import { PGlite } from '@electric-sql/pglite'
import { drizzle as drizzlePg } from 'drizzle-orm/node-postgres'
import { migrate as migratePg } from 'drizzle-orm/node-postgres/migrator'
import type { PgDatabase, PgQueryResultHKT } from 'drizzle-orm/pg-core'
import { drizzle as drizzlePglite } from 'drizzle-orm/pglite'
import { migrate as migratePglite } from 'drizzle-orm/pglite/migrator'
import { mkdirSync } from 'node:fs'
import { join } from 'node:path'
import pg from 'pg'
import * as schema from './schema.ts'

export type Db = PgDatabase<PgQueryResultHKT, typeof schema>

export interface Database {
  db: Db
  close(): Promise<void>
}

const migrationsFolder = join(import.meta.dirname, 'migrations')

/**
 * Opens the database and applies pending migrations.
 *
 * - `postgres://…` connects to PostgreSQL (production).
 * - `pglite://<dir>` uses embedded PostgreSQL stored in `<dir>` (local development, very small installs).
 * - `memory://` uses a throwaway in-memory database (tests).
 */
export async function openDatabase(url: string): Promise<Database> {
  if (/^postgres(ql)?:\/\//.test(url)) {
    const pool = new pg.Pool({ connectionString: url })
    const db = drizzlePg({ client: pool, schema, casing: 'snake_case' })
    await migratePg(db, { migrationsFolder })
    return { db: db as unknown as Db, close: () => pool.end() }
  }

  if (url !== 'memory://' && !url.startsWith('pglite://')) {
    throw new Error(`Unsupported DATABASE_URL: expected postgres://, pglite:// or memory://`)
  }
  const dataDir = url === 'memory://' ? undefined : url.slice('pglite://'.length)
  if (dataDir) mkdirSync(dataDir, { recursive: true })
  const client = new PGlite(dataDir)
  const db = drizzlePglite({ client, schema, casing: 'snake_case' })
  await migratePglite(db, { migrationsFolder })
  return { db: db as unknown as Db, close: () => client.close() }
}

/** True for a unique-constraint violation from either driver (Drizzle wraps driver errors in `cause`). */
export function isUniqueViolation(error: unknown): boolean {
  let current: unknown = error
  for (let depth = 0; current && typeof current === 'object' && depth < 5; depth++) {
    if ((current as { code?: unknown }).code === '23505') return true
    current = (current as { cause?: unknown }).cause
  }
  return false
}