import template from './dcf-calculator.html?raw';
import '../../css/dcf.css';
import { calculateDCF, calculateDCFPriceRange, classifyDCFPrice } from './dcf-math.js';
import { buildDCFPriceOption } from './dcf-price-chart.js';
import { buildDCFCashflowOption } from './dcf-cashflow-chart.js';
import { createDCFHelp } from './dcf-help.js';

const STORAGE_KEY = 'smart-fin-chart:dcf:v1';
let memory;
const defaults = () => ({basis: 'fcff', fcf: '', year: '2026', shares: '', shareDate: '',
  rate: '10', terminal: '2', debt: '0', assets: '0', minority: '0', margin: '20',
  premium: '20', marketPrice: '', quoteDate: ''});
const initialStages = () => [{years: '3', growth: '12'}, {years: '4', growth: '8'}, {years: '3', growth: '4'}];
const profile = (name, example = false) => ({name,
  inputs: {...defaults(), ...(example ? {fcf: '100', shares: '10', debt: '100', marketPrice: '138'} : {})}, stages: initialStages(), detailOpen: false});
const fmt = value => new Intl.NumberFormat('zh-CN', {minimumFractionDigits: 2, maximumFractionDigits: 2}).format(value);

function readStore() {
  if (memory) return memory;
  try {
    const saved = JSON.parse(localStorage.getItem(STORAGE_KEY));
    if (saved?.version === 1 && Array.isArray(saved.profiles)) {
      const profiles = saved.profiles.filter(item => typeof item.id === 'string' && typeof item.name === 'string' &&
        item.inputs && typeof item.inputs === 'object' && Array.isArray(item.stages) && item.stages.length >= 1 &&
        item.stages.length <= 5 && item.stages.every(stage => stage && typeof stage === 'object'));
      if (profiles.length || (saved.profiles.length === 0 && Array.isArray(saved.deletedProfileIds))) return {...saved, profiles};
    }
  } catch { /* Storage can be unavailable or corrupt; the calculator still works in memory. */ }
  return {version: 1, selected: 'example', profiles: []};
}

export function renderDCFCalculator(container, companies = []) {
  container.innerHTML = template;
  const root = container.querySelector('.dcf-calculator');
  const disposeHelp = createDCFHelp(root);
  const q = name => root.querySelector(`[data-${name}]`);
  const fields = Object.fromEntries([...root.querySelectorAll('[data-field]')].map(field => [field.dataset.field, field]));
  const store = readStore();
  store.deletedProfileIds = Array.isArray(store.deletedProfileIds) ? store.deletedProfileIds.filter(id => typeof id === 'string') : [];
  const addPreset = (id, name, example = false) => {
    if (!store.deletedProfileIds.includes(id) && !store.profiles.some(item => item.id === id)) store.profiles.push({id, ...profile(name, example)});
  };
  addPreset('example', '教学示例（假设参数）', true);
  companies.forEach(company => addPreset(company.id, company.name));
  let active = store.profiles.find(item => item.id === store.selected) || store.profiles[0];
  store.selected = active?.id ?? null;
  let stages;
  let chart;
  let chartData;
  let cashflowChart;
  let cashflowRows;
  let resizeFrame;
  let disposed = false;
  memory = store;

  function save() {
    if (active) {
      // Retain legacy saved fields without using them in this DCF-only interface.
      active.inputs = {...active.inputs, ...Object.fromEntries(Object.entries(fields).map(([key, field]) => [key, field.value]))};
      active.stages = stages.map(stage => ({...stage}));
      active.detailOpen = q('detail').open;
    }
    memory = store;
    try {
      localStorage.setItem(STORAGE_KEY, JSON.stringify(store));
      q('save-status').textContent = '已自动保存到本机 · 每家公司独立保存';
    } catch {
      q('save-status').textContent = '浏览器存储不可用，参数仅在本次页面中保留';
    }
  }

