feat: TA-Lib candlestick patterns — doji-star/gap/high-wave/hikkake (part 4 of 9) (#135)

* feat: add doji-star, gap, high-wave and hikkake candlestick patterns

Five patterns, all `Input = Candle`, `Output = f64`:

- Evening Doji Star (CDLEVENINGDOJISTAR) — bearish top reversal: long white bar,
  a doji gapping up, then a black bar closing deep into the first body; -1
  (penetration configurable, default 0.3).
- Morning Doji Star (CDLMORNINGDOJISTAR) — bullish bottom reversal mirror; +1.
- Gap Side-by-Side White (CDLGAPSIDESIDEWHITE) — two similar white candles
  opening side by side after a gap, a continuation; gap up +1, gap down -1.
- High-Wave (CDLHIGHWAVE) — a small body with very long shadows on both sides,
  an extreme indecision flag; +1 on detection.
- Hikkake (CDLHIKKAKE) — an inside bar followed by a failed breakout (a trap);
  bullish +1, bearish -1.

Counter 259 -> 264 (mod-count == lib counted block; FAMILIES total 254 -> 259).

* chore: sync indicator count to 264

---------

Co-authored-by: wickra-bot <wickra-bot@users.noreply.github.com>

crates/wickra-core/src/indicators/hikkake.rs

@@ -0,0 +1,198 @@
+//! Hikkake candlestick pattern.
+
+use crate::ohlcv::Candle;
+use crate::traits::Indicator;
+
+/// Hikkake — a 3-bar trap. An inside bar (bar2 fully contained by bar1) sets up a
+/// breakout that immediately fails on bar3, trapping breakout traders and pointing
+/// the opposite way.
+///
+/// ```text
+/// inside bar : bar2.high < bar1.high  &&  bar2.low > bar1.low
+/// bullish (+1.0): bar3 makes a LOWER high AND LOWER low than bar2
+///                 (a false downside break -> expect a move up)
+/// bearish (−1.0): bar3 makes a HIGHER high AND HIGHER low than bar2
+///                 (a false upside break -> expect a move down)
+/// ```
+///
+/// Output is `+1.0` (bullish setup), `−1.0` (bearish setup), or `0.0` otherwise.
+/// The detector fires when the three-bar setup completes on bar3; it does not
+/// separately flag the optional later confirmation bar. The first two bars always
+/// return `0.0` because the window is not yet filled. Pattern-shape check only —
+/// no trend filter is applied; combine with a trend indicator for actionable
+/// signals.
+///
+/// # Signed ±1 encoding
+///
+/// This detector emits the uniform candlestick sign convention shared across the
+/// pattern family — `+1.0` bullish, `−1.0` bearish, `0.0` no pattern — so it
+/// drops straight into a machine-learning feature matrix where the bullish and
+/// bearish setups occupy a single dimension.
+///
+/// # Example
+///
+/// ```
+/// use wickra_core::{Candle, Hikkake, Indicator};
+///
+/// let mut indicator = Hikkake::new();
+/// indicator.update(Candle::new(10.0, 15.0, 5.0, 12.0, 1.0, 0).unwrap());
+/// indicator.update(Candle::new(11.0, 13.0, 8.0, 12.0, 1.0, 1).unwrap());
+/// let out = indicator
+///     .update(Candle::new(9.0, 12.0, 6.0, 7.0, 1.0, 2).unwrap());
+/// assert_eq!(out, Some(1.0));
+/// ```
+#[derive(Debug, Clone, Default)]
+pub struct Hikkake {
+    prev: Option<Candle>,
+    prev_prev: Option<Candle>,
+    has_emitted: bool,
+}
+
+impl Hikkake {
+    /// Construct a new Hikkake detector.
+    pub const fn new() -> Self {
+        Self {
+            prev: None,
+            prev_prev: None,
+            has_emitted: false,
+        }
+    }
+}
+
+impl Indicator for Hikkake {
+    type Input = Candle;
+    type Output = f64;
+
+    fn update(&mut self, candle: Candle) -> Option<f64> {
+        self.has_emitted = true;
+        let bar1 = self.prev_prev;
+        let bar2 = self.prev;
+        self.prev_prev = self.prev;
+        self.prev = Some(candle);
+        let (Some(bar1), Some(bar2)) = (bar1, bar2) else {
+            return Some(0.0);
+        };
+        // bar2 must be an inside bar of bar1.
