// 数据层：dev-bridge 与 seed 共用
// v2：多端同步地基 —— uuid v7 / 软删除墓碑 / HLC / 变更日志（自建服务方案）
import { DatabaseSync } from 'node:sqlite';
import fs from 'node:fs';
import path from 'node:path';
import crypto from 'node:crypto';
import { fileURLToPath } from 'node:url';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
export const DATA_DIR = process.env.DATA_DIR || path.join(__dirname, '..', '.data');
export const ATT_DIR = path.join(DATA_DIR, 'attachments');
export const DB_PATH = path.join(DATA_DIR, 'footprints.db');

function getMeta(d, key) {
  const r = d.prepare('SELECT value FROM sync_state WHERE key=?').get(key);
  return r ? r.value : null;
}

function setMeta(d, key, value) {
  d.prepare("INSERT INTO sync_state (key, value) VALUES (?,?) ON CONFLICT(key) DO UPDATE SET value=excluded.value")
    .run(key, String(value));
}

function getDeviceId(d) {
  let id = getMeta(d, 'device_id');
  if (!id) {
    id = crypto.randomBytes(6).toString('hex');
    setMeta(d, 'device_id', id);
  }
  return id;
}

// UUID v7（RFC 9562）：48bit 毫秒时间戳 + 随机位，时间有序，索引友好
export function uuidv7() {
  const ts = Date.now();
  const b = Buffer.alloc(16);
  b.writeUIntBE(ts % 281474976710656, 0, 6);
  crypto.randomBytes(10).copy(b, 6);
  b[6] = (b[6] & 0x0f) | 0x70;   // version 7
  b[8] = (b[8] & 0x3f) | 0x80;   // variant 10
  const h = b.toString('hex');
  return h.slice(0, 8) + '-' + h.slice(8, 12) + '-' + h.slice(12, 16) + '-' + h.slice(16, 20) + '-' + h.slice(20, 32);
}

// 混合逻辑时钟：毫秒:计数:设备 —— 时钟回拨免疫，同设备单调，跨设备可比较
export function hlcNext(d) {
  const ms = Date.now();
  const lastMs = Number(getMeta(d, 'hlc_ms') || 0);
  const lastCnt = Number(getMeta(d, 'hlc_counter') || 0);
  let newMs, newCnt;
  if (ms > lastMs) { newMs = ms; newCnt = 0; }
  else { newMs = lastMs; newCnt = lastCnt + 1; }
  setMeta(d, 'hlc_ms', String(newMs));
  setMeta(d, 'hlc_counter', String(newCnt));
  return newMs + ':' + newCnt + ':' + getDeviceId(d);
}

function touchOplog(d, table, rowUuid, op, hlc) {
  d.prepare('INSERT INTO sync_oplog (table_name, row_uuid, op, hlc) VALUES (?,?,?,?)')
    .run(table, rowUuid, op, hlc);
}

function withTx(d, fn) {
  d.exec('BEGIN');
  try { const r = fn(); d.exec('COMMIT'); return r; }
  catch (e) { d.exec('ROLLBACK'); throw e; }
}

function getUuid(d, table, id) {
  const r = d.prepare('SELECT uuid FROM ' + table + ' WHERE id=?').get(id);
  return r ? r.uuid : null;
}

export function buildSearchText(title, description, result, tags, extras) {
  const extraFlat = Object.entries(extras || {}).map(([k, v]) => {
    if (v == null) return '';
    if (typeof v === 'object') return Object.values(v).filter(Boolean).join(' ');
    return String(v);
  }).filter(Boolean);
  return [title, description || '', result || '', (tags || []).join(' '), ...extraFlat]
    .filter(Boolean).join('\n');
}
// 老库迁移：补列 + 回填 uuid/hlc/origin（幂等）
const SYNC_TABLES = ['footprint', 'footprint_type', 'taxonomy', 'dimension', 'attachment',
  'semester', 'course_grade', 'metric_def', 'saved_view', 'grade_band'];

const SYNC_COLS = [['uuid', 'TEXT'], ['deleted_at', 'TEXT'], ['origin', 'TEXT'], ['hlc', 'TEXT']];

function preMigrateColumns(d) {
  const addCols = (t, cols) => {
    const exists = d.prepare("SELECT 1 FROM sqlite_master WHERE type='table' AND name=?").get(t);
    if (!exists) return; // 全新库：表由 schema.sql 创建，自带同步列
    const have = new Set(d.prepare('PRAGMA table_info(' + t + ')').all().map(c => c.name));
    for (const [name, ddl] of cols) {
      if (!have.has(name)) d.exec('ALTER TABLE ' + t + ' ADD COLUMN ' + name + ' ' + ddl);
    }
  };
  for (const t of SYNC_TABLES) addCols(t, SYNC_COLS);
  addCols('attachment', [['sha256', 'TEXT']]);
}

export function migrateSync(d) {
  const addCols = (t, cols) => {
    const have = new Set(d.prepare('PRAGMA table_info(' + t + ')').all().map(c => c.name));
    for (const [name, ddl] of cols) {
      if (!have.has(name)) d.exec('ALTER TABLE ' + t + ' ADD COLUMN ' + name + ' ' + ddl);
    }
  };
  for (const t of SYNC_TABLES) {
    addCols(t, [['uuid', 'TEXT'], ['deleted_at', 'TEXT'], ['origin', 'TEXT'], ['hlc', 'TEXT']]);
  }
  addCols('attachment', [['sha256', 'TEXT']]);
  for (const t of SYNC_TABLES) {
    const rows = d.prepare('SELECT id FROM ' + t + ' WHERE uuid IS NULL').all();
    for (const row of rows) {
      d.prepare('UPDATE ' + t + ' SET uuid=?, hlc=?, origin=? WHERE id=?')
        .run(uuidv7(), hlcNext(d), 'migrate', row.id);
    }
  }
}

