/** 迷你日 K 线图（Canvas） + 限速队列 */

const chartDataCache = new Map();
const chartQueue = [];
let chartQueueRunning = false;
const CHART_FETCH_GAP_MS = 120;

function enqueueCharts(root) {
  root.querySelectorAll(".mini-chart[data-symbol]").forEach((box) => {
    const symbol = box.dataset.symbol;
    if (!symbol || box.dataset.loaded === "1" || box.dataset.loading === "1") return;
    chartQueue.push(box);
  });
  runChartQueue();
}

async function runChartQueue() {
  if (chartQueueRunning) return;
  chartQueueRunning = true;
  while (chartQueue.length) {
    const box = chartQueue.shift();
    if (!box || !box.isConnected) continue;
    await loadMiniChart(box);
    await sleep(CHART_FETCH_GAP_MS);
  }
  chartQueueRunning = false;
}

function sleep(ms) {
  return new Promise((r) => setTimeout(r, ms));
}

async function loadMiniChart(box) {
  const symbol = box.dataset.symbol;
  if (!symbol) return;
  box.dataset.loading = "1";
  const canvas = box.querySelector("canvas");
  const status = box.querySelector(".chart-status");
  if (status) status.textContent = "加载…";

  try {
    let candles = chartDataCache.get(symbol);
    let source = "cache";
    if (!candles) {
      const res = await fetch(`/api/chart/${symbol}/daily?limit=300`);
      if (!res.ok) {
        const err = await res.json().catch(() => ({}));
        throw new Error(err.detail || res.statusText);
      }
      const data = await res.json();
      candles = data.candles || [];
      source = data.source || "db";
      chartDataCache.set(symbol, candles);
    }
    if (!candles.length) throw new Error("无K线数据");
    drawCandlestickChart(canvas, candles);
    box.dataset.loaded = "1";
    const srcLabel =
      source === "db" ? "本地" : source === "db_stale" ? "本地(旧)" : source === "cache" ? "缓存" : "同步";
    if (status) status.textContent = `${candles.length}日·${srcLabel}`;
    box.title = `${symbol} 最近${candles.length}根日K (${srcLabel})`;
  } catch (e) {
    if (status) status.textContent = "—";
    box.title = `${symbol}: ${e.message}`;
    drawEmptyChart(canvas);
  } finally {
    box.dataset.loading = "0";
  }
}

function drawEmptyChart(canvas) {
  if (!canvas) return;
  const ctx = canvas.getContext("2d");
  const w = canvas.width;
  const h = canvas.height;
  ctx.clearRect(0, 0, w, h);
  ctx.fillStyle = "#3a4558";
  ctx.fillRect(0, 0, w, h);
  ctx.fillStyle = "#8b9cb3";
  ctx.font = "11px sans-serif";
  ctx.fillText("暂无", 8, h / 2 + 4);
}

function drawCandlestickChart(canvas, candles) {
  if (!canvas || !candles.length) return;
  const ctx = canvas.getContext("2d");
  const w = canvas.width;
  const h = canvas.height;
  const pad = { t: 4, r: 4, b: 4, l: 4 };
  const plotW = w - pad.l - pad.r;
  const plotH = h - pad.t - pad.b;

  let min = Infinity;
  let max = -Infinity;
  for (const c of candles) {
    min = Math.min(min, c.low);
    max = Math.max(max, c.high);
  }
  const range = max - min || 1;
  const n = candles.length;
  const step = plotW / n;
  const bodyW = Math.max(1, step * 0.65);

  ctx.clearRect(0, 0, w, h);
  ctx.fillStyle = "#121820";
  ctx.fillRect(0, 0, w, h);

  const yOf = (price) => pad.t + plotH * (1 - (price - min) / range);

  for (let i = 0; i < n; i++) {
    const c = candles[i];
    const up = c.close >= c.open;
    const x = pad.l + i * step + step / 2;
    const yHigh = yOf(c.high);
    const yLow = yOf(c.low);
    const yOpen = yOf(c.open);
    const yClose = yOf(c.close);
    const color = up ? "#0ecb81" : "#f6465d";

    ctx.strokeStyle = color;
    ctx.lineWidth = 1;
    ctx.beginPath();
    ctx.moveTo(x, yHigh);
    ctx.lineTo(x, yLow);
    ctx.stroke();

    const top = Math.min(yOpen, yClose);
    const bodyH = Math.max(1, Math.abs(yClose - yOpen));
    ctx.fillStyle = color;
    ctx.fillRect(x - bodyW / 2, top, bodyW, bodyH);
  }
}

/** 点击放大 */
function setupChartModal() {
  let modal = document.getElementById("chart-modal");
  if (!modal) {
    modal = document.createElement("div");
    modal.id = "chart-modal";
    modal.className = "chart-modal hidden";
    modal.innerHTML = `
      <div class="chart-modal-inner">
        <button type="button" class="chart-modal-close" aria-label="关闭">×</button>
        <h3 id="chart-modal-title"></h3>
        <canvas id="chart-modal-canvas" width="900" height="360"></canvas>
      </div>`;
    document.body.appendChild(modal);
    modal.querySelector(".chart-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-chart[data-symbol]");
    if (!box || box.dataset.loaded !== "1") return;
    const symbol = box.dataset.symbol;
    const candles = chartDataCache.get(symbol);
    if (!candles) return;
    modal.classList.remove("hidden");
    document.getElementById("chart-modal-title").textContent =
      `${symbol} · 日K ${candles.length}根`;
    drawCandlestickChart(
      document.getElementById("chart-modal-canvas"),
      candles
    );
  });
}

setupChartModal();