//! # BTS: BackTest Strategy for Trading Algorithms
//!
//! **BTS** is a high-performance Rust library for backtesting trading strategies on candlestick (OHLCV) data.
//! It is designed for **speed, flexibility, and accuracy**, making it ideal for both **retail traders** and **algorithmic trading developers**.
//!
//! ## Why BTS?
//!
//! - **Optimized for Performance**: Uses O(1) operations on orders/positions, and parallel processing for optimization tasks.
//! - **Technical Analysis Ready**: Seamlessly integrates with popular indicators crates for 100+ indicators (EMA, MACD, RSI, etc.).
//! - **Risk Management**: Supports stop-loss, take-profit, and trailing stops with configurable rules.
//! - **Realistic Simulations**: Models slippage, fees, and latency for accurate backtesting.
//! - **Extensible**: Add custom indicators, strategies, or data sources with minimal effort.
//!
//! ## Core Components
//!
//! | Component       | Description                                                                      |
//! |---------------- |----------------------------------------------------------------------------------|
//! | **`Metrics`**   | Calculates performance metrics: P&L, drawdown, Sharpe ratio, win rate, and more. |
//! | **`Optimizer`** | Calculates bests parameters *(indicators, RR, etc...)*.                          |
//! | **`Draw`**      | Draw candlestick data, balance and metrics to a *SVG* or *PNG* file.             |
//! | **`Backtest`**  | The engine that simulates strategy execution over historical data.               |
//!
//! ## Features
//!
//! ### 1. **Technical Indicators**
//! - Compatible with indicators crates like the [`ta`](https://crates.io/crates/ta) crate for 100+ additional indicators.
//!
//! ### 2. **Order Types & Exit Rules**
//!
//! | Order Type                  | Description                                                   |
//! |-----------------------------|---------------------------------------------------------------|
//! | **Market Order**            | Executes immediately at the current price.                    |
//! | **Limit Order**             | Executes only at a specified price or better.                 |
//! | **Take-Profit**             | Closes the position when a target price is reached.           |
//! | **Stop-Loss**               | Closes the position to limit losses.                          |
//! | **Trailing Stop**           | Dynamically adjusts the stop price based on market movements. |
//! | **Take-Profit + Stop-Loss** | Combines both rules for risk management.                      |
//!
//! ### 3. **Performance Metrics**
//!
//! | Metric               | Description                                            |
//! |----------------------|--------------------------------------------------------|
//! | **Max Drawdown**     | Largest peak-to-trough decline in account balance (%). |
//! | **Profit Factor**    | Ratio of gross profits to gross losses.                |
//! | **Sharpe Ratio**     | Risk-adjusted return (higher = better).                |
//! | **Win Rate**         | Percentage of winning trades.                          |
//!
//! ### 4. **Optimization Tools**
//!
//! - **Parallelize**: Optimize strategy parameters (e.g., EMA periods) using multi-threading.
//!
//! ## Getting Started
//!
//! ### 1. Add BTS to your project:
//! ```toml
//! [dependencies]
//! bts_rs = "*"
//! ta = "*"  # Optional: For technical analysis indicators
//! ```
//!
//! ### 2. Run a Simple Backtest:
//! ```rust
//! use std::sync::Arc;
//! 
//! use bts_rs::prelude::*;
//! use chrono::{DateTime, Duration};
//!
//! let candle = CandleBuilder::builder()
//!     .open(100.0)
//!     .high(110.0)
//!     .low(95.0)
//!     .close(105.0)
//!     .volume(1.0)
//!     .bid(0.5)
//!     .open_time(DateTime::default())
//!     .close_time(DateTime::default() + Duration::days(1))
//!     .build()
//!     .unwrap();
//!
//! // Initialize backtest with \$10,000
//! let mut backtest = Backtest::new(Arc::from_iter(vec![candle]), 10_000.0, None).unwrap();
//!
//! // Execute a market buy order
//! backtest
//!     .run(|bt, candle| {
//!         let order: Order = (OrderType::Market(102.0), 1.0, OrderSide::Buy).into();
//!         bt.place_order(candle, order).unwrap();
//!         // Close the position at \$104.0
//!         if let Some(position) = bt.positions().last().cloned() {
//!             bt.close_position(candle, &position, 104.0, true).unwrap();
//!         }
//!         Ok(())
//!     })
//!     .unwrap();
//!
//! // Print performance metrics
//! #[cfg(feature = "metrics")]
//! {
//!     let metrics = Metrics::from(&backtest);
//!     println!("{}", metrics);
//! }
//! ```
//!
//! ### Output:
//!
//! ```bash
//! === Backtest Metrics ===
//! Initial Balance: 10000.00
//! Final Balance: 10018.00
//! Profit & Loss (P&L): 0.00
//! Fees paid: 0.00
//! 
//! Max Drawdown: 0.20%
//! Profit Factor: 2.00
//! Sharpe Ratio: 1.50
//! Win Rate: 100.00%
//! ```
//!
//! ## Use Cases
//!
//! - **Retail Traders**: Test manual strategies before risking real capital.
//! - **Algo Developers**: Build and optimize automated trading systems.
//! - **Quant Researchers**: Backtest statistical arbitrage or machine learning models.
//! - **Educational**: Teach trading concepts with a hands-on tool.
//!
//! ## Integrations
//!
//! | Crate                                           | Purpose                                                           |
//! |-------------------------------------------------|-------------------------------------------------------------------|
//! | [`rayon`](https://crates.io/crates/rayon)       | Parallel processing for optimization.                             |
//! | [`serde`](https://crates.io/crates/serde)       | Serialize/deserialize backtest results.                           |
//! | [`plotters`](https://crates.io/crates/plotters) | Visualize market candlesticks data, equity curves and indicators. |
//!
//! ## Error Handling
//!
//! BTS uses custom error types to handle:
//! - Insufficient balance.
//! - Invalid order types.
//! - Missing data (e.g., candles, positions) and more.
//!
//! Example:
//! ```rust
//! use std::sync::Arc;
//! 
//! use bts_rs::prelude::*;
//! use chrono::{DateTime, Duration};
//!
//! let candle = CandleBuilder::builder()
//!     .open(100.0)
//!     .high(110.0)
//!     .low(95.0)
//!     .close(105.0)
//!     .volume(1.0)
//!     .bid(0.5)
//!     .open_time(DateTime::default())
//!     .close_time(DateTime::default() + Duration::days(1))
//!     .build()
//!     .unwrap();
//! 
//! // Initialize backtest with \$10,000
//! let mut backtest = Backtest::new(Arc::from_iter(vec![candle]), 10_000.0, None).unwrap();
//! 
//! // Execute a market buy order
//! backtest
//!     .run(|bt, candle| {
//!         let order: Order = (OrderType::Market(102.0), 1.0, OrderSide::Buy).into();
//!         match bt.place_order(candle, order) {
//!            Ok(_) => println!("Order in the pool!"),
//!            Err(_) => eprintln!("Error to place an order")
//!         }
//!         Ok(())
//!     })
//!     .unwrap();
//! ```
//!
//! ## Contributing
//!
//! Contributions are welcome! See [`CONTRIBUTING.md`](https://github.com/raonagos/bts-rs/blob/master/CONTRIBUTING.md).
//!
//! ## License
//!
//! The project is licensed under the [`MIT`](https://github.com/raonagos/bts-rs/blob/master/LICENSE).
#![warn(missing_docs)]