function softDelete(d, table, id) {
  const uuid = getUuid(d, table, id);
  if (!uuid) return;
  const h = hlcNext(d);
  d.prepare('UPDATE ' + table + " SET deleted_at=datetime('now','localtime'), hlc=? WHERE id=?").run(h, id);
  touchOplog(d, table, uuid, 'delete', h);
}

const BUILTIN_TYPES = [
  ['学业', 'graduation-cap', '#3056d3', 10, JSON.stringify([
    { key: 'semester_label', label: '学期', widget: 'text', placeholder: '如：2024-2025-1' }
  ])],
  ['竞赛', 'trophy', '#7c3aed', 20, JSON.stringify([
    { key: 'my_work', label: '我的分工', widget: 'textarea', required: true },
    { key: 'deliverable', label: '最终产品', widget: 'text', placeholder: '作品 / 论文 / 系统名称' },
    { key: 'team_members', label: '队伍成员', widget: 'text' }
  ])],
  ['科研', 'flask-conical', '#0891b2', 30, JSON.stringify([
    { key: 'authors', label: '作者排序', widget: 'text', placeholder: '如：第 2 作者' },
    { key: 'outcome', label: '成果形式', widget: 'select', options: ['论文', '专利', '软件著作权', '研究报告'] }
  ])],
  ['实习实践', 'briefcase', '#0f766e', 40, JSON.stringify([
    { key: 'position', label: '岗位', widget: 'text' },
    { key: 'mentor', label: '带教人', widget: 'text' }
  ])],
  ['学生工作', 'network', '#d97706', 50, JSON.stringify([
    { key: 'duties', label: '职责', widget: 'textarea' },
    { key: 'term', label: '任期', widget: 'text', placeholder: '2024.09 - 2025.06' }
  ])],
  ['志愿公益', 'heart-handshake', '#16a34a', 60, JSON.stringify([
    { key: 'hours', label: '志愿时长', widget: 'number', unit: '小时', metric: 'volunteer_hours' },
    { key: 'contact', label: '组织负责人', widget: 'text' }
  ])],
  ['文体活动', 'palette', '#db2777', 70, JSON.stringify([
    { key: 'participation', label: '参与形式', widget: 'text', placeholder: '如：方阵队员 / 主唱' }
  ])],
  ['证书技能', 'file-badge', '#64748b', 80, JSON.stringify([
    { key: 'cert_no', label: '证书编号', widget: 'text' },
    { key: 'score', label: '成绩', widget: 'text', placeholder: '如：580 / 良好' }
  ])],
  ['荣誉惩处', 'award', '#b45309', 90, JSON.stringify([
    { key: 'issued_by', label: '授予 / 决定单位', widget: 'text' }
  ])]
];

const BUILTIN_LEVELS = [
  ['国际级', '#7c3aed', 10], ['国家级', '#dc2626', 20], ['省市级', '#ea580c', 30],
  ['区县级', '#2563eb', 40], ['校级', '#16a34a', 50], ['院级', '#0891b2', 60]
];

const BUILTIN_ROLES = [
  ['主导', '#3056d3', 10], ['核心', '#0891b2', 20], ['参加', '#64748b', 30]
];

const BUILTIN_DIMENSIONS = [
  ['学业深造', '#3056d3', 10], ['职业发展', '#0891b2', 20],
  ['综合素养', '#16a34a', 30], ['兴趣生活', '#db2777', 40]
];

function ensureBuiltin(db) {
  const cnt = db.prepare('SELECT COUNT(*) AS c FROM footprint_type WHERE deleted_at IS NULL').get().c;
  if (cnt === 0) {
    const ins = db.prepare(
      'INSERT INTO footprint_type (name, icon, color, sort, form_template, is_builtin, uuid, hlc, origin) VALUES (?,?,?,?,?,1,?,?,?)');
    for (const [name, icon, color, sort, tpl] of BUILTIN_TYPES) {
      const h = hlcNext(db);
      ins.run(name, icon, color, sort, tpl, uuidv7(), h, getDeviceId(db));
    }
  }
  const tcnt = db.prepare('SELECT COUNT(*) AS c FROM taxonomy WHERE deleted_at IS NULL').get().c;
  if (tcnt === 0) {
    const ins = db.prepare('INSERT INTO taxonomy (kind, value, color, sort, is_builtin, uuid, hlc, origin) VALUES (?,?,?,?,1,?,?,?)');
    for (const [v, c, s] of BUILTIN_LEVELS) {
      const h = hlcNext(db);
      ins.run('level', v, c, s, uuidv7(), h, getDeviceId(db));
    }
    for (const [v, c, s] of BUILTIN_ROLES) {
      const h = hlcNext(db);
      ins.run('role', v, c, s, uuidv7(), h, getDeviceId(db));
    }
  }
  const dcnt = db.prepare('SELECT COUNT(*) AS c FROM dimension WHERE deleted_at IS NULL').get().c;
  if (dcnt === 0) {
    const ins = db.prepare('INSERT INTO dimension (name, color, sort, uuid, hlc, origin) VALUES (?,?,?,?,?,?)');
    for (const [v, c, s] of BUILTIN_DIMENSIONS) {
      const h = hlcNext(db);
      ins.run(v, c, s, uuidv7(), h, getDeviceId(db));
    }
  }
  const mcnt = db.prepare('SELECT COUNT(*) AS c FROM metric_def WHERE deleted_at IS NULL').get().c;
  if (mcnt === 0) {
    const h = hlcNext(db);
    db.prepare('INSERT INTO metric_def (key, label, unit, agg, section, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?,?)')
      .run('volunteer_hours', '志愿时长', '小时', 'sum', '志愿服务', uuidv7(), h, getDeviceId(db));
  }
  const bcnt = db.prepare('SELECT COUNT(*) AS c FROM grade_band WHERE deleted_at IS NULL').get().c;
  if (bcnt === 0) {
    const bands = [
      ['优秀', '#16803c', 90, 100, 10],
      ['良好', '#0891b2', 80, 90, 20],
      ['中等', '#d97706', 70, 80, 30],
      ['及格', '#ea580c', 60, 70, 40],
      ['不及格', '#dc2626', 0, 60, 50]
    ];
    const ins = db.prepare('INSERT INTO grade_band (label, color, min, max, sort, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?,?)');
    for (const [label, color, min, max, sort] of bands) {
      const h = hlcNext(db);
      ins.run(label, color, min, max, sort, uuidv7(), h, getDeviceId(db));
    }
  }
}

