/**
 * Processing history (behandlingshistorik): append helper.
 *
 * Uses a service-role client internally (no INSERT RLS policy on
 * processing_history: matching the event_log pattern). Company scoping
 * is enforced by companyId in the event payload, not by RLS.
 * Throws on failure.
 *
 * PII BOUNDARY: payload MUST contain pseudonymous IDs only (user UUIDs,
 * company UUIDs, counterparty IDs). Never names, emails, personnummer,
 * addresses, or phone numbers. These live in their source tables (profiles,
 * customers, suppliers) and are referenced by ID. GDPR erasure pseudonymizes
 * the source tables; processing_history events become undecipherable by
 * reference, which is the required behavior per v0.2 §10.
 */

import type {
  ProcessingHistoryAggregateType,
  ProcessingHistoryActor,
} from '@/types'
import type { SupabaseClient } from '@supabase/supabase-js'
import { createServiceClient } from '@/lib/supabase/server'
import { z } from 'zod'

/**
 * Any service-role client with the query surface the append needs. Structural
 * so both the Next-bound createServiceClient() and a script's own
 * createClient(url, serviceRoleKey) satisfy it.
 */
type SupabaseClientLike = Pick<SupabaseClient, 'from'>

// ── Event type catalog ──────────────────────────────────────────
// Every event type the code emits, and the contract with the
// processing_event_types reference table: processing_history.event_type has an
// FK to it, and every append call site is best-effort try/catch, so a type
// that is missing from the table fails the insert silently and the act leaves
// no durable record at all. Ten types drifted out of the table exactly that
// way before this list existed.
//
// Adding an entry here therefore REQUIRES a migration registering the same
// string in public.processing_event_types, in the same change. The union
// makes an unregistered literal a compile error;
// tests/pg/processing-event-types.pg.test.ts makes an unregistered string a
// test failure. Keep it sorted.

export const PROCESSING_EVENT_TYPES = [
  'AttachmentsTruncated',
  'BankTransactionDuplicateDismissed',
  'ChannelQuestionAnswered',
  'ChannelQuestionAsked',
  'ChannelQuestionExpired',
  'DocumentDuplicateSkipped',
  'DocumentExtractionAttempted',
  'DocumentExtractionOverridden',
  'DocumentExtractionRetried',
  'DocumentIngested',
  'InboundMailReceived',
  'InboxUnderlagReconciled',
  'InvoiceDuplicatePaymentDismissed',
  'InvoiceJournalEntrySkipped',
  'InvoicePaymentRowBackfilled',
  'OAuthClientRevoked',
  'PendingOperationApproved',
  'PendingOperationRejected',
  'RateLimitedDropped',
  'TransactionDocumentReplaced',
] as const

export type ProcessingHistoryEventType = (typeof PROCESSING_EVENT_TYPES)[number]

// ── PII validator ───────────────────────────────────────────────
// Rejects payloads containing Swedish personal identity numbers.
// Personnummer:       YYMMDD-NNNN or YYMMDDNNNN (6+4 digits)
// Samordningsnummer:  Same format but day +60
// Organisationsnummer: NNNNNN-NNNN (10 digits, but we catch the pattern)

// Word boundaries prevent false positives on Bankgiro (123456-7890) and
// invoice references like 202312-1234 that share the digit shape but aren't PII.
const PII_PATTERNS = [
  /\b\d{6}-?\d{4}\b/,   // personnummer, samordningsnummer
  /\b\d{8}-?\d{4}\b/,   // 12-digit variant (YYYYMMDD-NNNN) or orgnr
]

// UUIDs (RFC 4122, 8-4-4-4-12 hex layout) frequently contain all-digit segments
// that incorrectly match the 8+4 personnummer pattern: e.g. `57484518-3409-...`.
// Strip UUID-shaped substrings before PII matching so legitimate identifiers
// aren't rejected. Personnummer always sit outside the UUID shape, so this keeps
// the original safety intent intact.
const UUID_PATTERN = /[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/gi

function stringContainsPii(value: string): boolean {
  const stripped = value.replace(UUID_PATTERN, '')
  return PII_PATTERNS.some(pattern => pattern.test(stripped))
}

function containsPii(value: unknown): boolean {
  if (typeof value === 'string') {
    return stringContainsPii(value)
  }
  if (Array.isArray(value)) {
    return value.some(containsPii)
  }
  if (value !== null && typeof value === 'object') {
    return Object.values(value).some(containsPii)
  }
  return false
}

const piiSafePayload = z.record(z.string(), z.unknown()).refine(
  (payload) => !containsPii(payload),
  { message: 'Payload contains PII (personnummer/samordningsnummer/orgnr pattern). Use pseudonymous IDs only.' }
)

function assertActorPiiSafe(actor: ProcessingHistoryActor): void {
  if (actor.label && stringContainsPii(actor.label)) {
    throw new Error(
      'actor.label contains PII (personnummer/samordningsnummer/orgnr pattern). Use a pseudonymous descriptor only.'
    )
  }
}

