#include "db.h"

#include <iomanip>
#include <iostream>
#include <mutex>
#include <unordered_map>
#include <sstream>
extern "C" {
#include <dirent.h>
}


static std::unordered_map<std::string,leveldb::DB*> dbs;
static std::mutex getDBmutex;

static bool sensor_name_is_sane(std::string& name) {
    for (auto it = name.begin(); it != name.end(); ++it) {
        if (not ((*it >= '0' and *it <= '9') or
                 (*it >= 'A' and *it <= 'Z') or
                 (*it >= 'a' and *it <= 'z') or
                 (*it == '.') or (*it == '_'))) {
            return false;
        }
    }
    return true;
}

std::string db_make_key(const uint64_t timestamp) {
    std::stringstream key;
    key << "ts-";
    key << std::setfill('0') << std::setw(20) << timestamp;
    return key.str();
}

leveldb::DB *db_get(std::string& name) {
    getDBmutex.lock();
    if (dbs.find(name) == dbs.end()) {
        if (not sensor_name_is_sane(name)) {
            getDBmutex.unlock();
            return nullptr;
        }
        leveldb::DB *db;
        leveldb::Options options;
        options.create_if_missing = true;
        leveldb::Status status = leveldb::DB::Open(options, "data/"+name, &db);
        if (not status.ok()) {
            std::cout << status.ToString() << std::endl;
            getDBmutex.unlock();
            return nullptr;
        }
        dbs[name] = db;
        getDBmutex.unlock();
        return db;
    } else {
        getDBmutex.unlock();
        return dbs.at(name);
    }
}


bool db_insert(std::string& name, const uint64_t timestamp, std::string& value) {
    leveldb::DB *db = db_get(name);
    if (db == nullptr) return false;

    auto status = db->Put(leveldb::WriteOptions(), db_make_key(timestamp), value);
    return status.ok();
}

void db_close() {
    auto it = dbs.begin();
    while (it != dbs.end()) {
	std::cout << "Close Database: " << (*it).first << std::endl;
        delete (*it).second;
        dbs.erase(it++); //post increment!
    }
    std::cout << std::endl;
}

std::list<std::string> * db_list() {
	std::list<std::string> * list = new std::list<std::string>();
	struct dirent * dp;
	DIR* dirp = opendir("data");
	if (dirp != NULL) {
		while ((dp = readdir(dirp)) != NULL) {
			if (dp->d_name[0] != '.')
				list->push_back(std::string(dp->d_name));
		}
		(void)closedir(dirp);
	}
	return list;
}