+        if !(bar2.high < bar1.high && bar2.low > bar1.low) {
+            return Some(0.0);
+        }
+        // Bullish: bar3 breaks below the inside bar (lower high and lower low).
+        if candle.high < bar2.high && candle.low < bar2.low {
+            return Some(1.0);
+        }
+        // Bearish: bar3 breaks above the inside bar (higher high and higher low).
+        if candle.high > bar2.high && candle.low > bar2.low {
+            return Some(-1.0);
+        }
+        Some(0.0)
+    }
+
+    fn reset(&mut self) {
+        self.prev = None;
+        self.prev_prev = None;
+        self.has_emitted = false;
+    }
+
+    fn warmup_period(&self) -> usize {
+        3
+    }
+
+    fn is_ready(&self) -> bool {
+        self.has_emitted
+    }
+
+    fn name(&self) -> &'static str {
+        "Hikkake"
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::traits::BatchExt;
+
+    fn c(open: f64, high: f64, low: f64, close: f64, ts: i64) -> Candle {
+        Candle::new(open, high, low, close, 1.0, ts).unwrap()
+    }
+
+    #[test]
+    fn accessors_and_metadata() {
+        let t = Hikkake::new();
+        assert_eq!(t.name(), "Hikkake");
+        assert_eq!(t.warmup_period(), 3);
+        assert!(!t.is_ready());
+    }
+
+    #[test]
+    fn bullish_hikkake_is_plus_one() {
+        let mut t = Hikkake::new();
+        assert_eq!(t.update(c(10.0, 15.0, 5.0, 12.0, 0)), Some(0.0));
+        assert_eq!(t.update(c(11.0, 13.0, 8.0, 12.0, 1)), Some(0.0));
+        assert_eq!(t.update(c(9.0, 12.0, 6.0, 7.0, 2)), Some(1.0));
+    }
+
+    #[test]
+    fn bearish_hikkake_is_minus_one() {
+        let mut t = Hikkake::new();
+        assert_eq!(t.update(c(10.0, 15.0, 5.0, 12.0, 0)), Some(0.0));
+        assert_eq!(t.update(c(11.0, 13.0, 8.0, 12.0, 1)), Some(0.0));
+        assert_eq!(t.update(c(12.0, 14.0, 9.0, 13.0, 2)), Some(-1.0));
+    }
+
+    #[test]
+    fn not_inside_bar_yields_zero() {
+        let mut t = Hikkake::new();
+        t.update(c(10.0, 15.0, 5.0, 12.0, 0));
+        // bar2 is not contained by bar1 (higher high).
+        t.update(c(11.0, 16.0, 8.0, 12.0, 1));
+        assert_eq!(t.update(c(9.0, 12.0, 6.0, 7.0, 2)), Some(0.0));
+    }
+
+    #[test]
+    fn outside_bar3_yields_zero() {
+        let mut t = Hikkake::new();
+        t.update(c(10.0, 15.0, 5.0, 12.0, 0));
+        t.update(c(11.0, 13.0, 8.0, 12.0, 1));
+        // bar3 engulfs bar2 (higher high and lower low) -> neither direction.
+        assert_eq!(t.update(c(11.0, 14.0, 7.0, 9.0, 2)), Some(0.0));
+    }
+
+    #[test]
+    fn first_two_bars_return_zero() {
+        let mut t = Hikkake::new();
+        assert_eq!(t.update(c(10.0, 15.0, 5.0, 12.0, 0)), Some(0.0));
+        assert_eq!(t.update(c(11.0, 13.0, 8.0, 12.0, 1)), Some(0.0));
+    }
+
+    #[test]
+    fn batch_equals_streaming() {
+        let candles: Vec<Candle> = (0..40)
+            .map(|i| {
+                let base = 100.0 + i as f64;
+                match i % 3 {
+                    0 => c(base, base + 6.0, base - 6.0, base, i),
+                    1 => c(base, base + 2.0, base - 2.0, base, i),
+                    _ => c(base, base + 1.0, base - 5.0, base - 4.0, i),
+                }
+            })
+            .collect();
+        let mut a = Hikkake::new();
+        let mut b = Hikkake::new();
+        assert_eq!(
+            a.batch(&candles),
+            candles.iter().map(|x| b.update(*x)).collect::<Vec<_>>()
+        );
+    }
+
+    #[test]
+    fn reset_clears_state() {
+        let mut t = Hikkake::new();
+        t.update(c(10.0, 15.0, 5.0, 12.0, 0));
+        t.update(c(11.0, 13.0, 8.0, 12.0, 1));
+        t.update(c(9.0, 12.0, 6.0, 7.0, 2));
+        assert!(t.is_ready());
+        t.reset();
+        assert!(!t.is_ready());
+        assert_eq!(t.update(c(10.0, 15.0, 5.0, 12.0, 0)), Some(0.0));
+    }
+}