#include <filesystem>
#include <fstream>
#include <iostream>
#include <map>
#include <regex>
#include <set>
#include <tuple>
#include <vector>

using namespace std;

namespace {

struct Claim {
	int id;
	int left;
	int top;
	int width;
	int height;
};

#if 0
ostream&
operator<<(ostream& ostrm, const Claim& claim)
{
	ostrm << "id: " << claim.id
	      << " (" << claim.left << ", " << claim.top << ": " << claim.width << "x" << claim.height;
	return ostrm;
}
#endif

vector<Claim>
read_file(const filesystem::path& filename)
{
	ifstream      file{ filename };
	vector<Claim> claims;

	regex  pattern(R"#((\d+) @ (\d+),(\d+): (\d+)x(\d+))#");
	smatch match;

	for ( string line; getline(file, line); ) {
		if ( !regex_search(line, match, pattern) ) {
			continue;
		}

		Claim claim{};
		claim.id     = stoi(match[1]);
		claim.left   = stoi(match[2]);
		claim.top    = stoi(match[3]);
		claim.width  = stoi(match[4]);
		claim.height = stoi(match[5]);

		claims.emplace_back(claim);
	}

	return claims;
}

void
solve(const vector<Claim>& claims)
{
	map<tuple<int, int>, vector<int>> fabric;
	set<int>                          allIds;

	for ( const auto& claim: claims ) {
		for ( int x = claim.left; x < claim.left + claim.width; ++x ) {
			for ( int y = claim.top; y < claim.top + claim.height; ++y ) {
				fabric[{ x, y }].emplace_back(claim.id);
			}
		}
		allIds.emplace(claim.id);
	}

	int overlapCount = 0;
	for ( const auto& [pos, ids]: fabric ) {
		if ( ids.size() > 1 ) {
			++overlapCount;
			for ( const auto& id: ids ) {
				allIds.erase(id);
			}
		}
	}

	cout << "Part 1: " << overlapCount << '\n';
	cout << "Part 2: " << *allIds.begin() << '\n';
}

} // namespace

int
main()
{
	auto claims = read_file("data/day03.txt");
	solve(claims);
}