#include <iostream>
#include <fstream>
#include "../cpp-httplib/httplib.h"
#include <filesystem>
#include <vector>
#include <string>
#include <direct.h>
#include <iostream>


using namespace std;
using namespace httplib;

const string SERVER_FILE_DIR = "/ServerFiles/";

string GetExeDir()
{
	char buff[_MAX_PATH];
	_getcwd(buff, _MAX_PATH);
	string currPath(buff);
	return string(buff);
}

bool file_exists(const string& path) {
	ifstream file(path, ios::binary);
	return file.good();
}

void send_file(const string& file_path, Response& res) {
	ifstream file(file_path, ios::binary | ios::ate);  
	if (!file) {
		res.status = 500;  // 服务器错误
		res.set_content("Failed to open file", "text/plain");
		return;
	}

	// 获取文件大小
	streamsize file_size = file.tellg();
	file.seekg(0, ios::beg); 

	res.set_content_provider(
		file_size, "application/octet-stream",
		[file_path](size_t offset, size_t length, DataSink& sink) {
		ifstream file(file_path, ios::binary);
		if (!file) return false;

		file.seekg(offset, ios::beg);
		vector<char> buffer(length);
		file.read(buffer.data(), length);
		sink.write(buffer.data(), file.gcount());  // 发送数据

		return true;  // 继续传输
	}
	);
}

int main() {
	Server svr;

	svr.Get(R"(/download/(.+))", [&](const Request& req, Response& res) {
		string filename = req.matches[1];  
		string file_path = GetExeDir()+SERVER_FILE_DIR + filename;

		if (!file_exists(file_path)) {
			res.status = 404;
			res.set_content("File not found", "text/plain");
			return;
		}

		send_file(file_path, res);
	});

	cout << "Server started at http://localhost:1234\n";
	svr.listen("localhost", 1234);
}