use std::sync::{Arc, RwLock};

use gilrs::{ev::Code, Event as GamepadEvent, EventType, GamepadId};
use winit::{
    event::{ElementState, KeyEvent},
    keyboard::PhysicalKey,
};

use crate::{
    emulator::{EmulatorClient, EmulatorCommand, SimId, VBKey},
    input::{InputMapping, MappingProvider},
};

pub struct Controller {
    pub sim_id: SimId,
    state: VBKey,
    mapping: Arc<RwLock<InputMapping>>,
}

impl Controller {
    pub fn new(sim_id: SimId, mappings: &MappingProvider) -> Self {
        Self {
            sim_id,
            state: VBKey::SGN,
            mapping: mappings.for_sim(sim_id).clone(),
        }
    }

    pub fn key_event(&mut self, event: &KeyEvent) -> Option<VBKey> {
        let keys = self.map_keys(&event.physical_key)?;
        match event.state {
            ElementState::Pressed => self.update_state(keys, VBKey::empty()),
            ElementState::Released => self.update_state(VBKey::empty(), keys),
        }
    }

    pub fn gamepad_event(&mut self, event: &GamepadEvent) -> Option<VBKey> {
        let (pressed, released) = match event.event {
            EventType::ButtonPressed(_, code) => {
                let mappings = self.map_button(&event.id, &code)?;
                (mappings, VBKey::empty())
            }
            EventType::ButtonReleased(_, code) => {
                let mappings = self.map_button(&event.id, &code)?;
                (VBKey::empty(), mappings)
            }
            EventType::AxisChanged(_, value, code) => {
                let (neg, pos) = self.map_axis(&event.id, &code)?;
                let mut pressed = VBKey::empty();
                let mut released = VBKey::empty();
                if value < -0.75 {
                    pressed = pressed.union(neg);
                }
                if value > 0.75 {
                    pressed = pressed.union(pos);
                }
                if value > -0.65 {
                    released = released.union(neg);
                }
                if value < 0.65 {
                    released = released.union(pos);
                }
                (pressed, released)
            }
            _ => {
                return None;
            }
        };
        self.update_state(pressed, released)
    }

    fn update_state(&mut self, pressed: VBKey, released: VBKey) -> Option<VBKey> {
        let old_state = self.state;
        self.state = self.state.union(pressed).difference(released);
        if self.state != old_state {
            Some(self.state)
        } else {
            None
        }
    }

    fn map_keys(&self, key: &PhysicalKey) -> Option<VBKey> {
        self.mapping.read().unwrap().map_keyboard(key)
    }

    fn map_button(&self, id: &GamepadId, code: &Code) -> Option<VBKey> {
        self.mapping.read().unwrap().map_button(id, code)
    }

    fn map_axis(&self, id: &GamepadId, code: &Code) -> Option<(VBKey, VBKey)> {
        self.mapping.read().unwrap().map_axis(id, code)
    }
}

pub struct ControllerManager {
    client: EmulatorClient,
    controllers: [Controller; 2],
}

impl ControllerManager {
    pub fn new(client: EmulatorClient, mappings: &MappingProvider) -> Self {
        Self {
            client,
            controllers: [
                Controller::new(SimId::Player1, mappings),
                Controller::new(SimId::Player2, mappings),
            ],
        }
    }

    pub fn handle_key_event(&mut self, event: &KeyEvent) {
        for controller in &mut self.controllers {
            if let Some(pressed) = controller.key_event(event) {
                self.client
                    .send_command(EmulatorCommand::SetKeys(controller.sim_id, pressed));
            }
        }
    }

    pub fn handle_gamepad_event(&mut self, event: &GamepadEvent) {
        for controller in &mut self.controllers {
            if let Some(pressed) = controller.gamepad_event(event) {
                self.client
                    .send_command(EmulatorCommand::SetKeys(controller.sim_id, pressed));
            }
        }
    }
}