// Copyright (C) 2024 Simon Quigley <tsimonq2@ubuntu.com>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

#include "authentication.h"
#include "utils.h"
#include <iostream>
#include <fstream>
#include <filesystem>
#include <regex>
#include <sstream>
#include <nlohmann/json.hpp>
#include <libsecret/secret.h>
#include <glib.h>

namespace fs = std::filesystem;

const std::string AUTH_PLAINTEXT_CREDENTIALS_FILE =
    std::string(std::getenv("HOME")) + "/.local/share/python_keyring/keyring_pass.cfg";

static const SecretSchema* get_schema(void) {
    static const SecretSchema* schema = secret_schema_new(
        "org.launchpad.lib.Secret",
        SECRET_SCHEMA_NONE,
        "credentials", SECRET_SCHEMA_ATTRIBUTE_STRING,
        "key", SECRET_SCHEMA_ATTRIBUTE_STRING,
        NULL
    );
    return schema;
}

bool read_plaintext_credentials_impl(std::string& consumer_key,
                                     std::string& consumer_secret,
                                     std::string& oauth_token,
                                     std::string& oauth_token_secret)
{
    std::ifstream file(AUTH_PLAINTEXT_CREDENTIALS_FILE);
    if (!file.is_open()) {
        std::cerr << "Plaintext credentials file not found: " << AUTH_PLAINTEXT_CREDENTIALS_FILE << std::endl;
        return false;
    }

    std::string line;
    bool in_launchpadlib_section = false;
    std::string encoded_credentials;
    bool credentials_found = false;
    std::string encoded_key;

    while (std::getline(file, line)) {
        line.erase(0, line.find_first_not_of(" \t\r\n"));
        line.erase(line.find_last_not_of(" \t\r\n") + 1);

        if (line.empty()) continue;

        if (line.front() == '[' && line.back() == ']') {
            std::string section = line.substr(1, line.size() - 2);
            in_launchpadlib_section = (section == "launchpadlib");
            continue;
        }

        if (in_launchpadlib_section) {
            size_t eq_pos = line.find('=');
            if (eq_pos != std::string::npos) {
                encoded_key = line.substr(0, eq_pos);
                encoded_credentials.clear();
                while (std::getline(file, line)) {
                    if (line.find("        ") == 0) {
                        encoded_credentials += line.substr(8);
                    } else {
                        break;
                    }
                }
                credentials_found = true;
                break;
            }
        }
    }

    file.close();

    if (!credentials_found || encoded_credentials.empty()) {
        std::cerr << "No credentials found in plaintext file." << std::endl;
        return false;
    }

    std::string decoded_credentials = base64_decode(encoded_credentials);
    if (decoded_credentials.empty()) {
        std::cerr << "Failed to decode Base64 credentials." << std::endl;
        return false;
    }

    std::istringstream iss(decoded_credentials);
    std::string token_line;
    while (std::getline(iss, token_line)) {
        size_t pos = token_line.find('=');
        if (pos != std::string::npos) {
            std::string key = token_line.substr(0, pos);
            std::string value = token_line.substr(pos + 1);
            if (key == "oauth_token") {
                oauth_token = value;
            } else if (key == "oauth_token_secret") {
                oauth_token_secret = value;
            }
        }
    }

    std::string decoded_key = decode_service_identifier(encoded_key);
    std::regex rgx("system-wide: ([^@]+)@https://api.launchpad.net/");
    std::smatch matches;
    if (std::regex_search(decoded_key, matches, rgx)) {
        consumer_key = matches[1];
    } else {
        std::cerr << "Failed to parse consumer_key from encoded key." << std::endl;
        return false;
    }

    consumer_secret = "&";

    if (oauth_token.empty() || oauth_token_secret.empty()) {
        std::cerr << "Incomplete credentials in plaintext file." << std::endl;
        return false;
    }

    return true;
}

bool create_plaintext_credentials_impl(const std::string& consumer_key,
                                       const std::string& consumer_secret_input,
                                       const std::string& oauth_token,
                                       const std::string& oauth_token_secret)
{
    fs::path dir = fs::path(AUTH_PLAINTEXT_CREDENTIALS_FILE).parent_path();
    std::error_code ec;
    if (!fs::exists(dir)) {
        if (!fs::create_directories(dir, ec)) {
            std::cerr << "Failed to create directory: " << dir << " Error: " << ec.message() << std::endl;
            return false;
        }
    }

