screensaver/main.cpp

//
// main.cpp
// screensaver
//
// Created by Bob Polis at 2020-10-23
// Copyright (c) 2020 SwiftCoder. All rights reserved.
//

// C++
#include <iostream>
#include <cstdlib>
#include <string>
#include <stdexcept>
#include <cmath>
#include <thread>
#include <fstream>
#include <algorithm>

// POSIX
#include <getopt.h>
#include <unistd.h>

// libraries
#include <cairo/cairo.h>
#include <libscgui.hpp>
#include <libscerror.hpp>
#include <libscscreensaver.hpp>
#include <libscstring.hpp>
#include <libscnumerics.hpp>
#include <sc/plugin.hpp>

const int WIDTH {1600};
const int HEIGHT {900};

sc::gui::Window* main_window {nullptr};
ScreensaverPlugin* main_saver {nullptr};
std::unique_ptr<sc::gui::Image> main_image {nullptr};
std::unique_ptr<cairo_t, void(*)(cairo_t*)> main_context {nullptr, cairo_destroy};
std::unique_ptr<cairo_surface_t, void(*)(cairo_surface_t*)> main_surface {nullptr, cairo_surface_destroy};

void print_help() {
    std::cout << "usage: screensaver [-h|-l|--version]\n";
    std::cout << "  -h, --help    show this help text and exit\n";
    std::cout << "  -l, --list    show available screensaver modules and exit\n";
    std::cout << "  -r, --random  choose random module from available ones\n";
    std::cout << "  --version     show version number and exit\n";
}

void print_version() {
    std::cout << "screensaver version 1.0\n";
}

void list_plugins() {
    for (const std::string& name : sc::plugin<ScreensaverPlugin>::names()) {
        std::cout << name << '\n';
    }
}

void create_image(int w, int h) {
    // create an SDL drawing surface and connect it to cairo
    main_image.reset(new sc::gui::Image {w, h});
    SDL_Surface* s = main_image->surface();
    cairo_surface_t* cs {cairo_image_surface_create_for_data(static_cast<unsigned char*>(s->pixels),
                                                             CAIRO_FORMAT_RGB24, s->w, s->h, s->pitch)};
    main_surface.reset(cs);
    cairo_t* cr {cairo_create(cs)};
    main_context.reset(cr);
}

void draw() {
    main_saver->update();
    sc::gui::ImageLock lock {*main_image};
    main_saver->render();
    main_window->dirty(true);
    main_window->show_image(*main_image);
}

bool handle_window_resize(const SDL_Event& event, bool quit) {
    if (event.window.data1 != main_image->width() || event.window.data2 != main_image->height()) {
        std::cerr << "window resized to " << event.window.data1 << "×" << event.window.data2 << " pixels\n";
        create_image(event.window.data1, event.window.data2);
        cairo_rectangle_t r {0, 0, static_cast<double>(event.window.data1), static_cast<double>(event.window.data2)};
        if (main_saver) {
            main_saver->setup(main_context.get(), r);
        }
    }
    return quit;
}

int main(int argc, const char * argv[]) {
    try {
        // gather plugins
#if DEBUG
        std::string plugin_dir {sc::dirname(sc::tool_path(argv[0])) + "/plugins"};
#else
        std::string plugin_dir {"/usr/local/share/screensaver/plugins"};
#endif
        sc::plugin<ScreensaverPlugin>::scan_plugins(plugin_dir, "saver");
        std::string saver_name;
        bool random_saver {false};
        int opt_char, opt_val;
        struct option long_options[] = {
            {"help", no_argument, nullptr, 'h'},
            {"list", no_argument, nullptr, 'l'},
            {"random", no_argument, nullptr, 'r'},
            {"version", no_argument, &opt_val, 1},
            {nullptr, 0, nullptr, 0}
        };
        while ((opt_char = getopt_long(argc, const_cast<char* const *>(argv), "hlr", long_options, nullptr)) != -1) {
            std::string arg {optarg ? optarg : ""};
            switch (opt_char) {
                case 0: {
                    // handle long-only options here
                    switch (opt_val) {
                        case 1:
                            print_version();
                            return EXIT_SUCCESS;
                    }
                    break;
                }
                case 'h':
                    print_help();
                    return EXIT_SUCCESS;
                case 'l':
                    list_plugins();
                    return EXIT_SUCCESS;
                case 'r':
                    random_saver = true;
                    break;
                case '?':
                    throw std::runtime_error("unrecognized option");
            }
        }
        std::vector<std::string> names {sc::plugin<ScreensaverPlugin>::names()};
        if (optind == argc) {
            // here when no file args
            if (random_saver) {
                saver_name = sc::random::choice(names);
            } else {
                saver_name = "Default";
            }
        }
        for (int i = optind; i < argc; ++i) {
            try {
                // process file argv[i]
                saver_name = argv[i];
                if (random_saver) {
                    std::cerr << "screensaver: warning: -r option overridden by file arg\n";
                }
                auto it = std::find(names.begin(), names.end(), saver_name);
                if (it == names.end()) {
                    saver_name = "";
                    throw std::out_of_range(saver_name);
                }
                break; // only first one used
            } catch (const std::runtime_error& ex) {
                std::cerr << "screensaver: " << ex.what() << '\n';
            } catch (const std::out_of_range& ex) {
                std::cerr << "screensaver: no such screensaver module: " << argv[i] << '\n';
            }
        }

        // RAII instances
        sc::gui::SDLWrapper sdl2;
        sc::gui::SDLImageWrapper sdl_image;

        // main window
        sc::gui::Window& window {sc::gui::Window::new_window("Living Art", SDL_WINDOW_FULLSCREEN)};
        main_window = &window;
        window.add_event_handler(handle_window_resize, SDL_WINDOWEVENT_RESIZED);
        window.add_event_handler(handle_window_resize, SDL_WINDOWEVENT_SIZE_CHANGED);

        // setup sdl surface and connect to cairo
        create_image(WIDTH, HEIGHT);

        // setup screen saver module
        if (saver_name.size() == 0) {
            saver_name = "Default";
            std::cerr << "screensaver: using standard 'Default' module\n";
        }
        std::unique_ptr<ScreensaverPlugin> saver {sc::plugin<ScreensaverPlugin>::get(saver_name)()};
        main_saver = saver.get();
        main_saver->setup(main_context.get(), {0, 0, WIDTH, HEIGHT});
        std::string config_path {plugin_dir + "/" + saver_name + ".json"};
        std::ifstream config_file {config_path};
        if (config_file) {
            std::cerr << "screensaver: reading config file " << config_path << '\n';
            nlohmann::json j;
            config_file >> j;
            main_saver->config(std::move(j));
        }

        sc::gui::app().fps(main_saver->fps());
        sc::gui::app().add_run_loop_action(draw);
        sc::gui::app().run();

    } catch (const std::exception& ex) {
        std::cerr << "screensaver: " << ex.what() << '\n';
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}