# indie:lang_version = 5
from math import isnan, nan
from indie import indicator, param, MainContext, color, plot

@indicator('FVG', overlay_main_pane=True)
@plot.line("p1")
@plot.line("p2")
@plot.fill("p1", "p2")
@param.int("fill_offset", default=2, title="Fill Offset")
class Main(MainContext):
    def __init__(self, fill_offset: int):
        self.fill_offset = fill_offset
        # Persistent gap boundaries – initialized as NaN.
        self.fvg_top: float = nan
        self.fvg_bottom: float = nan
        # We'll track the type: "bullish" or "bearish"; empty string if none.
        self.fvg_type: str = ""
        
    def calc(self):
        # --- Check for a new gap at the close of the current bar ---
        # Note: In Indie, self.low[0] is the current bar's low,
        # self.high[0] is the current bar's high,
        # self.high[2] is the high of the bar two bars ago,
        # and self.low[2] is the low of the bar two bars ago.
        
        new_gap = False
        gap_color = color.GREEN(0.5)  # default for bullish gap
        
        # Bullish FVG condition: current bar's low is above the high of the bar two bars ago.
        if self.low[0] > self.high[2]:
            new_gap = True
            self.fvg_top = self.high[2]
            self.fvg_bottom = self.low[0]
            self.fvg_type = "bullish"
            gap_color = color.GREEN(0.5)
        # Bearish FVG condition: current bar's high is below the low of the bar two bars ago.
        elif self.high[0] < self.low[2]:
            new_gap = True
            self.fvg_top = self.high[0]
            self.fvg_bottom = self.low[2]
            self.fvg_type = "bearish"
            gap_color = color.RED(0.5)
        
        # If no new gap is detected but one is already active, check for gap cancellation.
        # We cancel a gap if price re-enters the gap zone.
        if not new_gap and not isnan(self.fvg_top):
            if self.fvg_type == "bullish":
                # For bullish gap, if current close is between fvg_top and fvg_bottom, cancel the gap.
                if self.fvg_top < self.close[0] and self.close[0] < self.fvg_bottom:
                    self.fvg_top = nan
                    self.fvg_bottom = nan
                    self.fvg_type = ""
            elif self.fvg_type == "bearish":
                # For bearish gap, if current close is between fvg_bottom and fvg_top, cancel the gap.
                if self.fvg_bottom < self.close[0] and self.close[0] < self.fvg_top:
                    self.fvg_top = nan
                    self.fvg_bottom = nan
                    self.fvg_type = ""
        
        # Create a fill object using keyword arguments.
        # If a gap is active, use the computed gap_color; otherwise, use a default transparent color.
        current_fill_color = gap_color if not isnan(self.fvg_top) else color.AQUA
        gap_fill = plot.Fill(color=current_fill_color, offset=self.fill_offset)
        
        # Return three outputs (matching the three plot decorators):
        # p1: gap upper boundary, p2: gap lower boundary, p3: fill between them.
        return self.fvg_top, self.fvg_bottom, gap_fill