// ---------- 查询构建 ----------

function openDb(dbPath) {
  fs.mkdirSync(path.join(path.dirname(dbPath), 'attachments'), { recursive: true });
  const d = new DatabaseSync(dbPath);
  d.exec('PRAGMA foreign_keys = ON;');
  // 先补列（老库无 uuid/hlc 等列时，schema 中的索引会引用失败），再执行 schema，最后回填
  preMigrateColumns(d);
  d.exec(fs.readFileSync(path.join(__dirname, '..', 'schema.sql'), 'utf8'));
  migrateSync(d);
  ensureBuiltin(d);
  return d;
}

// 按数据库路径创建一套应用命令（多用户/服务器模式：每个用户一个独立档案库）
export function createAppCommands(dbPath) {
  const db = openDb(dbPath);
  const DATA_DIR = path.dirname(dbPath); // 工厂内遮蔽顶层默认值：附件按用户目录
  function getDb() {
    return db;
  }


// ---------- 同步基础设施 ----------


const SORTS = {
  date_desc: "COALESCE(NULLIF(fp.start_date,''), substr(fp.created_at,1,10)) DESC, fp.id DESC",
  date_asc: "COALESCE(NULLIF(fp.start_date,''), substr(fp.created_at,1,10)) ASC, fp.id ASC",
  updated_desc: 'fp.updated_at DESC, fp.id DESC',
  weight_desc: "fp.weight DESC, COALESCE(NULLIF(fp.start_date,''), substr(fp.created_at,1,10)) DESC"
};

function buildWhere(query) {
  const conds = [];
  const params = [];
  const joins = [];
  if (query.q) {
    // 中文检索策略：长度>=3 的词走 FTS5 trigram（子串匹配），更短的词回退 LIKE
    const ftsTerms = [];
    for (const raw of String(query.q).trim().split(/\s+/).filter(Boolean)) {
      const clean = raw.replace(/["\\]/g, ' ');
      if (!clean.trim()) continue;
      if ([...clean].length >= 3) {
        ftsTerms.push('"' + clean + '"');
      } else {
        conds.push('fp.search_text LIKE ?');
        params.push('%' + clean + '%');
      }
    }
    if (ftsTerms.length) {
      joins.push('JOIN footprint_fts ON footprint_fts.rowid = fp.id');
      conds.push('footprint_fts MATCH ?');
      params.push(ftsTerms.join(' AND '));
    }
  }
  if (query.types?.length) {
    conds.push('fp.type_id IN (' + query.types.map(() => '?').join(',') + ')');
    params.push(...query.types);
  }
  if (query.levels?.length) {
    conds.push('fp.level IN (' + query.levels.map(() => '?').join(',') + ')');
    params.push(...query.levels);
  }
  if (query.roles?.length) {
    conds.push('fp.role IN (' + query.roles.map(() => '?').join(',') + ')');
    params.push(...query.roles);
  }
  if (query.statuses?.length) {
    conds.push('fp.status IN (' + query.statuses.map(() => '?').join(',') + ')');
    params.push(...query.statuses);
  }
  if (query.dims?.length) {
    conds.push('fp.id IN (SELECT footprint_id FROM footprint_dimension WHERE dimension_id IN ('
      + query.dims.map(() => '?').join(',') + '))');
    params.push(...query.dims);
  }
  if (query.year) {
    conds.push("strftime('%Y', COALESCE(NULLIF(fp.start_date,''), substr(fp.created_at,1,10))) = ?");
    params.push(String(query.year));
  }
  if (query.polarity) {
    conds.push('fp.polarity = ?');
    params.push(query.polarity);
  }
  if (query.has_attachment) {
    conds.push("EXISTS (SELECT 1 FROM attachment a WHERE a.owner_type='footprint' AND a.owner_id=fp.id AND a.deleted_at IS NULL)");
  }
  if (query.tag) {
    conds.push('fp.tags LIKE ?');
    params.push('%"' + query.tag + '"%');
  }
  return { joins, conds, params };
}

const BASE_SELECT = `SELECT fp.*, ft.name AS type_name, ft.color AS type_color, ft.icon AS type_icon,
  (SELECT COUNT(*) FROM attachment a WHERE a.owner_type='footprint' AND a.owner_id=fp.id AND a.deleted_at IS NULL) AS attachment_count,
  (SELECT GROUP_CONCAT(dimension_id) FROM footprint_dimension fd WHERE fd.footprint_id=fp.id) AS dim_ids
  FROM footprint fp JOIN footprint_type ft ON ft.id = fp.type_id`;

function mapRow(r) {
  let metrics = {}, extras = {}, tags = [];
  try { metrics = JSON.parse(r.metrics || '{}'); } catch {}
  try { extras = JSON.parse(r.extras || '{}'); } catch {}
  try { tags = JSON.parse(r.tags || '[]'); } catch {}
  return {
    ...r,
    metrics, extras, tags,
    dimensions: r.dim_ids ? String(r.dim_ids).split(',').map(Number) : [],
    dim_ids: undefined
  };
}

function listFootprints(d, query) {
  const page = Math.max(1, query.page || 1);
  const pageSize = Math.min(2000, Math.max(1, query.page_size || 20));
  const { joins, conds, params } = buildWhere(query);
  const base = ' WHERE fp.deleted_at IS NULL';
  const where = conds.length ? base + ' AND ' + conds.join(' AND ') : base;
  const order = SORTS[query.sort] || SORTS.date_desc;

