// file: crates/apps/game-snake-poc-wasm/src/runtime.rs
// version: 3

const FIXED_STEP_MILLIS: u64 = 16;

/// WebAssembly-owned Snake game state consumed by the direct browser host.
#[wasm_bindgen::prelude::wasm_bindgen]
pub struct SnakeWasmGame {
    pending_input: engine_v1_common::InputState,
    provenance: engine_v1_platform_api::RuntimeProvenance,
    runner: engine_v1_common::FixedStepRunner,
    state: game_snake_poc::SnakeState,
}

#[wasm_bindgen::prelude::wasm_bindgen]
impl SnakeWasmGame {
    /// Creates a fresh Snake POC session using the shared gameplay crate.
    #[wasm_bindgen::prelude::wasm_bindgen(constructor)]
    pub fn new() -> Self {
        return Self {
            pending_input: engine_v1_common::InputState::none(),
            provenance: engine_v1_platform_api::RuntimeProvenance::new(
                engine_v1_platform_api::DeviceClass::Unknown,
                engine_v1_platform_api::ExecutionModel::Wasm,
                engine_v1_platform_api::InputProfile::Unknown,
                engine_v1_platform_api::PlatformFamily::Web,
                engine_v1_platform_api::RuntimeHost::Browser,
            ),
            runner: engine_v1_common::FixedStepRunner::new(std::time::Duration::from_millis(FIXED_STEP_MILLIS)),
            state: game_snake_poc::SnakeState::new(),
        };
    }

    /// Updates host-observed runtime provenance while preserving WebAssembly execution.
    pub fn configure_runtime_provenance(&mut self, platform_family: &str, runtime_host: &str, device_class: &str, input_profile: &str) -> bool {
        let platform_family = match parse_platform_family(platform_family) {
            Some(value) => value,
            None => return false,
        };
        let runtime_host = match parse_runtime_host(runtime_host) {
            Some(value) => value,
            None => return false,
        };
        let device_class = match parse_device_class(device_class) {
            Some(value) => value,
            None => return false,
        };
        let input_profile = match parse_input_profile(input_profile) {
            Some(value) => value,
            None => return false,
        };
        self.provenance = engine_v1_platform_api::RuntimeProvenance::new(
            device_class,
            engine_v1_platform_api::ExecutionModel::Wasm,
            input_profile,
            platform_family,
            runtime_host,
        );
        return true;
    }

    /// Returns the current physical device class label.
    pub fn provenance_device_class(&self) -> String {
        return device_class_label(self.provenance.device_class()).to_string();
    }

    /// Returns the current execution model label.
    pub fn provenance_execution_model(&self) -> String {
        return execution_model_label(self.provenance.execution_model()).to_string();
    }

    /// Returns the current primary input profile label.
    pub fn provenance_input_profile(&self) -> String {
        return input_profile_label(self.provenance.input_profile()).to_string();
    }

    /// Returns the current platform family label.
    pub fn provenance_platform_family(&self) -> String {
        return platform_family_label(self.provenance.platform_family()).to_string();
    }

    /// Returns the current runtime host label.
    pub fn provenance_runtime_host(&self) -> String {
        return runtime_host_label(self.provenance.runtime_host()).to_string();
    }

    /// Queues a logical left direction for the next deterministic update.
    pub fn left(&mut self) {
        self.queue_direction(engine_v1_common::GameAction::Left);
        return;
    }

    /// Queues a logical right direction for the next deterministic update.
    pub fn right(&mut self) {
        self.queue_direction(engine_v1_common::GameAction::Right);
        return;
    }

    /// Queues a logical upward direction for the next deterministic update.
    pub fn up(&mut self) {
        self.queue_direction(engine_v1_common::GameAction::Up);
        return;
    }

    /// Queues a logical downward direction for the next deterministic update.
    pub fn down(&mut self) {
        self.queue_direction(engine_v1_common::GameAction::Down);
        return;
    }

