#include "auth.h"

#include "hash/hash.hpp"

#include <print>

#include <leveldb/db.h>
#include <leveldb/write_batch.h>

using leveldb_ptr = leveldb::DB*;

auto user_db    = leveldb_ptr{nullptr};
auto iter_round = 10000;

auto filter(const std::string_view id) -> bool
{
    return id.contains(':');
}

auto mangle_user_id(const std::string_view id) -> std::string
{
    return std::format("{}:user_id", id);
}

auto mangle_permission(const std::string_view id) -> std::string
{
    return std::format("{}:permission", id);
}

extern "C"
{
    auto open_user_db() -> int
    {
        auto opts = leveldb::Options{};

        opts.create_if_missing = true;

        auto status = leveldb::DB::Open(opts, "db/user", &user_db);

        if (!status.ok()) {
            std::println(stderr, "Failed to open user database: {}", status.ToString());
            return 0;
        }
        return 1;
    }

    auto close_user_db() -> void
    {
        delete user_db;
    }

    auto check_user_exists(const char* user_id, int* result) -> int
    {
        if (filter(user_id)) return 0;

        auto value  = std::string{};
        auto status = user_db->Get(leveldb::ReadOptions{}, mangle_user_id(user_id), &value);
        if (status.ok()) {
            *result = 1;
        } else if (status.IsNotFound()) {
            *result = 0;
        } else {
            std::println(stderr, "Failed to check user existence: {}", status.ToString());
            return 0;
        }
        return 1;
    }

    auto set_user_password(const char* user_id, const char* password) -> int
    {
        if (filter(user_id)) return 0;

        auto hash   = generate_hash(password, iter_round);
        auto status = user_db->Put(leveldb::WriteOptions{}, mangle_user_id(user_id), hash);
        if (!status.ok()) {
            std::println(stderr, "Failed to set user password: {}", status.ToString());
            return 0;
        }
        return 1;
    }

    auto login(const char* user_id, const char* password, int* result) -> int
    {
        if (filter(user_id)) return 0;

        auto value  = std::string{};
        auto status = user_db->Get(leveldb::ReadOptions{}, mangle_user_id(user_id), &value);
        if (!status.ok()) {
            std::println(stderr, "Failed to login: {}", status.ToString());
            return 0;
        }
        *result = validate_password(password, value.data());
        return 1;
    }

    int registe(const char* user_id, const char* password)
    {
        if (filter(user_id)) return 0;

        auto batch = leveldb::WriteBatch{};
        batch.Put(mangle_user_id(user_id), generate_hash(password, iter_round));
        batch.Put(mangle_permission(user_id), "2");
        auto status = user_db->Write(leveldb::WriteOptions{}, &batch);
        if (!status.ok()) {
            std::println(stderr, "Failed to register: {}", status.ToString());
            return 0;
        }
        return 1;
    }

    auto delete_user(const char* user_id) -> int
    {
        if (filter(user_id)) return 0;

        auto batch = leveldb::WriteBatch{};
        batch.Delete(mangle_user_id(user_id));
        batch.Delete(mangle_permission(user_id));
        auto status = user_db->Write(leveldb::WriteOptions{}, &batch);
        if (!status.ok()) {
            std::println(stderr, "Failed to delete: {}", status.ToString());
            return 0;
        }
        return 1;
    }

    int get_user_permission(const char* user_id, int* result)
    {
        if (filter(user_id)) return 0;

        auto value  = std::string{};
        auto status = user_db->Get(leveldb::ReadOptions{}, mangle_permission(user_id), &value);
        if (status.ok()) {
            *result = std::stoi(value);
        } else {
            std::println(stderr, "Failed to get user permission: {}", status.ToString());
            return 0;
        }
        return 1;
    }

    int set_user_permission(const char* user_id, int permission)
    {
        if (filter(user_id)) return 0;

        auto status = user_db->Put(leveldb::WriteOptions{}, mangle_permission(user_id), std::to_string(permission));
        if (!status.ok()) {
            std::println(stderr, "Failed to set user permission: {}", status.ToString());
            return 0;
        }
        return 1;
    }

    int set_admin_password(const char* password)
    {
        auto hash   = generate_hash(password, iter_round);
        auto status = user_db->Put(leveldb::WriteOptions{}, "admin_password_hash", hash);
        if (!status.ok()) {
            std::println(stderr, "Failed to set admin password: {}", status.ToString());
            return 0;
        }
        return 1;
    }

    int admin_login(const char* password, int* result)
    {
        auto value  = std::string{};
        auto status = user_db->Get(leveldb::ReadOptions{}, "admin_password_hash", &value);
        if (!status.ok()) {
            std::println(stderr, "Failed to login admin: {}", status.ToString());
            return 0;
        }
        *result = validate_password(password, value.data());
        return 1;
    }

    int has_admin_password(int* result)
    {
        auto value  = std::string{};
        auto status = user_db->Get(leveldb::ReadOptions{}, "admin_password_hash", &value);
        if (status.ok()) {
            *result = 1;
        } else if (status.IsNotFound()) {
            *result = 0;
        } else {
            std::println(stderr, "Failed to check admin password existence: {}", status.ToString());
            return 0;
        }
        return 1;
    }
}