  function deleteCompany(item) {
    if (!window.confirm(`删除「${item.name}」？\n该公司保存在本机的估值参数将一并删除，无法撤销。`)) return;
    save();
    const index = store.profiles.findIndex(profile => profile.id === item.id);
    if (index < 0) return;
    store.profiles.splice(index, 1);
    if (!store.deletedProfileIds.includes(item.id)) store.deletedProfileIds.push(item.id);
    if (active?.id === item.id) active = store.profiles[Math.min(index, store.profiles.length - 1)];
    store.selected = active?.id ?? null;
    applyProfile();
    save();
    const selected = q('company-buttons').querySelector('[aria-pressed="true"]');
    (selected || q('company-name')).focus();
  }

  function renderCompanies() {
    q('company-buttons').replaceChildren(...store.profiles.map(item => {
      const chip = document.createElement('span');
      chip.className = 'df-company-chip';
      chip.dataset.profileId = item.id;
      const button = document.createElement('button');
      button.type = 'button';
      button.textContent = item.name;
      button.setAttribute('aria-pressed', String(item.id === active?.id));
      button.addEventListener('click', () => {
        if (active?.id === item.id) return;
        save();
        active = item;
        store.selected = item.id;
        q('company-form').hidden = true;
        applyProfile();
        save();
      });
      const remove = document.createElement('button');
      remove.type = 'button';
      remove.className = 'df-company-delete';
      remove.textContent = '×';
      remove.setAttribute('aria-label', `删除公司：${item.name}`);
      remove.title = `删除${item.name}`;
      remove.addEventListener('click', () => deleteCompany(item));
      chip.append(button, remove);
      return chip;
    }));
  }

  function chartColors() {
    const styles = getComputedStyle(root);
    const color = name => styles.getPropertyValue(name).trim();
    return {ink: color('--df-ink'), muted: color('--df-muted'), line: color('--df-line'), paper: color('--df-paper'),
      accent: color('--df-accent'), secondary: color('--df-chart-secondary'), low: color('--df-low'), fair: color('--df-fair'), high: color('--df-high')};
  }

  function drawChart() {
    if (disposed || !root.isConnected || !chartData) return;
    if (!globalThis.echarts) {
      q('market-error').textContent = '图表组件未加载，请检查网络后刷新页面；区间数值仍可查看。';
      q('market-error').hidden = false;
      return;
    }
    if (!chart) chart = globalThis.echarts.init(q('market-chart'), null, {renderer: 'svg'});
    chart.resize();
    chart.setOption(buildDCFPriceOption({...chartData, colors: chartColors(), width: q('market-chart').clientWidth,
      reducedMotion: window.matchMedia('(prefers-reduced-motion: reduce)').matches}), true);
  }

  function drawCashflowChart() {
    if (disposed || !root.isConnected || !cashflowRows) return;
    q('cashflow-error').hidden = true;
    try {
      if (!globalThis.echarts) throw new Error('图表组件未加载，仍可在上方表格查看逐年数据。');
      const element = q('cashflow-chart');
      if (!cashflowChart) cashflowChart = globalThis.echarts.init(element, null, {renderer: 'svg'});
      cashflowChart.resize();
      cashflowChart.setOption(buildDCFCashflowOption({rows: cashflowRows, colors: chartColors(), width: element.clientWidth,
        reducedMotion: window.matchMedia('(prefers-reduced-motion: reduce)').matches}), true);
    } catch (error) {
      q('cashflow-error').textContent = error.message;
      q('cashflow-error').hidden = false;
    }
  }

  function clearMarket(message) {
    chartData = undefined;
    chart?.clear();
    q('market-chart').hidden = true;
    q('zone-keys').hidden = true;
    q('market-badge').hidden = true;
    q('market-error').hidden = true;
    const price = Number(fields.marketPrice.value);
    q('market-current').textContent = fields.marketPrice.value.trim() && Number.isFinite(price) && price > 0 ? fmt(price) : '—';
    q('deviation').textContent = '—';
    delete q('deviation').dataset.priceRelation;
    q('price-position').textContent = '待补全有效的估值参数';
    q('market-message').textContent = message;
    q('market-message').hidden = false;
  }

