/*
 * 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 <bzlib.h>
#include <sqlite3.h>
#include <stdlib.h>
#include <cstdint>
#include <cstddef>
#include <string.h>
#include <gio/gio.h>
#include <curl/curl.h>
#include <string>
#include <regex>
#include <vector>
#include <forward_list>
#include <filesystem>

export module katja.slackpkg;

import katja.utils;
import katja.pkgtools;

export namespace katja
{
class Slackpkg final : public Pkgtools
{
public:
    /**
     * katja::Slackpkg::Slackpkg:
     * @name: Repository name.
     * @mirror: Repository mirror.
     * @order: Repository order.
     * @blacklist: Blacklist.
     * @priority: Groups priority.
     *
     * Constructor.
     *
     * Returns: New #katja::Slackpkg.
     **/
    Slackpkg(const std::string& name, const std::string& mirror,
            std::uint8_t order, const char *blacklist, char **priority) noexcept
        : Pkgtools(name, mirror, order)
    {
        if (blacklist != nullptr)
        {
            this->blacklist = std::regex(blacklist);
        }
        if (priority != nullptr)
        {
            for (char **cur_priority = priority; *cur_priority; cur_priority++)
            {
                this->priority.emplace_back(*cur_priority);
            }
        }
    }

    /**
     * katja::Slackpkg::collect_cache_info:
     * @tmpl: temporary directory for downloading the files.
     *
     * Download files needed to get the information like the list of packages
     * in available repositories, updates, package descriptions and so on.
     *
     * Returns: List of files needed for building the cache.
     **/
    std::forward_list<cache_entry> collect_cache_info(const std::filesystem::path& tmpl) noexcept
    {
        CURL *curl = nullptr;
        cache_entry source_dest;
        std::forward_list<cache_entry> file_list;
        GFile *tmp_dir, *repo_tmp_dir;

        /* Create the temporary directory for the repository */
        tmp_dir = g_file_new_for_path(tmpl.native().c_str());
        repo_tmp_dir = g_file_get_child(tmp_dir, this->name.c_str());
        g_file_make_directory(repo_tmp_dir, nullptr, nullptr);

        /* Download PACKAGES.TXT. These files are most important, break if some of them couldn't be found */
        for (const std::string& current_priority : this->priority)
        {
            source_dest.first = this->mirror + current_priority + "/PACKAGES.TXT";
            source_dest.second = tmpl / this->name / "PACKAGES.TXT";

            if (get_file(&curl, source_dest.first.c_str(), std::nullopt) == CURLE_OK)
            {
                file_list.emplace_front(std::move(source_dest));
            }
            else
            {
                goto out;
            }

            /* Download file lists if available */
            source_dest.first = this->mirror + current_priority + "/MANIFEST.bz2";
            source_dest.second = tmpl / this->name / (current_priority + "-MANIFEST.bz2");

            if (get_file(&curl, source_dest.first.c_str(), std::nullopt) == CURLE_OK)
            {
                file_list.emplace_front(std::move(source_dest));
            }
        }
    out:
        g_object_unref(repo_tmp_dir);
        g_object_unref(tmp_dir);

        if (curl)
        {
            curl_easy_cleanup(curl);
        }
        return file_list;
    }

    /**
     * katja::Slackpkg::generate_cache:
     * @job_data: A #JobData.
     * @tmpl: temporary directory for downloading the files.
     *
     * Download files needed to get the information like the list of packages
     * in available repositories, updates, package descriptions and so on.
     *
     * Returns: List of files needed for building the cache.
     **/
    void generate_cache(JobData *job_data, const std::filesystem::path& tmpl) noexcept
    {
        std::vector<std::string> pkg_tokens;
        char *query = nullptr, *filename = nullptr, *location = nullptr, *summary = nullptr, *line;
        unsigned pkg_compressed = 0, pkg_uncompressed = 0;
        std::uint8_t pkg_name_len;
        GString *desc;
        GFile *list_file;
        GFileInputStream *fin = nullptr;
        GDataInputStream *data_in = nullptr;
        sqlite3_stmt *insert_statement = nullptr, *update_statement = nullptr, *insert_default_statement = nullptr;
        sqlite3_stmt *statement;

