#include "intervals.hpp"
#include <algorithm>
#include <cmath>
#include <fstream>
#include <iomanip>
#include <sstream>
#include <ctime>

std::vector<Interval> find_intervals(const std::vector<DayStats>& days, double threshold) {
    if (days.empty()) {
        return {};
    }
    
    std::vector<Interval> intervals;
    
    size_t start_idx = 0;
    double price_base = days[start_idx].avg;
    
    for (size_t i = 1; i < days.size(); i++) {
        double price_now = days[i].avg;
        double change = std::abs(price_now - price_base) / price_base;
        
        if (change >= threshold) {
            Interval interval;
            interval.start_day = days[start_idx].day;
            interval.end_day = days[i].day;
            interval.start_avg = price_base;
            interval.end_avg = price_now;
            interval.change = change;
            
            // Находим min(Open) и max(Close) в интервале
            interval.min_open = days[start_idx].open;
            interval.max_close = days[start_idx].close;
            
            for (size_t j = start_idx; j <= i; j++) {
                interval.min_open = std::min(interval.min_open, days[j].open);
                interval.max_close = std::max(interval.max_close, days[j].close);
            }
            
            intervals.push_back(interval);
            
            // Начинаем новый интервал
            start_idx = i + 1;
            if (start_idx >= days.size()) {
                break;
            }
            price_base = days[start_idx].avg;
        }
    }
    
    return intervals;
}

std::string day_index_to_date(DayIndex day) {
    time_t ts = static_cast<time_t>(day) * 86400;
    struct tm* tm_info = gmtime(&ts);
    
    std::ostringstream oss;
    oss << std::setfill('0') 
        << (tm_info->tm_year + 1900) << "-"
        << std::setw(2) << (tm_info->tm_mon + 1) << "-"
        << std::setw(2) << tm_info->tm_mday;
    
    return oss.str();
}

void write_intervals(const std::string& filename, const std::vector<Interval>& intervals) {
    std::ofstream out(filename);
    
    out << std::fixed << std::setprecision(2);
    out << "start_date,end_date,min_open,max_close,start_avg,end_avg,change\n";
    
    for (const auto& iv : intervals) {
        out << day_index_to_date(iv.start_day) << ","
            << day_index_to_date(iv.end_day) << ","
            << iv.min_open << ","
            << iv.max_close << ","
            << iv.start_avg << ","
            << iv.end_avg << ","
            << std::setprecision(6) << iv.change << "\n";
    }
}