  function updateMarket(p, result) {
    clearMarket('填写当前股价后查看所处区间');
    if (result.perShare <= 0) {
      q('market-message').textContent = '无正的每股股权价值，无法划分股价区间';
      return;
    }
    try {
      if (!fields.premium.value.trim()) throw new Error('请填写高估溢价阈值');
      const range = calculateDCFPriceRange({perShare: result.perShare, margin: p.margin, premium: Number(fields.premium.value) / 100});
      q('zone-low').textContent = `< ${fmt(range.low)} 元`;
      q('zone-fair').textContent = `${fmt(range.low)}—${fmt(range.high)} 元`;
      q('zone-high').textContent = `> ${fmt(range.high)} 元`;
      q('zone-keys').hidden = false;
      q('market-message').hidden = true;
      q('price-position').textContent = '填写当前股价后查看所处区间';
      let price;
      if (fields.marketPrice.value.trim()) {
        const entered = Number(fields.marketPrice.value);
        try {
          const position = classifyDCFPrice(entered, range);
          price = entered;
          q('market-current').textContent = fmt(price);
          q('market-badge').textContent = `${position.zone}区间`;
          q('market-badge').dataset.zone = position.zone;
          q('market-badge').hidden = false;
          q('deviation').textContent = `${position.deviation <= 0 ? '折价' : '溢价'} ${fmt(Math.abs(position.deviation) * 100)}%`;
          q('deviation').dataset.priceRelation = position.deviation <= 0 ? 'discount' : 'premium';
          q('price-position').textContent = `处于${position.zone}区间`;
          q('market-message').hidden = true;
        } catch (error) {
          q('market-error').textContent = error.message;
          q('market-error').hidden = false;
        }
      }
      q('market-chart').hidden = false;
      q('market-chart').setAttribute('aria-label', `${price === undefined ? '尚未填写有效股价' : `当前股价 ${fmt(price)} 元`}，DCF 每股价值 ${fmt(range.perShare)} 元，合理区间 ${fmt(range.low)} 至 ${fmt(range.high)} 元`);
      chartData = {range, price};
      drawChart();
    } catch (error) {
      clearMarket(error.message);
      q('market-error').textContent = error.message;
      q('market-error').hidden = false;
      q('market-message').hidden = true;
    }
  }

  function renderStages() {
    q('stages').replaceChildren();
    stages.forEach((stage, index) => {
      const row = document.createElement('div');
      row.className = 'df-stage-row';
      const heading = document.createElement('div');
      heading.className = 'df-stage-name';
      heading.textContent = `阶段 ${index + 1}`;
      const range = document.createElement('small');
      range.dataset.stageRange = String(index);
      heading.append(range);
      row.append(heading);
      for (const [key, caption] of [['years', '年数'], ['growth', '年增长率 %']]) {
        const label = document.createElement('label');
        const text = document.createElement('span');
        text.className = 'df-stage-key';
        text.textContent = caption;
        const input = document.createElement('input');
        input.type = 'number';
        input.step = key === 'years' ? '1' : '0.5';
        input.value = stage[key];
        input.setAttribute('aria-label', `阶段${index + 1}${caption}`);
        input.dataset.stage = String(index);
        input.dataset.stageField = key;
        input.addEventListener('input', () => {
          stage[key] = input.value;
          update();
          save();
        });
        label.append(text, input);
        row.append(label);
      }
      const remove = document.createElement('button');
      remove.type = 'button';
      remove.textContent = '×';
      remove.setAttribute('aria-label', `删除阶段${index + 1}`);
      remove.disabled = stages.length === 1;
      remove.addEventListener('click', () => {
        stages.splice(index, 1);
        renderStages();
        update();
        save();
      });
      row.append(remove);
      q('stages').append(row);
    });
    q('add').disabled = stages.length >= 5;
  }

  function read() {
    const input = {basis: fields.basis.value};
    for (const key of ['fcf', 'year', 'shares', 'rate', 'terminal', 'margin', 'debt', 'assets', 'minority']) {
      if (input.basis === 'fcfe' && ['debt', 'assets', 'minority'].includes(key)) { input[key] = 0; continue; }
      if (!fields[key].value.trim()) throw new Error(key === 'shares'
        ? '请填写该公司的当前总股本（亿股），用于每股价值换算'
        : '请补全基期现金流、折现率和其他必填参数');
      input[key] = Number(fields[key].value);
    }
    for (const key of ['rate', 'terminal', 'margin']) input[key] /= 100;
    input.stages = stages.map(stage => ({
      years: stage.years.trim() ? Number(stage.years) : NaN,
      growth: stage.growth.trim() ? Number(stage.growth) / 100 : NaN,
    }));
    return input;
  }

