGetPaths();
	vBlacklist     = SettingsGetBlacklist();

	bExcludeCheckInitialized = true;
}

/// Check whether the program at |absExeName|
/// (with basename of |exeName|) is blacklisted.
///
/// Note that programs that are added as launchers
/// are also implicitly treated as being blacklisted.
static bool isBlacklistedExe(const std::string &absExeName, const std::string &exeName) {
	std::vector< string > combinedBlacklist = vmerge(vBlacklist, vLaunchers);
	for (size_t i = 0; i < combinedBlacklist.size(); i++) {
		std::string &val = combinedBlacklist.at(i);
		if (isAbsPath(val)) {
			if (val == absExeName) {
				return true;
			}
		} else {
			if (val == exeName) {
				return true;
			}
		}
	}
	return false;
}

/// Check whether the program at |absExeName|
/// (with basename of |exeName|) is in the Mumble
/// overlay program whitelist.
static bool isWhitelistedExe(const std::string &absExeName, const std::string &exeName) {
	for (size_t i = 0; i < vWhitelist.size(); i++) {
		std::string &val = vWhitelist.at(i);
		if (isAbsPath(val)) {
			if (val == absExeName) {
				return true;
			}
		} else {
			if (val == exeName) {
				return true;
			}
		}
	}
	return false;
}

/// Check whether the program at |absExeName|
/// is in the Mumble overlay path whitelist.
static bool isWhitelistedPath(const std::string &absExeName) {
	for (size_t i = 0; i < vPaths.size(); i++) {
		const std::string &path = vPaths.at(i);
		if (absExeName.find(path) == 0) {
			return true;
		}
	}
	return false;
}

/// Check whether an ancestor executable in
/// |absAncestorExeNames| (or |ancestorExeNames|,
/// for relative paths) is in the Mumble overlay's
/// launcher whitelist.
static bool hasWhitelistedAncestor(const std::vector< std::string > &absAncestorExeNames,
								   const std::vector< std::string > &ancestorExeNames) {
	for (size_t i = 0; i < vLaunchers.size(); i++) {
		std::string &val = vLaunchers.at(i);
		if (isAbsPath(val)) {
			if (std::find(absAncestorExeNames.begin(), absAncestorExeNames.end(), val) != absAncestorExeNames.end()) {
				return true;
			}
		} else {
			if (std::find(ancestorExeNames.begin(), ancestorExeNames.end(), val) != ancestorExeNames.end()) {
				return true;
			}
		}
	}
	return false;
}

bool ExcludeCheckIsOverlayEnabled(std::string absExeName_, std::string exeName_) {
	bool enableOverlay = true;

	std::string absExeName = slowercase(absExeName_);
	std::string exeName    = slowercase(exeName_);

	ExcludeCheckEnsureInitialized();

	switch (oemExcludeMode) {
		case LauncherFilterExclusionMode: {
			ods("ExcludeCheck: using 'launcher filter' exclusion mode...");

			std::vector< std::string > absAncestorExeNames;
			std::vector< std::string > ancestorExeNames;
			if (!GetProcessAncestorChain(absAncestorExeNames, ancestorExeNames)) {
				// Unable to get ancestor chain. Process is allowed.
				ods("ExcludeCheck: Unable to find parent. Process allowed.");
				enableOverlay = true;
			}
			absAncestorExeNames = vlowercase(absAncestorExeNames);
			ancestorExeNames    = vlowercase(ancestorExeNames);

			for (size_t i = 0; i < absAncestorExeNames.size(); i++) {
				std::string absAncestorExeName = absAncestorExeNames.at(i);
				ods("ExcludeCheck: Ancestor #%i is '%s'", i + 1, absAncestorExeName.c_str());
			}

			// The blacklist always wins.
			// If an exe is in the blacklist, never show the overlay, ever.
			if (isBlacklistedExe(absExeName, exeName)) {
				ods("ExcludeCheck: '%s' is blacklisted. Overlay disabled.", absExeName.c_str());
				enableOverlay = false;
				// If the process's exe name is whitelisted, allow the overlay to be shown.
			} else if (isWhitelistedExe(absExeName, exeName)) {
				ods("ExcludeCheck: '%s' is whitelisted. Overlay enabled.", absExeName.c_str());
				enableOverlay = true;
				// If the exe is within a whitelisted path, allow the overlay to be shown.
				// An example is:
				// Whitelisted path: d:\games
				// absExeName: d:\games\World of Warcraft\Wow-64.exe
				// The overlay would be shown in WoW (and any game that lives under d:\games)
			} else if (isWhitelistedPath(absExeName)) {
				ods("ExcludeCheck: '%s' is within a whitelisted path. Overlay enabled.", absExeName.c_str());
				enableOverlay = true;
				// If any of the process's ancestors are whitelisted, allow the process through.
				// This allows us to whitelist Steam.exe, etc. -- and have the overlay
				// show up in all Steam titles.
			} else if (hasWhitelistedAncestor(absAncestorExeNames, ancestorExeNames)) {
				ods("ExcludeCheck: An ancestor of '%s' is whitelisted. Overlay enabled.", exeName.c_str());
				enableOverlay = true;
				// If nothing matched, do not show the overlay.
			} else {
				ods("ExcludeCheck: No matching overlay exclusion rule found. Overlay disabled.");
				enableOverlay = false;
			}
			break;
		}
		case WhitelistExclusionMode: {
			ods("ExcludeCheck: using 'whitelist' exclusion mode...");

			if (isWhitelistedExe(absExeName, exeName)) {
				ods("ExcludeCheck: '%s' is whitelisted. Overlay enabled.", absExeName.c_str());
				enableOverlay = true;
			} else {
				ods("ExcludeCheck: '%s' not whitelisted. Overlay disabled.", absExeName.c_str());
				enableOverlay = false;
			}
			break;
		}
		case BlacklistExclusionMode: {
			ods("ExcludeCheck: using 'blacklist' exclusion mode...");

			if (isBlacklistedExe(absExeName, exeName)) {
				ods("ExcludeCheck: '%s' is blacklisted. Overlay disabled.", absExeName.c_str());
				enableOverlay = false;
			} else {
				ods("ExcludeCheck: '%s' is not blacklisted. Overlay enabled.", absExeName.c_str());
				enableOverlay = true;
			}
			break;
		}
	}

	return enableOverlay;
}