import {
  PALETTE, FONT, axisCommon, categoryAxis, titleStyle,
  lineSeries, footnote, watermarks,
} from '../theme.js';

/** 圆角卡片：ECharts 的 graphic.group + rect + 多段文字 */
function infoCard({ left, top, width, title, lines, fill, stroke, titleColor }) {
  const children = [
    {
      type: 'rect',
      shape: { x: 0, y: 0, width, height: 108, r: 8 },
      style: { fill, stroke, lineWidth: 1 },
    },
    {
      type: 'text',
      style: {
        x: 20, y: 20,
        text: title,
        fill: titleColor,
        fontSize: 15,
        fontWeight: 'bold',
        fontFamily: FONT,
      },
    },
  ];
  lines.forEach((line, i) => {
    children.push({
      type: 'text',
      style: {
        x: 20, y: 52 + i * 22,
        text: line,
        fill: '#555',
        fontSize: 12.5,
        fontFamily: FONT,
      },
    });
  });
  return { type: 'group', left, top, silent: true, children };
}

/**
 * 图 5：人民币兑美元两种口径对比
 * 只有两个时间点，重点在文字说明和端点标注，不在曲线本身
 */
export function fxChart(rows, { width, height }) {
  const stages = rows.map((r) => r.stage);
  const mid = rows.map((r) => r.mid_price);
  const spot = rows.map((r) => r.onshore_spot);

  // label.position 不接受函数（写函数会被静默忽略，退化成默认位置），
  // 想让首尾点位置不同只能逐点覆盖：起点标在上方，末点标在右侧
  const endpointLabels = (values) =>
    values.map((v, i) => ({
      value: v,
      label: { position: i === values.length - 1 ? 'right' : 'top' },
    }));

  // 偏离点数 = （中间价 - 即期）× 10000
  const gapStart = Math.round((mid[0] - spot[0]) * 10000);
  const gapEnd = Math.round((mid[1] - spot[1]) * 10000);
  const midGain = Math.round((mid[0] - mid[1]) * 10000);
  const spotGain = Math.round((spot[0] - spot[1]) * 10000);
  const midPct = (((mid[0] - mid[1]) / mid[0]) * 100).toFixed(1);
  const spotPct = (((spot[0] - spot[1]) / spot[0]) * 100).toFixed(1);

  const cardWidth = 340;
  const cardTop = 132;

  return {
    backgroundColor: '#fff',
    title: {
      ...titleStyle,
      text: '人民币兑美元的两种「升值」口径：中间价 vs 在岸即期',
      subtext: '口径区别在「谁定的价」：中间价是央行每日公布的锚，即期是市场在锚附近交易出来的成交价',
      top: 20,
    },
    grid: { left: 96, right: 110, top: 340, bottom: 88 },
    tooltip: { trigger: 'axis', textStyle: { fontFamily: FONT } },
    xAxis: {
      ...categoryAxis,
      boundaryGap: ['12%', '12%'],
      data: stages,
    },
    yAxis: {
      ...axisCommon,
      type: 'value',
      name: 'USDCNY（数值越小＝人民币越强）',
      nameLocation: 'middle',
      nameGap: 62,
      nameTextStyle: { color: PALETTE.grey, fontSize: 13, fontFamily: FONT },
      min: 6.75,
      max: 7.05,
      interval: 0.1,
      axisLabel: {
        ...axisCommon.axisLabel,
        formatter: (v) => v.toFixed(2),
      },
    },
    series: [
      {
        ...lineSeries({
          name: '中间价',
          data: mid,
          color: '#3b6ea5',
          formatter: (p) => p.value.toFixed(4),
        }),
        data: endpointLabels(mid),
        symbolSize: 11,
        itemStyle: { color: '#3b6ea5' },
        label: {
          show: true,
          fontSize: 15,
          fontWeight: 'bold',
          color: '#3b6ea5',
          fontFamily: FONT,
          distance: 10,
          formatter: (p) => p.value.toFixed(4),
        },
      },
      {
        ...lineSeries({
          name: '在岸即期',
          data: spot,
          color: PALETTE.coral,
          formatter: (p) => p.value.toFixed(4),
        }),
        data: endpointLabels(spot),
        symbolSize: 11,
        itemStyle: { color: PALETTE.coral },
        label: {
          show: true,
          fontSize: 15,
          fontWeight: 'bold',
          color: PALETTE.coral,
          fontFamily: FONT,
          distance: 10,
          formatter: (p) => p.value.toFixed(4),
        },
      },
    ],
    graphic: [
      ...watermarks(width, height),

      infoCard({
        left: 88, top: cardTop, width: cardWidth,
        title: '中间价（央行公布的「锚」）',
        lines: [
          '每交易日 9:15 由央行公布：做市商报价',
          '加权＋逆周期因子，是当日波动中心与政策信号',
        ],
        fill: '#eef4fa', stroke: '#c7dcf0', titleColor: '#2f5f8f',
      }),
      infoCard({
        left: 88 + cardWidth + 24, top: cardTop, width: cardWidth,
        title: '在岸即期（市场成交价）',
        lines: [
          '银行间外汇市场实时成交形成，16:30 收盘价',
          '最常被引用；每日只能在中间价 ±2% 区间内波动',
        ],
        fill: '#fdf1ed', stroke: '#f5d3c8', titleColor: '#c05a45',
      }),

      // 图例改成两行文字说明，信息量比色块图例大
      {
        type: 'text',
        left: 108, top: 272, silent: true,
        style: {
          text: `● 中间价：${mid[0]} → ${mid[1]}，累计升值 ${midGain}点（+${midPct}%）`,
          fill: '#3b6ea5', fontSize: 14, fontFamily: FONT,
        },
      },
      {
        type: 'text',
        left: 108, top: 296, silent: true,
        style: {
          text: `● 在岸即期：${spot[0]} → ${spot[1]}，累计升值 ${spotGain}点（+${spotPct}%）`,
          fill: PALETTE.coral, fontSize: 14, fontFamily: FONT,
        },
      },

      footnote(
        `注：涨幅差${midGain - spotGain}点＝期初偏离${gapStart}−期末偏离${gapEnd}（即期偏强收窄）｜` +
        '汇兑重估用市场汇率而非中间价｜数据：新华财经｜Joey 谨制'
      ),
    ],
  };
}