  const total = d.prepare(
    'SELECT COUNT(*) AS c FROM footprint fp ' + joins.join(' ') + where
  ).get(...params).c;

  const rows = d.prepare(
    BASE_SELECT + ' ' + joins.join(' ') + where + ' ORDER BY ' + order +
    ' LIMIT ' + pageSize + ' OFFSET ' + (page - 1) * pageSize
  ).all(...params).map(mapRow);

  return { items: rows, total, page, page_size: pageSize };
}

// ---------- 命令处理 ----------
  function handleCommand(cmd, payload) {
  const d = getDb();

  switch (cmd) {
    case 'app_info': {
      const pending = d.prepare('SELECT COUNT(*) AS c FROM sync_oplog WHERE synced_at IS NULL').get().c;
      return {
        app_name: 'Footprints 足迹',
        version: '0.2.0',
        db_path: DB_PATH,
        attachment_dir: ATT_DIR,
        schema_ok: true,
        device_id: getDeviceId(d),
        pending_ops: pending,
        last_sync_at: getMeta(d, 'last_sync_at')
      };
    }

    case 'sync_status':
      return {
        mode: 'local',
        device_id: getDeviceId(d),
        pending_ops: d.prepare('SELECT COUNT(*) AS c FROM sync_oplog WHERE synced_at IS NULL').get().c,
        last_sync_at: getMeta(d, 'last_sync_at')
      };

    case 'type_list': {
      const items = d.prepare(`
        SELECT t.*, (SELECT COUNT(*) FROM footprint f WHERE f.type_id = t.id AND f.deleted_at IS NULL) AS usage_count
        FROM footprint_type t WHERE t.deleted_at IS NULL ORDER BY t.sort, t.id`).all()
        .map(t => ({ ...t, form_template: JSON.parse(t.form_template || '[]'), is_builtin: !!t.is_builtin, closed: !!t.closed }));
      return { items };
    }

    case 'type_upsert': {
      const p = payload;
      const tpl = JSON.stringify(p.form_template || []);
      let id = p.id;
      if (id) {
        withTx(d, () => {
          const h = hlcNext(d);
          d.prepare('UPDATE footprint_type SET name=?, icon=?, color=?, sort=?, form_template=?, closed=?, hlc=? WHERE id=?')
            .run(p.name, p.icon, p.color, p.sort, tpl, p.closed ? 1 : 0, h, id);
          touchOplog(d, 'footprint_type', getUuid(d, 'footprint_type', id), 'upsert', h);
        });
      } else {
        withTx(d, () => {
          const h = hlcNext(d);
          const uuid = uuidv7();
          id = Number(d.prepare(
            'INSERT INTO footprint_type (name, icon, color, sort, form_template, closed, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?,?,?)')
            .run(p.name, p.icon, p.color, p.sort, tpl, p.closed ? 1 : 0, uuid, h, getDeviceId(d)).lastInsertRowid);
          touchOplog(d, 'footprint_type', uuid, 'upsert', h);
        });
      }
      return { item: { id } };
    }

    case 'type_delete': {
      const used = d.prepare('SELECT COUNT(*) AS c FROM footprint WHERE type_id=? AND deleted_at IS NULL').get(payload.id).c;
      if (used > 0) throw new Error('该类型下仍有 ' + used + ' 条记录，请先迁移后再删除');
      const row = d.prepare('SELECT uuid, is_builtin FROM footprint_type WHERE id=?').get(payload.id);
      if (!row) return { ok: true };
      if (row.is_builtin) throw new Error('内置类型不可删除');
      withTx(d, () => softDelete(d, 'footprint_type', payload.id));
      return { ok: true };
    }

    case 'taxonomy_list': {
      const sql = payload.kind
        ? "SELECT * FROM taxonomy WHERE kind=? AND deleted_at IS NULL ORDER BY sort, id"
        : "SELECT * FROM taxonomy WHERE deleted_at IS NULL ORDER BY kind, sort, id";
      const rows = payload.kind ? d.prepare(sql).all(payload.kind) : d.prepare(sql).all();
      return { items: rows.map(r => ({ ...r, is_builtin: !!r.is_builtin })) };
    }

    case 'taxonomy_upsert': {
      const p = payload;
      let id = p.id;
      if (id) {
        withTx(d, () => {
          const h = hlcNext(d);
          d.prepare('UPDATE taxonomy SET kind=?, value=?, color=?, sort=?, hlc=? WHERE id=?')
            .run(p.kind, p.value, p.color ?? null, p.sort ?? 100, h, id);
          touchOplog(d, 'taxonomy', getUuid(d, 'taxonomy', id), 'upsert', h);
        });
      } else {
        withTx(d, () => {
          const h = hlcNext(d);
          const uuid = uuidv7();
          id = Number(d.prepare('INSERT INTO taxonomy (kind, value, color, sort, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?)')
            .run(p.kind, p.value, p.color ?? null, p.sort ?? 100, uuid, h, getDeviceId(d)).lastInsertRowid);
          touchOplog(d, 'taxonomy', uuid, 'upsert', h);
        });
      }
      return { item: { id } };
    }

    case 'taxonomy_delete': {
      const row = d.prepare('SELECT is_builtin FROM taxonomy WHERE id=?').get(payload.id);
      if (!row) return { ok: true };
      if (row.is_builtin) throw new Error('内置条目不可删除');
      withTx(d, () => softDelete(d, 'taxonomy', payload.id));
      return { ok: true };
    }

    case 'dimension_list':
      return { items: d.prepare('SELECT * FROM dimension WHERE deleted_at IS NULL ORDER BY sort, id').all() };

