// ═══════════════════════════════════════════════════════════
//  本機資料庫（SQLite，使用 Node 內建的 node:sqlite，免安裝套件）
//  存三種東西：
//   1. cache         — 整包 /api/macro 結果，重啟伺服器可即時載入
//   2. series        — 每個指標的完整歷史序列，供「走勢大圖」使用
//   3. score_history — 每天記一筆健康分數，累積成「分數走勢」
//  資料庫檔：data.db（已在 .gitignore 忽略）
// ═══════════════════════════════════════════════════════════

import { DatabaseSync } from 'node:sqlite';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const DB_PATH = path.join(__dirname, '..', 'data.db');

const db = new DatabaseSync(DB_PATH);
db.exec(`
  CREATE TABLE IF NOT EXISTS cache (
    key TEXT PRIMARY KEY,
    payload TEXT NOT NULL,
    updated_at INTEGER NOT NULL
  );
  CREATE TABLE IF NOT EXISTS series (
    series_key TEXT NOT NULL,
    date TEXT NOT NULL,
    val REAL NOT NULL,
    PRIMARY KEY (series_key, date)
  );
  CREATE TABLE IF NOT EXISTS score_history (
    date TEXT PRIMARY KEY,
    score INTEGER NOT NULL,
    regime TEXT
  );
  CREATE TABLE IF NOT EXISTS trades (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    symbol TEXT NOT NULL,
    name TEXT,
    direction TEXT NOT NULL DEFAULT 'long',
    kind TEXT,
    entry_date TEXT,
    entry_price REAL,
    shares REAL,
    exit_date TEXT,
    exit_price REAL,
    entry_reason TEXT,
    exit_reason TEXT,
    principle TEXT,
    mistake INTEGER DEFAULT 0,
    mistake_note TEXT,
    note TEXT,
    created_at INTEGER,
    updated_at INTEGER
  );
`);

// ─── 整包結果的持久化快取 ───
export function savePayload(payload) {
  db.prepare('INSERT OR REPLACE INTO cache (key, payload, updated_at) VALUES (?, ?, ?)')
    .run('macro', JSON.stringify(payload), Date.now());
}
export function loadPayload() {
  const row = db.prepare('SELECT payload, updated_at FROM cache WHERE key = ?').get('macro');
  if (!row) return null;
  try {
    return { payload: JSON.parse(row.payload), updatedAt: row.updated_at };
  } catch {
    return null;
  }
}

// ─── 指標歷史序列 ───
const insertPoint = db.prepare('INSERT OR REPLACE INTO series (series_key, date, val) VALUES (?, ?, ?)');
export function saveSeries(key, points) {
  if (!points || points.length === 0) return;
  db.exec('BEGIN');
  try {
    for (const p of points) insertPoint.run(key, p.date, p.val);
    db.exec('COMMIT');
  } catch (e) {
    db.exec('ROLLBACK');
    throw e;
  }
}
export function getSeries(key, sinceISO) {
  if (sinceISO) {
    return db.prepare('SELECT date, val FROM series WHERE series_key = ? AND date >= ? ORDER BY date ASC')
      .all(key, sinceISO);
  }
  return db.prepare('SELECT date, val FROM series WHERE series_key = ? ORDER BY date ASC').all(key);
}

// ─── 每日健康分數快照（一天一筆，最新覆蓋）───
export function saveScoreSnapshot(score, regimeLabel) {
  const today = new Date().toISOString().slice(0, 10);
  db.prepare('INSERT OR REPLACE INTO score_history (date, score, regime) VALUES (?, ?, ?)')
    .run(today, score, regimeLabel || null);
}
export function getScoreHistory() {
  return db.prepare('SELECT date, score, regime FROM score_history ORDER BY date ASC').all();
}

// ─── 通用 JSON 快取（給財報健檢等，沿用 cache 表，含 TTL）───
export function putCachedJSON(key, value) {
  db.prepare('INSERT OR REPLACE INTO cache (key, payload, updated_at) VALUES (?, ?, ?)')
    .run(key, JSON.stringify(value), Date.now());
}
export function getCachedJSON(key, ttlMs) {
  const row = db.prepare('SELECT payload, updated_at FROM cache WHERE key = ?').get(key);
  if (!row) return null;
  if (ttlMs != null && Date.now() - row.updated_at > ttlMs) return null;
  try { return JSON.parse(row.payload); } catch { return null; }
}
// 取出快取連同寫入時間（不做 TTL 判斷，由呼叫端決定新鮮度策略）
export function getCachedEntry(key) {
  const row = db.prepare('SELECT payload, updated_at FROM cache WHERE key = ?').get(key);
  if (!row) return null;
  try { return { value: JSON.parse(row.payload), updatedAt: row.updated_at }; } catch { return null; }
}

