import { z } from 'zod';

/**
 * Environment contract for the relay. Validation happens once at boot: a
 * missing/typo'd variable must fail loudly at startup, never mid-conversation.
 */
/** `.default()` has to precede `.transform()` in zod v4, hence the factories. */
const boolish = (def: string) =>
  z
    .string()
    .default(def)
    .transform((v) => ['1', 'true', 'yes', 'on'].includes(v.trim().toLowerCase()));

const csv = (def: string) =>
  z
    .string()
    .default(def)
    .transform((v) =>
      v
        .split(',')
        .map((s) => s.trim().toUpperCase())
        .filter(Boolean),
    );

const schema = z.object({
  NODE_ENV: z.enum(['development', 'test', 'production']).default('production'),
  PORT: z.coerce.number().int().positive().default(3000),
  RELAY_MODE: z.enum(['dev', 'prod']).default('prod'),

  DATABASE_URL: z.string().min(1).default('file:../data/eks_relay.db'),

  // --- Chatwoot ---
  CHATWOOT_BASE_URL: z.string().url(),
  CHATWOOT_API_TOKEN: z.string().min(1),
  CHATWOOT_ACCOUNT_ID: z.coerce.number().int().positive().default(1),
  CHATWOOT_TICKET_LABEL: z.string().min(1).default('ticket'),
  CHATWOOT_SPAM_LABEL: z.string().default('spam'),
  CHATWOOT_APPLY_SPAM_LABEL: boolish('false'),
  CHATWOOT_UNASSIGN_ON_TICKET: boolish('false'),
  /// Webchat / API inbox — reserved for the later web widget adapter.
  CHATWOOT_API_INBOX_ID: z.string().default(''),
  CHATWOOT_API_IDENTITY_VALIDATION_TOKEN: z.string().default(''),

  // --- Flowise ---
  FLOWISE_PREDICT_URL: z.string().url(),
  FLOWISE_API_KEY: z.string().default(''),
  FLOWISE_BASE_URL: z.string().default(''),
  FLOWISE_TIMEOUT_MS: z.coerce.number().int().positive().default(90_000),

  // --- WooCommerce / WordPress ---
  WOOCOMMERCE_BASE_URL: z.string().url(),
  WOOCOMMERCE_CONSUMER_KEY: z.string().min(1),
  WOOCOMMERCE_CONSUMER_SECRET: z.string().min(1),
  WP_STORE_API_SECRET: z.string().default(''),
  STORE_CURRENCIES: csv('PLN,EUR,AED,CZK,HUF,DKK,SEK,NOK,RON,BGN,GBP'),

  // --- Relay auth ---
  RELAY_SHARED_SECRET: z.string().min(8),
  ADMIN_TOKEN: z.string().default(''),

  // --- Behaviour ---
  TENANT_ID: z.string().default('easyklima'),
  DEFAULT_LANGUAGE: z.string().default('pl'),
  TICKET_NUMBER_PREFIX: z.string().default('EKS'),
  WORKER_ENABLED: boolish('true'),
  WORKER_POLL_MS: z.coerce.number().int().positive().default(1_000),
  WORKER_MAX_ATTEMPTS: z.coerce.number().int().positive().default(3),
  SPAM_GATE_ENABLED: boolish('true'),
  HTTP_TIMEOUT_MS: z.coerce.number().int().positive().default(30_000),

  // --- Logging ---
  LOG_LEVEL: z.enum(['debug', 'info', 'warn', 'error']).default('info'),
  LOG_PII: boolish('false'),
});

export type Config = z.infer<typeof schema>;

let cached: Config | null = null;

export function loadConfig(env: NodeJS.ProcessEnv = process.env): Config {
  const parsed = schema.safeParse(env);
  if (!parsed.success) {
    // Only names of the offending variables — never their values.
    const issues = parsed.error.issues
      .map((i) => `${i.path.join('.') || '(root)'}: ${i.message}`)
      .join('; ');
    throw new Error(`Invalid environment configuration: ${issues}`);
  }
  return parsed.data;
}

export function config(): Config {
  cached ??= loadConfig();
  return cached;
}

/** Test hook: inject a config without touching process.env. */
export function setConfigForTests(cfg: Config): void {
  cached = cfg;
}