//
// Created by stas on 5/5/19.
//

#pragma once

#include "date.h"
#include "condition_parser.h"

#include <sstream>
#include <map>
#include <vector>
#include <algorithm>
#include <stack>
#include <utility>
#include <set>

using namespace std;

ostream& operator<< (ostream& os, const pair<Date, string>&);

class Database {
public:
    void Add(const Date& date, const string& event);

    void Print(ostream& os) const;

    template <typename Pr>
    int RemoveIf(Pr predicate);

    template <typename Pr>
    vector<pair<Date, string>> FindIf(Pr predicate) const;

//    void RemoveEmpty();

    pair<Date, string> Last(const Date& date) const;

private:
    map<Date, pair<vector<string>, set<string>>> database_;
};

template <typename Pr>
int Database::RemoveIf(Pr predicate) {
    int count = 0;
    stack<Date> empty_dates;
    for (auto& c : database_) {
        const Date& date = c.first;
        auto& events = c.second.first;

        auto it = remove_if(events.begin(), events.end(),
                [date, predicate] (const string& s) {
                    return predicate(date, s);
        });

        count += distance(it, events.end());

        if (it == events.begin())
            empty_dates.push(date);
        else
            events.erase(it, events.end());
    }
    while(!empty_dates.empty()) {
        database_.erase(empty_dates.top());
        empty_dates.pop();
    }
    return count;
}

template <typename Pr>
vector<pair<Date, string>> Database::FindIf(Pr predicate) const {
    vector<pair<Date, string>> res;
    for (const auto& c : database_) {
        const Date& date = c.first;
        const vector<string>& events = c.second.first;
        for (const auto& event : events) {
            if (predicate(date, event))
                res.push_back(pair{date, event});
        }
    }
    return res;
}