// server/skland/store.js — the per-player Skland credential store (docs/PACKS.md keeps packs data-only; this is
// server code, not a pack). A local, high-performance embedded database: node:sqlite (bundled with Node ≥ 22) in
// WAL mode — no native build step, no extra dependency, survives restarts, and the Docker image mounts one file.
//
// One row per pending transport, JWT account subject or administrator diagnostic id, holding the login chain state:
//   access_token  the HG account token (refreshes official bindings or rebuilds a Skland cred)
//   cred          the long-term API credential
//   cred_token    the HMAC signing key (never leaves the server)
//   user_id       the Skland internal user id
//   d_id          the device fingerprint the credentials are pinned to
//   nickname / binding  what the account reports (cache; refreshed on demand)
//   binding_source  selects official HG account lookup or the legacy Skland refresh path
//
// The store is synchronous (SQLite is), so callers never await; it is created per server instance (tests pass their
// own file, `:memory:` for pure in-memory). Reserved keys and account ownership are enforced by accountHttp.js.

import { DatabaseSync } from 'node:sqlite';
import { mkdirSync } from 'node:fs';
import { dirname, join } from 'node:path';

const SCHEMA = `
CREATE TABLE IF NOT EXISTS skland_players (
  player_id    TEXT PRIMARY KEY,
  access_token TEXT,
  device_token TEXT,
  hg_id        TEXT,
  cred         TEXT,
  cred_token   TEXT,
  user_id      TEXT,
  d_id         TEXT,
  nickname     TEXT,
  binding      TEXT,              -- the raw binding list from the selected provider (cache)
  binding_source TEXT NOT NULL DEFAULT 'skland', -- skland | hypergryph
  status       TEXT NOT NULL DEFAULT 'unbound',   -- unbound | scanning | bound | error
  error        TEXT,
  created_at   INTEGER NOT NULL,
  updated_at   INTEGER NOT NULL
);
CREATE INDEX IF NOT EXISTS idx_skland_status ON skland_players(status);
`;

/**
 * Node ≥ 22.5 has node:sqlite; an older 22.x has not. The store falls back to an in-memory map so the server still
 * boots (the credentials then do not survive a restart — logged once).
 * @param {{ file?: string, log?: object }} [opts]  file: the database path (default data/skland.db; ':memory:' for
 *   tests). The parent directory is created when missing.
 */
export function createSklandStore(opts = {}) {
  const file = opts.file || join(process.cwd(), 'data', 'skland.db');
  const log = opts.log || { warn: () => {} };
  if (typeof DatabaseSync !== 'function') {
    log.warn?.('[skland] node:sqlite unavailable on this Node — using an in-memory store (credentials lost on restart)');
    return createMemoryStore(file);
  }
  if (file !== ':memory:') mkdirSync(dirname(file), { recursive: true });
  const db = new DatabaseSync(file);
  db.exec('PRAGMA journal_mode = WAL;');
  db.exec('PRAGMA synchronous = NORMAL;');
  db.exec('PRAGMA foreign_keys = ON;');
  db.exec(SCHEMA);
  // Preserve existing QR/SMS bindings when opening a database created before official account lookup was added.
  if (!db.prepare('PRAGMA table_info(skland_players)').all().some((column) => column.name === 'binding_source')) {
    db.exec("ALTER TABLE skland_players ADD COLUMN binding_source TEXT NOT NULL DEFAULT 'skland'");
  }

  const now = () => Date.now();

  /** @returns {Record<string, any> | null} the row as an object, or null */
  function rowToObject(row) {
    if (!row) return null;
    return { ...row, binding: row.binding ? JSON.parse(row.binding) : null };
  }

  return {
    /** The database file (or ':memory:'). */
    file,
    /** The SQLite journal mode actually in force ('wal' on a file-backed store; 'memory' for the fallback). */
    journalMode() {
      try { return String(db.prepare('PRAGMA journal_mode').get().journal_mode).toLowerCase(); } catch { return 'unknown'; }
    },
    close() { db.close(); },

