#include <queue>
#include <vector>
#include "core.h"
#include "group.h"
#include "common.h"
#include "absl/container/flat_hash_map.h"

#include "type_id.h"

namespace klotski {

using Common::range_reverse;

uint32_t Group::type_id(const RawCode &raw_code) {
    return type_id(block_num(raw_code));
}

uint32_t Group::type_id(const CommonCode &common_code) {
    return type_id(block_num(common_code));
}

uint32_t Group::type_id(const block_num_t &block_num) {
    auto n_x2x = block_num.n_1x2 + block_num.n_2x1;
    auto flag = (n_x2x << 8) | (block_num.n_2x1 << 4) | block_num.n_1x1;
    return std::lower_bound(TYPE_ID_INDEX, TYPE_ID_INDEX + 204, flag) - TYPE_ID_INDEX;
}

Group::block_num_t Group::block_num(uint32_t type_id) {
    auto flag = TYPE_ID_INDEX[type_id];
    uint8_t n_x2x = flag >> 8;
    uint8_t n_2x1 = (flag >> 4) & 0b1111;
    return block_num_t {
        .n_1x1 = static_cast<uint8_t>(flag & 0b1111),
        .n_1x2 = static_cast<uint8_t>(n_x2x - n_2x1),
        .n_2x1 = n_2x1,
    };
}

Group::block_num_t Group::block_num(const RawCode &raw_code) {
    block_num_t result;
    auto tmp = raw_code.unwrap();
    for (int addr = 0; addr < 20; ++addr, tmp >>= 3) {
        switch (tmp & 0b111) {
            case B_1x1:
                ++result.n_1x1;
                continue;
            case B_1x2:
                ++result.n_1x2;
                continue;
            case B_2x1:
                ++result.n_2x1;
                continue;
        }
    }
    return result;
}

Group::block_num_t Group::block_num(const CommonCode &common_code) {
    block_num_t result;
    auto range = range_reverse((uint32_t)common_code.unwrap());
    for (; range; range >>= 2) {
        switch (range & 0b11) {
            case 0b01: /// 1x2 block
                ++result.n_1x2;
                continue;
            case 0b10: /// 2x1 block
                ++result.n_2x1;
                continue;
            case 0b11: /// 1x1 block
                ++result.n_1x1;
                continue;
        }
    }
    return result;
}

std::vector<RawCode> Group::group_cases(const RawCode &seed) {
    std::queue<uint64_t> cache;
    absl::flat_hash_map<uint64_t, uint64_t> cases; // <code, mask>
    cases.reserve(max_group_size(seed));
    cases.emplace(seed.unwrap(), 0); // without mask
    cache.emplace(seed.unwrap());

    auto core = Core(
        [&cache, &cases](auto &&code, auto &&mask) { // callback function
            auto current = cases.find(code);
            if (current != cases.end()) {
                current->second |= mask; // update mask
                return;
            }
            cases.emplace(code, mask);
            cache.emplace(code);
        }
    );
    while (!cache.empty()) { // until BFS without elements
        core.next_cases(cache.front(), cases.find(cache.front())->second);
        cache.pop(); // case dequeue
    }

    auto result = std::vector<RawCode>();
    result.reserve(cases.size());
    for (auto &&raw_code : cases) { // export group cases
        result.emplace_back(RawCode::unsafe_create(raw_code.first));
    }
    return result;
}




} // namespace klotski