import { z } from 'zod'

const boolFromEnv = (v: string | undefined, fallback: boolean) => {
  if (v === undefined || v === '') return fallback
  return v === '1' || v.toLowerCase() === 'true'
}

export const configSchema = z.object({
  databaseUrl: z.string().default('sqlite:data/app.db'),
  jwtSecret: z.string().min(8),
  jwtTtlHours: z.coerce.number().positive().default(1),
  refreshTtlDays: z.coerce.number().positive().default(14),
  issuer: z.string().url().default('https://auth.shnt.top'),
  /** OIDC issuer URL; defaults to `issuer`. */
  oidcIssuer: z.string().url().optional(),
  /** Optional PEM PKCS8 RSA private key; otherwise auto-generated & persisted. */
  oidcRsaPrivateKey: z.string().optional(),
  adminEmail: z.string().email().default('admin@shnt.top'),
  adminPassword: z.string().default('admin'),
  adminName: z.string().default('Admin'),
  returnToAllowlist: z.string().default('.shnt.top,localhost,private'),
  serverPort: z.coerce.number().int().positive().default(8080),
  staticDir: z.string().optional(),
  logLevel: z.string().default('info'),
  isProd: z.boolean(),
  auditIngestSecret: z.string().min(8).optional(),
  webauthnRpID: z.string().min(1),
  webauthnRpName: z.string().min(1).default('Auth Portal'),
  webauthnOrigins: z.array(z.string().url()).min(1),
})

export type AppConfig = z.infer<typeof configSchema>

export function loadConfig(env: NodeJS.ProcessEnv = process.env): AppConfig {
  const isProd = env.NODE_ENV === 'production'
  const jwtSecret = env.JWT_SECRET ?? (isProd ? '' : 'dev-secret-change-me')
  const auditIngestSecret =
    env.AUDIT_INGEST_SECRET ??
    (isProd ? undefined : 'dev-audit-ingest-secret')
  const issuer = env.ISSUER ?? 'https://auth.shnt.top'
  const { rpID, origins } = webauthnFromIssuer(issuer, env, isProd)

  return configSchema.parse({
    databaseUrl: env.DATABASE_URL ?? 'sqlite:data/app.db',
    jwtSecret,
    jwtTtlHours: env.JWT_TTL_HOURS ?? 1,
    refreshTtlDays: env.REFRESH_TTL_DAYS ?? 14,
    issuer,
    oidcIssuer: env.OIDC_ISSUER || issuer,
    oidcRsaPrivateKey: env.OIDC_RSA_PRIVATE_KEY || undefined,
    adminEmail: env.ADMIN_EMAIL ?? 'admin@shnt.top',
    adminPassword: env.ADMIN_PASSWORD ?? 'admin',
    adminName: env.ADMIN_NAME ?? 'Admin',
    returnToAllowlist:
      env.RETURN_TO_ALLOWLIST ?? '.shnt.top,localhost,private',
    serverPort: env.SERVER_PORT ?? 8080,
    staticDir: env.STATIC_DIR || undefined,
    logLevel: env.LOG_LEVEL ?? 'info',
    isProd:
      boolFromEnv(env.NODE_ENV === 'production' ? 'true' : undefined, false) ||
      isProd,
    auditIngestSecret,
    webauthnRpID: rpID,
    webauthnRpName: env.WEBAUTHN_RP_NAME || 'Auth Portal',
    webauthnOrigins: origins,
  })
}

function webauthnFromIssuer(
  issuer: string,
  env: NodeJS.ProcessEnv,
  isProd: boolean,
): { rpID: string; origins: string[] } {
  let issuerUrl: URL
  try {
    issuerUrl = new URL(issuer)
  } catch {
    issuerUrl = new URL('https://auth.shnt.top')
  }
  const rpID = (env.WEBAUTHN_RP_ID || issuerUrl.hostname).trim()
  const origins = new Set<string>()
  origins.add(issuerUrl.origin)
  const extra = env.WEBAUTHN_ORIGINS ?? ''
  for (const raw of extra.split(',')) {
    const value = raw.trim().replace(/\/$/, '')
    if (!value) continue
    try {
      origins.add(new URL(value).origin)
    } catch {
      /* skip invalid */
    }
  }
  if (!isProd) {
    origins.add('http://localhost:5173')
    origins.add('http://localhost:8080')
  }
  return { rpID, origins: [...origins] }
}

export function oidcIssuerFromConfig(config: AppConfig): string {
  return (config.oidcIssuer ?? config.issuer).replace(/\/$/, '')
}