/// Core trading engine components: orders, positions, wallet, and backtest logic.
pub mod engine;

/// Error types for the library.
pub mod errors;

/// Utility functions and helpers.
mod utils;

/// Performance metrics: drawdown, Sharpe ratio, win rate, etc.
#[cfg(feature = "metrics")]
pub mod metrics;

/// Strategy parameter optimization.
#[cfg(feature = "optimizer")]
pub mod optimizer;

/// Module for visualizing backtest results and candle charts.
#[cfg(feature = "draws")]
pub mod draws;

/// Re-exports of commonly used types and traits for convenience.
pub mod prelude {
    pub use super::PercentCalculus;
    pub use crate::engine::*;

    #[cfg(feature = "metrics")]
    pub use crate::metrics::*;

    #[cfg(feature = "optimizer")]
    pub use crate::optimizer::*;

    #[cfg(feature = "draws")]
    pub use crate::draws::*;
}

use std::ops::{Add, Div, Mul, Sub};

/// Trait for performing percentage-based calculations (human readable).
///
/// This trait provides methods to add, subtract, and calculate percentages
/// for numeric types, enabling common financial calculations.
pub trait PercentCalculus<Rhs = Self> {
    /// Adds a percentage to the value.
    ///
    /// ### Arguments
    /// * `rhs` - The percentage to add (e.g., 10.0 for 10%).
    ///
    /// ### Returns
    /// The value increased by the given percentage.
    fn addpercent(self, rhs: Rhs) -> Self;

    /// Subtracts a percentage from the value.
    ///
    /// ### Arguments
    /// * `rhs` - The percentage to subtract (e.g., 10.0 for 10%).
    ///
    /// ### Returns
    /// The value decreased by the given percentage.
    fn subpercent(self, rhs: Rhs) -> Self;

    /// Calculates the absolute value of a percentage.
    ///
    /// ### Arguments
    /// * `rhs` - The percentage to calculate (e.g., 10.0 for 10%).
    ///
    /// ### Returns
    /// The absolute value of the given percentage.
    fn how_many(self, rhs: Rhs) -> Self;

    /// Calculates the percentage change between two values.
    ///
    /// ### Arguments
    /// * `value` - The value to compare with.
    ///
    /// ### Returns
    /// The percentage change from the original value to the input value.
    fn change(self, value: Rhs) -> Self;
}

impl PercentCalculus for f64 {
    fn addpercent(self, percent: Self) -> Self {
        self.add(self.mul(percent.div(100.0)))
    }

    fn subpercent(self, percent: Self) -> Self {
        self.sub(self.mul(percent.div(100.0)))
    }

    fn how_many(self, percent: Self) -> Self {
        percent.mul(self.div(100.0))
    }

    fn change(self, value: Self) -> Self {
        value.sub(self).div(self).mul(100.0)
    }
}

#[cfg(test)]
mod percent {
    use super::*;

    #[test]
    fn add() {
        assert_eq!(110.0, 100.0.addpercent(10.0))
    }

    #[test]
    fn sub() {
        assert_eq!(90.0, 100.0.subpercent(10.0))
    }

    #[test]
    fn how_many() {
        assert_eq!(10.0, 100.0.how_many(10.0))
    }

    #[test]
    fn change() {
        assert_eq!(10.0, 100.0.change(110.0))
    }
}