        /* Check if the temporary directory for this repository exists, then the file metadata have to be generated */
        std::filesystem::path packages_txt = tmpl / this->name / "PACKAGES.TXT";
        list_file = g_file_new_for_path(packages_txt.native().c_str());
        fin = g_file_read(list_file, nullptr, nullptr);
        g_object_unref(list_file);

        if (!fin)
        {
            goto out;
        }
        /* Remove the old entries from this repository */
        if (sqlite3_prepare_v2(job_data->db,
                               "DELETE FROM repos WHERE repo LIKE @repo",
                               -1,
                               &statement,
                               nullptr) == SQLITE_OK)
        {
            sqlite3_bind_text(statement, 1, this->name.c_str(), -1, SQLITE_TRANSIENT);
            sqlite3_step(statement);
            sqlite3_finalize(statement);
        }
        if (sqlite3_prepare_v2(job_data->db,
                               "INSERT INTO repos (repo_order, repo) VALUES (@repo_order, @repo)",
                               -1,
                               &statement,
                               nullptr) != SQLITE_OK)
        {
            goto out;
        }
        sqlite3_bind_int(statement, 1, this->order);
        sqlite3_bind_text(statement, 2, this->name.c_str(), -1, SQLITE_TRANSIENT);
        sqlite3_step(statement);
        sqlite3_finalize(statement);

        /* Insert new records */
        if ((sqlite3_prepare_v2(job_data->db,
                                "INSERT OR REPLACE INTO pkglist (full_name, ver, arch, ext, location, "
                                "summary, desc, compressed, uncompressed, name, repo_order, cat) "
                                "VALUES (@full_name, @ver, @arch, @ext, @location, @summary, "
                                "@desc, @compressed, @uncompressed, @name, @repo_order, @cat)",
                                -1,
                                &insert_statement,
                                nullptr) != SQLITE_OK)
         || (sqlite3_prepare_v2(job_data->db,
                            "INSERT OR REPLACE INTO pkglist (full_name, ver, arch, ext, location, "
                            "summary, desc, compressed, uncompressed, name, repo_order) "
                            "VALUES (@full_name, @ver, @arch, @ext, @location, @summary, "
                            "@desc, @compressed, @uncompressed, @name, @repo_order)",
                            -1,
                            &insert_default_statement,
                            nullptr) != SQLITE_OK)) 
        {
            goto out;
        }
        query = sqlite3_mprintf("UPDATE pkglist SET full_name = @full_name, ver = @ver, arch = @arch, "
                                "ext = @ext, location = @location, summary = @summary, "
                                "desc = @desc, compressed = @compressed, uncompressed = @uncompressed "
                                "WHERE name LIKE @name AND repo_order = %u",
                                this->order);
        if (sqlite3_prepare_v2(job_data->db, query, -1, &update_statement, nullptr) != SQLITE_OK)
        {
            goto out;
        }

        data_in = g_data_input_stream_new(G_INPUT_STREAM(fin));
        desc = g_string_new("");

        sqlite3_exec(job_data->db, "BEGIN TRANSACTION", nullptr, nullptr, nullptr);

        while ((line = g_data_input_stream_read_line(data_in, nullptr, nullptr, nullptr)))
        {
            if (!strncmp(line, "PACKAGE NAME:  ", 15))
            {
                filename = g_strdup(line + 15);
                if (this->is_blacklisted(filename))
                {
                    g_free(filename);
                    filename = nullptr;
                }
            }
            else if (filename && !strncmp(line, "PACKAGE LOCATION:  ", 19))
            {
                location = g_strdup(line + 21); /* Exclude ./ at the path beginning */
            }
            else if (filename && !strncmp(line, "PACKAGE SIZE (compressed):  ", 28))
            {
                /* Remove the unit (kilobytes) */
                pkg_compressed = atoi(g_strndup(line + 28, strlen(line + 28) - 2)) * 1024;
            }
            else if (filename && !strncmp(line, "PACKAGE SIZE (uncompressed):  ", 30))
            {
                /* Remove the unit (kilobytes) */
                pkg_uncompressed = atoi(g_strndup(line + 30, strlen(line + 30) - 2)) * 1024;
            }
            else if (filename && !g_strcmp0(line, "PACKAGE DESCRIPTION:"))
            {
                g_free(line);
                line = g_data_input_stream_read_line(data_in, nullptr, nullptr, nullptr); /* Short description */

