#include <iostream>
#include <bitset>
#include <string>
#include <sstream>
#include <climits>
#include <cstdint>
#include <string>
#include <cassert>
#include <iomanip>
using namespace std::literals::string_literals;
static constexpr auto WORLD_ROWS = 16;
static constexpr auto WORLD_COLUMNS = WORLD_ROWS;
static constexpr auto FIRST_VALID_CELL = 1; //to shortcut collision testing we can check against the map boundary walls. Helps with mouse interaction and for Q&D respawn when stuck in a wall.
static constexpr auto LAST_VALID_CELL = WORLD_ROWS - 2; //0 == wall, 15 == wall. so if our position is below or above the valid spaces, we can bail without performing lookup.
static std::string WORLD_AS_STRING[WORLD_ROWS] = { //original world map, which we want to convert to bitmap. 
    "1111111111111111"s,
    "1000000000000001"s,
    "1001111100000001"s,
    "1001000101010101"s,
    "1001000100000001"s,
    "1001001100000001"s,
    "1000000000000001"s,
    "1000000000000001"s,
    "1000000000000001"s,
    "1001100111111001"s,
    "1001000000001001"s,
    "1001110000001001"s,
    "1001000000001001"s,
    "1001111111101001"s,
    "1000000000000001"s,
    "1111111111111111"s
};

uint_fast16_t toInt(const std::string& s) {
    std::bitset<WORLD_COLUMNS> bits;
    std::istringstream is(s);
    is >> bits;
    return static_cast<uint_fast16_t>(bits.to_ulong());
}

void prettyPrintBitMap(){
    std::cout << "static constexpr uint_fast16_t  WORLD[WORLD_ROWS] = { // world map\n";
    for (size_t i = 0; i < WORLD_ROWS; i++) {   
        std::cout << std::dec << "/*[" << std::setfill(' ') << std::setw(2) << i << "] " << WORLD_AS_STRING[i] << "*/\t0x" << std::hex << toInt(WORLD_AS_STRING[i]) << ",\n";
    }
    std::cout << "};\n";
}

////// this is the copy-pasted output from prettyPrintBitMap()
////// pick whatever unsigned type provides enough bits to fit all columns. 16 in my case. 
static constexpr uint_fast16_t WORLD[WORLD_ROWS] = {
        0xffff, // 1111111111111111
        0x8001, // 1000000000000001
        0x9f01, // 1001111100000001
        0x9155, // 1001000101010101
        0x9101, // 1001000100000001
        0x9301, // 1001001100000001
        0x8001, // 1000000000000001
        0x8001, // 1000000000000001
        0x8001, // 1000000000000001
        0x99f9, // 1001100111111001
        0x9009, // 1001000000001001
        0x9c09, // 1001110000001001
        0x9009, // 1001000000001001
        0x9fe9, // 1001111111101001
        0x8001, // 1000000000000001
        0xffff, // 1111111111111111
};
////// 

inline constexpr bool isWall(int x, int y) noexcept {
    if (x < FIRST_VALID_CELL || y < FIRST_VALID_CELL
        || x > LAST_VALID_CELL || y > LAST_VALID_CELL) {
        return true;
    }
    return (WORLD[y] >> ((WORLD_COLUMNS - 1) - x) & 0x01);
}
void testBitmapWorld() {
    assert(!isWall(FIRST_VALID_CELL, FIRST_VALID_CELL));
    assert(!isWall(LAST_VALID_CELL, LAST_VALID_CELL));
    assert(isWall(3, 3)); //test an arbitrary position that we know should be a wall
    for (size_t i = 0; i < WORLD_COLUMNS; i++) {
        assert(isWall(0, i)); //test first row, all wall
        if (i != 0 && i < WORLD_COLUMNS - 1) { //skip the outer edges (all wall)
            assert(!isWall(1, i)); //test second row
            assert(!isWall(2, WORLD_ROWS - 2)); //test second-to-last row
        }
        assert(isWall(WORLD_ROWS - 1, i)); //test last row
    }    
}

int main(){    
    prettyPrintBitMap(); //convert from string representation to bitmap, and dump the source-code to stdout.
    testBitmapWorld();
    return 0;
}