kestrel-chartkit 0.1.1

use std::collections::HashMap;

use crate::indicator::smoothing::{ExtremeWindow, Sma};
use crate::indicator::{Indicator, IndicatorAlert, IndicatorOutput};
use crate::model::Bar;

/// Williams VIX Fix Advanced indicator.
/// Measures market synthetic fear/volatility spikes to identify market bottoms.
pub struct WilliamsVixFix {
    #[allow(dead_code)]
    pd: usize,
    bband_len: usize,
    mult: f64,

    close_window: ExtremeWindow,
    wvf_window: Vec<f64>,
    sma: Sma,
    alerts: Vec<IndicatorAlert>,
}

impl WilliamsVixFix {
    pub fn new(pd: usize, bband_len: usize, mult: f64) -> Self {
        Self {
            pd,
            bband_len,
            mult,
            close_window: ExtremeWindow::new(pd),
            wvf_window: Vec::with_capacity(bband_len),
            sma: Sma::new(bband_len),
            alerts: Vec::new(),
        }
    }
}

impl Indicator for WilliamsVixFix {
    fn name(&self) -> &str {
        "vix_fix"
    }

    fn reset(&mut self) {
        self.close_window.reset();
        self.wvf_window.clear();
        self.sma.reset();
        self.alerts.clear();
    }

    fn on_bar(&mut self, bar: &Bar) -> Option<IndicatorOutput> {
        let highest_close = self
            .close_window
            .push(bar.close)
            .map(|(_, high)| high)
            .unwrap_or(bar.close);
        self.alerts.clear();

        let wvf = if highest_close > 0.0 {
            ((highest_close - bar.low) / highest_close) * 100.0
        } else {
            0.0
        };

        let sma_val = self.sma.update(wvf)?;

        self.wvf_window.push(wvf);
        if self.wvf_window.len() > self.bband_len {
            self.wvf_window.remove(0);
        }

        if self.wvf_window.len() < self.bband_len {
            return None;
        }

        let mean = sma_val;
        let variance = self
            .wvf_window
            .iter()
            .map(|v| (v - mean).powi(2))
            .sum::<f64>()
            / self.bband_len as f64;
        let std_dev = variance.sqrt();

        let upper_band = mean + self.mult * std_dev;
        let is_spike = wvf >= upper_band;

        if is_spike {
            self.alerts.push(IndicatorAlert::new(
                "panic_bottom",
                format!(
                    "Williams VIX Fix Spike ({:.2} >= Upper Band {:.2}) - Market Bottom Zone",
                    wvf, upper_band
                ),
                1.0,
            ));
        }

        Some(IndicatorOutput::new(wvf).with_secondary(upper_band))
    }

    fn alerts(&self) -> Vec<IndicatorAlert> {
        self.alerts.clone()
    }
}

pub fn build_vix_fix(params: &HashMap<String, f64>) -> WilliamsVixFix {
    let pd = params.get("pd").copied().unwrap_or(22.0) as usize;
    let bband_len = params.get("bband_len").copied().unwrap_or(20.0) as usize;
    let mult = params.get("mult").copied().unwrap_or(2.0);
    WilliamsVixFix::new(pd, bband_len, mult)
}