// ── Input type ──────────────────────────────────────────────────

export interface AppendEventInput {
  companyId: string
  correlationId: string
  causationId?: string
  aggregateType: ProcessingHistoryAggregateType
  aggregateId: string
  eventType: ProcessingHistoryEventType
  payload: Record<string, unknown>
  payloadSchemaVersion?: number
  actor: ProcessingHistoryActor
  rubricVersion?: string
  occurredAt: Date  // mandatory: no default. Caller must set explicitly.
}

// ── Append functions ────────────────────────────────────────────

/**
 * Append a single event to processing_history.
 *
 * Uses a service-role client internally (bypasses RLS) since processing_history
 * has no INSERT policy: matching the event_log pattern. Company scoping is
 * enforced by the companyId in the event payload, not by RLS.
 *
 * Returns the generated event_id (pre-generated client-side for causation chaining).
 */
export async function appendProcessingHistory(
  input: AppendEventInput
): Promise<string> {
  return appendProcessingHistoryWithClient(createServiceClient(), input)
}

/**
 * Same append, on a caller-supplied service-role client. For standalone
 * scripts (e.g. scripts/backfill-inbox-booked-underlag.ts) that cannot build
 * the Next-bound service client but must still write behandlingshistorik
 * through the one shared row shape and PII validation (BFNAR 2013:2 p. 9.16:
 * the change log has to reconcile across writers, so scripts never hand-roll
 * the insert).
 */
export async function appendProcessingHistoryWithClient(
  supabase: SupabaseClientLike,
  input: AppendEventInput
): Promise<string> {
  // Validate payload + actor.label contain no PII
  piiSafePayload.parse(input.payload)
  assertActorPiiSafe(input.actor)

  const eventId = crypto.randomUUID()

  const { error } = await supabase
    .from('processing_history')
    .insert({
      event_id: eventId,
      company_id: input.companyId,
      correlation_id: input.correlationId,
      causation_id: input.causationId ?? null,
      aggregate_type: input.aggregateType,
      aggregate_id: input.aggregateId,
      event_type: input.eventType,
      payload: input.payload,
      payload_schema_version: input.payloadSchemaVersion ?? 1,
      actor: input.actor,
      rubric_version: input.rubricVersion ?? null,
      occurred_at: input.occurredAt.toISOString(),
    })

  if (error) {
    throw new Error(
      `Failed to append processing_history event ${input.eventType}: ${error.message}`
    )
  }

  return eventId
}

/**
 * Append multiple events atomically (single INSERT).
 * Used for batch operations (e.g., migration commits, multi-event command handlers).
 *
 * Returns array of generated event_ids in input order.
 */
export async function appendProcessingHistoryBatch(
  inputs: AppendEventInput[]
): Promise<string[]> {
  if (inputs.length === 0) return []

  const eventIds = inputs.map(() => crypto.randomUUID())

  // Validate all payloads + actor labels before any DB write
  for (const input of inputs) {
    piiSafePayload.parse(input.payload)
    assertActorPiiSafe(input.actor)
  }

  const rows = inputs.map((input, i) => ({
    event_id: eventIds[i],
    company_id: input.companyId,
    correlation_id: input.correlationId,
    causation_id: input.causationId ?? null,
    aggregate_type: input.aggregateType,
    aggregate_id: input.aggregateId,
    event_type: input.eventType,
    payload: input.payload,
    payload_schema_version: input.payloadSchemaVersion ?? 1,
    actor: input.actor,
    rubric_version: input.rubricVersion ?? null,
    occurred_at: input.occurredAt.toISOString(),
  }))

  const supabase = createServiceClient()

  const { error } = await supabase
    .from('processing_history')
    .insert(rows)

  if (error) {
    throw new Error(
      `Failed to append processing_history batch (${inputs.length} events): ${error.message}`
    )
  }

  return eventIds
}