#include <iostream>
#include <merklecpp.h>
#include <openssl/sha.h>
#include <iomanip>
#include <fstream>
#include <iterator>

#include <sys/stat.h>

std::vector<uint8_t> read_tree(const char* tree_path) {
    std::ifstream file(tree_path, std::ios::binary);
    file.unsetf(std::ios::skipws);
    file.seekg(0, std::ios::end);
    const std::streampos file_size = file.tellg();
    file.seekg(0, std::ios::beg);
    std::vector<uint8_t> v;
    v.reserve(file_size);
    v.insert(v.begin(), std::istream_iterator<uint8_t>(file), std::istream_iterator<uint8_t>());
    return v;
}

void write_tree(const char* tree_path, const std::vector<uint8_t>& serialized_tree) {
    std::ofstream out(tree_path, std::ios::out | std::ios::binary);
    out.write(reinterpret_cast<const char*>(serialized_tree.data()), serialized_tree.size());
    out.close();
}

extern "C" {
#include "library.h"
    extern void register_to_merkle(const char* tree_path, const char* computed_hash) {
        struct stat st;
        if (stat(tree_path, &st) == 0) {
            const std::vector<uint8_t> tree_bytes = read_tree(tree_path);
            merkle::Tree tree;
            tree.deserialise(tree_bytes);
            const merkle::Tree::Hash hash(computed_hash);
            tree.insert(hash);
            std::vector<uint8_t> target;
            tree.serialise(target);
            write_tree(tree_path, target);
        } else {
            merkle::Tree::Hash hash(computed_hash);
            merkle::Tree tree;
            tree.insert(hash);
            std::vector<uint8_t> target;
            tree.serialise(target);
            write_tree(tree_path, target);
        }
    }
    extern void merkle_generate_root(char** hashes, const int n, char* root) {
        merkle::Tree tree;
        for (int i = 0; i < n; i++){
            tree.insert(merkle::Hash(hashes[i]));
        }
        std::memcpy(root, tree.root().to_string().c_str(), HASH_SIZE);
    }
    extern void compute_hash(char* computed_hash, const char *content) {

        unsigned char hash[SHA256_DIGEST_LENGTH];
        SHA256_CTX sha256;
        SHA256_Init(&sha256);
        SHA256_Update(&sha256, content, sizeof(content));
        SHA256_Final(hash, &sha256);
        std::stringstream ss;
        for (int i = 0; i < SHA256_DIGEST_LENGTH; i++)
            ss << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(hash[i]);

        std::memcpy(computed_hash, ss.str().c_str(), HASH_SIZE);
        // std::cout << "⚙️ COMPUTED HASH: " << computed_hash << std::endl;
    }

    extern int trash() { return 100; }
}