    case 'dimension_upsert': {
      const p = payload;
      let id = p.id;
      if (id) {
        withTx(d, () => {
          const h = hlcNext(d);
          d.prepare('UPDATE dimension SET name=?, color=?, sort=?, hlc=? WHERE id=?')
            .run(p.name, p.color ?? null, p.sort ?? 100, h, id);
          touchOplog(d, 'dimension', getUuid(d, 'dimension', id), 'upsert', h);
        });
      } else {
        withTx(d, () => {
          const h = hlcNext(d);
          const uuid = uuidv7();
          id = Number(d.prepare('INSERT INTO dimension (name, color, sort, uuid, hlc, origin) VALUES (?,?,?,?,?,?)')
            .run(p.name, p.color ?? null, p.sort ?? 100, uuid, h, getDeviceId(d)).lastInsertRowid);
          touchOplog(d, 'dimension', uuid, 'upsert', h);
        });
      }
      return { item: { id } };
    }

    case 'dimension_delete': {
      withTx(d, () => softDelete(d, 'dimension', payload.id));
      return { ok: true };
    }

    case 'footprint_list':
      return listFootprints(d, payload.query || {});

    case 'footprint_get': {
      const row = d.prepare(BASE_SELECT + ' AND fp.id=?').get(payload.id);
      if (!row) throw new Error('记录不存在');
      const attachments = d.prepare(
        "SELECT * FROM attachment WHERE owner_type='footprint' AND owner_id=? AND deleted_at IS NULL ORDER BY id"
      ).all(payload.id);
      return { item: { ...mapRow(row), attachments } };
    }

    case 'footprint_upsert': {
      const it = payload.item;
      if (!it.type_id) throw new Error('缺少记录类型');
      if (!it.title || !it.title.trim()) throw new Error('缺少标题');
      const search = buildSearchText(it.title.trim(), it.description, it.result, it.tags, it.extras);
      const metrics = JSON.stringify(it.metrics || {});
      const extras = JSON.stringify(it.extras || {});
      const tags = JSON.stringify(it.tags || []);
      const nowLocal = "datetime('now','localtime')";
      let id = it.id;

      withTx(d, () => {
        if (id) {
          const h = hlcNext(d);
          d.prepare(`UPDATE footprint SET type_id=?, title=?, role=?, level=?, polarity=?, award_grade=?, rank=?,
            organizer=?, start_date=?, end_date=?, status=?, description=?, result=?, metrics=?, extras=?,
            group_id=?, parent_id=?, tags=?, weight=?, search_text=?, hlc=?, updated_at=${nowLocal} WHERE id=?`)
            .run(it.type_id, it.title.trim(), it.role ?? null, it.level ?? null, it.polarity || 'positive',
              it.award_grade ?? null, it.rank ?? null, it.organizer ?? null, it.start_date ?? null, it.end_date ?? null,
              it.status || 'draft', it.description ?? '', it.result ?? '', metrics, extras,
              it.group_id ?? null, it.parent_id ?? null, tags, it.weight ?? 3, search, h, id);
          touchOplog(d, 'footprint', getUuid(d, 'footprint', id), 'upsert', h);
        } else {
          const h = hlcNext(d);
          const uuid = uuidv7();
          id = Number(d.prepare(`INSERT INTO footprint (type_id, title, role, level, polarity, award_grade, rank,
            organizer, start_date, end_date, status, description, result, metrics, extras, group_id, parent_id,
            tags, weight, search_text, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)`)
            .run(it.type_id, it.title.trim(), it.role ?? null, it.level ?? null, it.polarity || 'positive',
              it.award_grade ?? null, it.rank ?? null, it.organizer ?? null, it.start_date ?? null, it.end_date ?? null,
              it.status || 'draft', it.description ?? '', it.result ?? '', metrics, extras,
              it.group_id ?? null, it.parent_id ?? null, tags, it.weight ?? 3, search, uuid, h, getDeviceId(d)).lastInsertRowid);
          touchOplog(d, 'footprint', uuid, 'upsert', h);
        }
        if (Array.isArray(it.dimension_ids)) {
          d.prepare('DELETE FROM footprint_dimension WHERE footprint_id=?').run(id);
          const ins = d.prepare('INSERT OR IGNORE INTO footprint_dimension (footprint_id, dimension_id) VALUES (?,?)');
          for (const dim of it.dimension_ids) ins.run(id, dim);
        }
      });
      return { id };
    }

    case 'footprint_delete': {
      const row = d.prepare('SELECT uuid FROM footprint WHERE id=?').get(payload.id);
      if (!row) return { ok: true };
      withTx(d, () => {
        // FTS 内容表需同步移除：先物理删除 FTS 行，墓碑保留在主表
        d.prepare("INSERT INTO footprint_fts(footprint_fts, rowid, search_text) SELECT 'delete', id, search_text FROM footprint WHERE id=?")
          .run(payload.id);
        softDelete(d, 'footprint', payload.id);
      });
      return { ok: true };
    }

    case 'timeline': {
      const res = listFootprints(d, { ...(payload.query || {}), page_size: 2000, sort: 'date_desc' });
      const groups = [];
      const byYear = new Map();
      for (const row of res.items) {
        const date = (row.start_date && row.start_date.slice(0, 10)) || row.created_at.slice(0, 10);
        const year = Number(date.slice(0, 4));
        const month = Number(date.slice(5, 7));
        if (!byYear.has(year)) {
          const g = { year, count: 0, months: [] };
          byYear.set(year, g);
          groups.push(g);
        }
        const g = byYear.get(year);
        g.count++;
        let m = g.months.find(x => x.month === month);
        if (!m) { m = { month, items: [] }; g.months.push(m); }
        m.items.push(row);
      }
      groups.sort((a, b) => b.year - a.year);
      for (const g of groups) g.months.sort((a, b) => a.month - b.month);
      return { groups, total: res.total };
    }