    /// Advances one deterministic update and consumes the queued direction.
    pub fn tick(&mut self) {
        let input = self.pending_input;
        self.pending_input = engine_v1_common::InputState::none();
        self.runner.tick(&mut self.state, input);
        return;
    }

    /// Returns the current gameplay score.
    pub fn score(&self) -> u32 {
        return self.state.score().min(u32::MAX as u64) as u32;
    }

    /// Returns the current Snake length.
    pub fn length(&self) -> u32 {
        return self.state.length().min(u32::MAX as usize) as u32;
    }

    /// Returns the current scene background red channel.
    pub fn background_red(&self) -> u8 {
        return self.scene().background().red();
    }

    /// Returns the current scene background green channel.
    pub fn background_green(&self) -> u8 {
        return self.scene().background().green();
    }

    /// Returns the current scene background blue channel.
    pub fn background_blue(&self) -> u8 {
        return self.scene().background().blue();
    }

    /// Returns the number of occupied rectangle slots in the current scene.
    pub fn rectangle_count(&self) -> u32 {
        let scene = self.scene();
        let mut count = 0_u32;
        for slot in scene.rectangles() {
            if slot.is_some() {
                count = count.saturating_add(1);
            }
        }
        return count;
    }

    /// Returns one rectangle's normalized left coordinate or `-1.0` if absent.
    pub fn rectangle_x(&self, index: u32) -> f32 {
        return match self.rectangle(index) {
            Some(rectangle) => rectangle.rect().x(),
            None => -1.0,
        };
    }

    /// Returns one rectangle's normalized top coordinate or `-1.0` if absent.
    pub fn rectangle_y(&self, index: u32) -> f32 {
        return match self.rectangle(index) {
            Some(rectangle) => rectangle.rect().y(),
            None => -1.0,
        };
    }

    /// Returns one rectangle's normalized width or `0.0` if absent.
    pub fn rectangle_width(&self, index: u32) -> f32 {
        return match self.rectangle(index) {
            Some(rectangle) => rectangle.rect().width(),
            None => 0.0,
        };
    }

    /// Returns one rectangle's normalized height or `0.0` if absent.
    pub fn rectangle_height(&self, index: u32) -> f32 {
        return match self.rectangle(index) {
            Some(rectangle) => rectangle.rect().height(),
            None => 0.0,
        };
    }

    /// Returns one rectangle's red channel or zero if absent.
    pub fn rectangle_red(&self, index: u32) -> u8 {
        return match self.rectangle(index) {
            Some(rectangle) => rectangle.color().red(),
            None => 0,
        };
    }

    /// Returns one rectangle's green channel or zero if absent.
    pub fn rectangle_green(&self, index: u32) -> u8 {
        return match self.rectangle(index) {
            Some(rectangle) => rectangle.color().green(),
            None => 0,
        };
    }

    /// Returns one rectangle's blue channel or zero if absent.
    pub fn rectangle_blue(&self, index: u32) -> u8 {
        return match self.rectangle(index) {
            Some(rectangle) => rectangle.color().blue(),
            None => 0,
        };
    }
}

impl Default for SnakeWasmGame {
    fn default() -> Self {
        return Self::new();
    }
}

impl SnakeWasmGame {
    fn queue_direction(&mut self, action: engine_v1_common::GameAction) {
        self.pending_input = engine_v1_common::InputState::none().with_action(action, true);
        return;
    }

    fn scene(&self) -> engine_v1_common::EngineScene {
        return engine_v1_common::EngineGame::scene(&self.state);
    }

    fn rectangle(&self, requested_index: u32) -> Option<engine_v1_common::RenderRect> {
        let scene = self.scene();
        let mut occupied_index = 0_u32;
        for slot in scene.rectangles() {
            match slot {
                Some(rectangle) => {
                    if occupied_index == requested_index {
                        return Some(*rectangle);
                    }
                    occupied_index = occupied_index.saturating_add(1);
                },
                None => {},
            }
        }
        return None;
    }
}

