import { formatAxis, formatDay, formatNumber } from "./format.js";

const charts = new Map();
let resizeObserver = null;

function colors() {
  const styles = getComputedStyle(document.documentElement);
  return {
    text: styles.getPropertyValue("--text").trim() || "#2a201a",
    muted: styles.getPropertyValue("--muted").trim() || "#7b6a58",
    grid: styles.getPropertyValue("--grid").trim() || "#eadfce",
    accent: styles.getPropertyValue("--accent").trim() || "#a9702f",
    blue: styles.getPropertyValue("--blue").trim() || "#5f7f96",
    success: styles.getPropertyValue("--success").trim() || "#5f7a4e",
    danger: styles.getPropertyValue("--danger").trim() || "#b4553f",
    surface: styles.getPropertyValue("--surface").trim() || "#fffdf9",
  };
}

export function themeColor(name) {
  return colors()[name] || colors().accent;
}

function ensureEcharts() {
  if (!window.echarts) {
    throw new Error("ECharts 未加载，请检查 /static/vendor/echarts.min.js");
  }
  return window.echarts;
}

function mount(element, option) {
  const echarts = ensureEcharts();
  let chart = charts.get(element);
  if (!chart) {
    chart = echarts.init(element, null, { renderer: "canvas" });
    charts.set(element, chart);
  }
  chart.setOption(option, true);
  if (!resizeObserver && typeof ResizeObserver !== "undefined") {
    resizeObserver = new ResizeObserver((entries) => {
      for (const entry of entries) {
        charts.get(entry.target)?.resize();
      }
    });
  }
  resizeObserver?.observe(element);
  return chart;
}

export function disposeAll() {
  for (const chart of charts.values()) {
    try {
      chart.dispose();
    } catch {
      // 页面切换时忽略已销毁实例
    }
  }
  charts.clear();
  resizeObserver?.disconnect();
  resizeObserver = null;
}

export function lineChart(element, { dates, values, name = "数值", color, scale = false }) {
  if (!element) return null;
  const theme = colors();
  const lineColor = color || theme.accent;
  const option = {
    animationDuration: 300,
    backgroundColor: "transparent",
    grid: { left: 8, right: 12, top: 22, bottom: 8, containLabel: true },
    tooltip: {
      trigger: "axis",
      backgroundColor: theme.surface,
      borderColor: theme.grid,
      textStyle: { color: theme.text, fontSize: 12 },
      formatter(params) {
        const point = params[0];
        if (!point) return "";
        const value = point.value;
        return `<strong>${point.axisValue}</strong><br>${name}：${
          value === null || value === undefined ? "缺失" : formatNumber(value)
        }`;
      },
    },
    xAxis: {
      type: "category",
      data: dates,
      boundaryGap: false,
      axisLine: { lineStyle: { color: theme.grid } },
      axisTick: { show: false },
      axisLabel: {
        color: theme.muted,
        fontSize: 11,
        formatter: (value) => formatDay(value),
        hideOverlap: true,
      },
    },
    yAxis: {
      type: "value",
      scale,
      minInterval: 1,
      splitLine: { lineStyle: { color: theme.grid, type: "dashed" } },
      axisLabel: {
        color: theme.muted,
        fontSize: 11,
        formatter: (value) => formatAxis(value),
      },
    },
    series: [{
      name,
      type: "line",
      data: values,
      smooth: false,
      connectNulls: false,
      symbol: "circle",
      symbolSize: 5,
      showSymbol: values.length <= 45,
      lineStyle: { width: 2.2, color: lineColor },
      itemStyle: { color: lineColor },
      areaStyle: {
        color: {
          type: "linear", x: 0, y: 0, x2: 0, y2: 1,
          colorStops: [
            { offset: 0, color: `${lineColor}55` },
            { offset: 1, color: `${lineColor}00` },
          ],
        },
      },
    }],
  };
  return mount(element, option);
}

export function barChart(element, { labels, values, name = "数值", color }) {
  if (!element) return null;
  const theme = colors();
  const barColor = color || theme.blue;
  const option = {
    animationDuration: 300,
    backgroundColor: "transparent",
    grid: { left: 8, right: 12, top: 22, bottom: 8, containLabel: true },
    tooltip: {
      trigger: "axis",
      axisPointer: { type: "shadow" },
      backgroundColor: theme.surface,
      borderColor: theme.grid,
      textStyle: { color: theme.text, fontSize: 12 },
      formatter(params) {
        const point = params[0];
        if (!point) return "";
        return `<strong>${point.name}</strong><br>${name}：${formatNumber(point.value)}`;
      },
    },
    xAxis: {
      type: "category",
      data: labels,
      axisLine: { lineStyle: { color: theme.grid } },
      axisTick: { show: false },
      axisLabel: {
        color: theme.muted,
        fontSize: 10,
        interval: 0,
        rotate: labels.length > 8 ? 32 : 0,
        formatter: (value) => String(value).slice(0, 10),
      },
    },
    yAxis: {
      type: "value",
      minInterval: 1,
      splitLine: { lineStyle: { color: theme.grid, type: "dashed" } },
      axisLabel: {
        color: theme.muted,
        fontSize: 11,
        formatter: (value) => formatAxis(value),
      },
    },
    series: [{
      name,
      type: "bar",
      data: values,
      barMaxWidth: 26,
      itemStyle: { color: barColor, borderRadius: [4, 4, 0, 0] },
    }],
  };
  return mount(element, option);
}

export function emptyChart(element, message = "暂无数据") {
  if (!element) return;
  element.innerHTML = `<div class="chart-empty">${message}</div>`;
}