    case 'stats_overview': {
      const year = payload.year || null;
      const yearCond = year
        ? " AND strftime('%Y', COALESCE(NULLIF(fp.start_date,''), substr(fp.created_at,1,10))) = '" + String(year).replace(/[^0-9]/g, '') + "'"
        : '';
      const yearCondRaw = year
        ? " AND strftime('%Y', COALESCE(NULLIF(start_date,''), substr(created_at,1,10))) = '" + String(year).replace(/[^0-9]/g, '') + "'"
        : '';
      const DEL = 'fp.deleted_at IS NULL';
      const DEL_RAW = 'deleted_at IS NULL';

      const total = d.prepare('SELECT COUNT(*) AS c FROM footprint fp WHERE ' + DEL + yearCond).get().c;
      const curYear = year || new Date().getFullYear();
      const totalThisYear = d.prepare(
        "SELECT COUNT(*) AS c FROM footprint fp WHERE strftime('%Y', COALESCE(NULLIF(fp.start_date,''), substr(fp.created_at,1,10))) = ?"
      ).get(String(curYear)).c;
      const attTotal = d.prepare(
        "SELECT COUNT(*) AS c FROM attachment a JOIN footprint fp ON fp.id = a.owner_id AND a.owner_type='footprint' WHERE a.deleted_at IS NULL AND " + DEL + yearCond
      ).get().c;

      const byType = d.prepare(`SELECT ft.name AS label, ft.color, COUNT(*) AS count
        FROM footprint fp JOIN footprint_type ft ON ft.id=fp.type_id WHERE ${DEL}${yearCond}
        GROUP BY fp.type_id ORDER BY count DESC`).all();
      const byLevel = d.prepare(`SELECT COALESCE(fp.level,'未设置') AS label, COUNT(*) AS count
        FROM footprint fp WHERE ${DEL}${yearCond} GROUP BY fp.level ORDER BY count DESC`).all();
      const byRole = d.prepare(`SELECT COALESCE(fp.role,'未设置') AS label, COUNT(*) AS count
        FROM footprint fp WHERE ${DEL}${yearCond} GROUP BY fp.role ORDER BY count DESC`).all();
      const byStatus = d.prepare(`SELECT fp.status AS label, COUNT(*) AS count
        FROM footprint fp WHERE ${DEL}${yearCond} GROUP BY fp.status`).all();

      const monthlyRows = d.prepare(`SELECT substr(COALESCE(NULLIF(start_date,''), substr(created_at,1,10)),1,7) AS ym, COUNT(*) AS count
        FROM footprint WHERE ${DEL_RAW}${yearCondRaw} GROUP BY ym ORDER BY ym`).all();
      const monthlyMap = new Map(monthlyRows.map(r => [r.ym, r.count]));
      const monthly = [];
      const now = new Date();
      for (let i = 11; i >= 0; i--) {
        const dt = new Date(now.getFullYear(), now.getMonth() - i, 1);
        const ym = dt.getFullYear() + '-' + String(dt.getMonth() + 1).padStart(2, '0');
        monthly.push({ ym, count: monthlyMap.get(ym) ?? 0 });
      }

      const metrics = [];
      for (const m of d.prepare('SELECT * FROM metric_def WHERE deleted_at IS NULL').all()) {
        const path = '$."' + m.key + '"';
        let value = 0;
        if (m.agg === 'sum') {
          const r = d.prepare(`SELECT SUM(CAST(json_extract(fp.metrics, ?) AS REAL)) AS v
            FROM footprint fp WHERE json_extract(fp.metrics, ?) IS NOT NULL AND ${DEL}${yearCond}`).get(path, path);
          value = r.v ?? 0;
        } else if (m.agg === 'count') {
          value = d.prepare(`SELECT COUNT(*) AS c FROM footprint fp WHERE json_extract(fp.metrics, ?) IS NOT NULL AND ${DEL}${yearCond}`).get(path).c;
        } else if (m.agg === 'distinct') {
          value = d.prepare(`SELECT COUNT(DISTINCT json_extract(fp.metrics, ?)) AS c FROM footprint fp WHERE json_extract(fp.metrics, ?) IS NOT NULL AND ${DEL}${yearCond}`).get(path, path).c;
        }
        metrics.push({ key: m.key, label: m.label, unit: m.unit, agg: m.agg, value });
      }

      const years = d.prepare(`SELECT DISTINCT CAST(strftime('%Y', COALESCE(NULLIF(start_date,''), substr(created_at,1,10))) AS INTEGER) AS y
        FROM footprint WHERE ${DEL_RAW} ORDER BY y DESC`).all().map(r => r.y);

      return {
        total, total_this_year: totalThisYear, attachment_total: attTotal,
        by_type: byType, by_level: byLevel, by_role: byRole, by_status: byStatus,
        monthly, metrics, years
      };
    }

    case 'metric_list':
      return { items: d.prepare('SELECT * FROM metric_def WHERE deleted_at IS NULL ORDER BY id').all() };

    case 'metric_upsert': {
      const p = payload;
      const exist = d.prepare('SELECT id, uuid FROM metric_def WHERE key=? AND deleted_at IS NULL').get(p.key);
      withTx(d, () => {
        if (exist) {
          const h = hlcNext(d);
          d.prepare('UPDATE metric_def SET label=?, unit=?, agg=?, section=?, hlc=? WHERE id=?')
            .run(p.label, p.unit ?? null, p.agg || 'sum', p.section ?? null, h, exist.id);
          touchOplog(d, 'metric_def', exist.uuid, 'upsert', h);
        } else {
          const h = hlcNext(d);
          const uuid = uuidv7();
          d.prepare('INSERT INTO metric_def (key, label, unit, agg, section, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?,?)')
            .run(p.key, p.label, p.unit ?? null, p.agg || 'sum', p.section ?? null, uuid, h, getDeviceId(d));
          touchOplog(d, 'metric_def', uuid, 'upsert', h);
        }
      });
      return { item: p };
    }

    case 'metric_delete': {
      const row = d.prepare('SELECT id FROM metric_def WHERE key=?').get(payload.key);
      if (row) withTx(d, () => softDelete(d, 'metric_def', row.id));
      return { ok: true };
    }

