#include "clientaccess.h"

#include <cstring>

# include <sys/mman.h>
# include <dirent.h>
# include <fcntl.h>
# include <sys/types.h>
# include <sys/stat.h>
# include <unistd.h>

#include <algorithm>
#include <fstream>
#include <iomanip>
#include <string>
#include <vector>

#include <Log.h>

#include "defer.h"

static const std::string CLIENTNAME = "LeagueClientUx.exe";	// returns the name and value of a argument or empty string if it could not be parsed

static std::shared_ptr<ClientAccess> findUsingLockfile(const std::vector<std::string>& cmdline, pid_t pid);

static bool endsWith(const std::string& all, const std::string& end) {
	return all.size() >= end.size() && all.rfind(end) == all.size() - end.size();
}

// reads a procfile into a vector (strings are \0 seperated)
static std::vector<std::string> readProcFile(const std::string& path) {
	std::ifstream in(path);
	std::vector<std::string> out;
	std::string line;
	while(std::getline(in, line, '\0')) {
		if(!line.empty()) {
			out.push_back(line);
		}
	}
	return out;
}

std::shared_ptr<ClientAccess> ClientAccess::find() {

	DIR* procdir = opendir("/proc");
	if(!procdir) return nullptr;

	defer( closedir(procdir) );

	dirent* entry = nullptr;
	while ((entry = readdir(procdir)) != NULL) {
		if (entry->d_type != DT_DIR) continue;

		std::string name(entry->d_name);

		pid_t pid = -1;
		try {
			pid = std::stoi(name);
		} catch(std::exception& e) {
			// could not parse -> not a pid
			continue;
		}

		// get info on the exe
		std::string cmdfile = "/proc/" + std::to_string(pid) + "/cmdline";
		std::vector<std::string> args = readProcFile(cmdfile);

		// Log::debug << "process: " << pid << " has " << args.size() << " args";

		if(args.empty()) continue;

		std::string& exename = args.at(0);
		if(endsWith(exename, CLIENTNAME)) {
			Log::info << CLIENTNAME << " found: " << exename;

			std::shared_ptr<ClientAccess> out;

			out = findUsingLockfile(args, pid);

			if(out) {
				return out;
			}
		}
	}

	return nullptr;
}

std::shared_ptr<ClientAccess> findUsingLockfile(const std::vector<std::string>& cmdline, pid_t pid) {
	// get WINEPREFIX env
	std::vector<std::string> envs = readProcFile("/proc/" + std::to_string(pid) + "/environ");

	const static std::string WINEPREFIX = "WINEPREFIX=";

	// find WINEPREFIX
	auto found = std::find_if(envs.begin(), envs.end(), [](const std::string& s) {
		return s.find(WINEPREFIX) == 0;
	});

	// WINEPREFIX env not present
	if(found == envs.end()) {
		Log::debug << "WINEPREFIX environment variable not set";
		return {};
	}

	const std::string wineprefix = found->substr(WINEPREFIX.size());
	const std::string binarypath = cmdline.at(0);
	std::string gamefolder = binarypath.substr(2, binarypath.rfind('/')-1); // remove the "C:" and the name of the binary
	// TODO: gamefoldre could contain '\' so replacing every occurance with '/' would be a good idea
	const std::string lockfilepath = wineprefix + "/drive_c/" + gamefolder + "/lockfile";

	Log::debug << "lockfilepath: " << std::quoted(lockfilepath);

	// read lockfile
	std::ifstream lockfile(lockfilepath);
	return createFromLockfile(lockfile);
}