import fs from 'node:fs';
import path from 'node:path';
import Database from 'better-sqlite3';
import pg from 'pg';

const databaseUrl = process.env.DATABASE_URL;
if (!databaseUrl) throw new Error('缺少 DATABASE_URL，迁移未执行');

const replace = process.argv.includes('--replace');
const sqlitePath = path.resolve(process.env.SQLITE_PATH || 'data/app.db');
const schemaPath = path.resolve('db/postgres/schema.sql');
if (!fs.existsSync(sqlitePath)) throw new Error(`SQLite 数据库不存在：${sqlitePath}`);

const tables = [
  'operation_groups', 'users', 'projects', 'collections', 'notes', 'images', 'annotations',
  'work_comments', 'work_versions', 'review_events', 'sessions', 'customer_sessions',
  'audit_logs', 'api_keys', 'storage_configs',
] as const;
const booleanColumns: Record<string, Set<string>> = {
  users: new Set(['must_change_password']),
  projects: new Set(['customer_access_enabled']),
};

const sqlite = new Database(sqlitePath, { readonly: true });
const client = new pg.Client({ connectionString: databaseUrl, ssl: process.env.PGSSL === 'disable' ? false : undefined });

try {
  await client.connect();
  const schema = fs.readFileSync(schemaPath, 'utf8');
  await client.query(schema);
  const existing = Number((await client.query('SELECT COUNT(*)::int AS count FROM operation_groups')).rows[0].count);
  if (existing && !replace) throw new Error('PostgreSQL 已有数据。确认覆盖时请显式添加 --replace');
  await client.query('BEGIN');
  if (replace) await client.query(`TRUNCATE ${[...tables].reverse().map((table) => `"${table}"`).join(', ')} RESTART IDENTITY CASCADE`);

  for (const table of tables) {
    const exists = sqlite.prepare("SELECT name FROM sqlite_master WHERE type = 'table' AND name = ?").get(table);
    if (!exists) continue;
    const rows = sqlite.prepare(`SELECT * FROM "${table}" ORDER BY id`).all() as Record<string, unknown>[];
    for (const row of rows) {
      const columns = Object.keys(row);
      const values = columns.map((column) => booleanColumns[table]?.has(column) ? Boolean(row[column]) : row[column]);
      const names = columns.map((column) => `"${column}"`).join(', ');
      const placeholders = columns.map((_, index) => `$${index + 1}`).join(', ');
      await client.query(`INSERT INTO "${table}" (${names}) VALUES (${placeholders})`, values);
    }
    if (rows.length) await client.query(`SELECT setval(pg_get_serial_sequence('${table}', 'id'), (SELECT MAX(id) FROM "${table}"), true)`);
  }
  const collectionStatusRepair = schema.match(/-- COLLECTION_STATUS_REPAIR_START([\s\S]+?)-- COLLECTION_STATUS_REPAIR_END/)?.[1];
  if (!collectionStatusRepair) throw new Error('PostgreSQL schema 缺少作品交付集状态修复脚本');
  await client.query(collectionStatusRepair);
  await client.query('COMMIT');
  process.stdout.write(`迁移完成：${tables.length} 张表已从 ${sqlitePath} 导入 PostgreSQL\n`);
} catch (error) {
  await client.query('ROLLBACK').catch(() => undefined);
  throw error;
} finally {
  sqlite.close();
  await client.end().catch(() => undefined);
}