    // ---------- 学年学科成绩 ----------
    case 'grades_overview': {
      const DEL = 'deleted_at IS NULL';
      const bands = d.prepare('SELECT * FROM grade_band WHERE ' + DEL + ' ORDER BY sort, id').all();
      const bandOf = (score) => {
        if (score == null) return null;
        let hit = bands.find(b => score >= b.min && score < b.max);
        if (!hit) hit = bands.find(b => score >= b.min && score <= b.max);
        return hit ? { id: hit.id, label: hit.label, color: hit.color } : null;
      };
      const semesters = d.prepare('SELECT * FROM semester WHERE ' + DEL + ' ORDER BY term DESC').all();
      const activeSemIds = new Set(semesters.map(s => s.id));
      const courses = d.prepare('SELECT * FROM course_grade WHERE ' + DEL + ' ORDER BY id').all()
        .filter(c => activeSemIds.has(c.semester_id));
      for (const s of semesters) {
        s.courses = courses.filter(c => c.semester_id === s.id).map(c => ({ ...c, band: bandOf(c.score) }));
        const scored = s.courses.filter(c => c.score != null);
        const creditsAll = s.courses.reduce((a, c) => a + (c.credit || 0), 0);
        const creditsScored = scored.reduce((a, c) => a + (c.credit || 0), 0);
        s.stats = {
          credits: Math.round(creditsAll * 10) / 10,
          courses: s.courses.length,
          avg: creditsScored > 0 ? Math.round(scored.reduce((a, c) => a + c.score * c.credit, 0) / creditsScored * 100) / 100 : null
        };
      }
      const allScored = courses.filter(c => c.score != null);
      const creditsAll = allScored.reduce((a, c) => a + (c.credit || 0), 0);
      const overallAvg = creditsAll > 0
        ? Math.round(allScored.reduce((a, c) => a + c.score * c.credit, 0) / creditsAll * 100) / 100
        : null;
      const tierDist = bands.map(b => ({
        label: b.label, color: b.color,
        count: allScored.filter(c => { const x = bandOf(c.score); return x && x.id === b.id; }).length
      }));
      const gpaTrend = [...semesters]
        .filter(s => s.gpa != null)
        .sort((a, b) => a.term.localeCompare(b.term))
        .map(s => ({ term: s.term, gpa: s.gpa, avg: s.stats.avg }));
      return {
        semesters,
        bands,
        overall: {
          avg: overallAvg,
          credits: Math.round(courses.reduce((a, c) => a + (c.credit || 0), 0) * 10) / 10,
          courses: courses.length,
          gpa_trend: gpaTrend,
          tier_dist: tierDist
        }
      };
    }

    case 'semester_upsert': {
      const p = payload;
      if (!p.term || !String(p.term).trim()) throw new Error('缺少学期名称');
      const term = String(p.term).trim();
      let id = p.id;
      withTx(d, () => {
        if (id) {
          const dup = d.prepare('SELECT id FROM semester WHERE term=? AND deleted_at IS NULL AND id != ?').get(term, id);
          if (dup) throw new Error('学期已存在：' + term);
          const h = hlcNext(d);
          d.prepare('UPDATE semester SET term=?, gpa=?, rank=?, total_students=?, hlc=? WHERE id=?')
            .run(term, p.gpa ?? null, p.rank ?? null, p.total_students ?? null, h, id);
          touchOplog(d, 'semester', getUuid(d, 'semester', id), 'upsert', h);
        } else {
          const dup = d.prepare('SELECT 1 FROM semester WHERE term=? AND deleted_at IS NULL').get(term);
          if (dup) throw new Error('学期已存在：' + term);
          const h = hlcNext(d);
          const uuid = uuidv7();
          id = Number(d.prepare('INSERT INTO semester (term, gpa, rank, total_students, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?)')
            .run(term, p.gpa ?? null, p.rank ?? null, p.total_students ?? null, uuid, h, getDeviceId(d)).lastInsertRowid);
          touchOplog(d, 'semester', uuid, 'upsert', h);
        }
      });
      return { item: { id } };
    }

    case 'semester_delete': {
      withTx(d, () => {
        softDelete(d, 'semester', payload.id);
        // 级联墓碑该学期下全部课程，避免孤儿课程污染总览
        const courses = d.prepare('SELECT id FROM course_grade WHERE semester_id=? AND deleted_at IS NULL').all(payload.id);
        for (const c of courses) softDelete(d, 'course_grade', c.id);
      });
      return { ok: true };
    }

    case 'course_upsert': {
      const p = payload;
      if (!p.semester_id) throw new Error('缺少学期');
      if (!p.course_name || !String(p.course_name).trim()) throw new Error('缺少课程名');
      if (p.score != null && (p.score < 0 || p.score > 100)) throw new Error('分数需在 0-100 之间');
      if (p.grade_point != null && p.grade_point < 0) throw new Error('绩点不能为负');
      const name = String(p.course_name).trim();
      let id = p.id;
      withTx(d, () => {
        if (id) {
          const h = hlcNext(d);
          d.prepare('UPDATE course_grade SET semester_id=?, course_name=?, credit=?, score=?, grade_point=?, hlc=? WHERE id=?')
            .run(p.semester_id, name, p.credit ?? 0, p.score ?? null, p.grade_point ?? null, h, id);
          touchOplog(d, 'course_grade', getUuid(d, 'course_grade', id), 'upsert', h);
        } else {
          const h = hlcNext(d);
          const uuid = uuidv7();
          id = Number(d.prepare('INSERT INTO course_grade (semester_id, course_name, credit, score, grade_point, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?,?)')
            .run(p.semester_id, name, p.credit ?? 0, p.score ?? null, p.grade_point ?? null, uuid, h, getDeviceId(d)).lastInsertRowid);
          touchOplog(d, 'course_grade', uuid, 'upsert', h);
        }
      });
      return { item: { id } };
    }