  function update() {
    const fcfe = fields.basis.value === 'fcfe';
    q('rate-label').textContent = fcfe ? '股权资本成本（%）' : '折现率 WACC（%）';
    for (const name of ['debt-field', 'assets-field', 'minority-field', 'adjustment']) q(name).hidden = fcfe;
    q('value-label').textContent = fcfe ? '现金流股权价值' : '企业经营价值';
    q('basis-caption').textContent = `${fcfe ? 'FCFE' : 'FCFF'} 口径`;
    q('basis-note').textContent = fcfe ? '直接折现股东现金流，不再重复扣减净债务。' : '先折现企业现金流，再调整为股权价值。';
    q('model-note').textContent = fcfe ? 'FCFE 按股权资本成本折现，不再扣减净债务' : 'FCFF 按 WACC 折现，再调整为股权价值';
    let first = 1;
    stages.forEach((stage, index) => {
      const years = Number(stage.years);
      root.querySelector(`[data-stage-range="${index}"]`).textContent =
        Number.isInteger(years) && years > 0 && Number.isFinite(first) ? `第 ${first}—${first + years - 1} 年` : '请填写有效年数';
      first = Number.isInteger(years) && years > 0 ? first + years : NaN;
    });
    q('error').hidden = true;
    q('warning').hidden = true;
    try {
      const p = read();
      const r = calculateDCF(p);
      q('duration').textContent = `合计 ${r.years} 年 · ${p.year + 1}—${p.year + r.years} 年，各阶段逐年复利衔接`;
      q('table-summary').textContent = ` · ${r.years} 年`;
      const values = {pv: r.forecastPV, tv: r.terminalPV, ev: r.operatingValue, equity: r.equityValue,
        'debt-value': p.debt, 'assets-value': p.assets, 'minority-value': p.minority};
      for (const [name, value] of Object.entries(values)) q(name).textContent = fmt(value);
      q('price').textContent = r.equityValue > 0 ? fmt(r.perShare) : '无正股权价值';
      q('value-per-share').textContent = r.equityValue > 0 ? fmt(r.perShare) : '—';
      q('buy').textContent = r.equityValue > 0 ? fmt(r.entryPrice) : '—';
      q('discount-note').textContent = `内在价值打 ${fmt((1 - p.margin) * 10)} 折`;
      q('shares-note').textContent = `按 ${fmt(p.shares)} 亿股换算${fields.shareDate.value ? ` · 股本日期 ${fields.shareDate.value}` : ''}`;
      q('forecast-share').textContent = `${fmt((1 - r.terminalWeight) * 100)}%`;
      q('terminal-share').textContent = `${fmt(r.terminalWeight * 100)}%`;
      q('terminal-note').textContent = `永续终值占经营现金流现值的 ${fmt(r.terminalWeight * 100)}%，结果对折现率和永续增长假设敏感。`;
      q('rows').replaceChildren(...r.rows.map(row => {
        const tr = document.createElement('tr');
        for (const value of [`${row.year} · 阶段 ${row.stage}`, `${fmt(row.growth * 100)}%`, fmt(row.cash), row.factor.toFixed(4), fmt(row.presentValue)]) {
          const td = document.createElement('td');
          td.textContent = value;
          tr.append(td);
        }
        return tr;
      }));
      const warnings = [];
      if (r.terminalWeight > .75) warnings.push('永续终值超过总现值的 75%，结果对折现率与永续增长率高度敏感。');
      if (r.equityValue <= 0) warnings.push('调整后的股权价值不大于 0，无法据此给出正的每股估值或参考买入价。');
      if (warnings.length) { q('warning').textContent = warnings.join(' '); q('warning').hidden = false; }
      q('detail').hidden = false;
      cashflowRows = r.rows;
      q('cashflow-section').hidden = false;
      q('cashflow-caption').textContent = `${p.year + 1}—${p.year + r.years} 年 · ${r.years} 年预测期 · 现值合计 ${fmt(r.forecastPV)} 亿元`;
      q('cashflow-chart').setAttribute('aria-label', `${r.years} 年自由现金流与折现现值对比，${r.rows.map(row => `${row.year} 年现金流 ${fmt(row.cash)}、现值 ${fmt(row.presentValue)} 亿元`).join('；')}`);
      drawCashflowChart();
      q('composition-forecast').style.width = `${Math.max(0, Math.min(100, (1 - r.terminalWeight) * 100))}%`;
      q('composition-terminal').style.width = `${Math.max(0, Math.min(100, r.terminalWeight * 100))}%`;
      updateMarket(p, r);
      root.dataset.status = 'ready';
    } catch (error) {
      q('error').textContent = error.message;
      q('error').hidden = false;
      q('detail').hidden = true;
      cashflowRows = undefined;
      cashflowChart?.clear();
      q('cashflow-section').hidden = true;
      for (const name of ['price', 'buy', 'value-per-share', 'pv', 'tv', 'ev', 'equity', 'debt-value', 'assets-value', 'minority-value', 'forecast-share', 'terminal-share']) q(name).textContent = '—';
      q('shares-note').textContent = '补全总股本后换算每股价值';
      q('discount-note').textContent = '按设定的安全边际折价';
      q('terminal-note').textContent = '补全有效参数后查看价值构成';
      q('composition-forecast').style.width = '0%';
      q('composition-terminal').style.width = '0%';
      q('duration').textContent = '请补全有效参数后查看结果';
      clearMarket('请补全有效的现金流、股本与折现参数后查看估值区间');
      root.dataset.status = 'invalid';
    }
  }

