# indie:lang_version = 5
from math import nan
from indie import indicator, param, plot, color, MutSeriesF
from indie.algorithms import Atr
from indie.math import cross_over, cross_under


@indicator('Ultra Trend Alerts', overlay_main_pane=True)
@param.float('key_value', default=1.0, min=0.1, title="Key Value (Sensitivity)")
@param.int('atr_period', default=10, min=1, title="ATR Period")
@plot.line(id='trailing_stop', title='ATR Trailing Stop', color=color.BLUE)
@plot.marker(
    title='Buy',
    style=plot.marker_style.LABEL,
    position=plot.marker_position.BELOW,
    size=5,
    color=color.GREEN,
)
@plot.marker(
    title='Sell',
    style=plot.marker_style.LABEL,
    position=plot.marker_position.ABOVE,
    size=5,
    color=color.RED,
)
def Main(self, key_value, atr_period):
    src = self.close
    
    # Calculate ATR-based loss
    x_atr = Atr.new(length=atr_period)
    n_loss = key_value * x_atr[0]
    
    # ATR Trailing Stop calculation
    x_atr_trailing_stop = MutSeriesF.new(init=0.0)
    
    prev_stop = x_atr_trailing_stop[1]
    prev_src = src[1]
    
    if src[0] > prev_stop and prev_src > prev_stop:
        x_atr_trailing_stop[0] = max(prev_stop, src[0] - n_loss)
    elif src[0] < prev_stop and prev_src < prev_stop:
        x_atr_trailing_stop[0] = min(prev_stop, src[0] + n_loss)
    elif src[0] > prev_stop:
        x_atr_trailing_stop[0] = src[0] - n_loss
    else:
        x_atr_trailing_stop[0] = src[0] + n_loss
    
    # Position tracking
    pos = MutSeriesF.new(init=0.0)
    
    if prev_src < prev_stop and src[0] > prev_stop:
        pos[0] = 1.0
    elif prev_src > prev_stop and src[0] < prev_stop:
        pos[0] = -1.0
    else:
        pos[0] = pos[1]
    
    # Color for trailing stop line based on position
    x_color = color.RED if pos[0] == -1 else (color.GREEN if pos[0] == 1 else color.BLUE)
    
    # Crossover detection (src used directly instead of EMA(src,1))
    above = cross_over(src, x_atr_trailing_stop)
    below = cross_under(src, x_atr_trailing_stop)
    
    # Buy/Sell signals
    buy = src[0] > x_atr_trailing_stop[0] and above
    sell = src[0] < x_atr_trailing_stop[0] and below
    
    # Return trailing stop line and markers
    buy_marker = plot.Marker(
        value=self.low[0],
        color=color.GREEN,
        text='Buy'
    ) if buy else plot.Marker(value=nan, color=color.TRANSPARENT)
    
    sell_marker = plot.Marker(
        value=self.high[0],
        color=color.RED,
        text='Sell'
    ) if sell else plot.Marker(value=nan, color=color.TRANSPARENT)
    
    return (
        plot.Line(x_atr_trailing_stop[0], color=x_color),
        buy_marker,
        sell_marker
    )