import { ZodError } from 'zod'

// ── Action Result Type ───────────────────────────────────────────────

export type ActionResult<T = Record<string, unknown>> =
  | { ok: true; data?: T }
  | { ok: false; error: string; fieldErrors?: Record<string, string[]> }

// ── Helper to build results ──────────────────────────────────────────

export function actionOk<T = Record<string, unknown>>(data?: T): ActionResult<T> {
  return { ok: true, data: data ?? ({} as T) }
}

export function actionError(message: string): ActionResult<never> {
  return { ok: false, error: message }
}

// ── Throwable error ──────────────────────────────────────────────────

export class ActionError extends Error {
  constructor(message: string) {
    super(message)
    this.name = 'ActionError'
  }
}

// ── Error handler ────────────────────────────────────────────────────

export function handleActionError(error: unknown): ActionResult<never> {
  if (error instanceof ZodError) {
    return {
      ok: false,
      error: 'Validation failed',
      fieldErrors: error.flatten().fieldErrors as Record<string, string[]>,
    }
  }
  if (error instanceof Error && error.name === 'ActionError') {
    return { ok: false, error: error.message }
  }
  // Prisma P2025
  if (
    error instanceof Error &&
    error.constructor.name === 'PrismaClientKnownRequestError' &&
    (error as Error & { code?: string }).code === 'P2025'
  ) {
    return { ok: false, error: 'Not found' }
  }
  console.error('[Action error]', error)
  return { ok: false, error: 'Internal server error' }
}