//@version=6
indicator("Quad Witching Dates by @bitcoinfundmgr on x", overlay=true)

// Function to check if a date is the third Friday of the month
isThirdFriday(barTime) =>
    yearValue = year(barTime)
    monthValue = month(barTime)
    dayOfMonthValue = dayofmonth(barTime)
    dayOfWeekValue = dayofweek(barTime)
    
    // Check if it's a Friday (6 = Friday in Pine Script)
    isFriday = dayOfWeekValue == 6
    
    // Check if it's the third Friday (between 15th and 21st)
    isInThirdWeek = dayOfMonthValue >= 15 and dayOfMonthValue <= 21
    
    isFriday and isInThirdWeek

// Function to check if current month is a quad witching month
isQuadWitchingMonth(barTime) =>
    currentMonthValue = month(barTime)
    // Quad witching months: March (3), June (6), September (9), December (12)
    currentMonthValue == 3 or currentMonthValue == 6 or currentMonthValue == 9 or currentMonthValue == 12

// Check if current bar is on a quad witching date
isQuadWitching = isThirdFriday(time) and isQuadWitchingMonth(time)

// Input for line color
lineColor = input.color(color.red, "Line Color", group="Appearance")
lineWidth = input.int(1, "Line Width", minval=1, maxval=4, group="Appearance")
lineStyle = input.string("solid", "Line Style", options=["solid", "dashed", "dotted"], group="Appearance")

// Convert line style string to Pine Script line style
getLineStyle(style) =>
    style == "solid" ? line.style_solid : style == "dashed" ? line.style_dashed : line.style_dotted

// Draw vertical line on quad witching dates
if isQuadWitching
    line.new(x1=bar_index, y1=low[1] * 0.95, x2=bar_index, y2=high[1] * 1.05, 
             color=lineColor, width=lineWidth, style=getLineStyle(lineStyle), extend=extend.both)

// Optional: Add label to identify quad witching dates
showLabels = input.bool(true, "Show Labels", group="Labels")
labelPosition = input.string("bottom", "Label Position", options=["top", "bottom"], group="Labels")

if isQuadWitching and showLabels
    labelY = labelPosition == "top" ? high[1] * 1.02 : low[1] * 0.98
    label.new(x=bar_index, y=labelY, text="QW", color=lineColor, 
              style=labelPosition == "top" ? label.style_label_down : label.style_label_up,
              size=size.small, textcolor=color.white)

// Display next quad witching date
showNextDate = input.bool(true, "Show Next Quad Witching Date", group="Display")
tablePosition = input.string("top_right", "Table Position", options=["top_left", "top_center", "top_right", "middle_left", "middle_center", "middle_right", "bottom_left", "bottom_center", "bottom_right"], group="Display")

// Create table for displaying next quad witching date
var table infoTable = table.new(tablePosition, 1, 1)

if barstate.islast and showNextDate
    currentTimeValue = time
    currentYearValue = year(currentTimeValue)
    currentMonthValue = month(currentTimeValue)
    currentDayValue = dayofmonth(currentTimeValue)
    
    // Calculate next quad witching month
    nextMonthValue = 0
    nextYearValue = currentYearValue
    
    if currentMonthValue < 3
        nextMonthValue := 3
    else if currentMonthValue < 6
        nextMonthValue := 6
    else if currentMonthValue < 9
        nextMonthValue := 9
    else if currentMonthValue < 12
        nextMonthValue := 12
    else
        nextMonthValue := 3
        nextYearValue := currentYearValue + 1
    
    // Find third Friday of next quad witching month
    firstDayTimestamp = timestamp(nextYearValue, nextMonthValue, 1, 0, 0)
    firstDayOfWeekValue = dayofweek(firstDayTimestamp)
    
    // Calculate date of third Friday
    daysUntilFridayValue = (6 - firstDayOfWeekValue + 7) % 7
    if daysUntilFridayValue == 0
        daysUntilFridayValue := 7
    thirdFridayDate = 1 + daysUntilFridayValue + 14
    
    // Check if we've already passed the quad witching date this month
    if currentMonthValue == nextMonthValue and currentDayValue > thirdFridayDate
        if nextMonthValue == 12
            nextMonthValue := 3
            nextYearValue := nextYearValue + 1
        else if nextMonthValue == 3
            nextMonthValue := 6
        else if nextMonthValue == 6
            nextMonthValue := 9
        else
            nextMonthValue := 12
        
        // Recalculate third Friday for the new month
        firstDayTimestamp := timestamp(nextYearValue, nextMonthValue, 1, 0, 0)
        firstDayOfWeekValue := dayofweek(firstDayTimestamp)
        daysUntilFridayValue := (6 - firstDayOfWeekValue + 7) % 7
        if daysUntilFridayValue == 0
            daysUntilFridayValue := 7
        thirdFridayDate := 1 + daysUntilFridayValue + 14
    
    nextQWDate = str.format("{0}-{1,number,00}-{2,number,00}", nextYearValue, nextMonthValue, thirdFridayDate)
    
    // Update table
    table.cell(infoTable, 0, 0, "Next QW: " + nextQWDate, bgcolor=color.new(color.black, 80), text_color=color.white, text_size=size.small)