// file: crates/engines/engine-v1-sdl/src/runtime.rs
// version: 5

/// Minimal SDL3 runtime used by Desktop POC runners.
pub struct SdlRuntime {
    title: std::string::String,
    width: u32,
    height: u32,
    frame_duration: std::time::Duration,
}

impl SdlRuntime {
    /// Creates a minimal SDL3 runtime configuration.
    #[must_use]
    pub fn new(title: impl std::convert::Into<std::string::String>, width: u32, height: u32, frame_duration: std::time::Duration) -> Self {
        return Self { title: title.into(), width, height, frame_duration };
    }

    /// Runs a game until the user closes the window or presses Escape.
    pub fn run<G>(&self, game: &mut G) -> std::result::Result<(), std::string::String>
    where
        G: engine_v1_common::EngineGame,
    {
        let sdl = match sdl3::init() {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => return std::result::Result::Err(error.to_string()),
        };
        let video = match sdl.video() {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => return std::result::Result::Err(error.to_string()),
        };
        let window = match video.window(&self.title, self.width, self.height).position_centered().resizable().build() {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => return std::result::Result::Err(error.to_string()),
        };
        let mut canvas = window.into_canvas();
        let mut events = match sdl.event_pump() {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => return std::result::Result::Err(error.to_string()),
        };
        let mut runner = engine_v1_common::FixedStepRunner::new(self.frame_duration);
        let mut pointer = engine_v1_common::PointerState::inactive();
        tracing::info!(title = %self.title, width = self.width, height = self.height, "SDL3 runtime started");
        'running: loop {
            let mut input = engine_v1_common::InputState::none().with_pointer(pointer);
            for event in events.poll_iter() {
                match event {
                    sdl3::event::Event::Quit { .. } => break 'running,
                    sdl3::event::Event::KeyDown { keycode: Some(sdl3::keyboard::Keycode::Escape), .. } => break 'running,
                    sdl3::event::Event::KeyDown { keycode: Some(sdl3::keyboard::Keycode::Space), .. } => {
                        input = input.with_action(engine_v1_common::GameAction::Primary, true);
                    },
                    sdl3::event::Event::FingerDown { x, y, .. } | sdl3::event::Event::FingerMotion { x, y, .. } => {
                        pointer = engine_v1_common::PointerState::normalized(true, x, y);
                        input = input.with_pointer(pointer).with_action(engine_v1_common::GameAction::Primary, true);
                    },
                    sdl3::event::Event::FingerUp { x, y, .. } | sdl3::event::Event::FingerCanceled { x, y, .. } => {
                        pointer = engine_v1_common::PointerState::normalized(false, x, y);
                        input = input.with_pointer(pointer);
                    },
                    _ => {},
                }
            }
            if pointer.active() {
                input = input.with_pointer(pointer).with_action(engine_v1_common::GameAction::Primary, true);
            }
            runner.tick(game, input);
            canvas.set_draw_color(sdl3::pixels::Color::RGB(18, 18, 24));
            canvas.clear();
            canvas.present();
            std::thread::sleep(self.frame_duration);
        }
        tracing::info!(frames = runner.next_frame_index(), "SDL3 runtime stopped");
        return std::result::Result::Ok(());
    }
}