                summary = g_strstr_len(line, -1, "(");
                if (summary) /* Else summary = nullptr */
                {
                    summary = g_strndup(summary + 1, strlen(summary) - 2); /* Without ( ) */
                }
                pkg_tokens = split_package_name(filename).value();
                pkg_name_len = pkg_tokens[0].size(); /* Description begins with pkg_name: */
            }
            else if (filename && !strncmp(line, pkg_tokens[0].c_str(), pkg_name_len))
            {
                g_string_append(desc, line + pkg_name_len + 1);
            }
            else if (filename && !g_strcmp0(line, ""))
            {
                if (g_strcmp0(location, "patches/packages")) /* Insert a new package */
                {
                    /* Get the package group based on its location */
                    const char *cat = g_strrstr(location, "/");
                    if (cat)
                    {
                        ++cat;
                        statement = insert_statement;
                        sqlite3_bind_text(insert_statement, 12, cat, -1, SQLITE_TRANSIENT);
                    }
                    else
                    {
                        statement = insert_default_statement;
                    }
                    sqlite3_bind_int(statement, 11, this->order);
                }
                else /* Update package information if it is a patch */
                {
                    statement = update_statement;
                }
                sqlite3_bind_text(statement, 1, pkg_tokens[3].c_str(), -1, SQLITE_TRANSIENT);
                sqlite3_bind_text(statement, 2, pkg_tokens[1].c_str(), -1, SQLITE_TRANSIENT);
                sqlite3_bind_text(statement, 3, pkg_tokens[2].c_str(), -1, SQLITE_TRANSIENT);
                sqlite3_bind_text(statement, 4, pkg_tokens[4].c_str(), -1, SQLITE_TRANSIENT);
                sqlite3_bind_text(statement, 5, location, -1, SQLITE_TRANSIENT);
                sqlite3_bind_text(statement, 6, summary, -1, SQLITE_TRANSIENT);
                sqlite3_bind_text(statement, 7, desc->str, -1, SQLITE_TRANSIENT);
                sqlite3_bind_int(statement, 8, pkg_compressed);
                sqlite3_bind_int(statement, 9, pkg_uncompressed);
                sqlite3_bind_text(statement, 10, pkg_tokens[0].c_str(), -1, SQLITE_TRANSIENT);

                sqlite3_step(statement);
                sqlite3_clear_bindings(statement);
                sqlite3_reset(statement);

                /* Reset for the next package */
                g_free(filename);
                g_free(location);
                g_free(summary);
                filename = location = summary = nullptr;
                g_string_assign(desc, "");
                pkg_compressed = pkg_uncompressed = 0;
            }
            g_free(line);
        }
        sqlite3_exec(job_data->db, "END TRANSACTION", nullptr, nullptr, nullptr);

        g_string_free(desc, true);
        g_object_unref(data_in);

        /* Parse MANIFEST.bz2 */
        for (const std::string& current_priority : this->priority)
        {
            manifest(job_data, tmpl, current_priority + "-MANIFEST.bz2");
        }
    out:
        sqlite3_finalize(update_statement);
        sqlite3_free(query);
        sqlite3_finalize(insert_default_statement);
        sqlite3_finalize(insert_statement);

        if (fin)
        {
            g_object_unref(fin);
        }
    }

private:
    static const std::size_t max_buf_size = 8192;
    std::vector<std::string> priority;

    /*
     * katja::Slackpkg::manifest:
     * @job:      a #JobData.
     * @tmpl:     temporary directory.
     * @filename: manifest filename
     *
     * Parse the manifest file and save the file list in the database.
     */

    void manifest(JobData *job_data, const std::filesystem::path& tmpl, const std::string& filename) noexcept
    {
        FILE *manifest;
        int err, read_len;
        unsigned pos;
        char buf[max_buf_size], *pkg_filename, *rest = nullptr, *start;
        std::filesystem::path path;
        char *full_name = nullptr;
        char **line, **lines;
        BZFILE *manifest_bz2;
        GRegex *pkg_expr = nullptr, *file_expr = nullptr;
        GMatchInfo *match_info;
        sqlite3_stmt *statement = nullptr;

        path = tmpl / this->name / filename;
        manifest = fopen(path.native().c_str(), "rb");

        if (!manifest)
        {
            return;
        }
        if (!(manifest_bz2 = BZ2_bzReadOpen(&err, manifest, 0, 0, nullptr, 0)))
        {
            goto out;
        }

