/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */
module;

#include <cstdint>
#include <sqlite3.h>
#include <string.h>
#include <curl/curl.h>
#include <sqlite3.h>
#include <string>
#include <vector>
#include <optional>
#include <filesystem>
#include <boost/algorithm/string.hpp>

export module katja.utils;

export namespace katja
{
enum class Info
{
    // Error.
    unknown,
    // Installed in the same version.
    installed,
    // A different version is installed.
    updating,
    // Available, but not installed.
    installing,
    // Available.
    available
};

struct JobData
{
    sqlite3 *db;
    CURL *curl;

    virtual void package(Info info, const char *package_id, const char *summary) = 0;
    virtual void files(const std::vector<std::string>&) = 0;
    virtual void details(char *package_id,
            const char *group, const char *description, const char *homepage, int uncompressed) = 0;
    virtual void set_percentage(double) = 0;
};

struct DummyJobData final : JobData
{

    void package(Info info, const char *package_id, const char *summary) override
    {
    }

    void files(const std::vector<std::string>&) override
    {
    }

    void details(char *package_id,
            const char *group, const char *description, const char *homepage, int uncompressed) override
    {
    }

    void set_percentage(double) override
    {
    }
};

/**
 * katja::get_file:
 * @curl: curl easy handle.
 * @source_url: source url.
 * @dest: destination.
 *
 * Download the file.
 *
 * Returns: CURLE_OK (zero) on success, non-zero otherwise.
 **/
CURLcode get_file(CURL **curl, const char *source_url, const std::optional<std::filesystem::path>& dest)
{
    FILE *fout = nullptr;
    CURLcode ret;
    long response_code;
    std::string dest_dir_name;

    if ((*curl == nullptr) && (!(*curl = curl_easy_init())))
    {
        return CURLE_BAD_FUNCTION_ARGUMENT;
    }

    curl_easy_setopt(*curl, CURLOPT_FOLLOWLOCATION, 1L);
    curl_easy_setopt(*curl, CURLOPT_URL, source_url);

    if (!dest.has_value())
    {
        curl_easy_setopt(*curl, CURLOPT_NOBODY, 1L);
        curl_easy_setopt(*curl, CURLOPT_HEADER, 1L);
        ret = curl_easy_perform(*curl);
        curl_easy_getinfo(*curl, CURLINFO_RESPONSE_CODE, &response_code);

        if (response_code != 200)
        {
            ret = CURLE_REMOTE_FILE_NOT_FOUND;
        }
    }
    else
    {
        dest_dir_name = dest.value().native();
        if (std::filesystem::is_directory(dest.value()))
        {
            dest_dir_name += strrchr(source_url, '/');
        }
        if ((fout = fopen(dest_dir_name.c_str(), "ab")) == nullptr)
        {
            return CURLE_WRITE_ERROR;
        }
        curl_easy_setopt(*curl, CURLOPT_WRITEDATA, fout);
        ret = curl_easy_perform(*curl);
    }
    curl_easy_reset(*curl);
    if (fout != nullptr)
    {
        fclose(fout);
    }
    return ret;
}

/**
 * katja::split_package_name:
 * Got the name of a package, without version-arch-release data.
 **/
std::optional<std::vector<std::string>> split_package_name(const std::string& pkg_filename)
{
    std::string pkg_full_name;

    int len = pkg_filename.size();
    if (len < 4)
    {
        return std::nullopt;
    }
    std::vector<std::string> pkg_tokens(5);

    if (pkg_filename[len - 4] == '.')
    {
        /* Full name without extension */
        pkg_tokens[3] = pkg_filename;
        pkg_full_name = std::string(std::crbegin(pkg_filename) + 4, std::crend(pkg_filename));

        /* The last 3 characters should be the file extension */
        pkg_tokens[4] = std::string(std::cbegin(pkg_filename) + len + 1, std::cend(pkg_filename));
    }
    else
    {
        pkg_full_name = std::string(std::crbegin(pkg_filename), std::crend(pkg_filename));
    }

    /* Reverse all of the bytes in the package filename to get the name, version and the architecture */
    std::vector<std::string> reversed_tokens;
    boost::algorithm::split(reversed_tokens, pkg_full_name, boost::is_any_of("-"));
    pkg_tokens[0] = std::string(std::crbegin(reversed_tokens[3]), std::crend(reversed_tokens[3])); /* Name */
    pkg_tokens[1] = std::string(std::crbegin(reversed_tokens[2]), std::crend(reversed_tokens[2])); /* Version */
    pkg_tokens[2] = std::string(std::crbegin(reversed_tokens[1]), std::crend(reversed_tokens[1])); /* Architecture */

    return pkg_tokens;
}

/**
 * katja::is_installed:
 * Checks if a package is already installed in the system.
 *
 * @pkg_fullname: Package name should be looked for.
 *
 * Returns: Package installation information.
 **/
Info is_installed(const char *pkg_fullname)
{
    Info ret = Info::installing;
    const char *it;
    std::uint8_t dashes = 0;
    ptrdiff_t pkg_name;

    if (pkg_fullname == nullptr)
    {
        return Info::unknown;
    }

    // We want to find the package name without version for the package we're
    // looking for.
    for (it = pkg_fullname + strlen(pkg_fullname); it != pkg_fullname; --it)
    {
        if (*it == '-')
        {
            if (dashes == 2)
            {
                break;
            }
            ++dashes;
        }
    }
    if (dashes < 2)
    {
        return Info::unknown;
    }
    pkg_name = it - pkg_fullname;

    // Read the package metadata directory and comprare all installed packages
    // with ones in the cache.
    auto pkg_metadata_dir = std::filesystem::path("/var/log/packages");

    for (const auto& pkg_metadata_file_info : std::filesystem::directory_iterator{ pkg_metadata_dir })
    {
        std::string filename = pkg_metadata_file_info.path().native();
        const char *dir = filename.c_str();
        dashes = 0;

        if (dir == pkg_fullname)
        {
            ret = Info::installed;
        }
        else
        {
            for (it = dir + filename.size(); it != dir; --it)
            {
                if (*it == '-')
                {
                    if (dashes == 2)
                    {
                        break;
                    }
                    ++dashes;
                }
            }
            if (pkg_name == (it - dir) && strncmp(pkg_fullname, dir, pkg_name) == 0)
            {
                ret = Info::updating;
            }
        }
        if (ret != Info::installing) /* If installed */
        {
            break;
        }
    }

    return ret;
}

}