// ─── 交易復盤 ───
const TRADE_FIELDS = ['symbol', 'name', 'direction', 'kind', 'entry_date', 'entry_price', 'shares',
  'exit_date', 'exit_price', 'entry_reason', 'exit_reason', 'principle', 'mistake', 'mistake_note', 'note'];

// 已實現損益 / 報酬率 / 持有天數（多空與否、是否平倉皆處理）
function computeTrade(t) {
  const closed = t.exit_date != null && t.exit_price != null && t.entry_price != null;
  const out = { ...t, closed };
  out.cost = t.entry_price != null && t.shares != null ? t.entry_price * t.shares : null;
  if (closed) {
    const per = t.direction === 'short' ? (t.entry_price - t.exit_price) : (t.exit_price - t.entry_price);
    out.pnl = per * t.shares;
    const base = t.direction === 'short' ? t.exit_price : t.entry_price;
    out.pnl_pct = base ? (per / t.entry_price) * 100 : null;
    if (t.entry_date && t.exit_date) {
      out.hold_days = Math.max(0, Math.round((new Date(t.exit_date) - new Date(t.entry_date)) / 86400000));
    }
  }
  return out;
}

export function listTrades() {
  const rows = db.prepare('SELECT * FROM trades ORDER BY COALESCE(exit_date, entry_date) DESC, id DESC').all();
  return rows.map(computeTrade);
}
export function getTrade(id) {
  const row = db.prepare('SELECT * FROM trades WHERE id = ?').get(id);
  return row ? computeTrade(row) : null;
}
export function insertTrade(body) {
  if (!body.symbol) throw new Error('缺少股票代號 symbol');
  const now = Date.now();
  const vals = TRADE_FIELDS.map(f => normField(f, body[f]));
  const sql = `INSERT INTO trades (${TRADE_FIELDS.join(',')}, created_at, updated_at)
               VALUES (${TRADE_FIELDS.map(() => '?').join(',')}, ?, ?)`;
  const info = db.prepare(sql).run(...vals, now, now);
  return getTrade(Number(info.lastInsertRowid));
}
export function updateTrade(id, body) {
  const existing = db.prepare('SELECT id FROM trades WHERE id = ?').get(id);
  if (!existing) return null;
  const vals = TRADE_FIELDS.map(f => normField(f, body[f]));
  const sql = `UPDATE trades SET ${TRADE_FIELDS.map(f => f + '=?').join(',')}, updated_at=? WHERE id=?`;
  db.prepare(sql).run(...vals, Date.now(), id);
  return getTrade(id);
}
export function deleteTrade(id) {
  db.prepare('DELETE FROM trades WHERE id = ?').run(id);
}
function normField(f, v) {
  if (v === undefined) v = null;
  if (['entry_price', 'shares', 'exit_price'].includes(f)) return v === '' || v == null ? null : Number(v);
  if (f === 'mistake') return v ? 1 : 0;
  if (['exit_date', 'name', 'kind', 'entry_reason', 'exit_reason', 'principle', 'mistake_note', 'note'].includes(f))
    return v === '' ? null : v;
  if (f === 'direction') return v === 'short' ? 'short' : 'long';
  return v;
}

// 復盤統計：勝率、賺賠比，並依「交易/投資」「是否犯錯」「依據心法」分組
export function tradeStats() {
  const all = listTrades();
  const closed = all.filter(t => t.closed);
  const wins = closed.filter(t => t.pnl > 0);
  const losses = closed.filter(t => t.pnl < 0);
  const sum = arr => arr.reduce((a, t) => a + (t.pnl || 0), 0);
  const avgWin = wins.length ? sum(wins) / wins.length : null;
  const avgLoss = losses.length ? sum(losses) / losses.length : null;
  const group = (keyFn) => {
    const map = new Map();
    for (const t of closed) {
      const key = keyFn(t); if (key == null || key === '') continue;
      if (!map.has(key)) map.set(key, []);
      map.get(key).push(t);
    }
    return [...map.entries()].map(([key, arr]) => ({
      key,
      count: arr.length,
      winRate: arr.length ? (arr.filter(t => t.pnl > 0).length / arr.length) * 100 : null,
      pnl: sum(arr),
    })).sort((a, b) => b.count - a.count);
  };
  return {
    closed: closed.length,
    open: all.length - closed.length,
    wins: wins.length,
    losses: losses.length,
    winRate: closed.length ? (wins.length / closed.length) * 100 : null,
    totalPnl: sum(closed),
    avgWin, avgLoss,
    payoff: avgWin != null && avgLoss ? avgWin / Math.abs(avgLoss) : null,
    byKind: group(t => t.kind),
    byMistake: group(t => (t.mistake ? '有犯錯' : '無犯錯')),
    byPrinciple: group(t => t.principle ? t.principle.split('#').pop() : null),
  };
}