    std::string service_identifier = "system-wide: " + consumer_key + "@https://api.launchpad.net/";
    std::string encoded_key = encode_service_identifier(service_identifier);

    std::string credentials = "oauth_token=" + oauth_token + "\n" +
                              "oauth_token_secret=" + oauth_token_secret + "\n";

    std::string encoded_credentials = base64_encode(reinterpret_cast<const unsigned char*>(credentials.c_str()), credentials.length());

    std::ofstream file_out(AUTH_PLAINTEXT_CREDENTIALS_FILE, std::ios::trunc);
    if (!file_out.is_open()) {
        std::cerr << "Failed to open plaintext credentials file for writing: " << AUTH_PLAINTEXT_CREDENTIALS_FILE << std::endl;
        return false;
    }

    file_out << "[launchpadlib]\n";
    file_out << encoded_key << " = \n";

    size_t pos = 0;
    size_t line_length = 80;
    while (pos < encoded_credentials.size()) {
        file_out << "        " << encoded_credentials.substr(pos, line_length) << "\n";
        pos += line_length;
    }

    file_out.close();
    std::cout << "Credentials saved to " << AUTH_PLAINTEXT_CREDENTIALS_FILE << std::endl;
    return true;
}

bool read_gnome_keyring_impl(std::string& consumer_key,
                             std::string& consumer_secret,
                             std::string& oauth_token,
                             std::string& oauth_token_secret)
{
    std::string actual_consumer_key = "ubuntu (lugito-ci)";
    std::string service_identifier = "system-wide: " + actual_consumer_key + "@https://api.launchpad.net/";
    std::string encoded_key = encode_service_identifier(service_identifier);

    std::string serialized_credentials = get_secret("org.launchpad.lib.Secret", "credentials", "credentials").value_or("");
    if (serialized_credentials.empty()) {
        std::cerr << "No credentials found in GNOME keyring." << std::endl;
        return false;
    }

    std::string decoded_credentials = base64_decode(serialized_credentials);
    if (decoded_credentials.empty()) {
        std::cerr << "Failed to decode Base64 credentials from keyring." << std::endl;
        return false;
    }

    std::istringstream iss(decoded_credentials);
    std::string token_line;
    while (std::getline(iss, token_line)) {
        size_t pos = token_line.find('=');
        if (pos != std::string::npos) {
            std::string key = token_line.substr(0, pos);
            std::string value = token_line.substr(pos + 1);
            if (key == "oauth_token") {
                oauth_token = value;
            } else if (key == "oauth_token_secret") {
                oauth_token_secret = value;
            }
        }
    }

    std::string decoded_key = decode_service_identifier(encoded_key);
    std::regex rgx("system-wide: ([^@]+)@https://api.launchpad.net/");
    std::smatch matches;
    if (std::regex_search(decoded_key, matches, rgx)) {
        consumer_key = matches[1];
    } else {
        std::cerr << "Failed to parse consumer_key from encoded key." << std::endl;
        return false;
    }

    consumer_secret = "&";

    if (oauth_token.empty() || oauth_token_secret.empty()) {
        std::cerr << "Incomplete credentials in GNOME keyring." << std::endl;
        return false;
    }

    return true;
}

bool create_keyring_credentials_impl(const std::string& consumer_key,
                                     const std::string& consumer_secret,
                                     const std::string& oauth_token,
                                     const std::string& oauth_token_secret)
{
    std::string service_identifier = "system-wide: " + consumer_key + "@https://api.launchpad.net/";
    std::string encoded_key = encode_service_identifier(service_identifier);

    std::string credentials = "oauth_token=" + oauth_token + "\n" +
                              "oauth_token_secret=" + oauth_token_secret + "\n";
    std::string encoded_credentials = base64_encode(reinterpret_cast<const unsigned char*>(credentials.c_str()), credentials.length());

    const SecretSchema* schema = get_schema();

    GError* error = nullptr;
    if (!secret_password_store_sync(
            schema,
            "credentials",
            "launchpadlib",
            encoded_credentials.c_str(),
            NULL,
            &error,
            "credentials", "credentials",
            NULL)) {
        std::cerr << "Error storing credentials in keyring: " << error->message << std::endl;
        g_error_free(error);
        return false;
    }

    std::cout << "Credentials stored in GNOME keyring successfully." << std::endl;
    return true;
}