use std::collections::HashMap;
use std::fmt::{Debug, Formatter};

use dyn_clone::DynClone;
use log::info;

use crate::connectors::Connector;
use crate::events::{Event, EventKind, EventMetadata, Message};
use crate::managers::OptionUpdate;
use crate::models::OrderBookEntry::Trading;
use crate::models::{
    ActiveOrder, OrderBook, OrderBookEntry, OrderForm, OrderKind, Position, PositionProfitState,
    PositionState, TradingPlatform,
};
use crate::BoxError;

/***************
* DEFINITIONS
***************/

pub trait PositionStrategy: DynClone + Send + Sync {
    fn name(&self) -> String;
    fn on_tick(
        &mut self,
        position: Position,
        current_tick: u64,
        positions_history: &HashMap<u64, Position>,
    ) -> (Position, Option<Vec<Event>>, Option<Vec<Message>>);
    fn post_tick(
        &mut self,
        position: Position,
        current_tick: u64,
        positions_history: &HashMap<u64, Position>,
    ) -> (Position, Option<Vec<Event>>, Option<Vec<Message>>);
}

impl Debug for dyn PositionStrategy {
    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
        write!(f, "{}", self.name())
    }
}

pub trait OrderStrategy: DynClone + Send + Sync {
    /// The name of the strategy, used for debugging purposes
    fn name(&self) -> String;
    /// This method is called when the OrderManager checks the open orders on a new tick.
    /// It should manage if some orders have to be closed or keep open.
    fn on_open_order(
        &self,
        order: &ActiveOrder,
        order_book: &OrderBook,
    ) -> Result<OptionUpdate, BoxError>;
    // /// This method is called when the OrderManager is requested to close
    // /// a position that has an open order associated to it.
    // fn on_position_order(
    //     &self,
    //     order: &ActiveOrder,
    //     open_position: &Position,
    //     order_book: &OrderBook,
    // ) -> Result<OptionUpdate, BoxError>;
}

impl Debug for dyn OrderStrategy {
    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
        write!(f, "{}", self.name())
    }
}

/***************
* IMPLEMENTATIONS
***************/

#[derive(Clone, Debug)]
pub struct TrailingStop {
    stop_percentages: HashMap<u64, f64>,
}

impl TrailingStop {
    // in percentage
    const CAPITAL_MAX_LOSS: f64 = 17.5;
    const CAPITAL_MIN_PROFIT: f64 = 10.0;
    const CAPITAL_GOOD_PROFIT: f64 = 20.0;

    // in percentage
    const MIN_PROFIT_TRAILING_DELTA: f64 = 0.2;
    const GOOD_PROFIT_TRAILING_DELTA: f64 = 0.1;

    const LEVERAGE: f64 = 15.0;

    const MIN_PROFIT_PERC: f64 = (TrailingStop::CAPITAL_MIN_PROFIT / TrailingStop::LEVERAGE)
        + TrailingStop::MIN_PROFIT_TRAILING_DELTA;
    const GOOD_PROFIT_PERC: f64 = (TrailingStop::CAPITAL_GOOD_PROFIT / TrailingStop::LEVERAGE)
        + TrailingStop::GOOD_PROFIT_TRAILING_DELTA;
    const MAX_LOSS_PERC: f64 = -(TrailingStop::CAPITAL_MAX_LOSS / TrailingStop::LEVERAGE);

    pub fn new() -> Self {
        TrailingStop {
            stop_percentages: HashMap::new(),
        }
    }

    fn update_stop_percentage(&mut self, position: &Position) {
        if let Some(profit_state) = position.profit_state() {
            let profit_state_delta = match profit_state {
                PositionProfitState::MinimumProfit => Some(TrailingStop::MIN_PROFIT_TRAILING_DELTA),
                PositionProfitState::Profit => Some(TrailingStop::GOOD_PROFIT_TRAILING_DELTA),
                _ => None,
            };

            if let Some(profit_state_delta) = profit_state_delta {
                let current_stop_percentage = position.pl_perc() - profit_state_delta;

                match profit_state {
                    PositionProfitState::MinimumProfit | PositionProfitState::Profit => {
                        match self.stop_percentages.get(&position.id()) {
                            None => {
                                self.stop_percentages
                                    .insert(position.id(), current_stop_percentage);
                            }
                            Some(existing_threshold) => {
                                if existing_threshold < &current_stop_percentage {
                                    self.stop_percentages
                                        .insert(position.id(), current_stop_percentage);
                                }
                            }
                        }
                    }
                    _ => {}
                }
            }
            info!(
                "\tState: {:?} | PL%: {:0.2} | Stop: {:0.2}",
                position.profit_state().unwrap(),
                position.pl_perc(),
                self.stop_percentages.get(&position.id()).unwrap_or(&0.0)
            );
        }
    }
}

impl PositionStrategy for TrailingStop {
    fn name(&self) -> String {
        "Trailing stop".into()
    }

