use crate::macro_writer::MacroWriter;
use crate::x11_safe_wrapper::XDisplay;
use crate::{Instructions, Keycode, Position};
use std::mem;
use std::time;
use x11::xlib;
use x11::xrecord::{XRecordContext, XRecordInterceptData};

#[repr(C)]
pub struct EvCallbackData {
    pub writer: MacroWriter,
    pub xdpy: XDisplay,
    pub recdpy: XDisplay,
    pub ctx: XRecordContext,
    pub working: bool,
    pub last_event: xlib::Time,
    pub pos: Position<i16>,
    pub stop_key: Keycode,
    pub ev_nr: u32,
    pub max_delay: Option<xlib::Time>,
    pub no_keypress_yet: bool,
    pub moving: bool,
}

impl EvCallbackData {
    pub fn new(
        writer: MacroWriter,
        xdpy: XDisplay,
        recdpy: XDisplay,
        ctx: XRecordContext,
        stop_key: Keycode,
        pos: Position<i16>,
        max_delay: Option<xlib::Time>,
    ) -> Self {
        EvCallbackData {
            writer,
            xdpy,
            recdpy,
            ctx,
            stop_key,
            ev_nr: 0,
            working: true,
            pos,
            max_delay,
            no_keypress_yet: true,
            last_event: time::SystemTime::now()
                .duration_since(time::UNIX_EPOCH)
                .unwrap()
                .as_millis() as xlib::Time,
            moving: false,
        }
    }

    pub fn ptr_is_moving(&self) -> bool {
        self.moving
    }

    pub unsafe fn update_pos(
        &mut self,
        intercept_data: &mut XRecordInterceptData,
    ) -> Position<i16> {
        self.pos.0 = *((intercept_data.data as usize + mem::size_of::<i16>() * 10) as *const i16);
        self.pos.1 = *((intercept_data.data as usize + mem::size_of::<i16>() * 11) as *const i16);
        self.pos
    }

    pub fn write_pos(&mut self) {
        self.writer.write(Instructions::MotionNotify(self.pos));
        self.moving = false;
    }

    pub fn maybe_write_delay(&mut self, server_time: xlib::Time) {
        if server_time - self.last_event > 1 {
            self.writer.write(Instructions::Delay(calculate_delay(
                server_time,
                self.last_event,
                self.max_delay,
            )));
            self.last_event = server_time;
        }
    }
}

fn calculate_delay(server_time: xlib::Time, last_event: xlib::Time, max_delay: Option<xlib::Time>) -> xlib::Time {
    if let Some(max) = max_delay {
        let max = max as u64;
        let delay = server_time - last_event;

        if delay > max {
            max
        } else {
            delay
        }
    } else {
        server_time - last_event
    }
}