#include "copter.h"

#include <sstream>
#include <exception>
#include <cstring>

void
CopterState::dump_mem(std::ostream &out) const
{
    for (int i = 0; i < MEMORY_SIZE; ++i) {
        if (i > 0) out << ' ';
        out << int(mem_[i]);
    }
    out << std::endl;
}

CopterState::Direction
CopterState::neighbour_kind(const CopterState &other) const noexcept
{
    if (x_ == other.x_ && y_ == other.y_) {
        return Direction::SAME;
    } else if (x_ == other.x_ + 1 && y_ == other.y_) {
        return Direction::LEFT;
    } else if (x_ == other.x_ - 1 && y_ == other.y_) {
        return Direction::RIGHT;
    } else if (x_ == other.x_ && y_ == other.y_ - 1) {
        return Direction::UP;
    } else if (x_ == other.x_ && y_ == other.y_ + 1) {
        return Direction::DOWN;
    }
    return Direction::AWAY;
}

void
CopterState::parse_copter_output(int x, int y, std::string &str)
{
    std::istringstream ss(str);
    int dest = 0;
    ss >> dest;
    if (!ss || dest <= 0 || dest > int(CopterState::Direction::SAME)) {
        throw std::invalid_argument(std::string("invalid destination ") + std::to_string(dest));
    }
    unsigned char mem[MEMORY_SIZE] = {};
    for (int i = 0; i < MEMORY_SIZE; ++i) {
        int val;
        ss >> val;
        if (!ss) {
            throw std::invalid_argument(std::string("failed to read memory value ") + "[" + std::to_string(i) + "]");
        }
        if (val < 0 || val > 255) {
            throw std::invalid_argument(std::string("invalid memory value ") + "[" + std::to_string(i) + "]: " + std::to_string(val));
        }
        mem[i] = val;
    }
    // check for garbage
    switch (dest) {
    case 1: // left
        x_ = x - 1;
        y_ = y;
        break;
    case 2: // right
        x_ = x + 1;
        y_ = y;
        break;
    case 3: // up
        x_ = x;
        y_ = y + 1;
        break;
    case 4: // down
        x_ = x;
        y_ = y - 1;
        break;
    case 5: // stay put
        x_ = x;
        y_ = y;
        break;
    default:
        throw std::invalid_argument(std::string("invalid destination ") + std::to_string(dest));
    }
    memcpy(mem_, mem, sizeof(mem_));
}