use crate::*;


pub struct DynamicEmulator {
    pub br: BedrockEmulator<DynamicDeviceBus>,
    pub debug: DebugState,
}


impl DynamicEmulator {
    pub fn new(config: &EmulatorConfig, debug: bool) -> Self {
        Self {
            br: BedrockEmulator::new(DynamicDeviceBus::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);
    }

    pub fn run(&mut self) {
        loop {
            match self.br.evaluate(BATCH_SIZE, self.debug.enabled) {
                Some(Signal::Fork) => {
                    self.br.core.mem.pc = 0;
                    self.br.core.wst.sp = 0;
                    self.br.core.rst.sp = 0;
                }
                Some(Signal::Sleep) => loop {
                    if self.br.dev.wake() { break; }
                    std::thread::sleep(MIN_TICK_DURATION);
                }
                Some(Signal::Halt) => {
                    self.br.dev.stream.flush();
                    info!("Program halted, exiting.");
                    self.debug.debug_summary(&self.br.core);
                    std::process::exit(0);
                }
                Some(Signal::Debug(Debug::Debug1)) => {
                    self.debug.debug_summary(&self.br.core);
                }
                _ => (),
            }
            if self.br.dev.input.accessed || self.br.dev.screen.accessed {
                return;
            }
        }
    }

    pub fn to_graphical(self, config: EmulatorConfig) -> GraphicalEmulator {
        GraphicalEmulator {
            br: BedrockEmulator {
                core: self.br.core,
                dev: GraphicalDeviceBus {
                    system: self.br.dev.system,
                    memory: self.br.dev.memory,
                    math:   self.br.dev.math,
                    clock:  self.br.dev.clock,
                    input:  self.br.dev.input,
                    screen: self.br.dev.screen,
                    stream: self.br.dev.stream,
                    file:   self.br.dev.file,
                }
            },
            debug: self.debug,

            fullscreen: config.fullscreen,
            scale: config.zoom.into(),
            show_override_palette: config.override_palette.is_some(),
            render_mark: Instant::now(),

            config,
        }
    }

    pub fn to_headless(self) -> HeadlessEmulator {
        HeadlessEmulator {
            br: BedrockEmulator {
                core: self.br.core,
                dev: HeadlessDeviceBus {
                    system: self.br.dev.system,
                    memory: self.br.dev.memory,
                    math:   self.br.dev.math,
                    clock:  self.br.dev.clock,
                    stream: self.br.dev.stream,
                    file:   self.br.dev.file,
                }
            },
            debug: self.debug,
        }
    }
}


pub struct DynamicDeviceBus {
    pub system: SystemDevice,
    pub memory: MemoryDevice,
    pub math:   MathDevice,
    pub clock:  ClockDevice,
    pub input:  InputDevice,
    pub screen: ScreenDevice,
    pub stream: StreamDevice,
    pub file:   FileDevice,
}

impl DynamicDeviceBus {
    pub fn new(config: &EmulatorConfig) -> Self {
        Self {
            system: SystemDevice::new(0b1111_1100_1010_0000),
            memory: MemoryDevice::new(),
            math:   MathDevice::new(),
            clock:  ClockDevice::new(),
            input:  InputDevice::new(),
            screen: ScreenDevice::new(&config),
            stream: StreamDevice::new(&config),
            file:   FileDevice::new(),
        }
    }
}


impl DeviceBus for DynamicDeviceBus {
    fn read(&mut self, port: u8) -> u8 {
        match port & 0xf0 {
            0x00 => self.system.read(port & 0x0f),
            0x10 => self.memory.read(port & 0x0f),
            0x20 => self.math  .read(port & 0x0f),
            0x30 => self.clock .read(port & 0x0f),
            0x40 => self.input .read(port & 0x0f),
            0x50 => self.screen.read(port & 0x0f),
            0x80 => self.stream.read(port & 0x0f),
            0xa0 => self.file  .read(port & 0x0f),
            _ => 0
        }
    }

    fn write(&mut self, port: u8, value: u8) -> Option<Signal> {
        match port & 0xf0 {
            0x00 =>   self.system.write(port & 0x0f, value),
            0x10 =>   self.memory.write(port & 0x0f, value),
            0x20 =>   self.math  .write(port & 0x0f, value),
            0x30 =>   self.clock .write(port & 0x0f, value),
            0x40 => { self.input .write(port & 0x0f, value); Some(Signal::Interrupt) }
            0x50 => { self.screen.write(port & 0x0f, value); Some(Signal::Interrupt) }
            0x80 =>   self.stream.write(port & 0x0f, value),
            0xa0 =>   self.file  .write(port & 0x0f, value),
            _ => None
        }
    }

    fn wake(&mut self) -> bool {
        macro_rules! rouse {
            ($id:expr, $dev:ident) => {
                let is_eligible = test_bit!(self.system.wakers, 0x8000 >> $id);
                if is_eligible && self.$dev.wake() {
                    self.system.waker = $id;
                    self.system.asleep = false;
                    return true;
                }
            };
        }
        rouse!(0xa, file  );
        rouse!(0x8, stream);
        rouse!(0x5, screen);
        rouse!(0x4, input );
        rouse!(0x3, clock );
        return false;
    }
}