    /** Ensure a row exists for the player (idempotent). */
    ensure(playerId) {
      db.prepare(
        'INSERT INTO skland_players (player_id, status, created_at, updated_at) VALUES (?, ?, ?, ?) ' +
        'ON CONFLICT(player_id) DO NOTHING',
      ).run(playerId, 'unbound', now(), now());
    },

    get(playerId) {
      const row = db.prepare('SELECT * FROM skland_players WHERE player_id = ?').get(playerId);
      return rowToObject(row);
    },

    /** All rows (admin/debug views). */
    list() {
      return db.prepare('SELECT * FROM skland_players ORDER BY updated_at DESC').all().map(rowToObject);
    },

    /**
     * Merge fields into a player's row (created when missing). `binding` may be an object — stored as JSON.
     * @param {string} playerId
     * @param {Partial<{access_token: string, device_token: string, hg_id: string, cred: string, cred_token: string,
     *   user_id: string, d_id: string, nickname: string, binding: object | null, binding_source: string, status: string,
     *   error: string | null}>} fields
     */
    update(playerId, fields) {
      this.ensure(playerId);
      const allowed = ['access_token', 'device_token', 'hg_id', 'cred', 'cred_token', 'user_id', 'd_id', 'nickname', 'binding_source', 'status', 'error'];
      const sets = [];
      const values = [];
      for (const key of allowed) {
        if (key in fields) { sets.push(`${key} = ?`); values.push(fields[key] ?? null); }
      }
      if ('binding' in fields) { sets.push('binding = ?'); values.push(fields.binding == null ? null : JSON.stringify(fields.binding)); }
      if (!sets.length) return;
      sets.push('updated_at = ?');
      values.push(now(), playerId);
      db.prepare(`UPDATE skland_players SET ${sets.join(', ')} WHERE player_id = ?`).run(...values);
    },

    /** Remove a player's credentials (解绑). The row stays, marked unbound. */
    unbind(playerId) {
      this.update(playerId, {
        access_token: null, device_token: null, hg_id: null, cred: null, cred_token: null,
        user_id: null, d_id: null, nickname: null, binding: null, binding_source: 'skland', status: 'unbound', error: null,
      });
    },

    /** Delete a player's row entirely (e.g. session cleanup). */
    remove(playerId) {
      db.prepare('DELETE FROM skland_players WHERE player_id = ?').run(playerId);
    },

    /** For tests: raw row count. */
    count() {
      return db.prepare('SELECT COUNT(*) AS n FROM skland_players').get().n;
    },
  };
}

/** The in-memory fallback (same API; a pre-22.5 Node). Credentials do not survive a restart. */
function createMemoryStore(file) {
  /** @type {Map<string, Record<string, any>>} */
  const rows = new Map();
  const now = () => Date.now();
  const blank = () => ({
    player_id: null, access_token: null, device_token: null, hg_id: null, cred: null, cred_token: null,
    user_id: null, d_id: null, nickname: null, binding: null, binding_source: 'skland', status: 'unbound', error: null,
    created_at: 0, updated_at: 0,
  });
  return {
    file,
    journalMode() { return 'memory'; },
    close() { rows.clear(); },
    ensure(playerId) {
      if (!rows.has(playerId)) rows.set(playerId, { ...blank(), player_id: playerId, created_at: now(), updated_at: now() });
    },
    get(playerId) { const row = rows.get(playerId); return row ? { ...row } : null; },
    list() { return [...rows.values()].map((r) => ({ ...r })); },
    update(playerId, fields) {
      this.ensure(playerId);
      const row = rows.get(playerId);
      for (const [key, value] of Object.entries(fields)) {
        row[key] = key === 'binding' && value != null ? JSON.parse(JSON.stringify(value)) : (value ?? null);
      }
      row.updated_at = now();
    },
    unbind(playerId) {
      this.update(playerId, {
        access_token: null, device_token: null, hg_id: null, cred: null, cred_token: null,
        user_id: null, d_id: null, nickname: null, binding: null, binding_source: 'skland', status: 'unbound', error: null,
      });
    },
    remove(playerId) { rows.delete(playerId); },
    count() { return rows.size; },
  };
}