    case 'course_delete': {
      withTx(d, () => softDelete(d, 'course_grade', payload.id));
      return { ok: true };
    }

    case 'band_upsert': {
      const p = payload;
      if (!p.label || !String(p.label).trim()) throw new Error('缺少等级名称');
      if (p.min == null || p.max == null || p.min >= p.max) throw new Error('分数区间不合法（需 min < max）');
      const label = String(p.label).trim();
      let id = p.id;
      withTx(d, () => {
        if (id) {
          const h = hlcNext(d);
          d.prepare('UPDATE grade_band SET label=?, color=?, min=?, max=?, sort=?, hlc=? WHERE id=?')
            .run(label, p.color ?? '#64748b', p.min, p.max, p.sort ?? 100, h, id);
          touchOplog(d, 'grade_band', getUuid(d, 'grade_band', id), 'upsert', h);
        } else {
          const h = hlcNext(d);
          const uuid = uuidv7();
          id = Number(d.prepare('INSERT INTO grade_band (label, color, min, max, sort, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?,?)')
            .run(label, p.color ?? '#64748b', p.min, p.max, p.sort ?? 100, uuid, h, getDeviceId(d)).lastInsertRowid);
          touchOplog(d, 'grade_band', uuid, 'upsert', h);
        }
      });
      return { item: { id } };
    }

    case 'band_delete': {
      withTx(d, () => softDelete(d, 'grade_band', payload.id));
      return { ok: true };
    }

    case 'attachment_add': {
      const p = payload;
      const buf = Buffer.from(p.data_b64 || '', 'base64');
      const sha = crypto.createHash('sha256').update(buf).digest('hex');
      const safe = p.file_name.replace(/[\\/:*?"<>|]/g, '_');
      const rel = path.join('attachments', String(p.owner_id), crypto.randomUUID() + '_' + safe);
      const abs = path.join(DATA_DIR, rel);
      fs.mkdirSync(path.dirname(abs), { recursive: true });
      fs.writeFileSync(abs, buf);
      const uuid = uuidv7();
      let item = null;
      withTx(d, () => {
        const h = hlcNext(d);
        const r = d.prepare(
          "INSERT INTO attachment (owner_type, owner_id, kind, file_name, mime, size, rel_path, sha256, uuid, hlc, origin) VALUES ('footprint',?,?,?,?,?,?,?,?,?,?)"
        ).run(p.owner_id, null, p.file_name, p.mime ?? null, buf.length, rel.split(path.sep).join('/'), sha, uuid, h, getDeviceId(d));
        item = d.prepare('SELECT * FROM attachment WHERE id=?').get(Number(r.lastInsertRowid));
        touchOplog(d, 'attachment', uuid, 'upsert', h);
      });
      return { item };
    }

    case 'attachment_list':
      return {
        items: d.prepare(
          "SELECT * FROM attachment WHERE owner_type='footprint' AND owner_id=? AND deleted_at IS NULL ORDER BY id"
        ).all(payload.owner_id)
      };

    case 'attachment_delete': {
      const row = d.prepare('SELECT * FROM attachment WHERE id=?').get(payload.id);
      if (row) {
        withTx(d, () => softDelete(d, 'attachment', payload.id));
        const abs = path.join(DATA_DIR, row.rel_path);
        try { fs.unlinkSync(abs); } catch {}
      }
      return { ok: true };
    }

    case 'attachment_read': {
      const row = d.prepare('SELECT * FROM attachment WHERE id=?').get(payload.id);
      if (!row) throw new Error('附件不存在');
      const data = fs.readFileSync(path.join(DATA_DIR, row.rel_path));
      return { data_b64: data.toString('base64'), mime: row.mime, file_name: row.file_name };
    }

    case 'view_list':
      return { items: d.prepare('SELECT * FROM saved_view WHERE deleted_at IS NULL ORDER BY id').all().map(v => ({
        ...v, filter: JSON.parse(v.filter || '{}'), sort: JSON.parse(v.sort || '{}'), is_default: !!v.is_default
      })) };

    case 'view_upsert': {
      const p = payload;
      let id = p.id;
      withTx(d, () => {
        if (id) {
          const h = hlcNext(d);
          d.prepare("UPDATE saved_view SET name=?, filter=?, sort=?, is_default=?, hlc=?, updated_at=datetime('now','localtime') WHERE id=?")
            .run(p.name, JSON.stringify(p.filter || {}), JSON.stringify(p.sort || {}), p.is_default ? 1 : 0, h, id);
          touchOplog(d, 'saved_view', getUuid(d, 'saved_view', id), 'upsert', h);
        } else {
          const h = hlcNext(d);
          const uuid = uuidv7();
          id = Number(d.prepare('INSERT INTO saved_view (name, filter, sort, is_default, uuid, hlc, origin) VALUES (?,?,?,?,?,?,?)')
            .run(p.name, JSON.stringify(p.filter || {}), JSON.stringify(p.sort || {}), p.is_default ? 1 : 0, uuid, h, getDeviceId(d)).lastInsertRowid);
          touchOplog(d, 'saved_view', uuid, 'upsert', h);
        }
      });
      return { item: { id } };
    }

    case 'view_delete': {
      const row = d.prepare('SELECT id FROM saved_view WHERE id=?').get(payload.id);
      if (row) withTx(d, () => softDelete(d, 'saved_view', row.id));
      return { ok: true };
    }

    default:
      throw new Error('未知命令：' + cmd);
  }
}

// 工厂闭合
  return { handleCommand, getDb };
}

// ---------- 默认单例（开发桥接 / seed 兼容） ----------
let defaultCommands = null;
function getDefault() {
  if (!defaultCommands) defaultCommands = createAppCommands(DB_PATH);
  return defaultCommands;
}

export function getDb() {
  return getDefault().getDb();
}

export function handleCommand(cmd, payload) {
  return getDefault().handleCommand(cmd, payload);
}