use std::collections::HashMap;
use std::future::Future;

use tokio::task::JoinHandle;

use crate::managers::{OrderManager, PositionManager, PriceManager};
use crate::models::{Position, PositionProfitState};

#[derive(Clone, Debug, Hash, PartialEq, Eq)]
pub enum SignalKind {
    ClosePosition(Position),
    OpenPosition,
}

#[derive(Copy, Clone, Debug)]
pub struct EventMetadata {
    position_id: Option<u64>,
    order_id: Option<u64>,
}

impl EventMetadata {
    pub fn new(position_id: Option<u64>, order_id: Option<u64>) -> Self {
        EventMetadata {
            position_id,
            order_id,
        }
    }
}

#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
pub enum EventKind {
    NewMinimum,
    NewMaximum,
    ReachedLoss,
    ReachedBreakEven,
    ReachedMinProfit,
    ReachedGoodProfit,
    ReachedMaxLoss,
    TrailingStopSet,
    TrailingStopMoved,
    OrderSubmitted,
    NewTick,
    Any,
}

#[derive(Copy, Clone, Debug)]
pub struct Event {
    kind: EventKind,
    tick: u64,
    metadata: Option<EventMetadata>,
}

impl Event {
    pub fn new(kind: EventKind, tick: u64, metadata: Option<EventMetadata>) -> Self {
        Event {
            kind,
            tick,
            metadata,
        }
    }

    fn has_metadata(&self) -> bool {
        self.metadata.is_some()
    }

    pub fn kind(&self) -> EventKind {
        self.kind
    }
    pub fn tick(&self) -> u64 {
        self.tick
    }
    pub fn metadata(&self) -> Option<EventMetadata> {
        self.metadata
    }
}

pub struct Dispatcher {
    event_handlers: HashMap<EventKind, Vec<Box<dyn Fn(&Event, &PriceManager) -> JoinHandle<()>>>>,
    profit_state_handlers:
        HashMap<PositionProfitState, Vec<Box<dyn Fn(&Position, &PriceManager) -> JoinHandle<()>>>>,
    signal_handlers: HashMap<SignalKind, Vec<Box<dyn Fn(&SignalKind) -> JoinHandle<()>>>>,

    on_any_event_handlers: Vec<Box<dyn Fn(&Event, &PriceManager) -> JoinHandle<()>>>,
    on_any_profit_state_handlers: Vec<Box<dyn Fn(&Position, &PriceManager) -> JoinHandle<()>>>,
}

impl Dispatcher {
    pub fn new() -> Self {
        Dispatcher {
            event_handlers: HashMap::new(),
            profit_state_handlers: HashMap::new(),
            signal_handlers: HashMap::new(),
            on_any_event_handlers: Vec::new(),
            on_any_profit_state_handlers: Vec::new(),
        }
    }

    pub fn call_signal_handlers(&self, signal: &SignalKind) {
        if let Some(functions) = self.signal_handlers.get(&signal) {
            for f in functions {
                f(signal);
            }
        }
    }

    pub fn call_event_handlers(&self, event: &Event, status: &PriceManager) {
        if let Some(functions) = self.event_handlers.get(&event.kind()) {
            for f in functions {
                f(event, status);
            }
        }

        for f in &self.on_any_event_handlers {
            f(event, status);
        }
    }

    pub fn call_position_state_handlers(&self, position: &Position, status: &PriceManager) {
        if let Some(profit_state) = &position.profit_state() {
            if let Some(functions) = self.profit_state_handlers.get(profit_state) {
                for f in functions {
                    f(position, status);
                }
            }
        }

        for f in &self.on_any_profit_state_handlers {
            f(position, status);
        }
    }

    pub fn register_event_handler<F: 'static, Fut: 'static>(&mut self, event: EventKind, f: F)
    where
        F: Fn(&Event, &PriceManager) -> Fut,
        Fut: Future<Output = ()> + Send,
    {
        match event {
            EventKind::Any => self
                .on_any_event_handlers
                .push(Box::new(move |e, s| tokio::spawn(f(&e, s)))),
            _ => self
                .event_handlers
                .entry(event)
                .or_default()
                .push(Box::new(move |e, s| tokio::spawn(f(&e, s)))),
        }
    }

    pub fn register_positionstate_handler<F: 'static, Fut: 'static>(
        &mut self,
        state: PositionProfitState,
        f: F,
    ) where
        F: Fn(&Position, &PriceManager) -> Fut,
        Fut: Future<Output = ()> + Send,
    {
        match state {
            // PositionProfitState::Any => self
            //     .on_any_position_state_handlers
            //     .push(Box::new(move |p, s| tokio::spawn(f(&p, s)))),
            _ => self
                .profit_state_handlers
                .entry(state)
                .or_default()
                .push(Box::new(move |p, s| tokio::spawn(f(&p, s)))),
        }
    }

    pub fn register_signal_handler<F: 'static, Fut: 'static>(&mut self, signal: SignalKind, f: F)
    where
        F: Fn(&SignalKind) -> Fut,
        Fut: Future<Output = ()> + Send,
    {
        match signal {
            // PositionProfitState::Any => self
            //     .on_any_position_state_handlers
            //     .push(Box::new(move |p, s| tokio::spawn(f(&p, s)))),
            _ => self
                .signal_handlers
                .entry(signal)
                .or_default()
                .push(Box::new(move |s| tokio::spawn(f(s)))),
        }
    }
}