        /* Prepare regular expressions */
        pkg_expr = g_regex_new("^\\|\\|[[:blank:]]+Package:[[:blank:]]+.+\\/(.+)\\.(t[blxg]z$)?",
                               static_cast<GRegexCompileFlags> (G_REGEX_OPTIMIZE | G_REGEX_DUPNAMES),
                               static_cast<GRegexMatchFlags> (0),
                               nullptr);
        file_expr = g_regex_new("^[-bcdlps][-r][-w][-xsS][-r][-w][-xsS][-r][-w]"
                                "[-xtT][[:space:]][^[:space:]]+[[:space:]]+"
                                "[[:digit:]]+[[:space:]][[:digit:]-]+[[:space:]]"
                                "[[:digit:]:]+[[:space:]](?!install\\/|\\.)(.*)",
                                static_cast<GRegexCompileFlags> (G_REGEX_OPTIMIZE | G_REGEX_DUPNAMES),
                                static_cast<GRegexMatchFlags> (0),
                                nullptr);
        if (!(file_expr) || !(pkg_expr))
        {
            goto out;
        }

        /* Prepare SQL statements */
        if (sqlite3_prepare_v2(job_data->db,
                               "INSERT INTO filelist (full_name, filename) VALUES (@full_name, @filename)",
                               -1,
                               &statement,
                               nullptr) != SQLITE_OK)
        {
            goto out;
        }

        sqlite3_exec(job_data->db, "BEGIN TRANSACTION", nullptr, nullptr, nullptr);
        while ((read_len = BZ2_bzRead(&err, manifest_bz2, buf, max_buf_size - 1)))
        {
            if ((err != BZ_OK) && (err != BZ_STREAM_END))
            {
                break;
            }
            buf[read_len] = '\0';

            /* Split the read text into lines */
            lines = g_strsplit(buf, "\n", 0);
            if (rest)
            { /* Add to the first line rest characters from the previous read operation */
                start = lines[0];
                lines[0] = g_strconcat(rest, lines[0], nullptr);
                g_free(start);
                g_free(rest);
            }
            if (err != BZ_STREAM_END) /* The last line can be incomplete */
            {
                pos = g_strv_length(lines) - 1;
                rest = lines[pos];
                lines[pos] = nullptr;
            }
            for (line = lines; *line; line++)
            {
                if (g_regex_match(pkg_expr, *line, static_cast<GRegexMatchFlags> (0), &match_info))
                {
                    if (g_match_info_get_match_count(match_info) > 2)
                    { /* If the extension matches */
                        g_free(full_name);
                        full_name = g_match_info_fetch(match_info, 1);
                    }
                    else
                    {
                        full_name = nullptr;
                    }
                }
                g_match_info_free(match_info);

                match_info = nullptr;
                if (full_name && g_regex_match(file_expr, *line, static_cast<GRegexMatchFlags> (0), &match_info))
                {
                    pkg_filename = g_match_info_fetch(match_info, 1);
                    sqlite3_bind_text(statement, 1, full_name, -1, SQLITE_TRANSIENT);
                    sqlite3_bind_text(statement, 2, pkg_filename, -1, SQLITE_TRANSIENT);
                    sqlite3_step(statement);
                    sqlite3_clear_bindings(statement);
                    sqlite3_reset(statement);
                    g_free(pkg_filename);
                }
                g_match_info_free(match_info);
            }
            g_strfreev(lines);
        }

        sqlite3_exec(job_data->db, "END TRANSACTION", nullptr, nullptr, nullptr);
        g_free(full_name);
        BZ2_bzReadClose(&err, manifest_bz2);

    out:
        sqlite3_finalize(statement);
        if (file_expr)
        {
            g_regex_unref(file_expr);
        }
        if (pkg_expr)
        {
            g_regex_unref(pkg_expr);
        }
        fclose(manifest);
    }
};
}