    /// Sets the profit state of an open position
    fn on_tick(
        &mut self,
        position: Position,
        current_tick: u64,
        positions_history: &HashMap<u64, Position>,
    ) -> (Position, Option<Vec<Event>>, Option<Vec<Message>>) {
        let pl_perc = position.pl_perc();

        let state = {
            if pl_perc > TrailingStop::GOOD_PROFIT_PERC {
                PositionProfitState::Profit
            } else if TrailingStop::MIN_PROFIT_PERC <= pl_perc
                && pl_perc < TrailingStop::GOOD_PROFIT_PERC
            {
                PositionProfitState::MinimumProfit
            } else if 0.0 <= pl_perc && pl_perc < TrailingStop::MIN_PROFIT_PERC {
                PositionProfitState::BreakEven
            } else if TrailingStop::MAX_LOSS_PERC < pl_perc && pl_perc < 0.0 {
                PositionProfitState::Loss
            } else {
                PositionProfitState::Critical
            }
        };

        let opt_prev_position = positions_history.get(&(current_tick - 1));
        let event_metadata = EventMetadata::new(Some(position.id()), None);
        let new_position = position.clone().with_profit_state(Some(state));

        match opt_prev_position {
            Some(prev) => {
                if prev.profit_state() == Some(state) {
                    return (new_position, None, None);
                }
            }
            None => return (new_position, None, None),
        };

        let events = {
            let mut events = vec![];

            if state == PositionProfitState::Profit {
                events.push(Event::new(
                    EventKind::ReachedGoodProfit,
                    current_tick,
                    Some(event_metadata),
                ));
            } else if state == PositionProfitState::MinimumProfit {
                events.push(Event::new(
                    EventKind::ReachedMinProfit,
                    current_tick,
                    Some(event_metadata),
                ));
            } else if state == PositionProfitState::BreakEven {
                events.push(Event::new(
                    EventKind::ReachedBreakEven,
                    current_tick,
                    Some(event_metadata),
                ));
            } else if state == PositionProfitState::Loss {
                events.push(Event::new(
                    EventKind::ReachedLoss,
                    current_tick,
                    Some(event_metadata),
                ));
            } else {
                events.push(Event::new(
                    EventKind::ReachedMaxLoss,
                    current_tick,
                    Some(event_metadata),
                ));
            }

            events
        };

        return (new_position, Some(events), None);
    }

    fn post_tick(
        &mut self,
        position: Position,
        _: u64,
        _: &HashMap<u64, Position>,
    ) -> (Position, Option<Vec<Event>>, Option<Vec<Message>>) {
        let close_message = Message::ClosePosition {
            position_id: position.id(),
        };

        // if critical, early return with close position
        if let Some(profit_state) = position.profit_state() {
            match profit_state {
                PositionProfitState::Critical => {
                    info!("Maximum loss reached. Closing position.");
                    return (position, None, Some(vec![close_message]));
                }
                _ => {}
            }
        };

        // let's check if we surpassed an existing stop percentage
        if let Some(existing_stop_percentage) = self.stop_percentages.get(&position.id()) {
            if &position.pl_perc() <= existing_stop_percentage {
                info!("Stop percentage surpassed. Closing position.");
                return (position, None, Some(vec![close_message]));
            }
        }

        self.update_stop_percentage(&position);

        (position, None, None)
    }
}

#[derive(Clone, Debug)]
pub struct FastOrderStrategy {
    // threshold (%) for which we trigger a market order
    // to close an open position
    threshold: f64,
}

impl Default for FastOrderStrategy {
    fn default() -> Self {
        Self { threshold: 0.15 }
    }
}

impl FastOrderStrategy {
    pub fn new(threshold: f64) -> Self {
        Self { threshold }
    }
}

impl OrderStrategy for FastOrderStrategy {
    fn name(&self) -> String {
        "Fast order strategy".into()
    }

    fn on_open_order(
        &self,
        order: &ActiveOrder,
        order_book: &OrderBook,
    ) -> Result<OptionUpdate, BoxError> {
        let mut messages = vec![];

        // long
        let offer_comparison = {
            if order.details.amount() > 0.0 {
                order_book.highest_bid()
            } else {
                order_book.lowest_ask()
            }
        };

        // if the best offer is higher than our threshold,
        // ask the manager to close the position with a market order
        let order_price = order
            .details
            .price()
            .ok_or("The active order does not have a price!")?;
        let delta = (1.0 - (offer_comparison / order_price)).abs() * 100.0;

        if delta > self.threshold {
            messages.push(Message::SubmitOrder {
                order: OrderForm::new(
                    order.symbol.clone(),
                    OrderKind::Market {
                        amount: order.details.amount(),
                    },
                    order.details.platform().clone(),
                ),
            })
        }

        Ok((None, (!messages.is_empty()).then_some(messages)))
    }

    // fn on_position_order(
    //     &self,
    //     order: &ActiveOrder,
    //     _: &Position,
    //     order_book: &OrderBook,
    // ) -> Result<OptionUpdate, BoxError> {
    //     let mut messages = vec![];
    //
    //     // long
    //     let offer_comparison = {
    //         if order.current_form.amount() > 0.0 {
    //             order_book.highest_bid()
    //         } else {
    //             order_book.lowest_ask()
    //         }
    //     };
    //
    //     // if the best offer is higher than our threshold,
    //     // ask the manager to close the position with a market order
    //     let order_price = order
    //         .current_form
    //         .price()
    //         .ok_or("The active order does not have a price!")?;
    //     let delta = (1.0 - (offer_comparison / order_price)).abs() * 100.0;
    //
    //     if delta > self.threshold {
    //         messages.push(Message::SubmitOrder {
    //             order: OrderForm::new(
    //                 order.symbol.clone(),
    //                 OrderKind::Market {
    //                     amount: order.current_form.amount(),
    //                 },
    //                 order.current_form.platform().clone(),
    //             ),
    //         })
    //     }
    //
    //     Ok((None, (!messages.is_empty()).then_some(messages)))
    // }
}