Prior Day High/Low Fib Levels v2.6

describe_indicator('Prior Day High/Low Fib Levels v2.5');

// Ensure the indicator is not applied to higher timeframes
assert(
    !['D', 'W', 'M', 'Q', 'Y'].includes(constants.resolution),
    `not applicable to "${constants.resolution}" charts`
);

// ---------------------------------------------------------------
// Inputs
// ---------------------------------------------------------------
const showHL        = input.boolean('Show Prior Day High/Low', true);
const breakSessions = input.boolean('Break Lines at Session End', true);

// false = measure UP from prior low (fib 0 = low, fib 1 = high)
// true  = measure DOWN from prior high (fib 0 = high, fib 1 = low)
const fromHigh      = input.boolean('Measure From High', false);

const fib1 = input.number('Fib Level 1', 0,     { min: 0, max: 1 });
const fib2 = input.number('Fib Level 2', 0.236, { min: 0, max: 1 });
const fib3 = input.number('Fib Level 3', 0.382, { min: 0, max: 1 });
const fib4 = input.number('Fib Level 4', 0.5,   { min: 0, max: 1 });
const fib5 = input.number('Fib Level 5', 0.618, { min: 0, max: 1 });
const fib6 = input.number('Fib Level 6', 0.786, { min: 0, max: 1 });
const fib7 = input.number('Fib Level 7', 1,     { min: 0, max: 1 });
const fibArray = [fib1, fib2, fib3, fib4, fib5, fib6, fib7];

// Extensions - OFF by default. Each magnitude is drawn twice:
// once above the prior high, once below the prior low.
const showExt = input.boolean('Show Extensions', false);
const ext1 = input.number('Extension 1', 1.272, { min: 1, max: 5 });
const ext2 = input.number('Extension 2', 1.618, { min: 1, max: 5 });
const ext3 = input.number('Extension 3', 2,     { min: 1, max: 5 });
const extArray = [ext1, ext2, ext3];

// ---------------------------------------------------------------
// Palette: one neutral family + a single gold accent.
// All mid-luminance so nothing disappears on white or black.
// ---------------------------------------------------------------
const C_ANCHOR = '#607d8b'; // prior day H/L and 0% / 100% - slate
const C_LEVEL  = '#90a4ae'; // interior levels             - light slate
const C_GOLD   = '#c9a227'; // golden ratios               - gold

function isGolden(f) {
    return Math.abs(f - 0.618) < 0.02
        || Math.abs(f - 0.786) < 0.02
        || Math.abs(f - 1.618) < 0.02;
}

function isBoundary(f) {
    return f <= 0.001 || f >= 0.999;
}

function colorForFib(f) {
    if (isGolden(f))   return C_GOLD;
    if (isBoundary(f)) return C_ANCHOR;
    return C_LEVEL;
}

function thicknessForFib(f) {
    if (isGolden(f) || isBoundary(f)) return 2;
    return 1;
}

function styleForFib(f) {
    // 50% stays dotted so the midpoint reads without adding a color
    return (Math.abs(f - 0.5) < 0.02) ? 'dotted' : 'line';
}

// ---------------------------------------------------------------
// Daily data -> prior day high / low landed on the intraday series
// ---------------------------------------------------------------
const data = await request.history(constants.ticker, 'D');

const priorDayHigh = shift(data.high, 1);
const priorDayLow  = shift(data.low, 1);

const intradayHigh = land_points_onto_series(data.time, priorDayHigh, time);
const intradayLow  = land_points_onto_series(data.time, priorDayLow, time);

// ---------------------------------------------------------------
// Session-end detection
// Land each daily bar's timestamp on the intraday series, hold it
// constant, then flag any bar whose next bar belongs to a new day.
// ---------------------------------------------------------------
const dayStamp = interpolate_sparse_series(
    land_points_onto_series(data.time, data.time, time), 'constant'
);

const lastIdx = dayStamp.length - 1;
const sessionEnd = dayStamp.map((d, i) => {
    if (i >= lastIdx) return false;          // never blank the live bar
    return dayStamp[i + 1] !== d;            // final candle of the day
});

function applyBreaks(series) {
    if (!breakSessions) return series;
    return series.map((v, i) => (sessionEnd[i] ? null : v));
}

// ---------------------------------------------------------------
// Level builder
// mode 'retrace' respects the Measure From High toggle.
// mode 'up' / 'down' are always absolute: 'up' projects above the
// prior high, 'down' below the prior low, regardless of anchor.
// ---------------------------------------------------------------
function buildLevel(fib, mode) {
    return intradayLow.map((priorLow, i) => {
        const priorHigh = intradayHigh[i];
        if (priorLow === null || priorHigh === null) return null;
        const range = priorHigh - priorLow;
        if (mode === 'up')   return priorLow + range * fib;
        if (mode === 'down') return priorHigh - range * fib;
        return fromHigh ? priorHigh - range * fib : priorLow + range * fib;
    });
}

// Every series is always painted so the registered series count never
// changes between runs. Hidden series are painted as all-null instead
// of being skipped.
function paintLevel(fib, mode, seriesName, showLine) {
    const visible = (showLine === undefined) ? true : showLine;
    paint(visible
        ? applyBreaks(interpolate_sparse_series(buildLevel(fib, mode), 'constant'))
        : series_of(null), {
        style: mode === 'retrace' ? styleForFib(fib) : 'dotted',
        color: colorForFib(fib),
        thickness: thicknessForFib(fib),
        name: seriesName
    });
}

// ---------------------------------------------------------------
// Paint
// ---------------------------------------------------------------
paint(showHL ? applyBreaks(interpolate_sparse_series(intradayHigh, 'constant')) : series_of(null), {
    style: 'line', color: C_ANCHOR, thickness: 2, name: 'Prior Day High'
});
paint(showHL ? applyBreaks(interpolate_sparse_series(intradayLow, 'constant')) : series_of(null), {
    style: 'line', color: C_ANCHOR, thickness: 2, name: 'Prior Day Low'
});

// Static series names avoid the "already exists" error when two
// inputs are set to the same value.
const fibNames = ['Fib 1', 'Fib 2', 'Fib 3', 'Fib 4', 'Fib 5', 'Fib 6', 'Fib 7'];
fibArray.forEach((f, index) => paintLevel(f, 'retrace', fibNames[index], true));

const upNames   = ['Ext Up 1', 'Ext Up 2', 'Ext Up 3'];
const downNames = ['Ext Down 1', 'Ext Down 2', 'Ext Down 3'];
extArray.forEach((f, index) => {
    paintLevel(f, 'up', upNames[index], showExt);
    paintLevel(f, 'down', downNames[index], showExt);
});