/** 资金费率历史曲线 */

const fundingCache = new Map();
const fundingQueue = [];
let fundingQueueRunning = false;
const FUNDING_FETCH_GAP_MS = 200;

const FUNDING_MINI = { w: 200, h: 56 };
const FUNDING_MODAL = { w: 960, h: 320 };

function enqueueFundingCharts(root) {
  root.querySelectorAll(".mini-funding-chart[data-symbol]").forEach((box) => {
    if (box.dataset.loaded === "1" || box.dataset.loading === "1") return;
    fundingQueue.push(box);
  });
  runFundingQueue();
}

async function runFundingQueue() {
  if (fundingQueueRunning) return;
  fundingQueueRunning = true;
  while (fundingQueue.length) {
    const box = fundingQueue.shift();
    if (!box?.isConnected) continue;
    await loadMiniFundingChart(box);
    await new Promise((r) => setTimeout(r, FUNDING_FETCH_GAP_MS));
  }
  fundingQueueRunning = false;
}

function setupCanvas(canvas, w, h) {
  const dpr = Math.min(window.devicePixelRatio || 1, 2);
  canvas.style.width = `${w}px`;
  canvas.style.height = `${h}px`;
  canvas.width = Math.floor(w * dpr);
  canvas.height = Math.floor(h * dpr);
  const ctx = canvas.getContext("2d");
  ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
  return { ctx, w, h };
}

function drawFundingChart(canvas, history, current, large = false) {
  if (!canvas || !history?.length) return;
  const size = large ? FUNDING_MODAL : FUNDING_MINI;
  const { ctx, w, h } = setupCanvas(canvas, size.w, size.h);
  const pad = large ? { t: 20, r: 16, b: 24, l: 48 } : { t: 6, r: 4, b: 8, l: 4 };
  const plotW = w - pad.l - pad.r;
  const plotH = h - pad.t - pad.b;

  const rates = history.map((p) => p.rate_pct);
  let min = Math.min(...rates, 0);
  let max = Math.max(...rates, 0);
  const margin = Math.max(0.005, (max - min) * 0.15);
  min -= margin;
  max += margin;
  const range = max - min || 1;
  const n = history.length;
  const step = plotW / Math.max(n - 1, 1);

  ctx.clearRect(0, 0, w, h);
  ctx.fillStyle = "#0d1118";
  ctx.fillRect(0, 0, w, h);

  const y0 = pad.t + plotH * (1 - (0 - min) / range);
  ctx.strokeStyle = "#3a4558";
  ctx.lineWidth = 1;
  ctx.setLineDash([4, 4]);
  ctx.beginPath();
  ctx.moveTo(pad.l, y0);
  ctx.lineTo(w - pad.r, y0);
  ctx.stroke();
  ctx.setLineDash([]);

  if (large) {
    ctx.fillStyle = "#8b9cb3";
    ctx.font = "11px system-ui,sans-serif";
    ctx.textAlign = "right";
    for (let i = 0; i <= 4; i++) {
      const v = max - (range * i) / 4;
      const y = pad.t + (plotH * i) / 4;
      ctx.fillText(`${v.toFixed(3)}%`, pad.l - 6, y + 4);
    }
  }

  ctx.lineWidth = large ? 2 : 1.2;
  ctx.beginPath();
  history.forEach((p, i) => {
    const x = pad.l + i * step;
    const y = pad.t + plotH * (1 - (p.rate_pct - min) / range);
    if (i === 0) ctx.moveTo(x, y);
    else ctx.lineTo(x, y);
  });
  ctx.strokeStyle = "#5c7cfa";
  ctx.stroke();

  history.forEach((p, i) => {
    const x = pad.l + i * step;
    const y = pad.t + plotH * (1 - (p.rate_pct - min) / range);
    ctx.fillStyle = p.rate_pct >= 0 ? "#0ecb81" : "#f6465d";
    ctx.beginPath();
    ctx.arc(x, y, large ? 3 : 1.5, 0, Math.PI * 2);
    ctx.fill();
  });

  if (current != null) {
    const lx = w - pad.r - 2;
    const ly = pad.t + 2;
    ctx.fillStyle = current >= 0 ? "#0ecb81" : "#f6465d";
    ctx.font = `${large ? 13 : 10}px system-ui,sans-serif`;
    ctx.textAlign = "right";
    ctx.fillText(`当前 ${current.toFixed(4)}%`, lx, ly + (large ? 12 : 10));
  }
}

async function loadMiniFundingChart(box) {
  const symbol = box.dataset.symbol;
  if (!symbol) return;
  box.dataset.loading = "1";
  const canvas = box.querySelector("canvas");
  const label = box.querySelector(".funding-rate-label");

  try {
    let bundle = fundingCache.get(symbol);
    if (!bundle) {
      const res = await fetch(`/api/funding/${symbol}/history?limit=90`);
      if (!res.ok) throw new Error((await res.json().catch(() => ({}))).detail || res.statusText);
      bundle = await res.json();
      fundingCache.set(symbol, bundle);
    }
    const history = bundle.history || [];
    const curPct = bundle.current?.rate_pct ?? 0;
    if (label) {
      label.textContent = `${curPct >= 0 ? "+" : ""}${curPct.toFixed(4)}%`;
      label.className = `funding-rate-label ${curPct >= 0 ? "pct-up" : "pct-down"}`;
    }
    drawFundingChart(canvas, history, curPct, false);
    box.dataset.loaded = "1";
    box.title = `${symbol} 资金费率历史 ${history.length} 点，点击放大`;
  } catch (e) {
    if (label) label.textContent = "—";
    box.title = e.message;
  } finally {
    box.dataset.loading = "0";
  }
}

function setupFundingModal() {
  let modal = document.getElementById("funding-modal");
  if (!modal) {
    modal = document.createElement("div");
    modal.id = "funding-modal";
    modal.className = "chart-modal hidden";
    modal.innerHTML = `
      <div class="chart-modal-inner">
        <button type="button" class="chart-modal-close funding-modal-close">×</button>
        <h3 id="funding-modal-title"></h3>
        <p class="chart-modal-hint">资金费率历史（约 90 次结算，8h/次）· 虚线为零轴</p>
        <div class="chart-modal-canvas-wrap">
          <canvas id="funding-modal-canvas"></canvas>
        </div>
      </div>`;
    document.body.appendChild(modal);
    modal.querySelector(".funding-modal-close").onclick = () => modal.classList.add("hidden");
    modal.addEventListener("click", (e) => {
      if (e.target === modal) modal.classList.add("hidden");
    });
  }

  document.body.addEventListener("click", (e) => {
    const box = e.target.closest(".mini-funding-chart[data-symbol]");
    if (!box || box.dataset.loaded !== "1") return;
    const symbol = box.dataset.symbol;
    const bundle = fundingCache.get(symbol);
    if (!bundle) return;
    modal.classList.remove("hidden");
    document.getElementById("funding-modal-title").textContent =
      `${symbol} · 资金费率`;
    drawFundingChart(
      document.getElementById("funding-modal-canvas"),
      bundle.history,
      bundle.current?.rate_pct,
      true
    );
  });
}

setupFundingModal();