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

const STATE_LABELS = {
  initial: '期初持有',
  added: '新建仓',
  held: '持续持有',
  sold: '清仓',
};

const STATE_COLORS = {
  initial: PALETTE.sand,
  added: PALETTE.green,
  sold: PALETTE.coral,
};

const SHORT_NAMES = {
  '美国运通（American Express）': '美国运通',
  '可口可乐（Coca-Cola）': '可口可乐',
  '华特迪士尼（Walt Disney）': '迪士尼',
  '房地美（Freddie Mac）': '房地美',
  '吉列（Gillette）': '吉列',
  '旅行家集团（Travelers Group）': '旅行家集团',
  '华盛顿邮报（Washington Post）': '华盛顿邮报',
  '富国银行（Wells Fargo）': '富国银行',
  '大都会/ABC（Capital Cities/ABC）': '大都会/ABC',
  '盖可保险（GEICO）': '盖可保险',
  '甘尼特（Gannett）': '甘尼特',
  'PNC 银行（PNC Bank）': 'PNC 银行',
  '通用动力（General Dynamics）': '通用动力',
  '健力士（Guinness）': '健力士',
  "麦当劳（McDonald's）": '麦当劳',
};

function formatShares(value) {
  return Number(value).toLocaleString('en-US');
}

function quantityChange(current, previous) {
  if (!Number.isFinite(previous)) return '无可比上年数据';
  const change = current - previous;
  const sign = change > 0 ? '+' : '';
  return `${sign}${formatShares(change)} 股`;
}

export function brkHoldingsChart(rows, { width, height }) {
  const years = [...new Set(rows.map((row) => row.year))].sort((a, b) => a - b);
  const holdingsByYear = new Map(years.map((year) => [year, new Map()]));
  const firstYearByCompany = new Map();
  const maxSharesByCompany = new Map();

  rows.forEach((row) => {
    holdingsByYear.get(row.year).set(row.company, row.shares);
    firstYearByCompany.set(row.company, Math.min(firstYearByCompany.get(row.company) ?? row.year, row.year));
    maxSharesByCompany.set(row.company, Math.max(maxSharesByCompany.get(row.company) ?? 0, row.shares));
  });

  const companies = [...firstYearByCompany.keys()].sort((a, b) => (
    firstYearByCompany.get(a) - firstYearByCompany.get(b) || a.localeCompare(b, 'zh-CN')
  ));
  const dataByState = { initial: [], added: [], held: [], sold: [] };

  years.forEach((year, yearIndex) => {
    const current = holdingsByYear.get(year);
    const previous = yearIndex > 0 ? holdingsByYear.get(years[yearIndex - 1]) : new Map();

    companies.forEach((company, companyIndex) => {
      const shares = current.get(company);
      const priorShares = previous.get(company);
      let state;
      if (Number.isFinite(shares)) {
        state = yearIndex === 0 ? 'initial' : (Number.isFinite(priorShares) ? 'held' : 'added');
      } else if (yearIndex > 0 && Number.isFinite(priorShares)) {
        state = 'sold';
      } else {
        return;
      }

      const relativeSize = Number.isFinite(shares)
        ? Math.sqrt(shares / maxSharesByCompany.get(company))
        : 1;
      const color = state === 'held'
        ? `rgba(59, 110, 165, ${(0.38 + relativeSize * 0.62).toFixed(2)})`
        : STATE_COLORS[state];
      const labelColor = state === 'initial' || (state === 'held' && relativeSize < 0.55)
        ? PALETTE.ink
        : '#fff';
      dataByState[state].push({
        value: [yearIndex, companyIndex, shares ?? 0],
        shares,
        priorShares,
        state,
        shortName: SHORT_NAMES[company] || company,
        itemStyle: { color, borderColor: '#fff', borderWidth: 3 },
        label: { color: labelColor },
      });
    });
  });

  return {
    backgroundColor: '#fff',
    title: {
      ...titleStyle,
      text: '伯克希尔主要持仓变动（1988–1997）',
      subtext: '每格标注公司简称；持续持有的蓝色越深，表示相对持股数量越大',
    },
    legend: standardLegend([
      STATE_LABELS.initial,
      STATE_LABELS.added,
      STATE_LABELS.held,
      STATE_LABELS.sold,
    ], { selectedMode: false, itemGap: 20 }),
    tooltip: {
      trigger: 'item',
      textStyle: { fontFamily: FONT },
      formatter: (params) => {
        const data = params.data;
        const company = companies[data.value[1]];
        const year = years[data.value[0]];
        const lines = [`<b>${year} · ${company}</b>`, `状态：${STATE_LABELS[data.state]}`];
        if (Number.isFinite(data.shares)) {
          lines.push(`年末持股：${formatShares(data.shares)} 股`);
          if (data.state !== 'initial') lines.push(`较上年：${quantityChange(data.shares, data.priorShares)}`);
        } else {
          lines.push(`上年末持股：${formatShares(data.priorShares)} 股`);
        }
        return lines.join('<br/>');
      },
    },
    // ECharts 的 heatmap 组件要求声明 visualMap；实际颜色由每个状态单元格的 itemStyle 控制。
    visualMap: {
      show: false,
      min: 0,
      max: Math.max(...rows.map((row) => row.shares)),
      dimension: 2,
      inRange: { color: ['#ffffff'] },
    },
    grid: { left: 258, right: 48, top: LAYOUT.gridTop, bottom: 72 },
    xAxis: {
      ...categoryAxis,
      type: 'category',
      data: years.map(String),
      splitArea: { show: true, areaStyle: { color: ['#fbfbfa'] } },
    },
    yAxis: {
      ...categoryAxis,
      type: 'category',
      inverse: true,
      data: companies,
      axisLabel: { ...categoryAxis.axisLabel, fontSize: 12, margin: 14 },
      splitArea: { show: true, areaStyle: { color: ['#fbfbfa'] } },
    },
    series: Object.entries(dataByState).map(([state, data]) => ({
      name: STATE_LABELS[state],
      type: 'heatmap',
      data,
      label: {
        show: true,
        position: 'inside',
        fontFamily: FONT,
        fontSize: 12,
        fontWeight: 600,
        formatter: (params) => params.data.shortName,
      },
      emphasis: { itemStyle: { borderColor: PALETTE.ink, borderWidth: 2 } },
    })),
    graphic: [
      ...watermarks(width, height),
      footnote('绿色=相对上一年新增；红色=相对上一年清仓；蓝色深浅=相对持股数量 | @思考的Joey'),
    ],
  };
}