  function applyProfile() {
    root.dataset.empty = String(!active);
    q('company-empty').hidden = Boolean(active);
    if (!active) {
      stages = [];
      chartData = cashflowRows = undefined;
      chart?.clear();
      cashflowChart?.clear();
      root.dataset.status = 'empty';
      q('company-form').hidden = false;
      q('company-error').textContent = '';
      renderCompanies();
      return;
    }
    const values = {...defaults(), ...active.inputs};
    for (const [key, field] of Object.entries(fields)) field.value = values[key];
    stages = active.stages.map(stage => ({years: String(stage.years ?? ''), growth: String(stage.growth ?? '')}));
    q('detail').open = active.detailOpen !== false;
    q('context').textContent = active.id === 'example' ? '教学示例 · 非实时数据 · 人民币' : `${active.name} · 用户手动输入 · 人民币`;
    renderCompanies();
    renderStages();
    update();
  }

  q('add').addEventListener('click', () => {
    if (stages.length >= 5) return;
    stages.push({years: '3', growth: '3'});
    renderStages(); update(); save();
  });
  for (const field of Object.values(fields)) {
    const onChange = () => { update(); save(); };
    field.addEventListener('input', onChange);
    if (field.tagName === 'SELECT') field.addEventListener('change', onChange);
  }
  q('detail').addEventListener('toggle', () => { if (root.isConnected) save(); });
  q('new-company').addEventListener('click', () => {
    q('company-form').hidden = false;
    q('company-error').textContent = '';
    q('company-name').focus();
  });
  q('cancel-company').addEventListener('click', () => { q('company-form').hidden = true; });
  q('company-form').addEventListener('submit', event => {
    event.preventDefault();
    const name = q('company-name').value.trim();
    if (!name) { q('company-error').textContent = '请输入公司名称'; return; }
    if (store.profiles.some(item => item.name === name)) { q('company-error').textContent = '该公司已存在，请点击公司按钮切换'; return; }
    save();
    active = {id: `custom-${crypto.randomUUID()}`, ...profile(name)};
    store.profiles.push(active);
    store.selected = active.id;
    q('company-form').hidden = true;
    q('company-name').value = '';
    applyProfile(); save();
  });
  applyProfile();
  const observer = new ResizeObserver(() => {
    cancelAnimationFrame(resizeFrame);
    resizeFrame = requestAnimationFrame(() => { drawChart(); drawCashflowChart(); });
  });
  observer.observe(q('market-chart'));
  observer.observe(q('cashflow-chart'));
  return () => {
    disposed = true;
    disposeHelp();
    observer.disconnect();
    cancelAnimationFrame(resizeFrame);
    chart?.dispose();
    cashflowChart?.dispose();
  };
}