#include "hash.hpp"
#include <fstream>
#include <filesystem>
#include <iostream>

namespace dropshell {

XXH64_hash_t hash_file(const std::string &path) {
    // Create hash state
    XXH64_state_t* const state = XXH64_createState();
    if (state == nullptr) {
        std::cerr << "Failed to create hash state" << std::endl;
        return 0;
    }

    // Initialize state with seed 0
    if (XXH64_reset(state, 0) == XXH_ERROR) {
        std::cerr << "Failed to reset hash state" << std::endl;
        XXH64_freeState(state);
        return 0;
    }

    // Open file
    std::ifstream file(path, std::ios::binary);
    if (!file.is_open()) {
        std::cerr << "Failed to open file: " << path << std::endl;
        XXH64_freeState(state);
        return 0;
    }

    // Read file in chunks and update hash
    const size_t buffer_size = 4096;
    char buffer[buffer_size];
    while (file.read(buffer, buffer_size)) {
        if (XXH64_update(state, buffer, file.gcount()) == XXH_ERROR) {
            std::cerr << "Failed to update hash" << std::endl;
            XXH64_freeState(state);
            return 0;
        }
    }

    // Handle any remaining bytes
    if (file.gcount() > 0) {
        if (XXH64_update(state, buffer, file.gcount()) == XXH_ERROR) {
            std::cerr << "Failed to update hash" << std::endl;
            XXH64_freeState(state);
            return 0;
        }
    }

    // Get final hash
    XXH64_hash_t hash = XXH64_digest(state);
    XXH64_freeState(state);
    return hash;
}

XXH64_hash_t hash_directory_recursive(const std::string &path) {
    // Create hash state
    XXH64_state_t* const state = XXH64_createState();
    if (state == nullptr) {
        std::cerr << "Failed to create hash state" << std::endl;
        return 0;
    }

    // Initialize state with seed 0
    if (XXH64_reset(state, 0) == XXH_ERROR) {
        std::cerr << "Failed to reset hash state" << std::endl;
        XXH64_freeState(state);
        return 0;
    }

    try {
        // Iterate through all files in directory recursively
        for (const auto& entry : std::filesystem::recursive_directory_iterator(path)) {
            if (entry.is_regular_file()) {
                // Get file hash
                XXH64_hash_t file_hash = hash_file(entry.path().string());
                
                // Update directory hash with file hash
                if (XXH64_update(state, &file_hash, sizeof(file_hash)) == XXH_ERROR) {
                    std::cerr << "Failed to update hash" << std::endl;
                    XXH64_freeState(state);
                    return 0;
                }
            }
        }
    } catch (const std::filesystem::filesystem_error& e) {
        std::cerr << "Filesystem error: " << e.what() << std::endl;
        XXH64_freeState(state);
        return 0;
    }

    // Get final hash
    XXH64_hash_t hash = XXH64_digest(state);
    XXH64_freeState(state);
    return hash;
}

} // namespace dropshell