/********************************************************************
 *  Oura Stats  +  Regression‑based Trend & Δ %                     *
 *  – zebra‑striped rows for easier scanning                        *
 ********************************************************************/

/* ---------- helpers ---------- */
function fmtNum(n, d = 0) { return n.toFixed(d).replace(/\B(?=(\d{3})+(?!\d))/g, ","); }
function fmtDate(s)       { const [y, m, d] = s.split("-"); return `${parseInt(m)}/${parseInt(d)}`; }
function linReg(x, y) {
    const n = x.length,
          sx = x.reduce((a, b) => a + b, 0),
          sy = y.reduce((a, b) => a + b, 0),
          sxy = x.reduce((a, _, i) => a + x[i] * y[i], 0),
          sxx = x.reduce((a, v) => a + v * v, 0);
    const den = n * sxx - sx * sx;
    if (!den) return { a: 0, b: 0 };
    const b = (n * sxy - sx * sy) / den;
    const a = (sy - b * sx) / n;
    return { a, b };
}

/* ---------- metric config ---------- */
const metrics = [
  { k: "ActivityScore",         label: "Activity Score",      better: "high" },
  { k: "ActivitySteps",         label: "Steps",               better: "high" },
  { k: "ActivityTotalCalories", label: "Calories",            better: "high" },
  { k: "BodyBodyTemperature",   label: "Body Temp",           better: "low",  dec: 1 },
  { k: "BodyReadinessScore",    label: "Readiness Score",     better: "high" },
  { k: "BodyRestingHeartRate",  label: "Resting HR",          better: "low" },
  { k: "SleepREM",              label: "REM Time (min)",      better: "high" },
  { k: "SleepScore",            label: "Sleep Score",         better: "high" }
].sort((a, b) => a.label.localeCompare(b.label));

/* ---------- time‑range dropdown ---------- */
const spans = [
  { v: "1w",  lbl: "1 Week",  since: dv.date("today").minus({ weeks: 1 }) },
  { v: "2w",  lbl: "2 Weeks", since: dv.date("today").minus({ weeks: 2 }) },
  { v: "1m",  lbl: "1 Month", since: dv.date("today").minus({ months: 1 }) },
  { v: "6w",  lbl: "6 Weeks", since: dv.date("today").minus({ weeks: 6 }) },
  { v: "2m",  lbl: "2 Months",since: dv.date("today").minus({ months: 2 }) },
  { v: "90d", lbl: "90 Days", since: dv.date("today").minus({ days: 90 }) },
  { v: "all", lbl: "All Time",since: dv.date("1900‑01‑01") }
];

/* ---------- UI ---------- */
dv.paragraph(`
<select id="rangeSel">
  ${spans.map(r => `<option value="${r.v}" ${r.v === "1m" ? "selected" : ""}>${r.lbl}</option>`).join("")}
</select>
<button id="updBtn" style="margin-left:10px;">Update</button>
<div id="tblWrap" style="margin-top:12px;"></div>
`);

/* ---------- core calc ---------- */
function calcStats(vals, dates, key) {
    let rows = [];
    for (let i = 0; i < vals.length; i++)
        if (typeof vals[i] === "number" && !isNaN(vals[i]))
            rows.push({ v: vals[i], d: dates[i] });

    if (key === "BodyRestingHeartRate") rows = rows.filter(r => r.v >= 25);
    if (key === "BodyBodyTemperature")  rows = rows.filter(r => r.v >= 85);
    if (!rows.length)
        return { min: "N/A", max: "N/A", avg: "N/A", last: "N/A", trend: "—", delta: "—" };

    rows.sort((a, b) => new Date(a.d) - new Date(b.d));        // oldest → newest
    let min = rows[0], max = rows[0], sum = 0;
    for (const r of rows) {
        if (r.v < min.v) min = r;
        if (r.v > max.v) max = r;
        sum += r.v;
    }
    const dec  = key === "BodyBodyTemperature" ? 1 : 0;
    const avg  = sum / rows.length;
    const last = rows[rows.length - 1];

    const t0 = new Date(rows[0].d).getTime();
    const xs = rows.map(r => (new Date(r.d).getTime() - t0) / 8.64e7); // days since start
    const ys = rows.map(r => r.v);
    const { a, b } = linReg(xs, ys);
    const firstPred = a;
    const lastPred  = a + b * xs[xs.length - 1];
    const changePct = ((lastPred - firstPred) / firstPred) * 100;

    const cfg      = metrics.find(m => m.k === key);
    const upGood   = cfg.better === "high";
    const flatBand = 1.0;                   // ±1 % = flat band
    let arrow, color;

    if (Math.abs(changePct) < flatBand) {
        arrow = "➡";
        color = "darkgray";
    } else {
        const goingUp = changePct > 0;
        arrow = goingUp ? "▲" : "▼";
        const good = upGood ? goingUp : !goingUp;
        color = good ? "limegreen" : "crimson";
    }

    return {
        min:  `${fmtNum(min.v, dec)} (${fmtDate(min.d)})`,
        max:  `${fmtNum(max.v, dec)} (${fmtDate(max.d)})`,
        avg:  fmtNum(avg, dec),
        last: fmtNum(last.v, dec),
        trend:`<span style="font-weight:bold;color:${color};">${arrow}</span>`,
        delta:`<span style="color:${color};">${changePct >= 0 ? "+" : ""}${fmtNum(changePct, 1)}%</span>`
    };
}

/* ---------- renderer ---------- */
function drawTable() {
    const spanVal = dv.container.querySelector("#rangeSel").value;
    const since   = spans.find(s => s.v === spanVal).since;

    const files = dv.pages('"Body/Oura"')
        .where(p => p.file.name.match(/^\d{4}-\d{2}-\d{2}$/))
        .where(p => dv.date(p.file.name) >= since)
        .sort(p => p.file.name, 'desc');

    const rows = metrics.map(m => {
        const vals  = files.map(f => f[m.k]);
        const dates = files.map(f => f.file.name);
        const s     = calcStats(vals, dates, m.k);
        return [m.label, s.min, s.max, s.avg, s.last, s.trend, s.delta];
    });

    const headers = ["Variable", "Min", "Max", "Average", "Last Value", "Trend", "Δ %"];
    const html = `
      <table style="width:100%;border-collapse:collapse;">
        <tr>${headers.map(h => `<th style="border:1px solid #555;padding:6px;text-align:left;">${h}</th>`).join("")}</tr>
        ${rows.map((r, i) => {
            const bg = i % 2 === 0 ? "rgba(255,255,255,0.05)" : "transparent";
            return `<tr style="background-color:${bg};">
                      ${r.map(c => `<td style="border:1px solid #555;padding:6px;">${c}</td>`).join("")}
                    </tr>`;
        }).join("")}
      </table>`;
    dv.container.querySelector("#tblWrap").innerHTML = html;
}

drawTable();
dv.container.querySelector("#updBtn").addEventListener("click", drawTable);