fn parse_platform_family(label: &str) -> Option<engine_v1_platform_api::PlatformFamily> {
    return match label {
        "android" => Some(engine_v1_platform_api::PlatformFamily::Android),
        "desktop" => Some(engine_v1_platform_api::PlatformFamily::Desktop),
        "web" => Some(engine_v1_platform_api::PlatformFamily::Web),
        _ => None,
    };
}

fn parse_runtime_host(label: &str) -> Option<engine_v1_platform_api::RuntimeHost> {
    return match label {
        "browser" => Some(engine_v1_platform_api::RuntimeHost::Browser),
        "native" => Some(engine_v1_platform_api::RuntimeHost::Native),
        "tauri-webview" => Some(engine_v1_platform_api::RuntimeHost::TauriWebView),
        _ => None,
    };
}

fn parse_device_class(label: &str) -> Option<engine_v1_platform_api::DeviceClass> {
    return match label {
        "desktop" => Some(engine_v1_platform_api::DeviceClass::Desktop),
        "phone" => Some(engine_v1_platform_api::DeviceClass::Phone),
        "tablet" => Some(engine_v1_platform_api::DeviceClass::Tablet),
        "unknown" => Some(engine_v1_platform_api::DeviceClass::Unknown),
        _ => None,
    };
}

fn parse_input_profile(label: &str) -> Option<engine_v1_platform_api::InputProfile> {
    return match label {
        "gamepad" => Some(engine_v1_platform_api::InputProfile::Gamepad),
        "keyboard-mouse" => Some(engine_v1_platform_api::InputProfile::KeyboardMouse),
        "mixed" => Some(engine_v1_platform_api::InputProfile::Mixed),
        "touch" => Some(engine_v1_platform_api::InputProfile::Touch),
        "unknown" => Some(engine_v1_platform_api::InputProfile::Unknown),
        _ => None,
    };
}

fn device_class_label(value: engine_v1_platform_api::DeviceClass) -> &'static str {
    return match value {
        engine_v1_platform_api::DeviceClass::Desktop => "desktop",
        engine_v1_platform_api::DeviceClass::Phone => "phone",
        engine_v1_platform_api::DeviceClass::Tablet => "tablet",
        engine_v1_platform_api::DeviceClass::Unknown => "unknown",
    };
}

fn execution_model_label(value: engine_v1_platform_api::ExecutionModel) -> &'static str {
    return match value {
        engine_v1_platform_api::ExecutionModel::Native => "native",
        engine_v1_platform_api::ExecutionModel::Wasm => "wasm",
    };
}

fn input_profile_label(value: engine_v1_platform_api::InputProfile) -> &'static str {
    return match value {
        engine_v1_platform_api::InputProfile::Gamepad => "gamepad",
        engine_v1_platform_api::InputProfile::KeyboardMouse => "keyboard-mouse",
        engine_v1_platform_api::InputProfile::Mixed => "mixed",
        engine_v1_platform_api::InputProfile::Touch => "touch",
        engine_v1_platform_api::InputProfile::Unknown => "unknown",
    };
}

fn platform_family_label(value: engine_v1_platform_api::PlatformFamily) -> &'static str {
    return match value {
        engine_v1_platform_api::PlatformFamily::Android => "android",
        engine_v1_platform_api::PlatformFamily::Desktop => "desktop",
        engine_v1_platform_api::PlatformFamily::Web => "web",
    };
}

fn runtime_host_label(value: engine_v1_platform_api::RuntimeHost) -> &'static str {
    return match value {
        engine_v1_platform_api::RuntimeHost::Browser => "browser",
        engine_v1_platform_api::RuntimeHost::Native => "native",
        engine_v1_platform_api::RuntimeHost::TauriWebView => "tauri-webview",
    };
}

#[cfg(test)]
#[path = "../unit_tests/runtime.rs"]
mod tests;