use crate::*;


pub struct HeadlessEmulator {
    pub br: BedrockEmulator<HeadlessDeviceBus>,
    pub debug: DebugState,
}

impl HeadlessEmulator {
    pub fn new(config: &EmulatorConfig, debug: bool) -> Self {
        Self {
            br: BedrockEmulator::new(HeadlessDeviceBus::new(config)),
            debug: DebugState::new(debug, config.symbols_path.as_ref()),
        }
    }

    pub fn load_program(&mut self, bytecode: &[u8]) {
        self.br.core.mem.load_program(bytecode);
    }

    fn sleep(&mut self) {
        loop {
            if self.br.dev.wake() { break; }
            std::thread::sleep(TICK_DURATION);
        }
    }

    fn halt(&mut self) {
        self.br.dev.stream.flush();
        info!("Program halted, exiting.");
        self.debug.debug_full(&self.br.core);
        std::process::exit(0);
    }

    pub fn run(&mut self) -> ! {
        loop {
            if let Some(signal) = self.br.evaluate(BATCH_SIZE, self.debug.enabled) {
                match signal {
                    Signal::Fork | Signal::Reset => self.br.reset(),
                    Signal::Sleep => self.sleep(),
                    Signal::Halt => self.halt(),
                    Signal::Debug(debug_signal) => match debug_signal {
                        Debug::Debug1 => self.debug.debug_full(&self.br.core),
                        Debug::Debug2 => self.debug.debug_timing(&self.br.core),
                        _ => (),
                    }
                    _ => (),
                }
            }
        }
    }
}


pub struct HeadlessDeviceBus {
    pub system: SystemDevice,
    pub memory: MemoryDevice,
    pub math:   MathDevice,
    pub clock:  ClockDevice,
    pub stream: StreamDevice,
    pub file:   FileDevice,
    pub wake_queue: WakeQueue,
}

impl HeadlessDeviceBus {
    pub fn new(config: &EmulatorConfig) -> Self {
        Self {
            system: SystemDevice::new(0b1111_0000_1100_0000),
            memory: MemoryDevice::new(),
            math:   MathDevice::new(),
            clock:  ClockDevice::new(),
            stream: StreamDevice::new(&config),
            file:   FileDevice::new(),
            wake_queue: WakeQueue::new(),
        }
    }
}

impl DeviceBus for HeadlessDeviceBus {
    fn get_device(&mut self, slot: u8) -> Option<&mut dyn Device> {
        match slot {
            0x0 => Some(&mut self.system),
            0x1 => Some(&mut self.memory),
            0x2 => Some(&mut self.math  ),
            0x3 => Some(&mut self.clock ),
            0x8 => Some(&mut self.stream),
            0x9 => Some(&mut self.file  ),
            _ => None
        }
    }

    fn wake(&mut self) -> bool {
        for slot in self.wake_queue.iter(self.system.wake_mask) {
            if let Some(device) = self.get_device(slot) {
                if device.wake() {
                    self.system.wake_slot = slot;
                    self.system.asleep = false;
                    self.wake_queue.wake(slot);
                    return true;
                }
            }
        }
        return false;
    }
}